Concept maps Chemistry

The existence of so many organic molecules is a consequence of the ability of carbon atoms to form up to four strong bonds to other carbon atoms, resulting in chains and rings of many different sizes, shapes, and complexities.

The simplest organic compounds contain only the elements carbon and hydrogen, and are called hydrocarbons. Even though they are composed of only two types of atoms, there is a wide variety of hydrocarbons because they may consist of:

· varying lengths of chains

· branched chains

· rings of carbon atoms

· combinations of these structures

Hydrocarbons follow several molecular formulas that combine carbon and hydrogen atoms, and these bonds are called by different names, namely:

· Alkanes

· Alkenes

· Alkynes or acetylenes

· https://chem.libretexts.org/Courses/Heartland_Community_College/HCC%3A_Chem_162/22%3A_An_Introduction_to_Organic_Chemistry/22.2%3A_Alkanes%2C_Cycloalkanes%2C_Alkenes%2C_Alkynes%2C_and_Aromatics

· https://mawdoo3.com/بحث_عن_الهيدروكربونات

·

Alkanes , Alkenes

· Alkanes are organic compounds that consist entirely of single-bonded carbon and hydrogen atoms and lack any other functional groups. Alkanes have the general formula CnH2n+2

· Alkenes are hydrocarbons with at least a triple bond between two carbon atoms. Its general formula is CnH2n-2 and alkynes are also known as acetylene, relative to the simplest type of alkynes, the acetylene C2H2, for example, that acetylene is also the name of the first compounds of the chain, although its official name is ethane.

References

Organic Compounds Chemistry

· https://ar.wikipedia.org/wiki/%D8%A3%D9%84%D9%83%D8%A7%D9%8A%D9%86

· https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Hydrocarbons/Alkanes

Saturated hydrocarbon:

hydrocarbon molecule in which all the bonds between carbon atoms are single bonds (C−C) .

Alkanes: are saturated hydrocarbons.

The alkane homologous series: (

Methane	CH4
Ethane	C2H6
Propane	C3H8
Butane	C4H10
Pentane	C5H12
Hexane	C6H14
Heptane	C7H16
Octane	C8H18
Nonane	C9H20
Decane	C10H22

Name the first ten alkanes:

Unsaturated hydrocarbon:

hydrocarbon molecule in which there is at least one double bond (C=C).

Alkenes: are unsaturated hydrocarbons.

The alkene homologous series: (CnH2n)

The alkynes: are triple bond (C≡C), and it is unsaturated hydrocarbons.

The alkyne homologous series: (CnH2n-2)

Alkane	Alkene	Alkyne
Methane (CH4) Uses: Manufacturing ammonia for fertilizers and explosives.	Does not exist.	Does not exist.
Ethane (C2H6) Uses: plastic, Anti-freeze, detergent.	Ethene (C2H4) Uses: synthetic rubber, natural hormones in plants, polyester fibres.	Ethyne (C2H2) Uses: wildly used as a fuel in cutting of metals in welding.
Propane (C3H8) Uses: Fuel for engines, water heaters, furnaces.	Propane (C3H6) Uses: Manufacturing of resins, fibres, and elastomers.	Propane (C3H4) Uses: Rocket fuel.
Butane (C4H10) Uses: Fuel gas, fragrance extraction solvent.	Butene (C4H8) Uses: Butenes are more commonly used to make copolymer.	1-Butyne (C4H6) Uses: it has no significant or specific industrial application.
Pentane (C5H12) Uses: creating polystyrene for the insulation materials of refrigerators.	Pentene (C5H10) Uses: organic synthesis.	1-Pentyne (C5H8) Uses: used in preparation of other organic compounds.
Hexane (C6H14) Uses: extracting cooking oil from seeds.	Hexene (C6H12) Uses: General lubricants.	1-Hexyne (C6H10) Uses: organic synthesis.
Heptane (C7H16) Uses: in laboratories as a non-polar solvent.	Heptene (C7H14) Uses: organic synthesis.	Heptyne (C7H12) Uses: organic synthesis.
Octane (C8H18) Uses: important chemical agent in the petroleum industry.	Octene (C8H16) Uses: organic synthesis.	1-Octyne (C8H14) Uses: widely used in organic reactions such as halogenation, hydration, etc…
Nonane (C9H20) Uses: biodegradable detergents, organic synthesis.	Nonene (C9H18) Uses: organic synthesis.	Nonyne (C9H16) Uses: organic synthesis.
Decane (C10H22) Uses: component of engine fuel.	Decene (C10H20) Uses: organic synthesis.	Decyne (C10H18) Uses: organic synthesis.

References

"Ethane." Britannica Academic, Encyclopædia Britannica, 15 Jan. 2009. academic-eb-com.library.iau.edu.sa/levels/collegiate/article/ethane/33118#.

Ethylene (H2C=CH2). (2020). In Encyclopædia Britannica. Retrieved from https://academic-eb-com.library.iau.edu.sa/levels/collegiate/article/ethylene/33146

Acetylene. (2020). In Encyclopædia Britannica. Retrieved from https://academic-eb-com.library.iau.edu.sa/levels/collegiate/article/acetylene/3510

https://www.elgas.com.au/blog/1689-what-is-propane-gas

Propylene. (2020). In Encyclopædia Britannica. Retrieved from https://academic-eb-com.library.iau.edu.sa/levels/collegiate/article/propylene/61572

Methane. (2020). In Encyclopædia Britannica. Retrieved from https://academic-eb-com.library.iau.edu.sa/levels/collegiate/article/methane/52328

https://foodb.ca/compounds/FDB000759

https://energyeducation.ca/encyclopedia/Pentane#:~:text=In%20addition%20to%20being%20a,for%20refrigerators%20and%20heating%20pipes. https://pubchem.ncbi.nlm.nih.gov/compound/8004#section=Uses

https://www.worldofmolecules.com/solvents/heptane.htm#:~:text=Heptane%20(and%20its%20many%20isomers,compounds%20on%20a%20stained%20paper.

https://pubchem.ncbi.nlm.nih.gov/compound/356#section=Uses

https://pubchem.ncbi.nlm.nih.gov/compound/8141#section=Uses

https://www.alfa.com/en/catalog/A12440/#:~:text=1%2DOctyne%20is%20widely%20used,formation%2C%20polymerization%20and%20substitution%20reactions.

https://pubchem.ncbi.nlm.nih.gov/compound/15600#section=Uses

FUNCTIONAL GROUP Hydrocarbons are organic compounds containing only carbon and hydrogen.  They include alkanes, alkenes, alkynes and aromatics.

References

https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Alkynes/Naming_the_Alkynes#:~:text=Alkynes%20are%20organic%20molecules%20made,one%20alkyne%20in%20the%20molecule.

https://socratic.org/questions/what-is-the-functional-group-of-alkane-and-alkene

Reactions of Alkenes and Alkynes

Generally, it is more reactive than alkanes due to the electron density present in their pi bonds. In particular , these molecules can participate in a variety of addition reactions and can be used in polymer formation.

Addition Reactions

Unsaturated hydrocarbons can participate in a number of different addition reactions through their double or triple bonds.

Addition reactions Alkenes participate in a variety of addition reactions.

These addition reactions include catalytic hydrogenation (addition of H2), halogenation (reaction with X2, where X is a halogen), and hydrohalogenation (reaction with H-X, where X is a halogen), among others.

Cycloaddition

The group of alkenes undergo various cycloaddition reactions. More commonly the Diels-Alder reaction with 1,3-dienes to give cyclohexanes.

Diels-Alder reaction

Here to produce cyclohexene, the reaction of 1,3-butadiene (diene) reacts with ethylene (the dienophile).

There has been extensive development of this general reaction, and electrophilic alkenes and alkynes are particularly effective dienophiles. Processes of cycloaddition involving alkynes are also catalyzed by metals.

Oxidation

Oxidation of alkynes by strong oxidizing agents such as potassium permanganate or ozone will yield a pair of carboxylic acids. The general reaction can be pictured as:

[latex]RC\equiv CR'\xrightarrow{KMnO_4} RCO_2H+R'CO_2H[/latex]

By contrast, alkenes can be oxidized at low temperatures to form glycols. At higher temperatures, the glycol will further oxidize to yield a ketone and a carboxylic acid:

[latex](H_3C)_2C=CHCH_3\xrightarrow[\text{heat}]{KMnO_4}H_3CCOCH_3+H_3CCO_2H[/latex]

Here, we have 3-methyl-2-butene oxidizing to form acetone and acetic acid.

Hydrogenation

In the case of a catalyst - often platinum, palladium, nickel, or rhodium - hydrogen can be added via a triple or double bond to take an alkene to an alkene or an alkene to an alkane. From a practical method, it is not possible to isolate the alkene product for this reaction, although a toxic catalyst - a catalyst with lower reactive sites - can be used to do this. When hydrogen is fixed to the surface of the catalyst, the triple or double bonds are hydrogenated by synchronization method; This means that hydrogen atoms add to the same side of the molecule

Halogenation

In a similar way to hydrogenation, with the addition of halogen via the double or triple bond, alkenes and alkynes can also be halogenated. The halogenation of alkene results in a dihalogenated alkane product, while the halogenation of an alkyne can form a tetrahalogenated alkane.

Hydrohalogenation

Alkenes and alkynes, including HCl and HBr, can react with hydrogen halides. Depending on the number of HX equivalents added, hydrohalogenation yields the corresponding vinyl halides or alkyl dihalides. A similar reaction is the addition of water to alkynes, such that the original intermediate enol transforms to a ketone or aldehyde. If the alkene is asymmetric, the reaction will obey the law of Markovnikov. With more alkyl substituents, the halide will be added to the carbon.

Markovnikov’s rule

This rule dictates that the addition to an alkene of a hydrogen halide (HX, in the case of HBr) would lead to a product where the hydrogen with less alkyl substituents is attached to the carbon, while the halide group is attached to the carbon with more alkyl substituents.

Hydration

Water can be added via triple bonds in alkenes to produce aldehydes and ketones for the terminal and endogenous alkenes, respectively. Alkenes are hydrated by oxidative cracking with alcohol. This reaction occurs during the process of treating alkenes with a strong acid to occur as a catalyst.

https://courses.lumenlearning.com/introchem/chapter/reactions-of-alkenes-and-alkynes/