organic chemistry and biochemistry the study of carbon-containing compounds and their properties....

Organic Chemistry and Biochemistry

The study of carbon-containing compounds and their properties.The vast majority of organic compounds contain chains and rings of carbon atoms.The study of the chemistry of living things.

Hydrocarbons

. . . compounds composed of carbon and hydrogen.

Saturated: carbon-carbon bonds are all single - alkanes [CnH2n+2]

H C

H

H

C

H

H

H

Hydrocarbons(continued)

Unsaturated: contains carbon-carbon multiple bonds.

H C

H

H

C

H

CH

H

24.1

Classification of Hydrocarbons

24.2

Alkanes

Alkanes have the general formula CnH2n+2 where n = 1,2,3,…

• only single covalent bonds

• saturated hydrocarbons because they contain the maximum number of hydrogen atoms that can bond with the number of carbon atoms in the molecule

CH4 C2H6 C3H8

methane ethane propane

Rules for Naming Alkanes

1. For alkanes beyond butane, add -ane to the Greek root for the number of carbons.

C-C-C-C-C-C = hexane

2. Alkyl substituents: drop the -ane and add -yl.

-C2H5 is ethyl

Rules for Naming Alkanes

3. Positions of substituent groups are specified by numbering the longest chain sequentially.

C C-C-C-C-C-C

3-methylhexane

4. Location and name are followed by root alkane name. Substituents in alphabetical order and use di-, tri-, etc.

24.2

Structural isomers are molecules that have the same molecular formula but different structures

How many structural isomers does pentane, C5H12, have?

C C C C C

H H H H H

H

HHHHH

H

C C C C

H CH3 H H

H

HHHH

H

C C C

H CH3 H

H

HH

H

CH3

n-pentane

2-methylbutane

2,2-dimethylpropane

24.2

24.2

Alkane Nomenclature

1. The parent name of the hydrocarbon is that given to the longest continuous chain of carbon atoms in the molecule.

CH3 CH2 CH2 CH CH2 CH2 CH3

CH3

1 2 3 4 5 6 74-methylheptane

2. An alkane less one hydrogen atom is an alkyl group.

CH4

CH3

methane

methyl

24.2

Alkane Nomenclature

24.2

Alkane Nomenclature

3. When one or more hydrogen atoms are replaced by other groups, the name of the compound must indicate the locations of carbon atoms where replacements are made. Number in the direction that gives the smaller numbers for the locations of the branches.

CH3 CH CH2 CH2 CH3

CH3

1 2 3 4 5

2-methylpentane

CH3 CH2 CH2 CH CH3

CH3

1 2 3 4 5

4-methylpentane

24.2

Alkane Nomenclature

4. Use prefixes di-, tri-, tetra-, when there is more than one alkyl branch of the same kind.

CH3 CH CH CH2 CH2 CH3

CH3

1 2 3 4 5 6

CH3

2,3-dimethylhexane

CH3 CH C CH2 CH2 CH3

CH3

1 2 3 4 5 6

CH3

3,3-dimethylhexane

24.2

Alkane Nomenclature

5. Use previous rules for other types of substituents.

CH3 CH CH CH3

Br

1 2 3 4

NO2

2-bromo-3-nitrobutane

CH2 CH2 CH CH3

Br

1 2 3 4

NO2

1-bromo-3-nitrobutane

What is the IUPAC name of the following compound?

24.2

1 2 3 4 5 6 7 8CH3 CH CH2 CH CH2 CH2 CH3

C2H5

CH2

CH3

2-methyl-4-ethyloctane

What is the structure of 2-ethyl-4-methylhexane?

1 2 3 4 5 6CH3 CH CH2 CH CH2 CH3

CH3C2H5

24.2

Alkane Reactions

CH4 (g) + 2O2 (g) CO2 (g) + 2H2O (l) H0 = -890.4 kJ

Combustion

Halogenation

CH4 (g) + Cl2 (g) CH3Cl (g) + HCl (g)light

Cl2 + energy Cl• + Cl•

Cl• + C HH

H

H

C H

H

H

• + HCl

CH

H

H

• + Cl Cl C ClH

H

H

+ Cl•

Substitution Reactions

Primarily where halogen atoms replace hydrogen atoms.

CHCl Cl CCl HClh3 2 4

24.2

achiral chiral

24.2

Cycloalkanes

Alkanes whose carbon atoms are joined in rings are called cycloalkanes. They have the general formula CnH2n where n = 3,4,…

Alkenes and Alkynes

Alkenes: hydrocarbons that contain a carbon-carbon double bond. [CnH2n]

CC=C propene

Alkynes: hydrocarbons containing a carbon-carbon triple bond.

CCCCC 2-pentyne

Nomenclature for Alkenes

1. Root hydrocarbon name ends in -ene

C2H4 is ethene

2. With more than 3 carbons, double bond is indicated by the lowest numbered carbon atom in the bond.

C=CCC is 1-butene

24.2

Alkenes

Alkenes have the general formula CnH2n where n = 2,3,…

• contain at least one carbon-carbon double bond

• also called olefins

CH2 CH CH2 CH3

1-butene

CH3 CH CH CH3

2-butene

C C

Cl Cl

H H

C C

Cl H

H Cl

cis-dichloroethylene trans-dichloroethylene

Addition Reactions

. . . in which (weaker) bonds are broken and new (stronger) bonds are formed to atoms being added.

CH CHCH H CH CH CHcatalyst2 3 2 3 2 3

24.2

Alkene ReactionsCracking

Addition Reactions

CH2 CH2 (g) + HBr (g) CH3 CH2Br (g)

CH2 CH2 (g) + Br2 (g) CH2Br CH2Br (g)

C2H6 (g) CH2 CH2 (g) + H2 (g)Pt

catalyst

24.2

Alkynes

Alkynes have the general formula CnH2n-2 where n = 2,3,4,…

• contain at least one carbon-carbon triple bond

1-butyne 2-butyne

CH C CH2 CH3 CH3 C C CH3

Production of acetylene

CaC2 (s) + 2H2O (l) C2H2 (g) + Ca(OH)2 (aq)

24.2

Alkyne Reactions

Addition Reactions

Hydrogenation

CH CH (g) + H2 (g) CH2 CH2 (g)

CH CH (g) + HBr (g) CH2 CHBr (g)

CH CH (g) + Br2 (g) CHBr CHBr (g)

CH CH (g) + 2Br2 (g) CHBr2 CHBr2 (g)

24.3

Aromatic Hydrocarbons

C

CC

CC

C

H

H

H

H

H

H

C

CC

CC

C

H

H

H

H

H

H

24.3

Aromatic Compound Nomenclature

CH2CH3

ethylbenzene

Cl

chlorobenzene

NH2

aminobenzene

NO2

nitrobenzene

12

3

4

5

6

Br

Br

1,2-dibromobenzene

Br

Br

1,3-dibromobenzene

Aromatic Hydrocarbons

A special class of cyclic unsaturated hydrocarbons.

+ Cl2

FeCl3

Cl

+ HCl

benzene Chlorobenzene

24.3

Aromatic Compound Reactions

H

H

H

H

H

H

Br

H

H

H

H

H

+ HBr+ Br2

FeBr3

catalyst

H

H

H

H

H

H

CH2CH3

H

H

H

H

H

+ HCl+ CH3CH2ClAlCl3

catalyst

Substitution reaction

24.3

Polycyclic Aromatic Hydrocarbons

The Common Functional Groups

Class General Formula

Halohydrocarbons RX Alcohols ROH

Ethers ROR Aldehydes CR

OH

The Common Functional Groups

Class General Formula

Ketones

Carboxylic Acids

Esters

Amines RNH2

CRO

R'

CRO

OH

CRO

O R'

24.4

Functional Group Chemistry

Alcohols contain the hydroxyl functional group and have the general formula R-OH.

C6H12O6 (aq) 2CH3CH2OH (aq) + 2CO2 (g)enzyme

CH2 CH2 (g) + H2O (g) CH3CH2OH (g)H2SO4

Biological production of ethanol

Commercial production of ethanol

Metabolic oxidation of ethanol

CH3CH2OH CH3CHO + H2

alcohol dehydrogenase

24.4

24.4


Ethers have the general formula R-O-R’.

CH3OH + HOCH3 CH3OCH3 + H2OH2SO4

catalyst

Condensation Reaction

24.4


Aldehydes and ketones contain the carbonyl ( ) functional group.

O

C

R C H

O

• aldehydes have the general formula

R C R’

O

• ketones have the general formula

H C H

O

H C

O

CH3 C

O

CH3H3C

formaldehyde acetaldehyde acetone

24.4


Carboxylic acids contain the carboxyl ( -COOH ) functional group.

24.4


Esters have the general formula R’COOR, where R is a hydrocarbon group.

CH3COOH + HOCH2CH3 CH3 C O CH2CH3 + H2O

O

ethyl acetate

24.4


Amines are organic bases with the general formula R3N.

CH3NH2 + H2O RNH3+ + OH-

CH3CH2NH2 + HCl CH3CH2NH3+Cl-

Polymers

. . . are large, usually chainlike molecules that are built from small molecules called monomers.

Monomer PolymerEthylene PolyethyleneVinyl chloride Polyvinyl

chlorideTetrafluoroethylene Teflon

Types of Polymerization

Addition Polymerization: monomers “add together” to form the polymer, with no other products. (Teflon)

Condensation Polymerization: A small molecule, such as water, is formed for each extension of the polymer chain. (Nylon)

Proteins

•Natural polymers made up of -amino acids (molecular weight from 6000 to >1,000,000 g/mol).

•Fibrous Proteins: provide structural integrity and strength to muscle, hair and cartilage.

-Amino Acids

NH2 always attached to the -carbon (the carbon attached to COOH)

•C = -carbon

H2N C

H

COOH

R

Bonding in -Amino Acids

• + H2O

• A peptide linkage•There are 20 amino acids commonly found in proteins.

CNH

H

H

R

C

O

N

H

C

H

R'

CO

OH

organic chemistry and biochemistry the study of carbon-containing compounds and their properties....

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