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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
Functional Group Chemistry
Ethers have the general formula R-O-R’.
CH3OH + HOCH3 CH3OCH3 + H2OH2SO4
catalyst
Condensation Reaction
24.4
Functional Group Chemistry
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
Functional Group Chemistry
Carboxylic acids contain the carboxyl ( -COOH ) functional group.
24.4
Functional Group Chemistry
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
Functional Group Chemistry
Amines are organic bases with the general formula R3N.
CH3NH2 + H2O RNH3+ + OH-
CH3CH2NH2 + HCl CH3CH2NH3+Cl-
24.4
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