Hazardous Materials

Interactions of Hazardous Materials

This presentation was prepared to provide some

background or refresher notes on selected and limited

topics in basic organic chemistry that may be of help

for the chemistry portion of the OSH 3640 course.

Your textbook is needed for some parts of this

presentation.

Intro to Organic Chemistry Prepared by:

Dolores Gough, P.E.

George Gough, P.E., CSP

Basic Features of Atoms

Atom: smallest particle of an element; composed of smaller

particles known as electrons, protons, neutrons

Electrons: negative particles responsible for reactivity; charge of -1

Protons: positively charged particles; charge of +1

Neutrons: neutral particles; no charge

P+ N

e --

Protons and neutrons reside within the nucleus.

Electrons reside in designated regions surrounding the nucleus

called atomic orbitals.

Electron

Nucleus

Carbon has four (4) electrons in the outer shell that need to bond for stability.

Carbon can also share electrons with other carbon atoms to form the following

types of carbon bonds:

C – C (single bond)

C = C (double bond)

C Ξ C (triple bond)

Organic Chemistry – chemistry of compounds containing one or more carbon atoms. However, the hydrogen atom is almost always present in these compounds (shown in next slide).

6 P

6 N

-

-

-

-

- Atomic Structure of Carbon

-

Carbon electron sharing with Hydrogen: Hydrogen has one (1) electron in its outer shell that

can share with the C to form covalent bonds. However, C needs to share all 4 electrons in its

outer shell. Example: If all four electrons were shared with H, CH4 is formed.

H

H C H or CH4 (methane)

H

1 P

0 N

Atomic Structure of Hydrogen

-

Hydrocarbons (HC) are compounds whose molecules consist of only carbon and hydrogen atoms.

Carbon – Carbon Single Bond:

• Alkanes: have general formula of CnH2n+2 where n = number of carbon atoms

• Example: Butane has 4 carbons, all single bonds as shown:

H H H H

I I I I

H - C - C – C - C - H C4H10 (see Table 12.1)

I I I I

H H H H

• Cycloalkanes: same as alkane but the first and last C are linked (closed).

In naming them, just add “cyclo” to the alkane name. (Examples – see Sec. 12.2-B)

Cyclobutane ( http://commons.wikimedia.org)

Cyclohexane http://commons.wikimedia.org

Organic Chemsitry Graphics retrieved from http://commons.wikimedia.org

Carbon = Carbon Double Bond:

• Alkenes or Olefins: have general formula of CnH2n • Example: Butene has 4 carbons and at least 1 double bond

H H H H

I I I I

H - C - C = C - C – H or H – C = C – C – C - H

I I I I I I I

H H H H H H H

C4H8

Carbon Ξ Carbon Triple Bond:

• Alkynes: have general formula of CnH2n-2 • Example: Butyne has 4 carbons and at least 1 triple bond

H H H H

I I I I

H - C - C Ξ C - C – H or H – C ΞC – C – C - H

I I I I

H H H H

C4H6

General Properties/Characteristics:

Alkanes (paraffins or saturated HC): relatively stable to chemical

reactions. Low molecular weight alkanes are gases or

liquids, high MW are solids.

Alkenes (olefins ): unsaturated HC because they don’t have the

maximum number of atoms each carbon is able to

accommodate; physical properties are closely

related to those of the corresponding alkanes

Alkynes (unsaturated HC): physical properties similar to those

of alkanes and alkenes

IUPAC System of Nomenclature

IUPAC (International Union of Pure and Applied Chemistry – used

for naming complex hydrocarbons)

When a hydrogen atom is removed from an alkane, the resulting

group is called alkyl group or alkyl substituent. See Table 12.2 (page

472) for common alkyl substituents.

Rules for naming an alkane (pages 472-473)

1 2 3 4 5

Example: CH3 - CH2 – CH - CH2- CH3 I

CH3

3-methyl pentane

Methyl (one carbon)

IUPAC SYSTEM (cont.) Rules for naming alkenes (1 double bond), dienes (2 double bonds),

tienes (3 double bonds) & “cyclos”

1 2 3 4 5

Examples: CH3CH = CHCH2CH3 2- pentene

1 2 3 4

CH2 = CH – CH = CH2 1, 3 - butadiene

Rules for naming alkynes (pages 479-480)

1 2 3 4 5 6

Examples: CH3CH2C Ξ CCH2CH3 3- hexyne

1 2 3

CH Ξ CCH3 1- propyne

Aromatic Hydrocarbons

Regarded as compounds whose molecules are composed of

one or more special rings of carbon atoms

Benzene – simplest aromatic hydrocarbon

C6H6

http://commons.wikimedia.org

Other common aromatic compounds:

• Toluene (or methylbenzene)

• Xylene

1,4 dimethyl benzene

(para-xylene)

1,3 dimethylbenzene

(meta-xylene)

1, 2 dimethylbenzene

(ortho-xylene)

http://commons.wikimedia.org

http://commons.wikimedia.org http://commons.wikimedia.orghttp://commons.wikimedia.org

Organic Chemistry Graphics retrieved from http://commons.wikimedia.org

Polynuclear Aromatic Hydrocarbons (PAHs)

Two or more mutually-fused benzene rings per molecule (when a pair of

carbon atoms is shared and the bond between them)

Examples:

•Naphthalene (C10H8): colorless solid having odor of mothballs; poses

chronic respiratory hazard to humans; exposure is llinked with onset of

cancerous growths.

• Anthracene (C14H10): component of coal-tar.

http://commons.wikimedia.org

http://commons.wikimedia.org

Organic Chemistry Graphics retrieved from http://commons.wikimedia.org

Functional Groups In a hydrocarbon, one or more hydrogen atoms may be substituted with

another atom or group of atoms. This atom or group of atoms is called the

functional group, and this group determines many of an organic compound’s

characteristic chemical properties. It identifies an organic compound as alcohol,

ether, aldehyde, etc.

There are over 100 functional groups; some of the important ones are covered

in the book and listed in Table 13.1.

Let us take some examples:

Functional group: hydroxyl (-OH)

Class of organic compound: alcohol

General formula: R-CH2-OH

Functional group: oxy (-O-)

Class of organic compound: ether

General formula: R-O-R’

where: R and R’ are arbitrary alkyl or aryl substituent

Alcohols •Organic compounds derived by substituting one or more hydrogen

atoms in hydrocarbon molecule with hydroxy group (-OH)

•General chemical formula of simple alcohol is R-OH

Examples: H

I

Methyl alcohol H – C – O – H or CH3OH

(methanol) I

H

OH CH3 1 2 3 I 4 5 / 6

3,5 dimethyl 3-hexanol CH3 CH2 C CH2 CH

I \

CH3 CH3 methyl methyl

Ethers • Organic compounds that are highly volatile, flammable liquids

• Produce organic peroxides by reacting with atmospheric oxygen

catalyzed by light

• Highly reactive, potentially explosive

• General formula is R-O-R’

Example:

Diethyl ether CH3CH2 - O - CH2CH3 (ethyl) (ethyl)

Aldehydes and Ketones

\

• Both contain the carbonyl group C = O /

• Aldehydes - have carbonyl group located at end of chain of carbon

atoms O II

R – C – H

• Ketone - has carbonyl group located at nonterminal position

within chain O II

R – C – R’

Examples of aldehyde: formaldehyde or methanal (CH2O);

acetaldehyde or ethanal (CH3CHO;

2-propenal or acrolein (CH2=CHCHO)

Examples of ketone: acetone or 2-propanone (CH3COCH3)

methyl ethyl ketone or 2-butanone

(CH3COCH2CH3)

Organic Acids

• Organic compounds containing the carboxyl group (-COOH), so

they are also called carboxylic acids. They are weak acids,

inherently corrosive, and water-soluble with characteristic odors.

• General formula is R – COOH

• In the IUPAC nomenclature, the suffix – oic acid is used to

designate carboxylic acids; but when the functional group (-COOH)

is connected to a cyclic structure, - carboxylic acid becomes the

appropriate suffix.

• Examples:

Methanoic acid (or formic acid): H COOH

Ethanoic acid (or acetic acid): CH3 COOH

Propanoic acid (or propionic acid): CH3CH2 COOH

connected to cyclic structure:

2- hydroxybenzene carboxylic acid (or salicylic):

o-HOC6H4 COOH

Peroxo-Organic Compounds

• Organic hydroperoxides, organic peroxides

• Many compounds unstable

• Used to induce polymerization, process

essential to production of plastics

Meyer (2014)

Meyer (2014) Chemistry of Hazardous Materials. (6th ed). NJ: Pearson

More details and other common

hazardous organic chemicals

are in the textbook.

Reference

Meyer, E. (2014). Chemistry of Hazardous Materials. (6th ed.). Upper Saddle River, NJ:

Pearson.

Organic chemistry graphics retrieved from http://commons.wikimedia.org