Hazardous Materials

CHAPTER

,

Courtesy of FEMA.

,,Nfoi41 available chlorine, p. 433 chlorine bleach, p. 433 dasses of oxidizers, p. 427 fireworks, p. 438 Fireworks 1.3G (special fireworks, display fireworks), p. 439 Fireworks 1.4G (common fireworks, consumer fireworks), p. 439 flare,p.443

fM!HM!I

11 Chemistry of Some Oxidizers

half-reaction, p. 425 hexavalent chromium compounds, p. 452 high-test hypochlorite (HTH), p. 434 ionic equation, p. 424 nonchlorine bleach, p. 432 oxidation number, p. 423 oxidizer (Don, p. 422 oxidizer (NFPA), p. 427

oxidizer (OSHA), p. 422 oxidizing agent (oxidant), p. 422 safety matches, p. 461 signaling smoke, p. 443 smoke bomb, p. 443 spectator ion, p. 424 strike-anywhere matches, p. 461

Associate the physical and health hazards of the oxidizers noted in this chapter with the information provided by their hazard diamonds and GHS pictograms. Determine the oxidation numbers of the atoms and ions in a given substance .

1 Describe how NFPA distinguishes the degree of hazard potentially posed by different oxidizers. Identify the primary industries that use the oxidizers noted in this chapter.

1 Identify commercial products that contain oxidizers.

1 Describe the OSHA and OHS regulations that pertain to the handling, storage, stowing, loading, unloading, or discharge of bulk quantities of ammonium nitrate. ld~ntify the labels, markings, and placards that DOT requires on the packaging of oxidizers and the transport vehicles used for their shipment. Identify the resp onse actions to be executed when oxidizers are released fro m th eir Packaging into th e enviro nm ent.

ox id izing agen t (oxida nt) An oxygen• rich substance capable of read ily yield ing some of its oxygen; the substance reduced during an oxidation- reduction react ion

oxi dizer For the purposes of DOT regulations, any substance that may enhance or support the combustion of other mater ials, generally by yielding its oxygen

oxidizer (O SH A) Any gas, l iqu id, or sol id that read ily yields oxygen or other oxid izing gas, or that readily reacts to promote or initiate combustion of combus• t ible materials and, under some circum• stances, can undergo vigorous self.sustained decomposition due to contamination or heat exposure

Certain chemical reacrio~s s:ea rly benefit modern li~esryles. They ~nclude the c tion of fue- 1s, the ch_lo n n:Hlon of_ water, the ex.plos1on of dy~?mne, the bleaco~ fabrics, and the tbrm ~ o f recre~nom l fireworks . These spe~1f1c phenomena a; utgflf ciared wit h oxidarion-rcducuon reacuons, also call~d red ox rea~ttons. These rea crio e a.sSo- the ha zardous m~Herials associa ted with_ chem consmure the s~1b1ec r matter of thischansa~

\Vhen oxidation-reduction rcac11ons are conducted m a controlled fash · Pttr. ene rgy rh ey release can be harnessed to advantage. For example, the reaction hion, tht in devices such as barteries, dry cells, a nd fuel ce lls provide a suppl y of pona~ t ar 0ctlir energy. Howe\'er, whe n redox reactions occu r in an uncontrolled fashion th e elect~ energy is relea sed into the immediate _environment, where_ it can initiate ~r i:t:~~era~ and explosion and cause the loss of life an~ property. This potential for destructi~ firt necess iraces the examination of redox reaction s as a component of the st ud y of ha llC\s o us materials. lard.

11 . 1 W HAT IS AN OXIDIZER? Ir was noted in Chapter 7 that ~ydroge n burns in o~ygen an~ chlorine to produce \\'ite and hydrogen chloride, res pecnvely. These combustion reacuons a re represe nted b · h' fo llowing equations: ) 1 e

2H,(g) + 0 2(g) H~drogcn

H,(g) + Cl 2(g) H~drogcn Chlonnc

2H 20(g) Water

2HC l(g) H)drogen ch londe

The subs tances supporting these independent combustion processes are examples of oKi- dizers, o xidants, or oxidizing agents. The first two terms a re u sed by emergency respond- e rs, bur the third term is used by chemists. H ydroge n is an example of a reducing agrnt. Oxidizing agents always react wit h reduci ng agents in concert.

Because hydrogen burns in a chlorine atmosphere, it is evident chat oxygen is not tbr sole substance that s upports the combustion of other materials . Like oxygen, chlorine is an example of an oxidizer.

11 .1-A DOT CLASSIFICATION OF OXIDIZERS In the DOT regulati o ns, an ox idize r is defined as a subsrance that may enhance or sup- port the combustion of othe r mat e ri a ls, generally by yie lding its oxygen. DOT al so distinguishes berween two cla sses of oxidizers: inorganic (or metallic ) oxidizers, which are si mpl y called oxidizers, and o rganic peroxides. Their properties arc nocrd in 1lu5 chapter and Section 13.9, respectively.

11 .1-B OSHA/GHS IDENTIFICATION OF OXIDIZERS Formerly, OSHA defined an oxidizer as a substance other rhan a blasting agent ore~pt sive that initiates or promotes combu stion in other materials, thereby causing _fire e~t : of itself or through the relea se of oxygen or ocher gases . Following the adoption ° ~ GHS, OSHA no w considers oxidizers as any of the three cl asses, oxidizing gases, oxi · ing liquids, or oxidizing solids. As oxidizers, each of rh e latter stares of mat1cr ca use cw contribute to the combustion of ocher materia l, generally by providing oxygen. _ ht

Except for oxidizers that are organic compo und s, OSHA minimally req uires~ manufacturers, distributors, and importers of oxidizers ro post the GHS flain e•_o~•er• I : letter- .. 0 " pictogram ro the labels of chemical products consisting of an oxidizi~g:rr liquid, or solid, in addition to appropriate signal words and hazard and precauuo sta temenrs.

422 Chapter 11 Chemistry of Some Oxidizers

11 _2 OXIDATION NUMBERS

emists use ch e_ ~oncept 0 ~ an ox1dat1on ~umber, or oxidation state, to describe the Ch ibining capability of on~ ion for anorh_er ion or of one atom for another atom. In prac- c~ 11 an oxida tion number 1s formally ass igned to the atoms 1hat make up a substa nce by ::~~;g ihe following rules:

The oxidation number of each atom in an element is zero; rhus, the oxidation number 1 f each atom in the element~ H 2_, O z, Na , and Mg is O.

~h algebraic su m of the ox1dat1on numbers of the atoms in any substance is zero. 1 Th~ hydrog en acorn in hydrogen-containing compounds other than metallic hydri?es 1 has an oxidation number of +1. The hydrogen in a hyd ride ion (l-r) has an oxidation

number of -1 . The oxygen acorn in OX)'gen-containing compounds other than peroxides and super-

xidcs ha s an oxidation number of - 2. Each oxygen atom in a peroxide ion (O t ) \d a superoxide ion (O l ) has an oxidation number of-I and - 0.5, respectively. ~he oxidation number of a monatomic ion (i.e., ha vi ng one atom) is the same as its

1 net ionic charge; thus, the oxidation number of sodium is +1; of magnesium, +2; of the chloride ion, - 1; and of the sulfide ion, -2.

1 The algebraic sum of the oxidation numbers of the atoms in a polyatomic ion is equal to its ionic charge . The chemical formula of a substance must be known to use these rules and determine the

oxida tion numbers of its component atoms. As an example, let's use them to determine the oxidation number of each atom in sodium chlorate, an oxidizing agent used in fireworks and signaling flares. The chemical formula of sodium chlorate is NaCI03. This formula indicates that the compound is composed of two ions, the sodium ion (N a + ) and the chlorate ion (CIOj") . The oxidation number of each element in sodium chlorate is determined as follows:

OXIDATION CONSTITUENT NUMBER

Sodium ion, Na• +1

Orygenatom -2 Chlorat e ion, (10 3

_,

Chlorine atom +5

RELEVANT RULE The 01tidation number of a monatomic ion is the same as its ionic charge. Other than in peroxides, the oxidation number of oxygen is -2 . The algebra ic sum of the oxidation numbers of the atoms in a polyatomic ion is equal to its ionic charge; that is, -1 = +S + [3 x (-2)] = +5 + (-6) , The algebraic sum of the oxidation numbers in any substance is zero; that is, 0 = + 1 +5 + {3 x (-2)] = +6 + (-6).

Additio nal examples of determining the oxidation numbers of the atom s in some com- po unds a re noted in Tab le I 1.1.

11.3 OXIDATION- REDUCTION REACTIONS Brcause a redox reaction occurs between an ox idi zing ~1gent and a reducing agent, the ~quation illustrating a rcdox reaction is always written in the following generalized form:

O xidi zing agen t + Redu c in g age nt --t Produ c- L::, ~,S Pec_ific example of this is the reaction between iron (lll ) chloride and tin (ll ) chloride.

r Wrn c the eq uation for this reaction as follows:

2FeC l3(aq ) + SnC l2(aq) 2F('C 12(aqJ + S nCl.i(w1) lrun1 lll 1 ch lun,k Tin( l ll chlomlc lr0n ( II Jch londc Ti n\ lV)chlonJ,:

oxi dation number (o xid ation state) • A number assigned to an atom or ion by follow • ing established rules that aim to reflect its capacity for combining with other atoms or ions

Chapter 11 Chemistry of Some Oxidizers 423

spectator io n One or more o f the ions t h at do not participate in an oxidatio n-reduction re action

ion ic equation An equation th at dep icts only the ions that par• t icipate in an oxidation- reduction reaction

Mllhiiil SYMBOL OF ELEMENT OXIDATION NUMBER

0

Cl

- 1 I -2 so 2

1 H 20 2 -----~:3------- ~ N;:H-, -----

- 2 Ni H4 -1 NH20H +1 N20 +2 NO +3 HN02 +4 +5 _, +1 +3 +5 + 7

HN0 3

HCI HCIO KC I02 KCI0 1 HCI04

Because the chloride ions do not parricipare in this redox reactio n, they often are called spectator ions. We can eliminate them and write an ionic equation fo r the reaction as follows:

2Fc3 .. (aq) + Sn 2+(aq ) - 2Fc 2+(aq) + Sn-l+(aq) In an ionic equation, only rhe symbo ls of the ions cont ributing to the reaction are wm· ten . In this rep resentat ion , electrons have si mpl y been transferred between the iron ions a nd tin ions. The informa tion conveyed by chis equation is summa rized as foll ows:

The iron (ll1 ) ions become iro n(ll ) ions. The ox idation number of iron dec reases from +3 to +2; thus, rhe iron {III ) ions are reduced. lron (III ) chloride is ca lled rhe oxid,zmg agent, because it oxidizes tin (II ) chloride. The rin (Il) ions become rin (IV) ions. The oxidation number of tin increa ses from +l to +4; thus, the tin (Il) ions are oxidized . Tin (ll) chlor ide is ca ll ed the redu cing agttll, because it reduces iron (IJI ) chloride.

Because a simultaneous increa se and decrea se in oxidation numbers alwa )'S accomP'.1· oxidation and reduction , respecti vel y, we can summarize the natu re of this process in

1omc systems as follows:

Oxidation is the ph enomeno n associated wi th an increase in oxidation num~r and loss of electrons from an ion, a tom, or group of atoms . d Re~uction is the phenomenon associated with a decrease in oxidation number 30 gam of electrons from an ion, atom, or group of atoms.

424 Cha pter 11 Chemistry of Some Oxidizers

Some Common Ox1dmng Agents

ox101z1NG AGENT ~m pero)(ide

~ Ilic . nypocn to rItes

;;i'allic chlorates

Nitric ac id (concentrated)

Nitric acid (dilute)

Metallic peroxydisulfates

ELEMENT T HAT CHANGES OXI DAT I ON NUM BER

Oxygen

Chlorine

Chlorine

Nitrogen

Nitrogen

Sulfur

OXIDATION N UMBER

IN IN REACTANT PRODUCT -1 -2

+1 -1

+5 -1

+5 +4

+5 +2

+7 +6

EQUATION I LLU ST RAT I NG HA LF·REACTION

Na 20 2(aq) + 2H 20(f) - 2e - 2Na · (aq) ..,. 40H (aq)

00 (aq) + 2W(aq) + 2e - Cl (aq) _.. H 20(f)

CI0 3 (aq) ..,. 6W(a q ) ..,. 6e - Cl (aq) - 3H 20(f)

N 0 1 {aq) - 2W(aq) -r- e - N02{g) - H 20 (f)

N0 3 (aq) -r- 4W(aq) -r- 3e~ - NO(g) + 2H 20(f)

S20 .2 (aq) + 2e - 2so / (aq)

1 The substance that accepts electrons during a redox reaction is ca lled the oxidizing agent. The substance that lo ses electrons during a redox reaction is called the reducing agent .

Oxida tion and reduct ion phenomena can also be represented sepa ratel y by equations like the fo llowing:

Sn 2--- (aq ) - Sn4 .. (aq ) + 2r Fe3 .. (t,q ) + c- - Fc::! +- (a q )

The phenomenon illu strated by each equation is ca lled a h a lf-re action . One half.reaction repre sents oxidation, whereas the other represents reduction. The processes represented b)' half.reactions always occur simu ltaneo usly.

Se ve ral 01hcr exa mpl es o f oxidation-red uction phenomena ~ue provided in Table l l .2.

h alf.reacti o n An equ ation that sepa rately depicts eithe r oxidation o r reduction

SOLVED EXERCISE 11.1

ft

de ntify the element ox1d1zed, the element red uced. the ox1d1z1ng ag ent , and the reducing agen t in th e re dox reaa,on denoted by the following equation

6Fe50,:(aq) • Na 2Cr20 1(a q ) -r- 7H 2504(.:iql - lronill)\ulfd tf' So d,umd,c!uoma:.:- Su! fur,ca<•d

3Fe2(S0,1)]1a ql -r- Na2 SO.daq1 .,. Cr 2(SO.;l/aq -r- 7H 10 ri lron{llI) sul fate <,oo,um ~ull.u c ( t- ·,w uIr,,111> sul f,11 (.' \\ a\er

t this equat,on, the sodium and su lfate ions are 1dent1f1ed as spectator ions, because th e oxi dat ion ! ,minate: 1: d;~I:~I

~~u I ~n~;:q~:t~i~

I ~r:r:~:~.ame on each ~1de of the arrow . W hen the spect at or ,ans are

Chapte r 11 Chemistry of Some Oxidizers 425

:\

\

1, I I I

!!It r1 fl f I

I 1; I II I/ Ii' I I I

I /I

i I

ii

FI GURE 1 1.1 The cn m1na/ act of detonating awea.oon ofmass destruction at th e Oldahoma City federa l bu ildin g resulted ,n 168 iatal1t1esand8 S0m1u ri es The w ea pon was a 4000- po und ( 1800-kg) mtXture of amm onium nJtrate fer- ti lizer and fuel 01I (ANFO } Th e detonation occurred atth e rat e ofapproXJ• mat ely 13,000 ft.ls (4000 mis) (Courresyof FEMA /

ro aeterm,nt' the a,o: uat,on nu,.,ber of chrom um ,n the d ch romate on. reca ll that the aiget ra c sum of ~~~~r.,...o~c~r~~t::at~~; n a 001yatom •c ,on 1s equa l to ,ts 1on,c cha rge We thus de1erm ,ne that ll'ie~~

- 2 = /2 X ( .. 6)) -t- /7 X (- 2)) - 2 = - 2

Theo~ oat or number of the monatom ,c ,eris is the s.!lme as the ir 1on1c Ch.!lrge 1n tr'lt' on ,c eau.!lt on, we rt.:id· /y observe thai the ,ron(II} 1cm beco<Ti e or on (rl l) ,or,s The oxida•ion

;~:~:%~:,~~r~;d;io~~ ;3!' ;~,':;/ /~;n~:;~~l~;t!' ~;~~~s:~:;,~;~;:n~n ox,da;,on :~! cNo~-:~,~~~r:!~~1~~~~1:6 ;~ a~ _,~n:, be:~ohrnc~~~~;~u:~l l~~o~: ,;r:: :~:r~: rMJmb!f c( dKrN2 ,n QJ()dat en number ,s .!ISSOC•.!lt!'d with reduct,on, th e d,chroma te rons are reduced Thus, sooru~' mate ,s the oxrd.z,ng agenr ""'<i>

11 .4 COMMON FEATURES OF OXIDIZ ERS Oxidize r s generalJy are perce ived ~s rclari vel y_ powerful chemica l sub stances, becaUSttbry o fren react rapidl y, e ven a t e xplo sive ra 1es, with other s ub stan ces . These latter subsca include fuel s, lubri cants , grea se~, o ils, cotton , animal and ve~etable fa1s, paper, coal,~ straw, sawdu st, and wood sha\'mgs. Becau se the y a rc porent1llly powerful, oxidizers hart been chosen by te rrorists ro inre niio~all y c~use ma ss d~s1ru_ction and chaos. ln 1995,an A m e rican terrorist used an ammonium mtrar e/fuel oil mixture a s a weapon o( mau des truct ion. Ignition of the mixture des tro yed the Murra h Federal Building in Oklahomi: Ciry, sho wn in Figure I 1. I. The incident killed 168 people and injured 850.

Di ffe r e nt o xidiz er s ca n hav e di ss imilar srrengrh s . This va ri atio n in rhe strength of indi vidua l oxidizers can be approximat ed by examin ing the li sting in Table 11.3. In ,bu series, o x idi zing agents a rc arranged accordin g ro their decreasing oxidizing power. Any s ub stance w h ose name app ear s on thi s li st is a stronger oxidizing agent than the sub- s tanc es who se names are lis ted below it. Ir is not e wo nh y that many substa nces are s1ro11- ger oxidizing a gents than ox ygen itself.

426 Chapter 11 Chemistry of Some Oxidizers

Relative Strength of Ox1d1zing Agents ..

Fluor ine Ozone Hydrogen perox ide Hypoch lorous acid Metall icch1oratesb Lead diox ide Metallicpermanganatesb Met.!lll icd ichromatesb Nitric ac id (concentrated) Chlorine Su lfur ic ad d (concentrated)

Oxygen Metall ic iodates Bromine lron(U I) (Fe 1 · 1 compounds Iod ine Sutfur Tin(IV) (Sn4 · ) compounds

•u11ed In aescend,ng orde r of ox idi zing power b1~ an,md ,c envlron men1.

In its codes and standards, N FPA us es the term oxidizer to denote a substance that cJ n increase t he rate of combustion of Olher materials with whic h it contacts, NFPA dis - cmg ms he s the degree of haza rd posed by specific oxidizers by assigning them co classes of oxidizers as fo ll ows: 1

I Class I oxidi zer. This is a subs ta nce th at does nor moderatel y increase the burning rate of combustible materia ls wit h which it comes in co ntact. Cla ss 2 oxidizer. T hi s is a substance that causes a moderate increase in the burning rai e of combustible materia ls with whic h it comes in contact. Clas s 3 o xid izer. T his is a substa nc e that causes a severe inc rease in the burning rate of combustible materials with which it comes in contact.

1 Cla ss 4 oxidizer. This is a substance that can undergo an explosive reaction due co contamination or exposure to thermal or physical s hock , and that causes a severe increa se in the burning rare of combustible materia ls wi1h which it comes in contact.

Some specific o xidize rs are denoted in Table 11.4 using this system of classification.

11.5 HY DROGEN PEROXIDE Hrdrogen peroxide is an important substance having the che mical formula and molecul a r 11ructure l 110! and H- 0 - 0 - 1--1, respectively. Specific conce ntration s o f h ydrogen perox- id~ so lution s are designated b)' NFPA as me mbers of each class of o x idize r. They arc used Prrmarily for the fo ll owing purposes:

Solut ions ha ving a concentration from 1% co 3 % by mass are used as top ical anri scp rics on minor cues and wounds, as well as sterilizing a nd di s infecting a ge nt s . Th er

~ :.ardou.s M,ttenals uxle (Qui ncy, M.iss;a chUSfflS: N:1 tioru l Fire Protccuon ~ation), 2009.

o x idize r (NF PA) • As used in NFPA's stan- dards and codes, any substance that can increase the rate of combustion of other material and, under some ci rcumstances, can undergo vigorous self-susta ined decom- position due to con - tamination or heat exposure

cl as se s o f o x i d ize r s • As used in NFPA's standards and codes, any of four classes in to which in d ividua l oxidiz - ers are ass igned based on their ab ility to attect the burning rate of combustib le materials or to undergo self-sus- tained decompos ition

Hydrogen peroxide, 35.,,o solution

Chapter 11 Chemistry of Some Oxid izers 427

I I

~ I All 1norgar11c nrtrates (un less otherw,se (lass,f,W) All lnorgamc n rtrm~s (unless otherw ,se d,11slfred ) Ammon i um pef}u lfate B<1 num pero:iude U lc,um pero•1de

CLASS 1 Pota ssiu m d,chromate Potass1umpercarbonate Potass1umpersulfate Sod ium carbonate pero,ode

Ca lci um hypochtorite (66 % or less av.t ,l able ch lor,ne and a Sodium d•chlo1o+tr1a zi ne tr 1one di hydrate Sod1umd,chromate Sodium perborate (anhydrous)b Sod ium perborate monohydrate Sodium perborate tetrahydrate Sod,umpercarbona te

total water content of ,tt least 1 7% by mass) Hydrogen peroxide so lut,or,s (greater than 8% up to 17 5%) Leadd ,oxide t1th1um hypoch lori te (39 % or less ava d.,ble chlor,ne) Lith ,umpero:llde Magn~n.,m pero.1ude Manganesed10:ude Ni tric .tc, d (40 % concentrat,on or less) Perch loric <1c 1d solutions (h,m th<m 50 % by mass)

Bar ,umbromate Barium chlorate Baruam hypoch lorite Barium perc;hlorate Bar ium permanganate 1-Bromo-3-ch/oro-5,5-d ,methylhydantoin (B COMH) Calcium chlorate Ca!oumchtome Calcium hypochlonte (less than SO% by mass) Calcium permanganate Chrom ium tr10,11de (chromic ac rd ) Halane (t.J -d1chtoro-S,S -dimethyl hydantoin)

Sodium persulfate S1font1um peroxide Trichloro -s-tr1az1netr1one z ,nc pero:1Ude

CLASS2

N1troc acid (more than 40% but Jess than 86 % by mas~ Pe~~~~;" ac id solutions (more than SO% but less th,ri 60" ti,, Potass ium pe rchlorate Potass i um permanganate Potass1um perox1de Potass ium superoxide Slive r perox ide Sodium chlome (40% or le ss by mass) Sod ium perchlorate Sod ium perchlorate monohydrate Sod ium permanganate

Hydrogen pero1Ude (greater than .27.5 % up to 52% by mass) le~perchlor,ue

Sod11Jm perox ide Strontium chlor ate

Lrth1um chlorate lithium hypochlorite (more t h an 39 % available ch lorine) Lrth1um perch lorate Magnesi um bromate Magnes,umchlorate Magnesium perch /orate Mercurouschlorate

Ammonium d 1chromate Caluum hypochlorite (over 50 % by mass) Chlor,c ac id {10% max,mum concentrat 1on) Hyd ro gen perox ide solutions (grea te r than 52 ~0 up 10

9t %byma1s) Mono- {tr1 chloro)-tetra -(monopotaui um dochloro)-pent,H -

Per ch/or,, ac id solutions. 60 % to 72 .5% by mass

Strontium perchlorate Th allium chlorate Urea hydrogen perox ide Zmcbromate Zl ncchlorate Zinc permangan ate

CLASS3

Potass1umbromat e Potass ium chlorate Potass ium d 1chloro+triaz lnetrione Sodium bromate Sod ium chlorate Sod ium chlome (over 40 % by mass) Sod ium d 1chloro-s-tr1az1netr1one anhydrous

CLASS4

Ammonium perch!o r.;1te (part rd e size greater than Guar11 dme nitrate 15 m icrons) Hydrogen pero ~ide solutions (more than 91 % by man)

Ammonium perma n ga na te --

' ilepnmPd w~h pe,m~1or1 from "-FPA .:00-10 11, ~nra~ M,1tpn,1/s CodP. Copyrig ht C 201). N4t!Ofl.tl f ire Prote,ct,on Assoc;,;rtlon, Qui~ M-'- i'- "pnmPd m.J1Pr'-'/ a no1 the romplete o ffic, ar posrt,on oft~ NF PA on thP refe ,enad subi m wt, 1cn Is ,epresent e-d only by the ~•rd 111 iarntiflY. '1od ,uM perborJtP ii thP rommon namP fo, the sub1tan ce whole p1ope , chpm lcal namp 111od ,um pero• obo••te (Sect ,on 11 ~-El

428 Ch apte r 11 Chemistry of Some Oxidizers

nir11onl y av.111.iblc a s ovcr-1~e -co unter produc ts in drug s1ores. They ;1.re a lso wi~dy Jrrc0 h sp ira ls a nd medica l clinics 10 desfroy ge rm s lik e Escher, clna coli, botulism, u,eJ 111 II

O ;:1nd o th er mfect iou s microorsani sms that cause dr sease.

s.iln: "; 0

1::dons h.1ving co n~entra rio n of 6% by mass a re used m bl e.1c h ha ir. In the rocrss . hy dr ogen perox ide oxrd1zes the dark -colored pi gment called melarun to co lorless

~roJu cr-1 {ions having a conceniration from 30% 10 50% by mass are use d in th e chem!- •d

O l;, w sy nthesize peroxo-organic co mpound s (Sec1io n I 3. 9 ). T he JO% so lu110n rs cJI in _u~r : o bleach co tt o n, tlour. woo l, straw, leather, gelar m, and papt'r. T he- JO% so l u- JISO u>r I O be used instead of ch lorine for treati ng dnnkmg wa ter. Contempora neously, uon

5 :~~t1::1 has a lso ac hieved nmorir1y in con nection w ith rr s mi suse by terrorists for the th:iucuon of rhc- explos ive criaceto~e rr iperoxide (Secuon 13.9-C) . . _

rr • Sol ut ions ha ving a concentrauon _of 70 % by ma ss ar c use d by th e chem ica l 111du s try to cxrc ut e oxida rio n-reduct1on react ion s. They a re o flen dil ut ed befor e- u se and sto red

JS J!o/~~1~ ~:: ~o:~t~;n:. concentr.Hio n of 90 % by vo lu me a re use d b y the aerospa ce nd usrr)' as rocket-g rade so lu tion s. T hey have been used 10 o ~i di ze fuel s s uch_ as h ydra - 1 •hJCh lau nched the Apoffo roc kets a nd orhcr pa yload s mw space. Ru ss ia u ses the :;:;i:n 10 launc h Soyuz roc kets into s pace. T he 90 % so lu tio n ha s a lso been use d by the U.S. rml1rarr. Th ;e so lut io n s vis ibl )' re se mbl e wate r in p h ys ica l appea rance, alrh_oug h th ey may hJitt slightl y pungent, irrit atin g o dor s. Some o ther phys ica l properties of hydro ~e n

roxide so lution s a re no ted in Table I 1.5. Alth ough anh yd rou s h ydro ge n perox id e k, brc n p roduced, it is unava ilabl e commerciall y becau se ir is li kel y to decompo se nol ~~!r~·orld"s s uppl y of hydrogen perox ide is manufactured by a number of method s. Onr i,wok es rh e oxidation of 1sopropr l alcoho l, during which ace1one is coprod uced.

CH , I

C!-1 1- C - l·l(/J ...- O~ (x) I

O H l,or ror ; J .,kuh" I

CH3-n - CH 3(/J - H_-O~({J

0

The h>drogen pe ro xi de and ace tone a re se para1ed b y dis till ation. T h e h ydr oge n p('to:.:1 dl' sol 1111on may then be diluted to produce the d es ir ed concentration fo r co m - memal salc.

iiiiiiiii Phys ical Properties of Some Hydrogen Peroxide Solutions Melt,rigpo.nt

Bo ,lo11gpoin t Vipo1d ens1ty(drr: l )

S?tc,f1c~v, tyat68•F(20 "0

Vapo, preuure at 68"F (2_.:.0 "_:C:_) -'-"'-----' lo'~b,1tty1nwa1e,

Chapter 11 Chem istry of Some Oxidizers 429

H)drogen peroxide is an inherend y unstable substance. It slowly decomposes as fo!IO\\,: ~H,O ,(nq) __. 2H 20({) ... O ~(g)

ll ~ds"o~cn ~nn1J~ \\ ,,tn O, )gcn

The r.m:- of the decomposition reaction is c:1t~l yze d by sun lig ht as w~ll as certain metal most notabl y, iron, coppe r, chr omium, a nd sil ve r. An aqu eo us so luuon of 8% hydr 1, pe roxide LS comp letely deco mposed following a I 0 -mo n_th ex pos~ re to light, wh er:tn si milar soluti on kept in darkness fo r the s:m1e length of ume r~~1ams virtuall y unal ter~ In solutions of co nce nt rati ons of less than 30%, the dec':'~po ~mon °~ hydrogen ~ roxidt occu rs so s lowl y wh en sto red in dark gla ss bot~les tha~ It ~s virtually 1mp_erc eptible.

Conce nrrat c-d so luc io ns of hydrogen pe roxide (>6 Y~ 1110 i l beco me intensdy heat d when rh cr decompose. These hot solutions th en va porize. ,:-o preve nt th eir decom~i- rion from posing a haiard before th e intended u_s~ o f ch e oxidant, a ll commercial for111.1 of hydrogen peroxi de arc s ta bili zed by ad d1t1 o n of a s ubstanc e 1har retards Jts

deco~:n::i~~~:;ed hydroge n pero xide solutions ha ve rhe following properties:

Whe n co ncentrated hydrogen peroxide soluti o ns decompo_se, ample hcac may be evolved 10 cause th e spo ntan eo us ignition of nearby combusuble materials. Hydrogen peroxide so lutions having a concentrat!o,_, in _excess of 20% are highly cor- rosive. \'(/ hen exposed to skin, they ca use seve re 1rntat1on; and w hen exposed to the e)·es, th ey ca n cause blindness.

FI GU RE 11 .2 In comp hancewith DOT regulatoons, !he shipper affixes OXIOtZER and (OilROSfVE labels to 1h,s 1n1ermed1atebu lkconta1nerhold1ngahydrogenperox- 1de solutwn cons1s11ng of 30% to 32°,o hydrogen perox- ide The shipper also poru OXIO!ZER placards tha t display the DOT 1den1,f,ca1J o,, number 20 1~ across their center areas (CourresyofA-.mrorPerirxrndn<eMdrffiil/s, ln<:, Cenre,v,1 I1e;: Pe,,f!S}'N;m1<1 )

430 Chapter 11 Chemistry of Some Oxidize rs

11 .5-A THE KURSK H ydrogen peroxid e has been linked wi th the na val disam, onboard the Ru ssia n s ubmarin e Kursk. In 2000, the Kurd exploded and sank in the Barents Sea. Aboard were a numb(r 0f torpedoes, each of wh ose fuel system s consisted in part of highly co ncentrated h ydroge n p eroxid e. Inves tigators proposed tba1 the di sas ter was linked to a lea k of h ydrogen peroxide from a single torpedo. The oxidizer interact ed wit h the torpedo's stain• less steel casin g, which catalyzed the decomposition of tlu: hyd rog en peroxide. The subsequent buildup of oxygen rcsultrd in ovc rpress ur iza ti o n of th e torpedo and its sub sequent explo- sio n. Thi s first ex p lo sion th en ini t ia ted the det o nation of othtr torp edoe s wi thin the storag e compartmen t. The hull of the sub- ma rine burst, and the Ku rs k foundered and sank . There were no sur vivors.

11 .5-B WORKPLACE REGULATIONS INVOLVING HYOROGEN PEROXIDE

When hydrogen peroxide is us ed in the workp lace, OSHA requires employers to limit empl oyee ex pos ur e to an inhalation concentr.1· tion of I part per milli on , averaged over an 8-hou r workday.

11 .5-C TRANSPORTING HYDROGEN PEROX IDE Hydrogen peroxide solu t io ns may be tran spo rted by means of m?to r van s on public hi ghways or by rai l in boxca rs, u~uall y~: t.:uned in nonb ulk darkened glass or plastic bottles or inter~. ate bulk co nta iners like the type s hown in Fig ur e 11 .2. In 3 ddikOO. hydrogen peroxide may be transport ed in bu lk in a tank [fl.IC Of rai l tankca r.

20!i, to40'/o

;;;60¾ -,60¾

Shipping Oescnpt,ons of Aqueou s Hydroge n Peroxide Solut10ns

SHIPPING DESCRIPTION•

-t UN2984, Hydrogen pero)( ide, aqueous solut ion (co ntains 8 •/o - 20 % hydrogen pero)( ide). 5.1. PG Ill

UN2014, Hydrogen perox i de. aqueous solution (stabilized) (conta ins 20%-40 % hydrogen perox i de), 5.1. (8). PG II

UN201 4. Hydrogen perox ide, aqueous solut ion (stabilized) (conta ins40% -6Q 0;. hydrogen perox ide). S 1, (8), PG 11

UN2 015, Hydrogen perox ide, stab ili zed) (co ntains >60% hydrogen perox i de), 5.1, (8). PG I

'l!tlOff sh ipmtnl, OO T requ ires the adC1 1tlon of a subrtan.te to hydrog en pero• ldt to Inhibit In de co mP05!tl on.

When shippers offer a hydrogen peroxide solutio n for tran sportation, DOT require s h w provide the rel evant s hipp ing description s hown in Table l 1.6 on an accompany-

t ei;hipping pape r. DOT a lso requires s hippers and car riers to comply wit h a ll applicable ;~iling, marking, and placarding requirements. \'(' hen the solution co nrains more t han JO% hyd rogen peroxide, carriers must comply with a special marking requirement. DOT rrquirrs th em co mark each s ide a nd each end o f th e tank HYDROGE N PEROXIDE, AQUEO US SO LUTIO N o, HYDROGEN PEROXIDE, STAB ILI ZED.

SOLVED EXERCISE 11 .2

Whtn a sh, ppe r offers a carrier 2 500 pound s (1135 kg) of an aaueous solut,on containing 30% to 3 2 % hydrogen pero,;;de for transponat, on In a ca,go tan k by h,ghw4Y

(al What sh ,pp,ng descnpt,on does DOT requ ire the sh ipper to provide for th ,s chem ical commod i ty 7 (bl Wh ,ch DOT plac ards and markings does DOT reQ u•r e to be dis played on the cargo tank ?

Solution: (, ) DOT 1eQuIres the shi ppe r to provi de the foll owing shipping des.cnpt1on of an aQueous so!ut1on contain•

mg 30% to 32 % hydrogen pero)(1de so lution on the accompanying sh ,ppmg paper

I (1DENT1F1CAr1o~H:~:;E~~!~~1::~0s~1PP1NG NAME. I

f PRIMARY HAZARD CLASS OR DIVISION, SUBSIDIARY

UNITS HM HAZARD CLASS OR DIVISION, AND PACKING GROUP)

1 cargo X UN2014. Hydrogen pero 1C i de. aqueous solut ion

tank I ~:::!lr~:ts~~~7~~i ;~3 1 ~•/o to 32

1 /4 hydrogen

WEIGHT (lb)

2500

(b) Beca use more th an 100 1 pounds (454 kg) of the hy drogen pero -.ide solution 1s offere d for transporta • !<on, DOT reQuIres the carrier to display OXIDIZER and CORR05!VE placards on each si de and each end oi the ca rgo tank. Because the hydrogen pero•ide solut,on ,s offered ior tran sportat •on by highway DOT also reQ u• res the ca mer to d,splay tile 1dent1f1ca1Jo n number 2014 on an orange pane! across the ~enter a;ea of the OXIDIZER placards , or on whi te sQuare-on-pomt d •amonds poste d on each

0

s1de and each end ~r d~ e tank DOT proh ibits the d,splay of the 1dent1f1cat ,on number on th e subs1d1ary CORROSNE p lac•

F,nall y, as p1evIousl y noted In Table 6 7, because the solu tion contai ns more than 10% hydrogen

~Za~~~E~ch end of the ta nk HYDROGEN PEROXIDE . Chapter 11 Chem istry of Some O xi d izers 431

r I

I

11 I

:/ I I

ii'

I I

no nth lotin e blea ch • Any nonchl orine substance used as a b leach ing agen t durm g the la undering of fabr ics

11 .5 -D RESPONDING TO INCID ENTS INVOLVING A REL EASE OF HYDROGEN PERO XIDE

\,? hen eme rgency- res pons e team s encou nt ~r h ~·d rog en _pe r~x id e so lutio ns at ace· scenes, they should :mem pc no r onl y to extmgmsh o ngoing fires but 10 dam 1dci.; wa te r r unoff ge ner.11 ed w hil e com b:mng th em . When :1 fir e has no t occ urredor ~ike tlit t1o ns sho uld be seg rega ted fro m co mbustibl e materials. ' 1 e 50!11.

11 .5 - E NONCHLORINE BLEACHES A nu mber of pro duces are available commerc iall y that remo ve und es irable srai d the la un de ring of ga rme nt s :ind other fabrics. Those that d1 ssoke in water tons lltuJc hyd roge n peroxid e are called nonchlorine bleaches. Their use during launderin Prodllct tio ns provi des ch e ad vant age th a t th ey do not destroy most fabrics or harm th/ ~ ance of the ir colors. whic h ca n occur wh e~ chlo_rin e bleaches _(Section I 1.6 ) arc us~:31·

An exampl e of a no nch lo rine bleach is Ox1Clean. Its active component is an dd o f sodium carbonate and hydrogen perox ide whose chemical formula is 2N az CO .3~ ; It 1s al so known as sodium ct rbo na te peroxyhydrate and sodium percarbona:c. 1/ ! whit e ~owder th:it dissociates into sodium carbonate and hydrogen peroxide wh~n :: solved in wa rm or hot water.

2Na_.,C03·J H:,0 1(aql Sod 1umc.1!bo nJ!c~ ru \)h)dr'JIC

('iod1ur11p1:rcarb,m.Ut)

2Na_.,C 0 3(aq) + 3H_., 0 2foq1 SoJ1umcMbon.11c M)J ruge npc ru\l(k

Sodmm ca rbon :i te perox yhydrat e 1s also 3 component of T;de Lau11dry Detergent anj severa l clean ing agenrs and laundry detergents manufocrured by Arm & Hammer. Anotbtr exampl e is Clo rox 2, a liquid product whose act ive ingredi ent is hydrated sodium p(roxo. bo r:1 te, co mm onl y called sodium pcrbor:1te.

[

HO 0 - 0 0 111' \! \/

"'Na· 8 U j ·-l ll 10 - / \ I\

110 0 - 0 Oil Sodmmp..·ru~o borl k' {S,>J1ump,;:rbura1.· 1

When sodiu m peroxoborate is di ssoln:d in cold wat er, it di ssociates and form s h)·drogru peroxi de.

N .1_., 8 2(O1)l O H )4 -H-!2O(aq! -- 2Na l3 0 ](aq 1 ,_ 2H20 z(a11) - ~l l10tfl Sod,u,n pcnJ\ o borme S .. hum m,.IJl>urJtc H)ll •o~,-o J'O:nl\ ld~ IIJ1cr ('ioJ1um~rbor31c 1

When sodium peroxoborat e is dissolve d in hot w:i ter, th e hrdrogen peroxide dN"omposts to wa 1cr and oxygen. Table 11. 3 illu strates rh at hydrogen peroxide is :1 mongrr ox~• age nt than oxygen; hence, a gre ater bleachin g act io n is accomplished when fabncs arc laund ered wirh Clorox 2 in cold wa rer.

11 .6 METALLIC HYPOCHLORITES 1\lleta llic hr pochlorires are co mpounds compo sed of a metallic ion :ind 3 hyp~hlont~ ion (ClO - ). The mos t co mmon con~mercial examp les are sodium hypochlorire a~ ca lcium hypoc hlo ri te, each of whi ch ts encount ered a s th e acri,,e componcni of seH 1 h ouse hold a nd comm ercial bleaching and sanitation product s. Their chemica

432 Chapter 11 Chemistry of Some Oxidizers

Il l.i s arc N.1CI O and CJ (CI_O )1 ,. re specti vel y. When 1he y a re used a s bleach(n~ fo :1

1 ~1> - th ese substan ces :1 re d1 strngu1 shcd fr om metall ic perox id e bleaches by cal l mg

Jf tilorine bleaches . ihe n~~iring launder ing, bleaching_ age nt s ar ~ mixed with detcrgems 10 remo ve unde sira _ble

15 fro J!l fa brics and o.th cr textil es. Chlorrn ~ bl eache s can be used saf~ly onl y on tex ul es

1tJ\ fr or11 co u on and hn ~n, ~ut not w~I , silk, ;ind nr lon. N? nchcmtsrs generall_y c?n - niJ ~ ch ;H th e bleaching ~ct'.on 1s accomplished by chlor ine, bu1 1t 1s actua ll y the ox1d 1zrng c,n , f th e hypoc hlonte 1011 . _ 1'°11~:en chlorine bl e:1 ches can be used safel y during rh c laundering of fabric s, Am erican

l ,anufacturers post on th e fabric's 13bel the open triangular sy mbol shown below cex\e ~cfi . Wh en the use of chlorine bleaches should be entirely avoided, th ey post the 0~J1dl: srrnbol ; :ind wh en neither a ch lorine bl each nor a nonchlorine bleach can be used ~,,~.~"·E·A· •

The effectiveness of the hypochlorite bleaching agents is commercially described h)' heir available chlorlne. This term is used to compare th e effectiveness of bleaching ~gents :itch elemental chlorine, which has 100% a\·aibb le chlorine. A bleaching agent hav1~g_an JiJilable ch lorine value of 99.2 % has th e same bleaching power as a solution contammg 99.2% chlorine by mass. .

The available chlorine in any chlorine bleach is determined by using rhe reaction be twe en its :1ctive ingredi ent and an acid; for instance, th e a\'ailable chlorine in a bleaching ai;e nt containing calcium hypochlorite is determin ed by subjecting the agent to a reaction 111th hrdrochlori c :icid. Chlorine is produced as follo ws:

C i(CIOh(~) + -t HC l(oq) -- CaClz(aq) ... 2H~O(1) ..,. 2Cl ~(g) fJIClu lll h}[XXhl Onle ll }droc hlonc 11rnl C11lc1u1n chlumk Ch lon ne

The percentage of chlorine produced from the gi\'en amount of calcium hypochlorite is then determin ed.

So me hypochlorite bleaching agents are solids at room temperature, but they are also a1a11J ble co mmercia ll y as aqu eous solu tions. When they arc. he:1tcd, metallic hr pochlo- mes decompose to produce oxygen. For instance, th e thermal decomposition of calcium h)poch lornc is represented as follow s:

Cnlci11 mh)pc... hlonte C:ik1u m ,hlon dc o~) p:n

When thi s decomposition reaction occurs at a fire scene, the oxygen suppo rts combustion reactio ns and co ntributes to the degree of fire hazard.

11 .6-A SODIUM HYPOCHLORITE So lid sodium hypochlorire is an uns1able compo und, but its aqueous so lutions are suffi - cient! )· stable when their contact with light is averted. Even 1he solutions of 1he metall ic h) pochlori tes decompose when exposed IO th e ultrav iolet radiation in sunlight.

\X'e are mos t familiar wi1h sodium hypochloritc solutions that are used as bleaches and a, components of other household laundry products. A well-known example is th e hou sehold bleaching ag ent known as Clorox. an aqueous solution of sodium hyp ochlorite hJi'ing 5. 7% avai lab le chlorine.

So lu1 ions th at contain from 10 % to 12 .5% sodium hypochlorite arc also av ai la ble commerciall y. The solution kn own commercia ll y as Multi-cbfor is a sodium hypoc hl o ri te

chlorine bl ea ch • Any metallic hypochlo• rite or other ch lori ne - conta ining substa nce used as a bleaching agent during the laundering offabrKs

availabl e chlorine • The amount of free chlor ine that a sub- stance yields when treated w ith an acid

Sodium hypochlorite

Chapter 11 Chemistry of Some Oxi di zers 433

Ii

rr- 1

11

I I

l/1

Potable wate r

Vent

Ched( val~,

Q=..::J:_=::Hy=~~ Water

softener Brine tank

Potable water

To,~ ... FIG URE 1 1 .3 Tht' process by w h,ch sodium hypochlor,te m ay be electro lyt,call y proc:!uced on-s,te from a bnrie {sodium chlonde) soll/llQrl The Cllld,zer ,s I.ISed by hO"lP•tal pe~onn l.'I to d s,n fect su rfaces and equ•pm ent contam ,nated w ,tri m1crob ,al pathogens It may alsobtl.l5ed lll co ntrol a!gae grOW-J1 1n ldrge bcd,es ol stand ing water

Calcium hypochJorite

high-tu t hy pochlorit e { HTH) • A commernal oxidizer composed of a meta lli c hypoch lorite

so lution havin g 12.5 % a va ilable chlorine. It is used as a disinfectant and sa niriurfortht rreatme nt of water s upplies, sewage effluents, and the wate r in swi mming pools, spas,an,S hot mb s. It is al so used to sanitize equipme nt and surfaces on dairy forms and P<>Wtrf planes , food-processing planes, breweries, and beverage planes.

Sodium hypoc hlor icc formerl y wa s ma nu factured for commercial use by pa ssinggu. eous chlo rine mro an aqueous solu tion of sodium hydroxide. A mixture of sodium hrpo- chlorite and sod rum chloride was produced.

~N aOH(aq) + Cl;(I.' • - NaCJO(nq) + NaCl (aqJ ..- H10</) S00 111 mh) Jnn1Jc Chlonn~ S0J1u111 h)P•><.hk,mc 'ioJ111rn .:hfonJe \ \Jl(T

Today, citing the de sire to 1mpro\'e security, Clorox dilu1es high-strength (15 %) bleJQ wuh water ro produce its household product. The new process eliminates the risks mori· ated with stori ng, transporting, and using elemental chlorine (Section 7.3 ).

Sodium hypochlorire may also be generated fo r use on demand. In the system sbot.'I in Figure 11.3, for example, it is prepared by electrolyzing a portable brine so lu tion.

' ./:J. C Haq) ...- H 2O (ll - N .tClO(a qJ + H z(g ) S<.1J1umchlunJ.: So.:! 11nnh~po.. hlon tc· l l)dn:•gcn

11 .6-B CALC IUM HYPOCHLORITE Calci um hypochlome is commonly us ed for ];arge-sca le bleaching o perations, sanicizir4 municipal drinking water, disinfecting domestic and municipal swimming pools, and SC\11' tre-atmenr. The commercial gra des of calciu m hypochlorite are avaibble a s unique subscJnr;l5, solutions, and other mixtures with drying agenis and o th er additi\'es. It is frcquentlycnciut' tered in products known commercia ll y by che rrade name high-test hypochlorite, or HTl'l,

Calcium hypochlorire is manufacrured b)' reacting chlor in e wirh a lime sl urry. AII\IJ rure of calcium hypochlorire and calcium ch loride is produced.

2Ca(Oli )1(aq) + 2Cl ~(x) - C a(CIO l~((lqJ + C:1C l2((1q ) + 2H 2CX/) Cat.1um h) J ro"Je Clilonnc CJluurn l!)pv..hk•nl( C.1l,111m ,hlorulc \\'lier

Sodium chloride is 1hen added 10 th e so lution. This ca uses the calci um hyp0chlon1tlO precipitate as th e solid.

434 Chapter 11 Chem istry of Some Oxidizers

Contact of calciu m hypochlorite wit h Oa mmab le and combustible mat er ials causes ihrin to burn with an increased intensity a nd to generate a signifi cant \'o lu me of gaseous products. This is 1llu sirated by rhe test result ~hown in Figure 1 1.4.

11.6-C TRANSPORTING METALLIC HYPOCHLORITES \'fhrn shippe rs offer a metallic hypoch lorite for transportation, DOT requires them to iden- ri~· thr appropriate !'tubs tance as shown in Table 11.7 on an accompanymg shipping paper. DOT also requires shi ppe rs and carriers to co mply wit h a!\ applicable la beli ng, marking, and pbcJrd ing reqtnremenrs.

FI GURE 11 .4 Th ,s test ,\l usIraIes I he enhance d rate at v,h ,ct> cellulose powderburnswrien ,I ,s m,xedw1thh1gh-strer1gtt"I ca lc,um hypochlori te {7 26%ava ,l ablect11orine and56%wate1) l 81fJN· m,won, fhf;i/>elh8<K. PhD , pf , f,,e;JndMil/e<"odis pee-,1,r;fll;Jl>Orarory, UC. F,n.i , Rt'DO't. o~>d•ll!·' C1Jssd,- r,111on Rese.irr:.n Pro~r resu ;indCr,rer,.i. Fo1e ProleCTO'I ;i~,r;r,F-oundilt/Ofl Qv,rcy, MA No~ber 7009 )

1/li!IIW Shipp ing Oescn pt1ons o f Some Re p rese ntative Me t a lhc Hypochlontes METALLIC HYP.:.OC.:.H::.LO:cR.:.IT.:.E ___ _ _ _____ I :_:SH:::._IPPING DESCRIPTION 81111.1m liypochlorl te (con ta ins more than 22% avail able (hlorine) UN2741, Barium hypochlori t e, 5. 1, (6 .1), PG U (Po lson)

Ca lci um hypochlor, te, dry, and c.a ldum hypochlorite dry mixtures lcontaim more than 39 ~1 availab le chlorine (8.8% ava,lable oxygen))

ClltJum hypoc h lonte, hydrated and calc ium hypochtorite hydfite<I m(xtu res (contai ns not less than 5.5% but not more th1nl&%water)

Ca k 111m hypoc h lor1te, dry (contains more than 10% but not more than 39 % ava il abl e chlori ne) U lci1.im hypoc h lorite mixtur es dry (contains more than 10% but not more tha n 39% avai lable~hlor1ne)

UN1748, Ca lcium hypochlor1te, dry, 5 .1, PG II

UN1748, Calcium hypochlom e, dry. 5.1. PG 111 UN2880. Ca lci um hypochlori te, hydrated, 5 .1, PG II

UN2880, Calci u m hypochlorite, hydrated mixture, 5.1, PG II

UN2208, Calcium hypochlorite, 5 1, PG Ill

UN2208, Ca lcium hyp oc hlori te m i xtures, dry, 5.1, PG Ill

UN1471, Lithium hypochlor1t e. dry. 5.1. PG II

UN147I , Lithium hypochlonte m i xture. 5. 1, PG II

Chapter 11 Chemi stry of Some Oxidizers 435

I I

j • ._

The s hippwg de~npuons of :1 11 01hC'r metallic hypochl orJt l'S :1nd th eir so l ,d,::-niified gene n cJll }' m i hc Ha z.irdo us l\hr en.ll s Table 3S " UN 179 1. H)'~

1 ~fnsl!,

inorgJmc, n.o.s .• 8. PG 11 .- "Ui': 179 1. H ypochlontc: solut ions (cont:1 1n s sodi urn ~rn'\ chlome ), 8 , PG 11. - or -uN I 79 1. t-l ypochlorHc so lut ions _(con r:1i ns sod nun hyP<>c fPr>. nrc ). 8, PG Ill . - Shippers mu sr include th e n:1me of th e sp ec1f1 c compou nd s pa remh bJo. m tht' proper shipping nam e. Fo r exampl e, \_,-hl:·_n s h1pp t'rs ~ffc r zmc hypochJo~ 1rJnsportJt1on, th ey enter th e followmg s h1 pp1~g d_escnp11o n o n_ a s hi pping p~ or -u:-.J 179 1. J-l ypoc hl o rnes, inorg:1 n1c, n.o. s. (con ta in s zin c h ypoc hl ori tc ), 8, PG u.~ Pf!"

Sod,"m 11 .7 D I· A ND TR ICHLORO ISOCYANURIC ACIDS A ND TH EIR SALTS

436

Although C;J.lcium hypochlonte conti nues to be a popular component ~f industrial saruulloit products. 1r h:1s been largely repl3cl"d Ill mod em prod~cts w1~h certa m _ch lorina ted dem,. t1ves of isocyanunc acid . T hese compo und s mclude d1chl o ro1socya nunc :icid :ind tnchb. ro1socyanunc acid . The molecul.1r srructures of the se compounds are relatively complex,

1-1 Cl I

N N I \ I \

o - C C - 0 O = C C - 0 I

CI - N N - Cl CI - N N - CI \ I \ I C C

II O 0

1)1<h\,>nm,,)11t111n<""-•J.(,r Tn,hloro"OC}:mu nc ... ,d.ur l)"'-hh,ro '"" ,n.um, 1,6 !n<>nc Tnchl<>f1) 11m· ln~nn,· 2A .(Hnonc

We sru d y the natu re o f th e bondmg m th ese compou nd s more hi ll y in Chap ter 12. Di- :1nd mchloro1 socy anu n c acid s are w hi1e tabl e1s or powders havi ng an ava!Ublt

chlo ri ne va lue cha1 ran ges from 90 % to 99%. They are a lso ava ilable co mmercially u their sodium :1n d potassi um sa l1 s. These compo und s a rc typical ly encountered in 50-poun.:I (ll.7 -kg ) pai ls o r buc kets.

11 .7-A COMMERCIAL USES OF 0 1· AND TRICHLOROISO CYANURIC A CID S AND THE IR SA LTS

The major use o( th e d s· and m chloro1soc y:mun c aci d pro ducts is t o chl o rin:u e the watrr11 sw immin g pools. Fo r thi s purpose, th ese compound s arc usually rcforred to as d,cl,/o,ind trichlor, respectivel y. 0 1- and rr ichloro1 socyan11n c acid s a nd th eir sa h s rel ease their chlorut slm, Ir in to swimnung poo l wa tl:' r. They have much longe r li fes pans when dissolved in water 1han either free chlorine or th e metalli c hypoc hloriies, a ll of w hich rapidl y dccompose 1\.-hrn exposed ro rh e ultr:iviolct rad ia u on in s unlig ht. Thus, di - and tri chloroi socya nuric aodsand th ei r salr s a rc considered more desirable fo r th e purpo se of c hlorination, es prci.illy in areas \\he re sw imming poo ls are exposed to inie nse s unli g ht fo r t'X lended periods.

Di· and tr ic hJoroisocyanunc :icids are a lso co m po nents of dry laundry bl eaches, dcur- genrs :ind ~ther di sh washing compo un ds, scouring p O\\ ders, and bactericides. They 1\3\·calso been med tor rh e punficanon of drm king water a nd rhe non shrink ing trea tment of wool

11 .7 -B TRANSPORTING DI· AND TRI CHLORO ISOCYAN URIC ACIDS AND THEIR SA LTS

When shipper s offe, r d1ch loroisocya nun c ac id , tn chloroi socpnuric 3 ci d, o r th e sa lts of ;~;~e schoo7no~~ ds for tra ns portation, DOT requi res them to provide t he ship ping dCSCtlP- Ta bl e 11 .8 on an :iccompanr in g s hippin g paper. DOT .:dso requil'd

Chapter 11 Chemi stry of Some Ox id izer s

-- Shipping O@Scr1 pt1on ,;. o f t h e O,lo n n a t ~d l,;.ocy-1 nun c Aci d ,;. cttLORINATE D 1so~ NURIC ACID l),,hl or o• iocyanuncac id SHIPPING DESCRIPTION UN246s. ~ a n~ c aci d, dry, 5.1. PG II o, UN2465, Oichloro,iocyaf'lur ic ad d ~alts, dry. 5 1, PG II

,tiip pt rs 3

nd c:irricrs to compl y wu h a ll applicabl e labe lin g, ma rking, a nd placa rdin g

rr.:iiu rtinents.

11.8 CHLORINE DIOXIDE Al hou gh chemists recogn ize rhr ee oxides of chlorine, on lr one is commercia ll y ~mpor- • 1 • chlorin e dioxide. At room 1cm perature, thi s sub srance is a red -ye llow gas h a \'lllS th e ~~1;::U,:11 fo rmu la Cl01 • h is a h ig hl y unstab le s ub stance , dec ompos ing inro its elements at 3n ex pl osi\' t rJ. te.

Chlonn("d10 , 1tk

Chlo ri ne dioxide is routinel y produc ed nea r 1he pomt of i1 s imended u se. In the si m- rhfied ge nerator in Figu re 11 .5, it is produced in a two -step process, each of w h ich is ron duc ied under vacuum conditi o ns. In 1he fi rst step, so dium hypoc h\orit e is reacted with h) drochlork acid to genera te ch lo rine.

N,1CI O(mJ) - ~H C l(dq ) - • NJCl(aq l • 1-1 ~0 (/) + Cl~(gl <;o<1,11mclll;m..k

In 1hesc-cond step, the c hl orine 1s rea cted with a sodi um chlorite so lution, whic h re s ulc s in the gtnera tion of th e chlorine d iox id e.

:: -.:.1CI01(aq) + Cl 1t 8) - X10 ~1g) - '.!NaC lf w/l w,J, 11 111, hh•nl c Chlonn,· Chl,,nncd"' '"k <;,...,1,umchlt>nJ.:

\'!;' hen chlorine dioxi d e is di ssolved in water, an aqueous so lur ion is produced known JS rl,/o r111e d1ox1de h ydrate. In commerce, this so lution is froze n before II is shipped 10 a

Chlorine- dio1<.i de

~GURE 11 .5 Cnlorme dio xide usua ll y Is generated at 1111:• locat,onwl'Lere it ,s to be used 1n tn ,s ~1mp\•f1ed ;c ;,r-ia~c. two ,n dependeni chem ical 1eactIom work In 1.m,son to genera te the gas Although ,ts p nm ary use ,s , 1 ~~a oa~r Pul p, m mo::1ern tim es . ch lorine d,o;,;.,d e freque nt ly nas been selected over otner m ,c100LOOes to

" tctareascontam ,natedw1thmold,bacteria. and v1ru ses

Chlorin• dio• lde

Chapter 11 Chemistry ot Some Oxidi zers 437

'1

I I I

I I

Consum., Fir•works and

Special Flr• works

firewo rks • Pyrote ch - nic dev ices in tentiona lly des igned for th e pur - pO!>e of pro duci ng a vis- ib le or audtble eff ect by me ans o f combu n ion, ex p lo si on, deftagra t 1o n. or deto nat ion react ions

r;~~l~ ~fe:~1t~;!::sl;:\t ~:h;e"c1:;~~~-t he aqueou s solu ti o n surv ives for 3 long hlTlc, Illa As wic h chlo_nnc it sel f, the prin cipal risk associated w11h expo sure to chlorine d

1s mhala 1to n toxici t y. Ex pos ure 10 chlo rin e d1ox1de a lso caus es severe respirato 10~ d :11na se. ry and 'Tt

1 1 .8 -A COMMERCIAL USES OF CHLORINE DIOXIDE C h lo rine d1ox1de a nd cle-mem a l c hl o nn e gtncrall y are used for the same p co mpari son, how~ v: r~ chlo nne dm x1d~ is approx im:uely 2 ~2 11_mes more po~~::s. By chlo rin e as a n ox1dmn g agent. For thi s rea son, chlonne d1ox1dc is sometim I 1~ o ver ~hl o ~i nc_ fo~ blt·achin g pape r pulp and producin g white wh i:- a t flou r, cv:~ ~h'Cttd chlorine d1ox1dc 1s mor e cos tl y. OIICh

C hl o rine d ioxide 1s somet imes al so use d as a microbicide. For example it · Ustd di sinfe~ I wat ~r in th e dair y. be ve rage , and oth er food i~dus1r ies. At wa:,r. ;:,a t IO pl a nts, n s use 1s g~ ni:-rall y s upplem em_ary to the use of chlo ri ne fo r killing bacteria Bttall\tJtt 11 is capable of killing Cryptosporu/mm partm m, the use of chlorim· dioxide to ,disin:: dr in ki ng water compares favorabl y w uh o zone.

In 2002, when anthrax-laden ma il was di sco vered in postal areas and in 1hc Han Stq at e Office Building, EPA contractors chose chlonne diox ide to ~cstroy the anthra x. n.; m.:111 pac k:t ges and Sena1e offices were decontaminated by discharging th e gas into lhca sphere of seale~ -o ~f area s, where i_t ~emamed f?~ seve ra l h~urs _be~ore ncu1ralization.~ ha rd surfaces wnhm the Senate bu1ldmg were d1smfected using l1qu1d chlorine dioxick

In 2 0 05, fo ll o w ing th e Hurr icane Kat ri na di sas ter alo ng the Gu lf coas t, chlorine ~ox- id c w as also used to erad1 ca1 c the mold that gr ew in homes that had been inu ndJtcd 11,tlt war er. It ha s al so been used rn control the infcs ra1ion of the pipe-clogging, 1h um bna~- sized quagga mussel in wa terwa ys .

11 .8-B TRANSPORTING CHLORINE DIOXIDE DOT a ll o ws chlorine d io xide to be mm s po n ed onl y w hen i1 is fro ze n as its h>drair. When shippe rs offer the fro zen hyd ra te for tran s portatio n, DOT require s them to nmn• tai n th e gas in 1he so lid scare using dry ic e or other mea ns and to ide nt ify th e gas 0111n acco mpan yi ng shipping paper as follo ws:

NA9191 , C hl orinc d iox.idc, hydra1 c, frozen, 5. 1, (6.1 ), PC II (Poison)

DOT a lso requi res s hippers and ca rr ier s to comply wit h a ll applicable labeling, mJtkmg, and p lacarding requi rem ent s.

11 .9 OXIDIZERS IN FIREWORKS AND OTHER PYROTECHNICS

Fireworks ~re ite ms des igned primanl )' for entertai nm ent purposes wi th 1he inte lll of pro- du ci ng aud ibl e and vi si b le pyr0technic effect s by co mbustion, explosion, deflagra tion,01' deionauon reactio ns. Some famil iar examp les include fi recrac ke rs, Roman candles, pill" w hee ls, fla res. serpent s, s par kl ers, skyroc kets, and to y tor pedoes. Spccia l- effee1s firc" orks include com ets, fou nt a ins, strobe s, and kaleidoscope she ll s. To ch o reogra ph an aerial fut- wo rk s prog ram, modern profess ionals use compu1e rs, flame generators, and firing s)1· te~ s ihat. actuat e a set o f redox reactions , each of w h ic h is precisely tim ed to prornlt lav is h ae nal sc ene s s uch a s chrysant hem um s hell s. In a modern program, li ghting consoles sy nc hron ized ~vith th e act ivation of the se reaction s are int egra ted inr o 1he pcrfo rm:i_ncr, . In th e Unued Sta tes, the GI-IS sys tem (Sec 1ion 1.9 ) is u se d for th e classificauon ol

firewor ks. Two cl asses are espec i:-. ll y imporlant: Fi reworks 1.3G and Fireworks !.4G(for; merly call ed s pec ia l firc\v o rk s and com mon fireworks, re s pectivel y) . ·· I.JG" and "1.4G

438 Chapter 11 Chemistry of Some Oxidizers

h oOT d1 v1s1on num bers o f the rel evant haz.ard class and its compatibility gro up JfC' :,;n 15.4 - B). Fireworks 1 .3G,_ or specla_l fireworks , a_re rclati~·cly la rge fir ework 15~ de-signed for use b y profcss1onall y tramed expert s. Fireworks 1.4G, or consumer dc11'es ks are relauvcly sma ll firework dev ice s designed prim ari ly as cons um er products fifew or b}: th e ge nera l public. The GHS sy mbo ls pertaining 10 fi reworks in both h:nard fo r use are provid ed in the marginal a rt, but 1hc hazard diamond mforma1 ion is noc noted c\J•;e:hey va ry according to their chemica l com po sit ion . ,ince,\I l6 C.F.R. S 1500.1 7, CPSC -~as ban~cd 1he use of cer1ain firework s devices intcn ~cd

oduce audible effects. In addit ion, ch1\d -protecuon laws ha,•c b:mned the possession , ::~~fociure, and sal e of cherry bombs, a rype of fi reworks physica ll y resembling red chc r- ot5 with green stems. _Cherry bombs were_ acti vated by ,gmting fuses t1hc gree n ste ms) ch~t co ntacted a pyrotechnic mixture of potassium perc hlorate and metallic alumin um . The ac n - iau on of this mixture caused i_he loss of hundreds of eyes and fingers each year; hence, C PSC ,nsumted an outright ban agamst the sa le and~ of ch~rry bombs i_n the Uni_tcd States.

crsC al so compels manufacturers 10 pr ov ide special labeling mformauon on the con - tai ners of ccrrnin consu mer fireworks. Although th ere are far 100 man y t)' pC$ a nd s1a 1e- rnent> t0 list here. they may be accessed at 16 C.F.R. S \ S00._14 (b )l 7) .

rl rew ork s 1.3G (spe ci 11 I fir eworks , displ il Y f i r e- works) • Relat ively largef1rewo r k dev i ces desi gned pr i marily for d i splay by professi onal uperts

fi re w orks 1 .4 G {comm on firewori<.s. cons um er fi reworks)• Relatively small firework devices d~igned primarily for use as consumer prod - uru by the general public

Although sta le and loca l laws attempt to prevent 1hc widespr ead sa le of firewo rk s to unau ihonzed individuals, incidents involving 1he misuse of fireworks annuall y ca use num er- ous $CCOndaT)' fi res, bli ndness, deafness, the mutilation of fi ngers, and death. In most sta tes,

10 reduce or eliminate the likel ihood of 1hesc incidents, only a licensed re1ail ou tl et that posts

a pcrnut 1s all owed to sell fi rewo rks 10 the public. To further reduce o r climm:nc 1hc risk of ino den1s caused by th ei r mi suse, state and loca l laws rigidly require 1hat common fi rewo rks \'( actua ted on ly tn acco rdance wit h the manufacrurer's wa rn ings and instruc1ions. Display fi rc-11o rks must be actuated by trained experts only. Even und er 1he best of cond it ion s, the 3cruauon of all fireworks ofte n consti tut es a risk of fi re and explosion.

Onr co mponent of all pyro1echnics is a pyrotechnic m ixture of a n ox idi zing agent 3nd a reducing agent, The most co mmonl y encountered oxi dizers arc sodi um chl ori te , sodium chlorate, and sod ium perch lo ra1e, all of which arc a lso co mpon ent s of veh ic ular m bai;s, solid rocke t fue ls, and certain fenilizer s. Sodi um perchlorate is the oxid izing Jge m of cho ice fo r most p yrotech nic displays, and charcoal, sulfu r, pulverized magne- sium, and aluminum flakes arc t he reduci ng agen1s. To pro\'ide co lo r w h en fireworks are actu:i trd, one o r more meta llic com po unds a rc added 10 firewo rk s formu\a1ion s.

Sodium chloritc. sodium chl ora 1e, a nd sodiu m pe rch lo ra te deco mpose 10 produce ox}gcn when th ey arc h eated.

N:1C102(s) - · N aC1(s ) ..., 0 2(g) So <l1u111d-.!o n 1c SoJ,umchlo n<lc U,) i; cn

So<l1um ~hlorah: 5<'-.hum ,h\un<l~ (h ) i:C"

NaC\0.i{() - N:iCl(s) + 20 ::_lg) 'ioJ 1um 1i.:rchl or:11c 'il)lhumchl onJc O,;grn

.-\ltho ngh th e o xn;cn produced by these reactions aids in actuating the display, mo re complex rtdox rcarnons arc responsible for the brilliant lighting and sound effects associa ted with f1 re- 11 0rks displa ys . Whe n 1hc mixture of an oxidizer, charcoal , sulfur. and finely divided magne - iium or alu rmnum is acti va ted, th e resulting redox reactions occur at explosiv e rat es. The P~est nc e o f m;i_gnes ium powder enhances the brilliance of a fireworks di splay, wherea.s the 1 diuon of CO.'\rsc aluminum flakes produces lum inous ta.ils. The sc1s of equati o ns in Ta hle 11 ·9 illustrate some of lhe redox reactions associated with 1he actuation of 1he rcacti\'e m ixt ure .

The uniqu e co lo rs obse r ved during the display o f fi reworks re s ult a s ce r1ain co m- pound s vapori ze or decompose. T h ese compounds are almos t exclusivel y m eta llic

Chapter 11 Chemistry of So me O xidize rs 4 3 9

I I I

Ahi%11 Examples of the Chemical Phenomena Associated with the Actuation of Ft~works OXIDI ZING AGENT

Sod1umch!onte

Sodium ch lorate

Sodium pe rch lorate

REDUCING AGENT

Charco.il

Sulfur

Magnesium

A h,1m,num

Charcoa l

Su lfur

M.Jgnes ium

Alum inum

Ch omoa l

Sulfur

I Magn e1ium 1 Aluminum

EQ UATIO N REP RES ENTI NG THE REDOX REACTioN

- ,(JC) • NaCI01{S) ___, Na (l{s~ Caroon Sod um{hlor If Soa-1,mchlor,de C••bond'°l.Of

Ss(s) • 8"-:.aCI01M - 8NaCl(s) • as o2(g) Su•fur Sodlum(hlor,te SOd,um<hlo r,de Sulfufdeo,~

2Mg(.l) • NaCI01(l) 2""g0 (s) • NaO(I) Md<)n p11vm $()(1,um 1h'or,1e r.Ja.ine11um o.,d, Sod~,, Olb-di

4Al(l) 3Na(101(s) - 2Al103 (.I) + 3N•O(JJ Alum,m,m Sodumchlo,.!e Alumlf\u'TlOl idf S<xllu"'chb-.

K b) , lNaCI01(!) - lNa Cl[l:) 3COJ(g) ca1bM SOClumchlorate Sod -umchlo,,de C•rbond>Ollat

35 8(1) 16NaCI0 1{s) - 16NaCl (s) -t 24 SOi(9) Sulfur Sod,umch lor.itt SOd,umchlono, S!l'furdOMld!

JMg (s) • NaCI01{s) - JMg O(s) - NaC!(J) M•gr,t\,um Sod,um u,iorite M.ign,1,um o• lde So.:lnifl'Hl'tlor,d!

2Al{s) NaCI 0 1(s) - Al201(s) • NiiO(s) Alum,num Sod,umchlora te Alum,oumo •1de l,odiull'ltl'IQ

2C(s) • N•C10~(s) - • NaCl(s) • 2C0 1(g) Carbon Sod1um~,chlo,a1, Sod umchlor11:lt Orbon(l,01Jdt

58(s ) • 4NaCl04(S) __, 4NaCl(s) - 8501(91 Sulfur >odumpe,ct,lorau Sod•umchlo11(1e Sulh.rrd,olldt

4/v'g(s ) NaCI04(s) - 4Mg0 (s) • NaQ(I) Magne1•um SOC11um p,rchlo •.ite M agne1,um o• •de So(l,u'" clllordt

8A l(s) • 3Na(l04(S) - 4A l201(s) .,. JNaO(I) Aluminum Sod,~m ~rthlorate Atum,f\1/m o, lde Sodl<lffl i;Hor«

chlo ride s, whic h fl uoresce strongly in the visible wave length s. Some examples and tM colo rs they exhibi t on va porizati on are noted here:

Ba rium chlor ide ydlow-grcen Cupr ic chlorid e blue-gmn Li th iu m chlo ride crimson red Ca lci um chloride orange red Potassiu m chl oride lavender Sodium chloride go lden yell ow Str onti um chloride ca rm ine red

Firework s have also bern usrd as wea pons of mass des truction. The mixture of~ uve substances in fi rewo rks was the active 1:x plosive in the pr1:ssure-cooker bombs u.td dunng the 2013 Bos ton Marath on cerror is t :mac k.

11.9-A TRANSPORTI NG FI REWORKS When sh1pp ~rs offer fi reworks for transpomitio n, DOT requi res th em to d1:scribe cht firt" ;•orks genmcally as shown in Table 11.1 0 on a shipp ing pap rr. DOT re quires shippers!O incl ude the app licable EX •num br r (d1:sign:i 1cd here as EX-xxxx.x), Department of~

440 Ch a pter 11 Chem istry of Some Oxi d izers

Shipping Descriptio ns o f Fireworks"'

REWOR KS --- _ ~ PINGDESC l!.I PT!O N ~ ~isi on .!..:_1 _ I UN03B, Fireworks, 1 I G, PG II (EX-,c.~ _ f!!.

1 ~ d ivisio n \ 2~ _____ U_ N_OB4. Firewo rks, I 2G. PG II (EX •xl()()O() __

~rk1. d,v islon 1 3 UN OB S, Fir ew or ks, 1 ) G, PG II (EX-)(.l(U)() ::woru. d,v1s, on 1 4 ~;0336. Firework s, 1 4G , PG II (EX.-x)()()(x)

UNOJJ7, Fi reworks, 1 4S, PG II {[X •)()()(lUI)

~1,r,esforShPl)(l9¥idTrM61)0n"'9Fi~M'Wl,ngtan. OC: U5. ~mtmofTransport~h01'\ lOl l)

DOD ) nauonal stoc k number, product code, or otht' r idenn fyi ng information in th e sh1ppmg · don. The naiu re of these latter req uirt'mems 1s di sc ussrd in Sect1on 15.4-C. .

tSCl"rior requ ires shippers and car rie rs 10 compl y with all ap plicable labeli ng, markmg, d )Jcarding requ irem1: nr s. h al so req uires carrir rs m bloc k and brace packa ging con·

::im~g fire wor ks to restrict mo \'e ment m a transport ve hicle and protect them a g:H ns l rxpasu re to ignition sources. . .

Wh en eme rgency responders encountr r fi rewo rks durin g a 1ransponat1o n mishap, ihw pacbgin g mu st iden tify th e app ropri ate EX -number, EXPLOS IVE labe~, pr? per shi pping nam1:, UN idr nrification number, and UN pac kaging specifica uon ma rk in g. Eac h of ,he)( DOT req uirements is illustrated in the exa mplt: shown in Fig ure 11 .6.

11.9-B DI SPLAYING FIREWORKS 1.oc3! or dina nct's reg ulatr how fireworks are dis pl ay1:d. Rega rdl ess of their natu re, fi re· 11 orks shou ld never be actuated when climatic cond itions are dangerously dry or when the 1nnd spt t:d exceeds 30 mi/hr (48 km/h r).

NFPA h:is also bee n concr rned wit h the trai ning of indi vi dua ls who di spla y fir eworks. 1t requi res the m !O co mpl y wit h al least 1he fo ll owing/ • Professionals who pubhcly display fi reworks must be experienced, res ponsible, and bonded. 1 fo r bo th land and watr r di spl ays, professionals ma)' act uat e aeri al shell dis pla ys out -

doors only b)' adh r ri ng !O specified minimum sepa ration distances between the :1.ct ua- 11on pom t an d th e spectators.

EXApprova l Numbet(onoackag e or shipping paper ) 49C .F.R. \172 .320

E~2016

Haia rdlabol. 49C ,F.R § 172 .4 11, 49C .FR §172406

PVRO FOUNTAIN

"'''"''"'°' ~ !FIR~~:i~: General Mark ing UN Pack;igmg Speci fica1, on Require ments172 .J0 1, Ma rk, no 173.22 l al & 178 .503

~9 1 ; ·; .~! ~ll7i.J 0

4 , UN ID. Numbe r 49 C. 1'" R. § 172 30 Ha )

~odr (or fo ni-ork.lDuplay (Quinc-y,Mawdt=: Nlt•=I Flre r ro1«tion,\gfflq ), 2010.

FI GU RE 11 .6 Th1spack- a91ngfo r t1anipon ,ng fireworks 1s a f ,berboard OOJ;thathasbeenprop- erlyma rke da ndlabe led fortransportallon Due to space constramts the nam es o f the shipper and receiver are not noted IR.>QularcwyGulOo."bneslor 511.pp,ngM!dlta,uponmg frre,.,,o'l:S l','45/'lxlgrM , DC USDtp,l r1 mentofTr,;;nspo1- ra1,onJ,JOIJI

Chapt t t 11 Che mistry of Som e Oxi dize rs 44 1

442

ifriiiiifi Shipping Descriptions of Some Representative Metallic Chlontes, Chlorates, and Perchlorate s METALLI C CHlORITE , CHLORATE , OR PERCHLORATE SH IPPI NG DESCRIPTI ON

UN1 445,Bariumch lo1ate. s 1.(6 1). p~ UN1447,B ariumperchlo rate, 5 1,(6 1). ~ UN1452, Calc lumch(~l. PG~

UN14S3. Ca lclum chlo r1t e, S 1, PG 11 -- UN14S5, Calc1umperchlorate, S l ~

Barium chlorate Ban umperchlorate Ca lc1umchlorate Ca lcium ch lor ,te Ca /ciump@rc hl ora t e Magnes,umchlorate Magnesium perchlorate Potarnumchlorate Potu11 um perch lorate Sod ,um cnlorate Sod1umchlor1 t e Sod iumperchlora~ Z,ncch lorate

--~UN271J, Magnes,um ch lor~ ~ 75. Magnesiu m pe rchlo rat ~

..... UN~otass ium chlorate, 5. 1, PG 11 UN1489, Po tas s,umperchlor ate, so lid, S. 1, PG u UN1 495, Sod ,um chl orat e,_ s_. l,_PG_ 1_1 __ _ UN1 4915, Sod ium ch!or 1t e, S 1, PG 11 UNISOl , Sodium pe rchlorat l!', S~l ,_PG_ I_I __ _ UN1513. z,ncchlora t e, S 1, PG /I

11.9-C TRANSPORTING METALLIC CHLORITES, CHLORATES, AND PERCHLORATES

T he oxidize r s used in fi rewo rks a re avaibb/e as com me rci al c he nuc al products, Whn, sh ip p e rs offe r th ese in d ivid ua l co m p o u n ds fo r tra nsp o rt a u o n, DOT requ ires tht m ro provi d e th e r cleva m s h ipp ing desrnp tion o n a n acco mpan yi ng sh ipp ing paper. Somt exa m ples for severa l represent at ive m etal lic ch lo rn cs, c hl o rar es , a nd perch/orates arr Ii seed in Tab le 11 . 11 . Wh en me ta ll ic ch lornes. chlo rac es , a nd pe rch lora tes a re not sp«ifi• ca ll y lis ced a t 4 9 C.F. R. SI 72 . 10 1, DOT requires rh ei r sh ipp er s to prov ide a generic s/up, p ing desc r ip tio n o n sh ipping p ;1 per s a nd n ame rh e speci fic co mpo u nd pa rentheriaUy. 11 a lso requ ires shippe rs ;1nd ca rrier s to com pl y wit h all a pphcabl e la bel ing , ma rk ing,JnJ p lacard in g requir ements.

11.9-D ILL EFFECTS CAUSED BY EXPOSURE TO METALLIC PERCHLORATES

Considerab le co ncern abo ut th e hea lth effoct s lik ely co r es ult fro m expos ure to ptrdtlo, r are ions has bee n p u blicly \'Oice d, p J rt1cu!arly because perc hlo ra te ha s been idenci/itdlll the wa te r su ppl ies o f 35 sta res. This wi desprea d g ro und wate r co n c:i min a tion isassociJtd wi rh th e fo r me r mi lita ry use of me ta lli c pe rc hl ora ce s as roc ke r fu els. Today, rh est COOi' pounds have been r epl aced in fi rewo r ks a nd roa ds ide fl a r rs w ith compo u nd s rhar ~ft' fr iend ly ro pu blic hea lrh an d rhe enviro nm ent .

Does h uman exposu re to pe rchl o ra tes p ose a h ea lth ris k? S1udies rr 1•e:1 l a link bc~ttn the consumpt io n o f p r rchlo rare-co m a min ;11cd wat e r and dama ge ro th e thyroid gbod. neu ro logica l p roblem s, and th e in ability of hum a ns to p rope r ly p ro duce gro wth · fe cal-d eve lopmen ta l hormones. 3 Perc hlo ra te polluti o n pOf e n ria ll y affects 1he heahho

JNJ11onJJ Rewcar,h Coun" I of rhe NmonJ J AcJJemy ol Sc, r 11, r~. /fra//h /mJ,l1wt10I/S o/ Per.blo•.1lr l•!d1.,. 1WJ~hmg1on, DC: Nmon~I Audem,ell Press, 1005 ).

Chapt er 11 Chem istry o f Som e Oxi d ize rs

t n• of null1on s of Amenc.1 11 women and 1he ch ild ren tht·y conce ,1•e , especiall y bt·cause t hlorate pre1•c n ts 1hc propc.- r p rodu ct io n of 1hr hormones nee d ed fo r d c1•clop in g ~~'56 In 1005, EPA set a d a rl~• dose o f pc rc hlowe rh a1 pt."op!r ca n s;ifc ly ingest a t 0.7 i;l1 of body werg h t.

~- ~crchlor,H e con r:a m rn a u on 1s a ho tl y co nt este d po l1u cal m ue in Ca l 1forn1;1 and '\eiJdJ , tll'O r.t.1tes m wh ic h perch~o ra te pollu t 10 11 rs es peciall y p ronounced. O w mg to · ubhc pressu re, a ddmon a l i'.1forma t1 o n on rh r hea lth eff« ts rcl J n ng to perchlora te e xpo · :ute ,s iikel)' ro he fo rthco ming .

11.10 OXIDIZERS IN FLARES, SIGNALING SMOKES, AND SMOKE BOMBS

Flarts, signaling smokes, and smoke bombs a rr d ev ices th a t co nta in :i p yro r«h n ic m1x- mreof an oxi J1 zi ng age nt a nd rr duc1ng ?ge nt . Th ry a rc usrd by ci\'il i.1n poli ce an d the .m 1l1 -

r; ro 1dr nr ify a nd o bsc ure scenes o f interest, cordo n off acc ide nt sites, a nd coo rdinat e :u,iti rs dur ing local assa ult opr ra t1 on s. Wh en thrr arr used by the m1 l1rary, th ese d evices ;i re he lpful in locat ing frir ndl y unit s as well as e nem y ta rge1s :i nd cont ro ll ing the la yi ng a nd bhingofJ rt1lle ry.

In 1he cw1han wor ld, roadsi dr fl a res arc used to com mum ca te d1su ess, ident ify a tra ns• ronJt10 rl ,1cci d r nt or mec han ica l fa ilure, a nd cont ro l traffic du r in g n ig httime ho u rs. Fo r th~ purposes, 1he flares a re composrd of a mi xture of stront ium nit r;ltt' , sulfu r, pota ssi um p(rch/orJtC, a nd s:i wdu st, the co mbma t10 11 o f w hic h 1s tn '.>C'rted in to cardboJrd tu bes. Whe n rht)' art· ign11 ed , the sa wdu st burn s a t th e approxi mJt e ra ce of I in J mi11 . Th e red ox reaction prod uces an 111 1e nscly ca rmme-red glo w. Th e chenuca l rra rn o n is re prcsc.-nr ed as fo llows:

,•1.",01m!rJI~ ~ulf~r l\llJ\\I Ulll ['."n.hl.:,r.nc

fl .:, re • Any art,cl e co ntal ningapyrot ec h- mc su bstan ced l!'s•gnl!d t o lllum,na tl!, /d@n t 1fy, sign al, or wa rn

s,gn • lin gsm oke • Any typ, of smo ke bomb w hose actuat ion co m - mun icates p rearranged ,nfor matlon to troops orothe rs whos ubse- quent!yobserv@t he sig nal from a dlsta n<I!

smo ke bomb • Any de vice conta in ing sub · stances that produce smoke wh en actuated , g,ner all yforus, ln concea ling m ili tary

~111.>nt.0 11 1 o"J~ '- ultur J,,,,1Je p,,u,,1u111 ,hJ,,n,k 'i tn•;:c·n J 11,.,J,· O•)i~n operat ions

.\l rl rtJ f}' an d c ivi lia n aviato rs an d sa ilo r s use fl ares or fl a re/sig na lin g s mo ke co mbin a- oo ns ro com m u ni ca te di st ress wh en a m m a mes. The U.S. Coas t Guard regul a t es the feJturcs of se1·era l ty pes, including the handh eld, rt'd fl a re: fl o a ti ng o r:ingc-s rn o kc fl a re, rmul -prowc red pa rac h u te red fla rr; se lf-con tai ned , roc ket•pro pcllrd para c hut e, red fla re : handhrl d o ra nge sign ali ng smo ke; fl o ating oran ge signalin g s mo ke, ;1nd red a erial p yro· 1echn1c fl are. 1\ desc rip tion of r ac h d e\•ice is p ro vi d ed ar 46 C. F.R . Pa rr 160. Each is c om - posed of a urnqu e mi x tu r e of subst ance s.

11.10-A CHEMICAL ACTUATI ON OF FLARES, SIGNALING SMOKE S, AND SMOKE BOMBS

ln add tt1on to a n oxid i:u ng a gent and rc.-d ucin g agent , flares , si gnaling smokes , and smo ke bombs ofte n co nt3in so di u m b ica rbon ,u e a nd a n o rgan ic d )'e. M ose co mm o n ly, 1he o xi- dlllng an d redu ci ng agents are potass ium chlora te and ele me nt a l su lfu r, respectiv el y. The mJxture of co mpo nent s is comp ressed into ca rtrid ges, ha nd gr enades , a nd cani ster s.

When rh e ch e111 1ea l mix tu re in fl a res , signa lr ng smo krs , a nd smo ke bo mb s is a ctivated by ignmon, at !eas t t wo ch e mic a l reacuons occ ur: 1 The oxidat 1o n- rcd uct10 11 react ion betwee n po ta smim chl o ra te a nd s u lfur

JOKC/O~!l) + J ~ ~( q - • 16 KC l( sl .,. :!4S0,: IC') Pu1J,"umrhk,rn1,· Sul fur l'o!J-.,u m,h k•nJ~ SuUurd,u , 11!.

Ch apter 11 Ch em istry o f Som e Oxid izers 443

' I

/I 444

r he th (' rm.11 d t·com pos 11 mn of sodrnm b1carbon.H t'

~N.1 HC0 ,11l -• N,1: C0 1t 1 l -+ CO:(cl .. H:Oi,~J -;,..,J,Jm t,a.ut,,.,n.11~ ~. ,J,u111 ,JrNJ!lJ!( Curto,,n J1>•\IJ~ 11 31_,

As c.irbo n di o xide ,in d s ul fur d 1ox1de evo hc 1n 10 the :m, th q · d1 <: pcrsr lhC' dr . 1mmed1.1tt." area . e l!llf.:

Th e usr of smo ke bombs an d orh u py rorcc hmc s as r spe c1all y 1•1rn l to the succ~ rrnl1t:1ry oprr:m ons. An ;ators rouu nd y c;irry flares m th eir fli ght SUHS or 011 I f 11.1/ use as d1s 1r~s srg nal s 1f thei r a irc raft foi\ Fbr('S are al so used by military ~v:,1~bi deco ys ro thwa rr he:11 -seck ing mi ssi le s. \'( hen they an· :1eruatcd, th ese flares emit I.I infrared signal that mimics the heat d1 sc h.1rged by a n :urcraft rngin c. When it fl.a e1rcted from th e :urcr::ift, 1hc nms de rravd s towards 11 rather than t he ai rcra ft. rt 11

Smo ke bo mbs a rc- usl!' d by th e 1111l 11 ary to vis uall y ma sk the movl!' ment of treo~a , chi cles dur ing combJ 1 ac t1 v1t1es. A po pular smo ke bomb USt'd by tht' U.S. Arm d nd t he Ko rea n co nflic t wa s a pyro tec hni c m ix ture co mam ing 6.7% g ranula tl!'d al : rni:~ 4 6.7 % zmc oxi de, and 46.7% (C~ H~, o r CCl3-CCl 1) hexach lor~ thane by rnau. rh e co mponC' nts of thi s nmo urc werC' acru at r d with 3 fu se , th e products th.1t appearr,J ih e s moke were a lu min um ox ide, zinc c hl o ndC", and ca rbon (soo t) . 11

2A](q - CCli - CCh(j) - JZnO{1J __. 3ZnCl:/ n + Al1O3(s) + 2C(iJ ,\lummu,n HcuchloJroclhJac lonco,,J,• 7Jnc , hl,mdc A/ u11u numo,..i., Carbal

The zi nc chl o rid e attract ed atm osph e ric mo istur e ro form a fog . rhr alumin um oltdt: refl ectC"d light , and th e carbon co lored th e smok e cl oud gray.

11 . 10-B TRANSPORTING FLARES, SIGNALING SMOKES, AND SMOKE BOMBS

Wh e n s hippe rs offer fJarC's , signal ing smokes, and smoke bo mb s fo r 1ra nspo rt:1tion, DOT requires them ro idenrify rhe appropnatr it em generica ll y as show n m Tab le I l.l l . DOT al so rr qu in: s shippe rs and carri e rs to comp ly with alt applicab le labelmg, mar king, and pl aca rding reqmrr ment s.

11 . 11 THE THERMAL STABILITY OF AMMONIUM COMPOUNDS

Ammo nium compo und s are substan ces whose unm co ntai n an ammon ium ion (t-.li/J an d a negativ e io n . . \fosr :1re th e rmall y unstabl e. When rher a rc heated, :i mmonium com· pounds decom pose m eith er of the foll o wing ways:

Ammonium compounds ma y decompose imo the compou nd s from which they war inirfa ll y ma de. For instance, when ammo nium chl o ride is heat ed, it the rmally dmim- poses to fo rm ammon ia and hyd rogen ch lo r ide .

/'. H~CI({) - • NH i(g J ., /ICl (g) Arnrnomu111chlonJc Ammo n,J l l ) Jn;,i;,·nc hl on Je

Th e a mm o nium compo und s that deco mpo se III this simp le manner ge nerall y are~ regard ed as ha zard o us nwe ria ls. of Am mo nium compo und s ma r a lso decompose by o x idati o n-redu ct io n, Examples a m mon ium co mpounds that decompose m this manner are illu strated by the eqlll· 1ions in Ta ble 11. 13. T he rna1ority o ( them decompose at ex pl os ive rares when hea rrd. For th is reaso n, DOT proh ibns the ir tran sporra11on by an y mode. Exarnplrs of 1hesr

Chapter 11 Chem ist ry of Some Ox id izers

Sh1ppmg Descnpt1ons of A-ires, S1gn•hng Smokes, and Smoke Bombs

SHIP,INGOESCRIPTION

UN009l, f lares, aerial. l J G, PG II (EX •u ~u )

UN0403 , Flare s, aerial, I 4G. ?G II (fX •x.uu)

" UN0404. f l;i•e~. aerial, 14S, PG II (EX ·lX.UX) UN0420. Flar es. aen al , 1 lG. PG II

" ___ __:Ucc.:N04 21 , Flare1. aer ial. I 2G . PG II (EX •x~ ~ none,p los1ve), w ,thcorros,ve ' UN2028, Bomb1, 1moke. nonup/01ive. 8, PG 11

~;:d ;in~ 1t ia t m g d e~1c@ ___ .._ __

s,:;;e 1,gna ls I ~:0196, Signa ls, smoke, 1 1G, PG u (EX · XJOllOll

~ tllMeS

: UN019 7, s,gna ls, smok e, 1 4G. PG II (EX· XJOllOI )

I ~~0113, s,gna ls, smoke, 1.2G, PG II (EX ·unx) 1 "

UN0487, Signals, smoke~ G. P~ · XJOllOl....2_

UN009 2, f lares, surface. 1 JG, PG U (EX·lOUlXX )

UN0418, Flares, surface, 11G. PG II (EX-uxxx)

UN0419, f \;i res, surface, 1 2G, PG II (EX·)()IUX)

ammomu m com po und s are ammonium azidc, ammonium bro mare, ammonium c hl o- ra te, ammonium fulminate, ammonium mtr i1e, and ammon ium permanganate.

11.11-A COMMERCIAL USES OF AMMONIUM COMPOUNDS S«Juse few compound s conta ining the ammonium ion arr th e rm a ll y st:i ble, th e indu s- tnJI um of the se co mpound s are foi rl y limn ed. Ammonium rmra t e is by for th e mo st imponam compo und co n1a111ing the ammonium ion. In Sectio n 11 , 12, we obsen'e 1ha1 it 112n important commr rcia l femhu r a nd explosive component.

Ammomum perc hlorate is 1he only o th er ammoni um co mpound use d m sig nifi ca nt •mo unts m th e Un ited States. 11 accou nts for 70 % of th e sol id propellants used by the mospacc mdu s1ry 10 propel space sh uul es. T he ammon ium perc hlo ra te is mix ed with a fud lrkc powdered a lum in um and a binder. When igm ted, a n oxida tion-rcducuon rt"ac • hon occurs t hat ge nerates sufficie nt ga s 10 propel the shun le imo o ut er sp:1ce.

\ lum ,n~ ni o\l..k ,\l ununum chl,,n,k \\' J t~I

11.11 -B TRANSPORTING AMMONIUM COMPOU N DS \t1hen amm o ni um co mpou nd s are 1ra nspo md , DOT req uires shippers 10 provid e th e rel - ri·ant 1h1pp ing de scr ip t ion shown in Tabl e 11. 14 on a n accompanying shipping paper.

Chapter 11 Chemlrtry of Some Oxid ize rs

I

445

r ii-'=i1iiiii Ex,i11mpl~ of Ammo ni um Compounds Th a t Are Hazo1rd o us Mate n al s AMMON IU M COMPOUND EQUATION llLUSTRATIN G THERMAL DECOMPOSITION

Ammon ium az1de1 N H,N 1(s) - 2 Ni{g) 2 H!(g) ----

Ammonium brom•ll!• 1 lNH1 8 r0 1(.1) - lNH,Br(!) 301(9) Am ,., on um b•O'"'alt ,,. ..,,.,0<1,um t;i,om ,clt O')' g en

Ammonium chlorate• lNH1 CI0 1(s) - 2NH,CI • 30 i(g) Ar-mon ,um tnl011te Arimo~""' c~Jor.de Orygeri

Ammon ium d,chromate ---(NH.J2Cr10 1M - · (•101(1) N~4H10(g~ ~..,on,um cHt,rorr>•t e (hrom 1,m ( I/ o•,cle I\ 1,09en Wn,,

Ammonium fu lminate• lCO(g)----

Ammon,umn1tnte1

l\uogen

Ammonrum perchlorate -2NH~CI04(s) - Ni(g) • Cl2(g) • 201 (9) • 4H20 (g) Ammoo,.,m perc~loraU N ffogen ( hlor,ne 0,yge n Yl•ter - - ----- ----- --- ----- Ammon ium permanganat e• lNH,MnO.Cs) - 2Mn0 {1) N;(g) • 01(9) 4H10(g)

Am.,,on,u.., ~1m•n91r,1•e Mdngane1e(11)0 1·de N1!ro9en Ory gen Wi'lt1

~--m-.-~---~-,-~-d-.-~-~-~-----,-~-~-b-½-~----- - - --•-•~ A.'"lmon,~'"l Pt''O•~a ,su tl~T~ Ammo.,,a N,trogen Ox;g en Sulfuri:t.o...oe W,re,-

0D0Tprohibitsthe 1r1mponat,011of 1htsema1er l•'1 "Also ri,mt-d ammon iym perJu lfate

1Fi1iikti Shipping Descnpt1ons of Som@ Representative Ammonium Comp ounds AMMONIUM COMPOUND

Ammomum dichromate

Ammon iu m n itrate fertilizer

, SHIPPJNG DESCRIPTION

UN143 9, Ammon ium dlc hromate, S 1, PG II

UN2067, Ammon ium nitrate ba1ed fertiliur, 5 I, PG II ., ____ uN_10_71, Ammon ium nhra te based fertlliztr, 9, PG III

Ammonium nittal! emulsion UN 3175, Ammonium nitrate emulsion, 5.1, PG U Ammon ium nitrat e su1pens ion , UNJ375, Ammon iu m nit rate suspension. 5.1, PG N Ammonium nitrat e gel (int ermed iate for blast ing eJrplos 1ves) UN3375, Ammonium nitrate gel, 5. 1, PG II

Ammon ium nitrate/fuel oil minures (conta ins pr, lled ammon ium NA0JJI, Ammon ium nitrate-fue l oil mfxtures, 1.SD nitraieandfvel o il) (fX-.1ooooc:)

Ammonium ni trate, liqu id (hot concentrated solution) UN2426, Amm on ium nitrate, liquid, 5.1 Ammon ium nitrate (conta ins more I.Man o.i •i. combustible substances ) UN0222, Ammonium nitrate, 1 1 D, PG II (EX·~ Ammoniu m perchlorate UN0402, Ammon ium perchlorate, 1 ID, PG U (EX·xo:o.1

Ammonlumpersu lfate

446 Chapter 11 Chemistry of Some Ox idize rs

UN 1442, Ammonium perchlorate, 5.1. PG U --- UN1444, Ammonium persulfate, 5.1, PG Ill

f Jl su rrq u1res sluppt'rS and GJ rnrrs 10 comply with :ill app l1c:1ble labding, m.ukmg, ~ p].K.irdingreq u1rcm r n1 s.

11_12 AMMONIUM NITRATE . :unrno111um nHrJte 1s the most co mm r rc1a tl y 1m por1:1 nr chrm1c:1 I prod uct co nta in ·

61 IJ;, 311 rn 10 111 um 1011 . its ch r mica l form ula is :\'H-1;,."0 ;. s~' \'eral gradrs arr :1vai la ble in!r~J~ns a fert1l1zu, dy11ami1r, nitro us oxide, and techn ica l grade, all o( which a re av~ il - 1;1tconune rc1,1!l y as cr)'stals, tl akes,gram s, and pn ll s (s mall, bead-like pe-llrts ). Thr ch.1r• ;,rwsocs of th ese gradrs :are bridl y noted next.

fauli ir r-gr..1dr a mrnoruurn mtr:1t r JS commonl y encount ered a l forms and fo rm d is• mbunon centr rs. fr ml1 ze r-gr:1de ammo ni um nmat r is a formulation of ammonium mtrJ ft" with ammoni um sulfat e or ca lcium ca rbonau, l'ach of which reduces the portn nal risk of m self-drcomposition. As its na me imphrs, it 1s imrnded fo r use as Jn Jgricu ltur.il fertilizer. It is co mmon ly so ld m 50-pound (23•kg ) bags. O)n ami te-gradr ammonium nitrate is wide ly used during road construction a.nd b!Jstms opera nons 111 rnmes and quarries, wherl' it is th e ncrive componl'nt of blasnng Jgtnrs. his also a compontnt of uniqur ex plosivl"s hk r am mona l, a mixture o( am mo· mum mtra lt' :1.n d powdered a lum in um . Ammonium nitrat e ha s also bren co mbmed wuh n.rr ma bursting charge use d in demo lition bombs. Ir is also 3\'a1/abl r com· mcw all )' mixed with d il"sel fuel, ca ltr d :ammonium mt ra tdfuel o il mixture, o r AN FO . Th e prcsencr o( th e die sel ml mak es AN FO easier to deto na te th:1 n a mmomum mtrate Jlone. Although H ca n br safely handl td and transponrd, ANFO dr tonat rs wit h a powerful force whr n it is ig nite d. A!\' FO ha s been mis use d m acts of trrroris m to ausr c.11 :1stroph1 c dnmage ro human health, safr ry, and nat io nal sec urit )'. \ "1 rrous ox id e-g rade arnmomum nitrat e is ustd to prod uce drn itrogrn ox1d r, or rn rrou s oxr dc, by gen llr hea ring. It 1s know n commonl y as laugh mg gas. an anes thet ic used n1J1nl y by dent ists 10 lessen th e anxiety rx perie ncr d by some patients.

Nll .iNO i! sl - N~0 (11l + 211 20/d ,\mmom11m111ia1r \\ Jt~ •

I Techmc.i l-grnde :a mmon iu m mirate 1s producrd for a \'anety of uses. For rxa mpl r, 1t l:i a component of cold packs used for 1reatmg minor athl r tic in1ur1 rs. Beca use the d1sso ll'lllg of ammo nium nitrate in wate r is an endmht rm 1c procrss, the solution is co ld wh en fim produced a nd pro vides reli c( fro m pain wh en a pplied to bruises.

11 .1 2-A AMMONIUM NITRATE AT FIRE SCENES Ammoni um nitrat e melts at 337°F (l 70 °C) and decomposes brtween 350 and 4 l0°F ( 177 ~nd 210°C). Whrn a bulk quant ity of ammoni um nitrate is presrn t at a fi re scr nr, it may undergo tht'rn1al decomposi ti o n ar :111 rx:p!osh·e rate. The dec om po si tion producrs an Jrra)' uf products includin g thosr illusrratrd by thr followmg two eq uat io ns:

\ mrr1<:m1ummtr:11c N11roiicn Nitrug,:nd,o\lJe \\ ,,J cr

lhest decompomi on products are gaseo us. f When rhe ga ses produced by 1he dccompostt ion of ammonium nitrate a re venrrd rorn the fire scene, rh e threat of explosi ve dl"com posirion is redu crd o r ehminarrd. How-

t irr, wh en the deco mposition produces are confined or ca nnot be \'ented from the storage

Ammoolum oitrat•

0initrog,o oxide

Ch1pter 11 Chem istry of Some Oxidiz ers 447

I

1

I!

s,um addod '""" ""'H;'""" 2200ronsof I ..

ammon ,um nr:rl'le \ ..,

15001onso1 fue l oil

~•i"~R!i~d °;,e~~"G?;;;~,1 :'F:~:~~c~: ~~;t..,'?~ :!: 1: ~:~;ra~~:,~ tre h~c,'1~ to tne 'lO-C'I anc: 3PO 'I ste.tm t/'1e 're co,triwtd to ::M'n. trie ammomut"I rma-" o«xr~ rl:t rto" m.x,,_re o• nrtrogen. n,irogen d ox;ce or19tt1. ana wa:tr vaoor Tr s oroduct1on of 9_a1.ts a.

01J•l a1Joof 1rt,er'lal or~rewtn.n uiehoc-;tna!Y,1i1sreevtooru~ v. nenu,ecargo'lh,ps!JOSlol.leUI),~ $J1hunared oec,:ievlt"!( lf'daroano:--tr 35 00 •.-.ere -i,¥red ihepro;?fftyc:,imagewascomparQ !tJh: e.Qe r eri~ea Cur ng a rra,or wart -re bQ..-blng '1CJcw1t i'lt total orootrty oss was t"S"...ma:ed as S33 f"'.lo, c.:lseaon19,<:7costs

area. a ma 1or explo~1on rs hkdy co occuL This was th e fau of the Fr('nch cargo ship s_s Grandcamp, a pomon of whoSt" features a re illustrated in Figure 1 1. 7.

In 1947, the Grandcamp ,..,as docked :it rhe harbor in Texas City, Texas, wbeu c:iughc fire " 'Hh nea rly 2280 rons (2070 [) of fcnilizcr-gr;1de ammo n ium nitmeonhoanl s rored w1thm PA·o hol ds. The he;1c generated by the fire caused 1he ammonium wtrut 11 mdc and decompo~.

Altho ugh fi re s m 1olnng ox1dmng agenr s can effec11l'el)' be ex t ing uis hed throap. ;1pplicat1on of warer. this attempt was nel'er made onboa rd rhe Grandcamp. lnste:ad, orders were issu ed ro seal the hatches to rhe holds to eliminare rhe air suppl y to thtfin and pre1·ent damJ ge co the cargo by water. Supporred by oxid izi ng agents, howe,ce:r,~ fire conunut"d m burn m the abst"nce of air. Internal press ur e withm the holds incrcutd until .i major explosion rdeast"d the confined g.a ~s.

Tht" explosion of th e Grandcamp is now rega rded as t he worst ma ri ume 111C1dal in rn lvmg a chemic.ii subru.n ce. Ir caused the dC';Jth s of nearl)' 600 people, including l id Galves1on's 28 firefighcers. h sen·es to 11lumate dramaucally t h e potenril ll)' h.1urdous nature of oxidizers in gene ral and ammonium niuate in pa rt icu la r.

fn contempora ry tlllles, the worsr industrial accident fo r emergency responders inl"(ihrd th e explosion of ammonium niuate ac a fi re scene. In ZOU, 28 w 34 tons (25 103 1 t d ammonium ruttatt' exploded at a feniliu r storage and distr ib ution cent er tn West, _TCUS; Ftfrecn people, including 11 fi refighters, lost their li1·es and Ol'C'r 200 res idents " 'ere UJrurtd.

11 .12-B WORKPLACE REGULATIONS INVOLVING THE BULK STORAGE OF AMMONIUM NITRATE

OSHA has pro mulga red regula tions rel aring to the sto rage of bu lk quanmies of J(TIQ)' mum nitrate ar 29 C.F. R. § 1910.1~9. T~ese regulations a ppl r to fa r mers a~d at~ e mployers w ho ~to.re and use ammonium nitrate m workp laces , as well ~s cht _o11 n~ in lessee of any bu1ldmg, p remise, or sc rucrure in which th e ammo n ium mtratt 1s sro q uanrnies of 1000 poun ds (454 kg ) or more.

'Gl,nn HCi~. ·frmluer B!nt lgnue, Concerns.• Chr,,r. £rig . . Vru,s. Vo l. 91 (! 0 J J ), p. jj_

448 Cha pt er 11 Ch e m istry of Some Oxid ize rs

fhe OSHA rt"gulau~n s J>t".n a m 10 thrt"e sub1ect areas: 1he nature of the building m bJch storage of ammonium nmare 1s in tend ed; the storagt of .i mmonium nnrare m ,on-

\\ or piles wirh,n an a pproved butldmg; and the sto ragr of ammonium nimue w ith u;,:~ul,,ra nce5. \X'e note rach su b1ect arC';J st-pa ra1el y to appreciate 1he exten t of the pre • :unon.i th,.u muse be undertaken w pre1·ent mi shaps.

fll, ~ .,rure of t he Build ing in Wh ich A mmon ium Ni rra tt' Is Sror ed

1 A building ust-d to store ammonium nmate may h..1 \ea basemenr on ly when th e base- men! has b«n cons tructed so IT 1; ope n on at fa ~t one side. n,, buil ding used to store amm oni um nmate ts hmHed 10 one story m height. n,e building u,;ed for the Storage of am monium mt rare must be adequately \C'ntilacrd or~ of a co nstruct10n that allows self•venula1mg m the e1ent of 3 fire. n,e "all on the exposed side of an ammomum nmate sto rage bu , ldmg that is wirhm 50 {et" ! (15 m ) of a combmtible building, fo rrst , p iles of combusuble materia ls ,md sim ilJr exposure haz.uds must be of fire- res1 sm ·e construcn on. In lieu of a fi r r- resist1\e wall, ot her suuable means of exposure protC"Ct.ion, such ;1s a frtts t and1ng .,,, 3 JI, ml} be u~d.

• All floo nng m storage a nd ha n dling a reas within an ammonium nit rate sto ra ge budd - ,ni; must be of nonco m bus u ble material or p ro1ccted agam st 1mpr egnanon of ammo- ni um niua1e, and m ust be "ithoU! open d rams , craps. runnels, pllS, or pockets in ro .,,,h1ch anr mohen ammo nium ni tra te could flow and be confined in the e vent of fir e.

1 The ammonium n it r at e stora ge build ing a nd 1cs struct urrs must be dry and free from wlrer '>C't"pJge th rough th e roo f, wa lls, a nd floon .

1 Unlt"Ss consrrucred of nonco mb usn ble ma te n al, or unless adequa t e facilit irs for fight - mg a roof fi re are ;n •ai la b le, b ulk sto ra ge suucrures w n hm an ammon iu m nit r ;1 1e stor- 3i;e build mg cann ot exceed a he igh t of 40 feet ( 12 m).

• Sui1.1blt" fi re-com rol d e1·icrs, suc h a s small -hosc or pan.abl e fi re exrmguLSher. . mus, be pr011ded th rou g ho ut J n a mmonium m tra t e sto rage bui lding and in che load in g ~nd unlo.idmg a reJs.

1 \rater supplies a nd fi re h ydrants m U5t be located nC'"3.rby an ammonium nitrate sw r- agt bu1ldmg m acco rda nce wi th recog nizt"d good pramces.

The Storage of Ammo ni um Nitr a t e in Con t a in ers • C.Omainers of ammo ni um m trar e can not be accep red fo r sto rage w hen che temper a -

nm of rh t" prod ucr C'XCC'C'"d s 130°F (54"C). I Bags of ammoni um n m att"ca nnoc be stored wi1hm 30 inches (76 cm ) of , he wall s and

panmons of the J ntmo nium nitra te storage bu ildin g. 1 '.\o more than 2500 ions (21 70 r) o f bagged a mm o mu m ni trate ma y be st ored m an

ammonium n ic r;1 ce sto rage bu ild ing ch a t is not cquippc-d wit h an automa u c spri nkle r system .

Th , Storag e of Amm oniu m Nitra t e in Piles 1 Ammonium nm are ca n no t be accept ed fo r storage in pi les when th e te m pe r:1 m rr of

the product rxceeds ! 30° F (54°C). 1 Pi les of ammoniu m n m are o rdin ari ly ca nno t rx,eed 20 fee t (6 m ) in h eigh t, 20 fC't"t

16 m) m w1 drh , :1n d 50 feet ( 15 m ) m lengt h. When the pi lts a re sto red wi t h in a b u il d - ing of noncombustible constr uction o r p ro tect ed wit h ::auro ma ri c sprin kle r s, 1hr lengt h of the pil es is unl imi1ed . Ammon ium n i1r::1te piles c:1 nn ot be stacked cl ose r th an 36 inch es (91 cm ) be low t he roof o r s uppor ting an d sp reader beams.

1 A1s!t-s mus r be pro l'id ed ro sepa ra te am mo n iu m n itrate piles by a clcn space of nor lm than 3 ferc (0.9 m ) in wi d t h. At le::ast one ser"ice or ma in ai sle m the sto rage ;irca tlut is no r less tha n 4 fee t (1.2 m ) m width a lso must be pro,·1ded.

1 Bm s must bt" kept clea n an d frre of ma tena ls that ,a n contaminate ammonium nm.He.

Ch il ple r 11 Ch e mistry of Some Oll idlzers 449

11

FIGURE 11 .8 Al 29 C FR §1910 109, OS t'A reQ u me 'Tl ployer1tostoreby lk Q~nti l.eS [>1000 P01Jnd:1 (454 kglJ of amnonivm Mme W1th1n a blfl tha t IS dean ard free ol coma m,na'll5 'Nhtn the a'l'l"lOl\.vfl~ 1s stored as a p le, ,t mus! be sized 1n a manner th al a'/ ma teri al w1h1n the pil e may be pe nod,ca:t, Mer~ i; b 1ri must be separated by fa" wdlls from tla mMable and combustible matenais, COHOS/Ve mat@N:s. other ix:fi9t and substances l'llth wh ,ch th e ammonium cO\Jl d react Employers ma~ no1 store e~plos1Vf'! or blasting '9flll3 wn/'l ,n th es.ame bu1ld111 g

• O wi ng to rhe corro s1\'e and reacri ve p roperties of ammonium nitrate and to ar~ comam inauon , ga lvanized iro n, copper, lead, an d zi nc can not be ust'd in the eonsrnr, tion of a bin unle ss the y are sui tab ly protected . Although a lum inum and woodrn }q protect ed against im pr egna tion by amm onium mmue are permi ssible, 1he putitiocll di vi din g the ammonium mt rate storage area from t he s torage of other prod uru dw could contaminate the ammonium nitrate mu st be o f "tig ht~ co nstructio n, as illus- tr a ted in Fig ure 11 .8. Ammonium ni1rate storage b ins and piles must be clearl y marked wnh signs mding a s fo llows:

I AMMONIUM NITRATE I The piles of ammomum nitrate mu st be sized and arranged so that all material in the piles is mm·ed periodically to min irruze caking of rhe ammoni um nitrate during its storagt.

• The height or depth of th e a mmonium nnrare piles is limited by th e pressure-srnhnc ren den q of rhe pr od uc1; howeve r, in no case can rhe ammonium nitrate bt- piled high er at any point than 36 inches {91 cm ) be low the roof o r th e suppo rting anil spr eade r beams overhead. Dynamite, Ol hr r ex plo sives, a nd bla sti ng agents are prohibited for loosening amroo- mum nitrare that ha s ca ked.

Th e St o ra ge o f Am m onium Nitrat e w ith Other Su b sta nc es • ~mmoniu m nitrat r mu st be sto red in a se parat e bu ilding, sepa rated b)' approred~1~

firewa ll s of no t lrss than I -hour fire-resis tance r aling, or sepa rat ed by a spa« rt !e:ast 30 fet't (9 rn ) from the storage of organic chemicals, acids, or 01her _corroil m:iterials; mat e rial s 1h :1 t ma y requ ire bla sting dur ing proce ssi ng or ha ndling; '°; p r essed flammable g a ses; and flamm a ble and combustible mater ia ls or 01 ir

450 Chapt er 11 Chem istry of Some Oxidizers

,on i:1nun:111 ng sub srnncc s, mcludmg but 1101 l1mJt cd to anm1Jl fat s, bJled co 11 on, bJ kd rags, baled sc rap pape r, bleaching powder, burlap o r cotton b.ig.s, ca usnc w da , ,o.il, coke.", charcoal, cork, ca mpho r, exce lsior, fibrrs o f a ny kmd , fis h OLIS, fis h mea l, foJm rubber, hay, lubricating oil , lmseed oil, o r o ther ox1d1uble or dryin g oi ls, nap h· thJk ne, oa kum, oiled cl?1h ing, oilrd pJper, mle d textil es. pamr, maw, sawdus t, wood shJv ings. o r ,•egr1.1ble mis.

1 Flammable liquid s (s uch as gasoline, krrosenr, so h·rnts. and light fuels ), liquefied pt'rroleum gJs, sulfur, and fine l)' di vided metals cannot be sro red o n the sa me prcm • isrs whne bulk :immonium nitrate 1s stored .

11.12-C HOMELAND SECURITY ME ASU RE S INVO LVIN G AMMONIUM NIT RAT E FERTILI ZER

$1J1ce 9-11. la w enforcement agencie s h:i,·e taken measures to reduce the potemfa l for the ,nmi nal mi suse of ammon ium nitrate fe r11h zer that 1s sto red, handled , o r tra nspo r1ed v,uhin their jurisdictions. Given th e uno rth odox wa ys m whJCh terrorists ma y ob tain a nd u>(' rhe ferti lizer. l.iw enforceme nt :igencies mu s1 be provided with su fficirm info rmat io n to 3ccou nt for bulk quantities of ammonium nitrate potrnt iallr av:ii lablc to terrori s ts

11-1ihm iheir junsd ic rions. Because ammonium nit ra te ca n be used hr te rrorists, feruhze r com panies must notify the Depanmem of Homeland Security when 1hey possess I ton 1o. 91 1) or mor e of agricu ltural material.

DHS and the U.S. Coast Guard (USCG ) have been especially sensi t iv e to the entry of bulk quanllllt'S of ammonium nitrate fertilize r at the nation's pom. At 49 C.F.R. S 176.415 Jnd 33 C.F. R. § 126.28, respecti\'ely, DHS .ind USCG require the owne r o r oper.uor of a 11 :1trrcraf1 loJded with hulk quan1ities of ammonium nitr:it r, o r a watercraft on which bul k quant ities a re imended to be loaded, to recdve w rin en permissi on from th e Cap tain of the Po rt before the load ing o r unloading operations occur. The permit stipulates that iheowne r or operJtor must load or unload the ammonium nit rat e at a facility r emoved fro m congemd areas or high -v a lu e or high -ha za rd ind ustria l fac1h1i es and at whJCh an Jbunda nce of water for fi refighting purposes is available . DHS a lso req u ires the water- mft to be moored bow to seawa rd and ma imamed m a mobile statu s hr the presrnce of rngs and th e re.idmess of its engines so it may pas s unres tri ct ed to oprn wa t er in th e evem of3neme rge11q·.

SOLVED EXERCISE 11 .3

-. , os~ ~ regu1a1011 at 29 CF R §1 910 109 st1ou lates th;it ammonium rwate fen:1h1er cannot Ofdnar,ly be r.nd 1n the Scll'1e lx,- ld ng with either sulfur or finely dM ded metal'S What 1s the mO\t hke!/ rea~o'l OSHA '~-·~ammon um fll!rate to be segregated from these substa nces? »lution: Ammon ,um nitrate 1s cnem ,call y 1nco mpatio'e wnh both elemental su lfur and finely d,·11ded !'!'eta's '.',"hf1e , oom!toan1gr1otonso,me , the resu lt1 ngcombust1onreact,ons arev1olemand0<curatexplos,ve ••:11 TI-tie re arno ns are deno:e d as fo llows . whe re metall>e magnesium has been selected as the combust,ble ~,tal

S.5, • 32 •11--1~ .... oj'.S\ - eSO;g, • c·~0:9' CJ'1,0,9 ]P,.!] f,'T'mcn,u~ r 'JJ\~ Su''•' a d •, :-C•(lNl ~-o•

Ci~.! "'~1t lkely requires t/'le seg re ga tion oi am mon um nitrate from sulfur and foie ly drded me:a's to 1ec..1::e Oit '1''\dle the 111~ of f, re and e,pios,on

Chapter 11 Chem istry of Some Oxi d izer s 45 1

r

htuva!e nt chrom ium Any

compoundconta in1n9 thr om1um1nthe+6 ox idation state

At J.3 C. F. R. S 126 .l S, DHS h.1s prnmulgarcd rrguL111ons rrl.111ng 10 thr ~1ur.1ge. sto wrng, loJdmg, unlo.idmg, d1schJrgmg, and tran spon.mon of bulk hJndJlllg, of ammonium mrr a rc- a t J w:nafront f.1c1 l11 y. Thesr n·g11Li11om are ar qu.i.nllllts fo llo,, s: p, aphra~d~

• L~; 3 ~:o:r:l~~~ii;

1 ~;r:~1e of thC' a rnm omum n11r,11r mus t br mJrhd on the OUflldt

• ~;;:: 5 1i1~:ts/s: 3

3 :~~:{[::~t ;~:~tte~~J~c~~~'.hr stor.1ge of ammonium nitrate~

• ~~:~r;:;::, :!~,:t:~~1i;1:,~;t~~~re~~:~ 1:;u;::1i:~;s~·,.d1~w1ce from rl~rric ~1nnL The am monium nurare musr be S(' paraced b)' a fire -n•s1s111•r wall orb dis JC lease 30 fee t (9 m ) from organic ma1.cr1als or o rh c-r subst:inces ch!/coul~ nct ~ conrammau on, suc h a~ fla mmable liquids, _combus11ble liquids, corrosi\'e Ii C11at me1all1c chloraces. me ral!JC permanganaces. finely dJ\'lded metal s, caus ric soda quid.I, co.i i. sulfur, con on, coal, fats, fis h otls, or 1•egrr:ible o il s. , chu. Ammonium nit rate ~ usr bt' srorr1 on a clean wooden or concrete floor or on lkn 01•<.'r a clean floor. When :immonium nitrat e 1s stored on a concrrte floor. : mus t first be co11errd 111t h a moisture barr ir r suc h as a polyet hylen(.' sher t 0 ; a: Ju~ l.i mmared paper. P tic Any spilled ammo111 um mt rate mu st br promp_rl y and thoroughly deaned up and removed from t.he waterfront facility. If ammomurn nmare ha s remained in 11 i1h a wooden floo r for an y leng ch of time, the floor mu se be sc rubbed wirh~: and all spilled m:11 wa l muse be thoroug hl y di sso lved and flu shed away. An abundance of wat er for fi re f,gh cmg must be readily a11:1ibb le . Open drams, trap s, pm . or pockr cs that co uld be filled with molttn ammonaua nitrate in rhe e1·ent of a fire must be eliminated or plu gg<.' d.

11 . 13 OXIDIZING CH ROM IUM COMPOUNDS Chrom1u m-co nra 1n1ng com pound ~ m which the chromium assumes the+6 oxid:mon stair are call ed oxidizing chromium compound s. The +6 oxidation s1::ite of ch romi um is W hex::ival enr chromi um ion. The oxidizing chromium compounds :ire also callrd he.ovalent chromium compounds. The y are metallic chromates, m<.'tal11c dichromates chrorruum trioxide, and chromi um oxychlonde. '

The metallic chrom::ites an d met::illic dich romace s :ire compounds composed of aJIOSI· ti_,e aon and th e chromate .aon (CrOi ·) and di chromate ion (Cr1O~- ). re~pecrivel y. Pow- sJUm chromate :ind po1:1ss111m dichrom:1.te are spt·cific examples. Their chemical formUW Jre K2Cr04 an d K2Cr20·, res pectivel}'.

Th e o xidizing chromium compounds a re manufactured for comme rcia l use from ch ro mite ore. whic~ we represen t here as FcCr1 0 4 • For ex ample, co produce potassium dtchromate the ore 1s first 11(.'at rd at kiln rcmper:irures with pot:iss ium c:irbona rc 10 pro- duce po1Jss1 um chroma te as follows:

-H l( r~04(11 - KK2C01(il + 70 .:f~J ----------. 8K,C r0,11) .,.. 2Fc , 0 1(s) + SCOi(tl 1 lmn le 1' .. 1,,,,umca,t,,,n,1~ (1,H,·n 1'.-i.1,,:un1,hrnmJI(" 1n,n1 l;l1 0,1dc c.t,,,11 ...

Pora srnun d1chroma te 1s dll'n produced by rhc r<.' JCtio n of sulfu rJC :icid with porass1Ulll ch rom;1te.

2K:l rO ,/llql 11 2so 1raqJ l',,1J OUPllch, ra,t, \uUunc.1,11 l',,1.",1u111J,chrwnJlc

452 Chapte r 11 Chemistry of Some Ox id ize rs

p,) tJssnun chrom ate m;1y be produc ed from po1::i ss1 um di chromJte, and 1•1cc vers:1 . by ;tieri ng rh e pH cond1uon s as follo\1 s:

K: Cr20;(aq) • 2KU ll !aq/ • 2K: Cr0~1 01/J 11 _: 0 (/l

2 K,Cr0Jfilql + .:' ll Cl(aq) --- K:Cr ,O·lmf) - 1-f , 0 (/l

p,.,,: ,n, _im,,,~1,c 1/ "JrO<hknc ,1<1J l',,u.,"un1 dh.ht,,m.,tc \~.11.:-r • .? KC llwf)

The mcra ll1 c chroma tcs and metallic d1chromJt es are sohd yellow .1nd or,mge com- roun ds, re spec ti vel y. Co nsl•quemly, compounds such :is lea d chr o mat<.', s1romiurn ,hrorna te, and w 1c chromate hJre been use fu l as pigments m 1ndusm al p.:imt s. The o:,a - dizi ngchron11urn compounds ha1·e also been us<.'d to mJnufacture tcxule dres and presenc

11 ood an d lc.nh er. Th ey are also th e ma1or compon r nr s of chrome electroplating ba 1h

sciluuons. !kfore the i 990s. he xavalem chromium compounds commonl y were used as water-

trratmen r agents to pre1·en t the formation of a minera l sca le that oth erw ise would form m ihe ,irc ulaung waters use d m air cond1t1oners and mdusmal cooling 1owers. The produc- uo n of this sca le reduced the efficiency by which heat was trans·

loca ted at petro eum re menes, power plants, chem ical plants, ferrtd ro ch e wa

1 ter. Cof~ J;ng wwm often m h,g, "'""""' [ J I

Jnd elsewhere, where 1he y :ire used ro cool water by evaporar.ion. The rnosc readil y recogmz.able t)'pe of cooling tower is prob::ibl y ,,,.~ _,,,. .. , .. -~" .•. , ~" ..... : cooling rower s :ire also loc::it ed wherever large heating, venti la - - 110n, ,m d.a1r-cond 1taomng or refrigeration systems a rc needed. I The coolmg rower shown m Figure I 1.9 is a component of :in 31 r- cond1t1omng and venti lat ion system 1har cools a major hot el.

In 1he past, the waste ge nerated in connection with us ing hexa1·Jltnt chro mium -ba sed water-tre;nment agents at petroleum :=- refinwes, powe r plants, and chemical plants w::is of1en discharged D 1n10 ons1 te unlined surface impoundments. Rainwater caused rhe hexJ1alc m chromium compound ro see p inro ch e subsurface and co ntJrnmate the underl ying groundwater aquifer.

Ilic :ibsorption of a hex:ivalrnc chromium compound into the boor cJn cau se a number of hea lth ailments. In particular, ch e mhalJri on of th e dust or fin es of hex::ivalent chromium com- pounds has bee n linked with th e onset of lung cancer in humam. Thus, th es e co mpounds :ire ranked as human carcinogens br the mhJla1ion route of exposure.

Erm Brocko\'ic h, 1he heroine in the blockbuster mo\'ie of 1hc same name, alleged in th e film that the long-term consumption of wate r contaminated with elevated le ve ls of hexavalcnr chro- mium causes cancer :ind other health ailments. Ar the time of th<.' mo ~ic 's rcleJse m 2000, there was scant evidence to definitively link th ese hralth problems with the consumption of hexaval<.'tH chromm m-contaminated w::i 1er. Toda y, howe ver, scientiscs ha1·(.' dw e1·idence 1har ingestion of chis contaminant nor only causes the onset of stomach ulcers and sto mach :ind in1 cs tinal cancers bu r rnJ.)' also damage the kidneys :ind liver.5

FIGURE 11 .9 Cool,ng 1owers ofte n are mass,~e wate,- rewculat,on ruucturei. used to 1emove heat fro m me water by contact.ng th e flu,d with <1<r A comme rcial productconta•n,ng a heXc1va !en t ch1om1umcomoou nd fc rme,ly was added to the water in ,ndusma! cool,n g to,..,e~ to prevent 1he fo rmat,on of a mmeral scie on grates and ottier towe r components Because hexa, a- lent chromi um 1s a human caw no gen, EPA promulgated regulat,on~at 40C FR §749 68thatnfN1proh ,o.tthe use olacompound con ta,n,ng hfo ~ava!l'fltchrom rum for th,~puroose ((o,xt('S)'olfvgme~ )

:i~•r of En, 1ronmcn 1a! Heal th HH ,lrd A;sc11mcn 1, E, 1dr"ct 011 th , Drvtlopmtn lJ/ a•rd R ,produc/,0 11 Tu r ic- f Ch, o,,,11m, / l/r,;J1.•J/t111 Com/io ,mds} 1Ca lifo rmJ EnrnonmcniJ I Pro r.-.:t ,o n Agrnn\ 2009).

Chapter 1' Ch emirt ry of Some Oxid ize rs 4 53

I

1

//'/ 1 I / I I. I

f!/ 454

Pot•»•um dlthromat• EPA hJ s Set J m n:irnum rnm.umn .rnr k1t·I o t JOO µg/L of fot:il chrom

11 ;m •r. EPA h.1 s al~ o used the.' :iurhora y of 1hr To'(JC Subsr,mces Co ntrol A,:~: 1; 1 d~ US(' of "-ll c.'r-trC':Hmrnr .1g t"nls conr.u mng hrx;11•alcn c chromium m hearing l 0 lub11 ~ and ;ur-conJmonmg ;1nd rdriger.Hion S} )tcms. This ban .11ms ro rrducr 0;n(' 11 ;'C'1Jtil.i¾I po rr nr1.d of l' .-..:posmg md 1v1du:.1/s IO their :ur enms1ons. ninafttbe

A1 40 C.F.R. 5749.68, FPr\ rcquirC's d1 s1r1burors to labe l contamrr s of h ~::~:~.~;~ :~':l;;~-~:~;:rmenr agenrs d1~1nbwc-d rn comm C' rce and mtrndrd fo r u;~

1 ::

This product contains hexava/ent chromium . Inhalation of hexavalent chromium air emissions increases the ri sk of

lung cancer. Federal law prohibits use of this substance in comfort cooling towers, which are towers that are open water•recirculation devices and that are dedicated exclu-

sively to, and are an integral part of, heating, ventilation air conditioning, or refrigeration systems. ·

EPA req ui res th is label 10 I,(' J ffix ed ro the conramrrs wit h such cons pi cuous ness tha dit warnrng stJtemenr is read and understood by thC' ordinJr)' rndi vidua l under custo

1

condHJons of purcha se ;rnd use. llUry

11 .13 -A POTASS IU M OICHROMATE Pora ssrum dichromJ le 1s frequently used commercially as :1 strong ox1d1ze r; fo r enmpk, 1c 1s a component of rhe bJ rh solutions usC'd for ch romrum p lating. Whc- n hc-a ted, potas- st um dichromate decomposes to gene-rare ox ygc- n as follows :

Bec:iuse ir 1s a s1rong oxid izer, potass ru m dic hromare is che rrn ca l/ y rnco mpauble 1orli man y orhc-r substa nces. For example-, po1asmun Jrc hro ma tC' an d hydrochloric acrd rm ro produce chlorine.

K:Cr20 · laqJ - l -lH Cl (aq) ---,. 2CrC l 3( {1{f) .. 2KCUaqJ t 7H20 (/) + 3Cl~) Pou,, ,umd ,rltrom.ire lhd nx hl onc .lm! ChmmKr hJvnde POIJ,"um , h/,;,n<l~ \\ Jler <lbn'

The eme rgency inciden ts 111\'0 h·ing 1h1s ha za rdous ma teria l genc- r.:tll y are assocfa tc-d 111th ir s tendency to oxidize the substances with whic h it ma kes co nr:i ct.

11 .1 3-8 CHROMIUM TRIOXIDE The acids associa ted wuh the meia Hic chroma res a nd morgan ic dic hroma tcs cXJJI only in aqueous sol urrn ns, but when the wa ter is eva po ra ted fr o m rh em, a compound formally called chromium / VI) oxide remarns . This :1 nh )' drou s co mpoun d is ~lso known as chromium trioxide, chromium a nhydri de , a nd chro mi c acid . Je s chemtCJl formulJ is C rO, . . Chromium moxrde is ;1 red so/rd preparc-d indus rri:1H y by .i dd ing co nctn rraied su!fu.

nc aci d to a s.irur.ircd sohmon of potass ium dic hrom:it e.

-. 2K I/S0 Jraq! + PotJ, , 1~tl\ h1,ulfJI~

11~0 ({) + 2Cr0j.(J) (hronuu!II U')Ol#

Ch ap t er 11 Chem istry of Some Ox id ize rs

Ch r<'r11uin1 moxidc ,s usrd for mrIJI 1re,1t mrm procesr.es such as ch rome pla1mg, copper ,inppuig, alt1m1nu111 a nodlllng. and corrosion prt\'tntion.

11.13.C CHROMIUM OXYCHLORIDE CJ, 1,1111111 oxychforidr ts a da rk red !1qu1d 1h:1.t fo rm s \ 1 hen a nuxtu rt of conct·nrra ctd

~:,. hl ortc aci d and sulfuric ac id IS added IO a SJtu ra1rd solun on o f pota ss ium dic hro - ~;J[r. It 1s also CJIIC'd chromyl chl orrd C', and its chrm1ca l formu la 1s CrO! CI :,

Chromium ox}chlondt 1s no r onl y an ox1d1ztr. It also reacts 1ery violrnt ly 11 1, h w.i rer, forn 11 ng chrormum( JI /) ch londl', chrom ic :1.ci d, ,m d chlorine.

(,(r0:Cl2/// ,.. ·Ul .? 0 (/l _,. 2CrClt ((1ql -+- 4 1-1 :C rOJ(uql 3Cl:1 1;) C~rom1ulTL( llllchl onJo ChrotnfflM.ld

ln ,his 1ns1;1ncl', the chro mrc ,wd is the Mtru rM chromic aci d (nor ch romium tnox1de ), 11

hic h t XJ>IS onl}' m solm1on.

11 ,13-D AMMONIUM DICHROMATE Ammonium d1chromat ~ is an orange so li d used as a compo nent of cert ai n pyro tec hm cs. Ir is ~/so u;cd ro dye fabri cs a nd ro :i her th t tex1ure of animal hides du rmg rhe produw on of /el thtr. hs chemical formula 1s (l\l-l.;)2Cr 20 -. Wh r n hea ted, amm omu m d1chr oma1 c drcomposesio fo rm nitroge n.

11 .13-E WORKPLACE REGULATIONS INVOLVING THE OXIDIZING CHROMIUM CO MPOUNDS Whtn used in the work pla ce, OSHA rl'qulfts tmploytrs to limi r l' mpl oyec expo5ure to a hm1·ale nt chrom ium inh.i bt ion conce ntration of 5 µg/ml, :wer.1.gc-d over :m 8-hour wo rkd.J }',

11.13-F TRANSPORTING THE OXIDIZING CHROMIUM CO MPOUN DS \ihen shippe rs offrr au oxid izi ng chro miu m co mpound fo r transportation. DOT rcq uirC's rhtm to dc-scnbe it as show n in Tabl e 11. 15 o n an acco mpan ying shippi ng pape r. DOT 1/w req uires ship pers .i nd ca rric-rs ro compl y wirh a ll appli c.iblc !a bd mg, mark ing, :md p/Jcard1ng rrqu ire mc-nts.

ifriiilifi OXIOIZING CH ROMIU M COMPOUND

Chromi c acid

Shipping Desrn pt1ons o f the 0 1ud1Z1ng Chro mium Co mpo und s

I SHIPPING DESCRIPTION UN1755, Chromic ad d solution, 8, PG ll o, UN17SS, Chromic add solution, 8, PG Ill

~um~e UN2720, Chromium nitrate, 5 1, PG Ill ~ th lo-rid- ,--+-U-Nl_75_a---'C-h,o- m- ,,-m-o~- ,-hl-~ ~ld-,, ~a ~PG~,------

Ch1om,umtriox1d _ _:, ___ -i-=-UN'-l --''6"-3, -'-Ch---',o-m_i, _m _u l_o,_id_, . _ao~hy_d,_o,_••-' ·-'• -" -'• '- G_II __ _ Chromoiulfur ic acrd UN2240, Chromosulfu ric ac id, 8, PG I

Chromiu m oxychtor ldt

Chapter 11 Chemistry of Som e Oxid iz ers 4 5 5

ill I I

.,

I I I 1

i, / 11 ,

I I ' ''I

I

1/

Ammonium dkh,om•lf

Potns ium

11 .14 SODIUM PERMANGANATE AND POTASSIUM PERMANGANATE

Meta/l,c permang<111a1es arc compounds in which m,111 g.111 cse assumes the +? OJC • sta r~· - Tht"r art" gl·nrral!y encountrr('d as dar k \Wier. mdcsccnt crys r,1 !s. There ar{' t¥.·1d.i.~ mercially 1mporrant mrmbe rs of th ts class of comp~unds: sod ium, pe rmangJna ie ando ~ sium permang.mJte. Their chr micJI formulas are -...: .1 \ l n0 -1 a nd K\l n0 4 , resP«'tn el}~

11 .14-A PRODUCTION AND COMM ERC IAL USES The metallic perman ganates arc ma nufoccurcd from ma nganese ore contain · 70 % manganese dioxide. As th e ore 1s heated wuh either sodium hydroxide or mg about hydro xide, th e mangan c-se und ergoes ox1da1ton to produce the co rrespon ding alk~a»i taai mang.1~.He. For examp lr, potass 111m manga nate 1s formed from the ore and poi~s~ hydroxid e. 11.tri

2,\ l nO, r~J + ~KO H f/) ,- 0 :IC?J - · 2K~ ~fo0-1(l ) - 2Hi 0 /g ) \ t111i;.1~\eJ1011Jc l'uu"1urnh)Jnl\1ck (h ~e•n f',1u,-1u mnu opn;uc Watrr

solut ion of the porassium mang:rnare is th en ox1di u d dcctro lytica l/ y to prod uce pota~ s1umpc-rmangan arc .

2K 21\ l nU-1( oq) - 2Hz0 I/J - • 2K,\l n0 -1( aq) + 2KO H (t1q) + lli(f) P,,1J1,1urn IIIJfl,JflJ[l" \~ J r,, l ',,tJ"IUlll r•:nuJfl~Jn.11,· !'01 .1--,u m h),lro .. ,k H) lh'fQ

The potassium permang.ma1e is tht'n se paraied from t he po tassiu m hydroxi de br crystal lization.

You ma y be familia r wi th dilute so lution s of sod ium pc-r manga nate an d pormWII permanganatc thac are used pharmaceutically to cure derma titis having a bacterial or fu 12- gal origin (~athlete's foor" ), Th ese sa me so lu uons are used to trea t fis h dise ases. Jbr concentratcd solutions are usc-d !O remo1·e objectio nable matte r from chemica l and bto, log ical process wa ste s by oxidation. The effluen t gases fro m ma ny in dustrial sources an also often elim inared or reduced in concentration throug h red ox rea ctions im·ol11ng tbt use of sodium permanganate or pot;1ss iu m pe rm:rngana rc.-.

Porassmm permanga nate ha s al so been used ro co ntrol the infestation of the qwgp mussel (Section 11.8-A) in warerw:i ys. Po tas sium perma ngana te solutio ns are inj ecredmro pipes where the mus sels congrega te and th t'rt" by di sturl> 1he now of warcr in the intakeJnJ discharge sys tems. The oxidizing agent kills 1he pesky mu sse ls.

11.14-B TRANSPORTING METALLIC PE RMANGANATES Wht'n shippe rs offer a me1al/ic permanga nat e for trnnspo rt ario n, DOT requ ires them ro id entify it as show n in Table 11.1 6 on an :iccompa nying shippi ng paper. When shippm offer a metallic permangana te no r li sted in Tab le J l .1 6 fo r trans portat ion, DOT requires th em t~ id ent1~ rhecompound gene rically on 1hc.- shipping pape r as "UN 1482, Pu mang.,· nates, morgamc, n.o.s., 5.1 , PG II ," "UN l 482, Permanga nates, inorga nic, n. o. s., S.I , PG Ill," or ~uNJ 2 l 4, Pr rmanganates, inorganic, aqueous solution, n.o.s., 5.1 , PGII.' DOT ?]so requires s~ippers to enter 1he name of rhe specific co mpo und parent he ticall pn ihc sht ppmg descn ptJOn. It also req111re s shippe rs and carrie rs ro co mply wirh all labeflllg, markmg, and placard ing req uirements.

11 .15 METALLIC NITRITES AND METALLIC NITRATES .\1 ctalli_c nitrites and mt'~allic nir r,Hes arc co mpound s co mposed of metallic ions ~nd tbr nitrtte ion {NO~) and nir ratc 10 11 :\O i ). res pcc ti1·ely. In th ese co mp oun ds, the nirrogtll atom ass umes ox ida tion numbe rs of +3 and +5, respt"c rivcl y. 1\,lerallrc nit r

3 rrs 456 Chapter 11 Chem istry of Some Ox idize rs

jtl:lliilfl ~lfl-"LUC PE MA NGANATE

a,r,.-m perm.i~anate

Clc,umPerman~nate

~ ermangana t e

SC{lumPe~a nganate

z,r,cperm anganate

Shipping Descn pt1ons o f the Meta lli c P@rmanganates

SHIPPIN G DESCRIPTION

~ N1 448, Bar, um permanganatt', S 1, (6 1). PG II (Po,son)

UN1456, Ca1< 1um p,rmangana1e, 5 1, PG II

UN1 490. Pot,m1u m pe rm anga na tt', 5 1, PG II

t uN1So1 Sod ,um pt'fmanganatt', 5 1, PG II UN151S, Zincpt>rmanganat,, 51 , PGII

Jre ,spcci,1ll }' commo n ox id ize rs; for exam pl e, sod ium nitrate and potass mm mtrate are rornmon compo nent s of blas ting age nts and ot her explosives. Sel'c- ral me1a lh c nit rates arc Jlso used to prod uce color in act iv ated signali ng Oa rcs.

For decades, sodium mrrite and sodium mtrat e have bet"n ad ded 10 mw meat (bacon . hot dogs, and luncheo n mea ts), poultry, and fis h to fix thei r color and inh 1b1c th e growt h of Clos trrdmm bo1ulm11m, the bac1erial spo res thar cause bo1u hsm. This use was limited bi ih e U.S . FooJ and Drug Adm imstrat ion when scic-nris ts demons tra ted rh:u nu.r ites ca n rroduce carcinogenic N-mt rosa mm es in the stomac h. The nimr cs r('aCt wi1h stomac h acid ro fo rm mtrou s aci d, which in rum re.:icts wi th the pro1ei ns in meat 10 form N-mtrosa - rnmcs {Sectio n 13.8- 8 ), organic compo un ds containi ng the gro up of atom s - N- N= O. Loll' co ncentr:iuons of N-ni1ro s:1n 11 nes have been iden tJ fied in smoked fis h, cured mea t, ~m. and chee se. Beca use res1 an imal s exposed to N- nitrosami nes deve lop ca nce r, .\'• mtro samme s arc rcg;1rded as probable hum:m ca rci noge ns.

When ind 1l'idua ls ingrst or inh ale sodi um nimt e or sodi um nim1t e in excess, 1hey arc l,kd)· to suffer fro m methcmoglobinemia (St"C tio n 10. 14 -8 ). In ra re mstance s, rh1 s a 1l111 r m c~n also be comracted by abso rpt 10n through the skm , e.g., from ex posure to molt en sodiu m nnrite or sodium niir are.

11.1S·A SOME PROPERTIES OF METALLIC NITRITES .\l (tJ lhc nitri tes can ac t as ei th er oxidizing age nt s or reducing agents. They are oxidized 10 metallic nitrntes and rc- du ced to ni tric oxide (NO) as fo ll ows:

:-l-1.'-:0 ~1mn -- Na20 2(aq) + H20 U1 - N .1i\'0 1(aq \ + 2N :iO H (oq) SJ,uu11>1trn , ~('<l 1u 111pc ro\J<.k \\ a1er SnJ1 u1 11t1 iJ10 ,1 Jc

I >J,"rn n,u ,•~ ~o.h u1 11 \u lli1 r ll _,d rod1 lonc~ ,J 2N .1C l(oq) + 2NO(g l + H; U (/J

';o ,h uu11u lfru c \,,J1um ch lon,lc \ nm:n., de \1 ,!tcr

Although me talli c nitn tes ge nera ll y are sr:ible to he:i r, they decompose :It r le \' ared tem per:nures, For example, sodium nit rite decomposes as fo ll ows:

2N.iN0 1( 1) - • Na10 ( 1) + N0~11:) NO(.~ l ~oJ tu m mini ~

ll, 15,B SOME PROPERTIES OF META LLIC NI TR ATES .\letall 1c n11 ra tes rrac t on ly as oxidiz in g age nt s. In rhe presence of acids, th ey arc conve n ed to nir ric oxi de, nitrogen dioxide, or ammo nia . This chc-mical bcha vio r is exe mpl ific-d by tht' chemi c~I rcactJon~ of zinc with concenira ted nitric aci d noted in SeC1 io n 8.8-A.

Sod ium nitrit e

Sodium

Chapter 11 Chemistry of Some Oxid izers 457

r

I' I

I I I I I I

\\'' hen hl',irt:d , mc1.1.ll1c mrr.w:s decompo:.t· m the fo llo wmg wa >·s:

Thr albl 1 mer:d m trates decompose ro form !he respC'ct1vt• alkali metal nitrne ox) grn . For ex:.1mple. sodmm rn r rJ tl' therm.1.ll y decompo ses to form oxygen.

2,,; .:i:-: 0 1rq _. 2;,J,1NO:r11 + 0 ~(.111

:\11r.1tes of the no ble me tals decompme to produce th e metal, nit rogen dio -d oxy~en. For ex:imple, silve r ni trate thermally deco mposes to produce sd vet~

1 ~ ar.1

d1ox 1de, and oxygen.

::!Ag\ ' 01(1) __. :!Ag(') ... ~N0 2f1) - 0 2ft; ) <;,her

.\!era! mrr:1 tes other than the alkali metal nitrates and the noble metal nitrates d«ornflOlt m fo rm th e respecme metallic o,udc-, mtrogen dioxide, and oxrgrn: For rxamplc,lcadl!Jl nitntc- thrrmall r deco mposes to produce lrad ox ide, rutrogrn dioXJde, and oxygen.

::! PhlN0 1)z( 11 - • ::! Ph0 /f ) "1" + 0 2(1n

11 .1S-C FDA REGULATIONS INVOLVING SODIUM NITRITE AND SODIUM NITRATE

At 21 C.F.R. §§ 172. l iO and 172.175, FDA publi shes maximum permissible concentra. tions of sodium nimt C' and/or sodium m1rat e in arrain foods intended fo r ust as fol10'A1:

As a color fixative in smoked, cured tuna fi sh products so that the level of sodium nitnte does not exceed 10 pans pe r million in th e finished product As a preservarivr and color fixati ve , with or without sodium nitrate, in smoked, CtJnd sa bl efis h, smoked. cured salmon, and smoked, cured shad so rh :ic the level of sodi1111 nitr ite does not exceed 200 parts per million and rh e level of sodium nitrate docs oor exceed 500 pamper million in the fini shed product As a preservarh·e and color fix :ni ve, with sodium nitra1e, in meat-curing prepam1om for the home-c uring of meat and meat produc1s (including poultry and wild gamti with directions for use that limit rhe amount of sodi um nitrite to not more 1h.1.n200 parts per milli on in th e finished meat product, and the amount of sodium nimucto nor more than 500 part s per million in !he finished meat product

FDA also req ui res the finished product to be labeled with the name of the addi1we, 11S concentration, direcuons for use, and th e statement "Keep Out of 1he Rrach of Childun.·

11 .1 S-D TRANSPORT ING METALLIC NITRITES AND NITRATES When shippers offer :1 metallic nitritr or met;1ll 1c nitrate for transportation, DOT rNjUll'tS them ro describe th e appropnare substan ce on an accompanying shipping pa prr. Somt exampl es for several represe nrar ive metallic nirrim and nitrates are listed in Ta ble I 1.17, \'(

1hen shippers offer ro transport :l meta llic nitrate or metallic nitrite that is not lisrtdal 49 C.F.R. Sl72.l01 , DOT requires them ro identify 1he co mpound generi c;1ll y and to rn trr the name of th e spmfic compo und parenthetica lly 1n the shipping description. DOT also requires shippers and ea rn ers ro complr wi1h all applicablr labe lin g, ma rking,aM pbcarding requirem en ts.

When carr iers transport a pota ss ium nitrate and sodium nitrate mixtu re by hi ghway or rail, DOT requ ires th em to d1sp la r the n;Hne on rwo opposing sides of the pac kaging.

POTASSIUM NITRATE AND SOD IUM NITRATE MIXTURE

458 Chapter 11 Chemistry of Some Ox idizers

- Sh1pp1n9 Descnpt,on s of Some Re p~se nta tJve Meta lh c Nltntu a nd N1tro11 t H ,-4ETALUCNITRITEOR~ TE SHIPPING DES CRIPTION Alurmnum~•~ s,numn1tr ate

c~:(,~m nitrate

tudn1trate

N·C~e -

-------r-UN1438, Aluminu m nitr~ S 1, UN\ 438, PG I~

, UN1446, B,m um nitr ate, S 1. (6 1), PG ll (Po i~onl

~ ~ 1454, Calclum M rate, 51,PG II~

_!. UN146~ Lead nitr at~. 5 1, (6 1), PG II (Po!sonl UN2726, Nickel nitrite, 5 1, PG 1(1

Po~ n1tra1_, ___ I UN1486, Potass ium nitrat0 1,_PG_ I_II _

Potm~ rlte UN1488, Pota111um nitr,te, S 1, PG n 5

1 1v, rn ltrate _ j UN1493, 511vern ,tratt, 51 ~ ~Ill~ ------~ UN \ 498, Sod ium nitrate, 5.1 , PG III So(lu~ ____ UN1~00.Sod,umn,tr1te,Sl,PGII

z,ncnitrate UN1514, Zlncnitratt, 5 \, PG l1

11.16 METALLIC PEROX IDES AND SUPEROXIDES The compounds composed of metallic ions and p<:rox1de ions [0 ~- or t--0- 0 - 1> 1 are CJl lrd mera/1,c peroxides, and th e compounds composc-d of metallic io ns and superox1de ion> [0 .: or (-0 - 0 - r] are called meta/be rnperox1des. The commercially important meiJlhc peroxides are co mpounds that contain an alkali metal 1011 or an alkaline earth 111ml 1011 . Ex;im pl es are sodium p<:rox1de ;ind banum p<:roxide, whose chemical fo rmula s are \' J20 2 and ll.10 2, respectively. There is onlr one commerci:1\ly impor1ant mrtallic supe rox1de: pot::issium sup<:ro xide . hs chc-mic::i l formu la 1s K0 2•

11.1 6-A PROPERTIES OF METALL IC PEROXIDES The metallic peroxides are therma ll y unmble, highl y reactive compounds. When heated, the y decompose to the corresponding metallic oxidr and oxygen.

2Na20 2(1l _____, 21\',110 ( ,) + 0 2! g) So<11u m 1x:ro " Jc SoJ1 um o11<k o ,, i:cn

2(3301(5) - • ::!ll.10(l l 1 · 0 ~(t; J B;mum(,(rm 1Jc l! Jn umo ,,Jc l h: gc n

They also ox1d1ze finely divided combustible metals like- powdered aluminum.

~Al{1 ) T JN;1102(fl -+- 3Hz0 (/ J - Al ~OJ< ,) + 6N ~10H11) \l" 111 mum "W, um l)(f011J~ \ \mu Alu1111num n\1d<' So.hum h)dro\l J,

The metalli c pero xides are also wate r-reacti ve substances. 2N,120 2(s / + 2H20 U) __. •\NaO H(,uf) - 0 2(1."l

S0<hu m ix: ro " dc \\ utrr S,xl1u roh 1Jnn 1d , lh )~-.:n

To pre\'ent metal lic peroxides from ab~orbing atmospheric m01s1ure, they should be stored in right!)' closed, mois1ure-proof contamers.

ll .16-B PROPERTIES OF METALLIC SUPEROXID ES lhr meta llic superoxides arc rhermaUy unstable, warer-re'Jctive. compounds. Their water reac- 111·1ry is put to use in a type of chemical oxygen ge nerator that provides breathable oxyge n to

Sodium peroxld1

t Barium

p1roxld1

Pot11sium s up1roxld1

Chapter 11 Chem lrtry of Some Oxidizers

I

4 59

r

460

Sod ium persulfate

ffrjifMI METALLIC PEROXIDE OR METALLIC SUPEROXIDE

Bar 1umperox1de

Ca lciu m peroude

l •t'1 iumperox 1de

Magnes,umperox,d e

Potass ,u m pero .,de

Potau1um sup1uo x1de

Sod1 um perox 1de

Sod ium superox1de

Shipping Descnpt1ons of Some Represe ntative Met.i lhc Peroxides and Supe rox,des

SHIPPING DESCRIPTION

UN1449, Ba rium perox ,de, 51,(61), PG U(P~

UN1 457, Ca!c,um pe roxide, 5 1, PG II -----

UN1472, Lith+umperOl1de, S 1, PGII ----

UN1476, Magnesium pe roxide, 5 1, PG 11 ---- _. UN1 491 , Potarn um perox1de, 5 1, P~

UN 2466, Potan1um superoxide, S

UN1504. Sod iu m peroxide, 51, PGI ---- UN2547, Sod ium supero11.1de, 5 1, PG 111

its u~ r for .:i period ranging from 51111nuti.'S to SC\'era l hours. The moistu re andcarbon d10t· idc m rhe user's breath are :1bsorlx-d by potassium superoxidc containrd in a canistet Tut chemica l acuon of the moisture :md the suJ)('roxidc generat es oxygen. The oxygen rntm, breathmg bag for subsequent inh.1bt10n , :rnd the exhaled breath repeals the cycle.

!2 K0;(1) -1- 6H~O(g) - , 12KOH(sl -r- 90~(g) l'nra,,,um ,uf<m"J' \\ ~In

l\11J"IUIIIO\!JC Cdrhnnth \)\IJC f'c>ld,\IUnl<.~1 1'<.lll,IIC

11 .16-C TRANSPORTING METALLIC PEROXIDES AND SUPEROXIDES DOT requ ir es shippers who offer a met.il lic peroxide or supero xi de for tra nspon.i tionto rdent 1fy the rele\'3nt submnce on an .iccomp.in)'ing shipping pape r. Some examplaflX sever.ii rep rese ntar ive nmaltic pero xides and sup eroxides are listed in T.ible 11.1 8. Whtn shi ppers offer a metallic peroxide or its so lutions rha! are 1101 l1 sred at 49 C.F.R. 172. 101, DOT rrqu ires them to id.:- nt 1fy the compounds or solutions generically and to list thtu sprof1c names parenthetica ll y. DOT requ ires shippers and ca rrie rs ro comply with all appl 1c.:a ble labeling, ma rking, and placardi ng requirernems.

11 .17 POTASSIUM PERSULFATE AND SODIUM PERSULFATE

,\oletall1c pcrsulfotes arc compo und s co mposed of a merallic ion and the persu lfa 1e till. also ~ailed t~e peroxyd 1sulfo1c ion (S~ O~ ). T he pt"rsulfot e ion is :il so known as rhtpcr· oxyd1su/fa1e 1011. It ha s the followmg Lewis stru cture:

r o a ' l" o-o i uj

Tw o cx:imp!cs of met::illi c pe rs ulfa 1es are potassi um persulfot e ;ind sodi um persu!falt, whose clwrn1c,1I formul:l s :ire K.:5!0 g and ,'\,1/ )~0 ~, res pectively. They arr white sofid;.

Chapter 11 Chemistry of Some Ox idizers

Shipping Otou np tions o f M@talltc Pt>"'ullat H

"4{TAlliCPERSULFATE rot~iilurn persulfa te

soourn Persu lfc1te

SHIPPING DESCRIPTION

+ N1491 , Pota11 ,um per1u lfate, s~u UN 1505. Sod ,umpersulfate, S 1, PG Ill

11_17-A PROPERTIES AND COMMERCIAL USES The rllt'tallic persulfates are th_e s.:i hs of peroxyd1sulfuric ac id, whose chemica l formukl 1s 11 ,s,O~. The latte r sub srnn ce is a liquid prep ared by mixing 30% hydroge n peroxide and 9sr; sulfunc acid 111 a 1:3 rati o by ,olume.

.Hi.:SOJ(/) + H.: O!(ll - H.: S.: 0 8(/J + 21-110 (/ ) '\ullum;,,,.,.J ll ) J'<'bc n1"- n.>"J.: l'>.'nl\).Jisu1fun, '1<,J \\ ao,·r

Thi s highl y co rr os iv e solution is popular for seve r.ii tec hn ical a pplica tio ns. Most nora - hil 111 the computer-chip mduStr}', whf're it is known as piranha, perox yd isulfuri c acid 15 ·~sed co cl.:-an 1he wafe rs th at are processed into chips.

The metallic persulfotes .ire thermall y unstabl e. For exa mpl e, oxygen and sulfur diox ide arr gl' nerat cd whe n sodium pl'rsulfate is he.1 1ed.

~Na ,: S~O~(,) - 2N:l~0( JJ + -lS01(g l - 30~(g ) "W iumo ,,Jt Su ltur ,1, ,:, .,,Jc O, H-,:"

11.17•8 TRANSPORTING METALLIC PERSULFATES \ihm shippers offer pota ssi um persulfote or sodi um pt"rsulfare for transportation, DOT crqu 1rcs them to provide the relevant shipp ing description shown in T::ib le I 1.19 on an Jccompanying shipping p::iprr.

When shipp.:- rs offr r metallic persulfates oth er than potassi um persulfate or sodium pm ulfa1e and thm solutions for 1ranspona1ion, DOT requires th em 10 identify the sub- sunccs generical ly as ~uNJll 5, Persulfat es, inorganic, n.o. s., 5. I, PG Ill " or "UN32 I 6, Pmulfa1cs, inorg.inic, aqu eous so lution, n.o .s. , 5.1, PG 111 ." DOT also requires shippers to enter th.:- n:iml's of the specific compounds parenthetically in the shipping description, Jnd to affix an OXIDIZER label to their packaging. DOT also requires shi ppl'rs and car- nm to complr with all applicabl e labeling, marking, and placarding requiremen ts.

11.18 MATCHES M:udm are 1m ns usl'd to intentionally initiate fire when 1he mixture of substances con- tJinc d 111 their heads is rubbed against ::i hard surface. They have long served as one of the whcs t comm.:- rcia l products in which redo x react io ns were used to pro vide fire on drmand. hen today, th ey .ire th e most common items used to int entionally initiate fires.

The rwo types of matches shown in Fi gure 11 .10 are commercially popular. They are c•llcd strike-anywhere matches and safety matches. It is app rop ri:ue ro examine rhe chtrnistrr associa ted with their burning, especia ll y insofa r as th ese processes invol ve the u5r of oxidizers.

l1.1 B-A STRIKE-AN YWHERE MATCHES ~c head of a srr ike-a n)'\Vhl're m:itch co nsis ts of a mixtu re of 1e1raphosphorus trisulf1de i\'0 ca_lli:d phosphoru s sesquisulfidt) , sulfur, lead(IV ) oxide, powdered glass, and glue.

11 n11 xt ure is mou nt ed on :i small stick of wood and covered with paraffin wax.

strike-a nyw here mat ch • A ma tch with a bu ll s-eye head con sisting ofawh1te tip containing t@tra- phosphoru s trisu lfide that Is actuat@d by rubb ing it aga inst an abrasive strip

s,:ifety m,:,tch • A match desig ned to ign ite only when iu head is rub bed on a prepa red surface con - sisting of red phospho- rus and powder ed g lass

Chapt er 11 Chemistry of Some Oxi d izers 461

FICiU RE 11 .1 0 Th, wlr.,-•nr,-,,he!'fr-1•tch ,f'I {a)ign1~whentnl!Sur· faceof1t1,ma1chhud ,s ruobedaga.t'l:stahard surface Thes,i,tymatcn n (bl gnt~,,.,henthe surfaefof a matcnh,ad s W\lck aga,nsta surfa" cont.an1ng red ohospho- rus and POY.rdered gl,m Th,f1f'!tnangles tothe ri ghtofP<Khmatcn 10 ~trate tM comPOs-t1on ofthefuels, 1hesub- stal'lCestna1react to prov rdetheacw,a1,on energy. and th, rele~ant o, a ,rrr

/ P•S:i- powdere d gins, gl11e

~S, PbO1, glue

-r- Paralfinw u - Wood

Red phosphorus

'"'~~

Af'\ KCI03, SbiS :i, glut P1raffl nw 1• Cardboard

1,1

ibl

I Rtdpho19horu1+ KCIO,

+ friction

Tetraphosph oru s tr isu lfide ignites as the match head is struck against a hard surface. Tbt evolve d hear of combustion miwn es the comb ustion of the sulfur and wood.

P4S~(s) - 802(e) - • P40 10(s) + 3S0z(g ) T e1r:tpho:,pllofu 1 ln111ll1dc U\ )f<'n r ~ndpho,rh<)f\l, ,.k,,m.k- S111iur dlO~Kk

11 .18-B SAFETY MATCHES The acme compon r ms of a safe ty match com1st of a mixturr of antimony irisulfide, sul· fur, and pota ss ium chlorate, glued to a pi ece of ca rdboard. A safety ma rch ignit~ br mea ns of friction agains t a prepared su rface con sistin g of red phosphorus and powdmd gl:m. Th is surface is usuall )' on th e box, book, or ca rd . When the match head is ru bld on rhi s sur facr, th e hea t initia1es a redox rea ction as follows:

l6KC!Od1) .,. )~,(1) - · HlKCII J l + ~.tS01(g) 1•,~.u\1UIII chlorJIC Sulfu1 l'<>l.1>,mmc hlvnde S v!fu1J10 >1Jc

Th en, th e energy evoh·ed from th e ox idation of 1hc sulfur ignit es th e antimony trisu.1 6dt.

1.'.\ b!S ,f} ) + 90 !(0 - • 2Sh;U 1tg l t 65 0 118) ,\n11n11H1) 1mulfi,k l)\) f<n \nun•in> 1ncn1< Sul1 ur J1mnk

462 Chapte r 11 Chem ist ry of Some Ox idizers

iilhilE·I Sh1pp1ng D~u npt1ons of M.itch~s MATC_HE_S-:--=-:----t-,',--",--"',--IN:.:G.:.OE:cSC:::R::_>n:::10:::N __ S.,fl'IY boo k mltchu UN\ 944, Mltches, safety boolr., 4 1, PG Ill 5u, ke-anywhffe m,tches UN13]1 , Mltchet strikt anywhere, 4 \ , PCi Ill

11 , 18·C TRANSPORTING MATCHES \\"htn shippers offe r matches for tran spo rtation, DOT req uires them 1o provide the rel e- 11ni shipping d_escripuon as shown i~ Table 11 .20 on the accompanying ~hipping paper. !)OT ~lso requires s~1ppers and ea rners to comply with all applicable labthng, marking, JnJpbca rd1n g reqm rem ent s.

11 .19 RESPONDING TO INCIDENTS INVOLVING A RELEASE OF A METALLIC OXIDIZER

fu·s t•on-1h n cc ne respo nders generally can identify rhe prt"S("nce of a metallic oxidize r at J trJnS pi.lrl:lt1on mi shap by obse rving at least one of the following:

1 Th~ number 5. 1 as a component of a sh ipping description of a haz.ardo us matenal hmd on a shipping paper Tii t word OXID IZER an d the number 5. I printed on yellow labels a.ffuced to pa cka g,mg The word OXID IZE R and the number 5. 1 printed on yellow placa rd s pos1ed on tJch sid e and eac h end of a rr.rn sport vehicle conta imng 1001 pounds (454 kg ) or mortof an oxidizer

The rcrommended method of r xtinguishing fi res supponed by mos t liquid or solid ox1 · J1m-s 1~ 10 deluge them with water. Metallic oxidizers generally are soluble in wate r. \Vh r n tht)' arc dilut ed with water, their chemical react i,·ity is sharply reduced or eliminated.

Although water effec1ivdy extin gui shes most fires supportrd b)' meta llic oxidizers, emcrgr nC)' rt"sponders need to exercise cauiion when applying the wa ter. Many solid ox1• dizm melt befo re 1hey decompose. These hot molten mat eria ls flow to adjoining arra s, 11 hm th r r ma r mix with combusrible materia ls and support their ignition . Although IIJ ttr mar be :ipplie"d to fires supported by oxi di zers, it should be app lied onl )' to bulk quanti ti es of mol ten oxidizers as a fog to avoi d 1he rapid generation of steam th:it ma y c;1 u1r th e molten material to splauer. Experts al so reco mmend the use of sand on fire s in1oh•mg bulk quamit irs of mol ten oxidizers.

SOLVED EXERCISE 11 .4

l'.'ny i11! e11en t,al lo dam or d,l,;,e the water runoff grf'lerated during , response aruon ITTYOlvlng a wltd OX!.d1ler1

S!il~tlon : 1/Jhen watl'I ,s used during a re1p011se Ktloo 1n.o\1m9 a solid ox.d zer l".S pnmar, function IS to d,lut, tr,o1 dwa ppreoably1o thattherateofano.adauon-reduaionre.Ktionkl.reducedV-Jhen1h,runoff -ste't '-~ "ended ho·,, e, er , the waterevap01ates and lea~t$ the ox,d1zer 1n a dr, state wheteupon 11 19a.nsvscec11- bi to SIJPP0!11ng the com bustion of manr1 For this realOn the wa~r runoff genera1ed dul'1ng a re:s.oorue acoon ·o!l i ng a 101 d o, 1d,z, r should always bt damm,d 01 d, ~ed so tnat tne oxd1:er may bl' rieutra ' ZM Delore JU •·~a:e d,socwt,on So dumsu\f1te1sal)p,calneulfal,z n9agff'lt

Chapt er 11 Chem istry of Some 0 1d d1zers 463

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