Transcript Organic Chemistry

Chapter Twenty-Two:
ORGANIC MOLECULES
Organic Chemistry
• The study of carbon/hydrogen containing compounds and their
properties.
• The vast majority of organic compounds
contain chains or rings of carbon atoms.
Hydrocarbons
• composed of ONLY carbon and
hydrogen.
• Saturated hydrocarbons: C—C bonds
are all single
alkanes [CnH2n+2]
H
H
H
C
C
H
H
H
22.1
Hydrocarbons
• Unsaturated hydrocarbons: contains
carbon-carbon multiple bonds.
H
H
H
C
C
H
H
H
C
H
H
C
C
C H
H
22.1
Organic Nomenclature
1. Designate the number of carbons in the longest
continuous carbon chain (the molecular
“backbone”) using the following prefixes:
1 carbon
2 carbons
3 carbons
4 carbons
5 carbons
6 carbons
methethpropbutpenthex22.1
Rules for Naming Alkanes
1. Add -ane to the prefix for the number of
carbons. This is usually called the “root” name
or the “backbone” name.
C-C-C-C-C-C = hexane
22.1
Cyclic Alkanes
• Carbon atoms that form rings containing
only C—C single bonds.
• Nomenclature:
– Add “cylco-” to the root name
22.1
Alkenes and Alkynes
Alkenes: hydrocarbons that contain at least one
carbon-carbon double bond.
CC=C
propene
Alkynes: hydrocarbons containing at least one
carbon-carbon triple bond.
CCCCC
pentyne
22.2
Hydrocarbon Derivatives
• Molecules that are fundamentally
hydrocarbons but have additional atoms
or groups of atoms (other than alkyl
groups) called functional groups.
22.4
• All of these are
polar.
• Alcohols, acids and
amines are capable
of hydrogen bonding
with themselves
• All the others except
halohydrocarbons
can H-bond with
water.
• Note that all lone
pairs on O, N and
halogens are
missing
Simple Organic Reactions
• Condensation reactions
– Ester formation:
Alcohol + acid  ester + water
The –OH from the acid and an H from the
alcohol break off and form water. The carbon
chains then bond to form an ester
22.1
Simple Organic Reactions
• Condensation reactions
– Protein formation from amino acids:
22.1
Amino Acids
H
R = side chains
H 2N
C
COOH
R
22.6
Peptide Bond Formation –
Condensation Reaction
H
H 2N
C
R
H
COOH
H 2N
C
R‘
COOH
22.6
Bonding in Amino Acids
H O H H
H
N
H
C
R
C
N
C
R'
O
C
+ H2O
OH

The C-N bond here is commonly
called a “peptide linkage”
(the whole grouping in purple is called
the amide functional group)
• There are only 20 amino acids found in
human proteins.
22.6
Combustion Reactions of Alkanes
• At a high temperature, alkanes react
vigorously and exothermically with
oxygen.
• Basis for use as fuels.
• Form carbon dioxide and water
22.1
Addition Reactions
• Pi Bonds (which are weaker than the C-C
σ bonds), are broken, and new bonds are
formed to the atoms being added.
Substitution Reactions of Alkanes
• Primarily where halogen atoms replace
hydrogen atoms.
22.1
Polymers
• Large, chainlike molecules that are built
from small molecules called monomers.
Monomer
Ethylene
Vinyl chloride
ester
Polymer
Polyethylene
Polyvinyl chloride
polyester
22.5
Condensation Polymerization
• Condensation Polymerization: A polymer
containing carbonyl (-C=O) , amide (C-NH-)
and/or ether (-C-O-C-) groups are formed
by condensation.
• The monomers:
– Carbonyl: usually a carboxylic acid (losing –OH)
– Amide: amine (losing –H)
– Ether: alcohol (losing –H)
Addition Polymerization
• monomers “add together” across double
bonds to form the polymer, with no other
products.
n CF2=CF2 
F F
C C
F F n
(Teflon)
22.5
Addition Polymerization
22.5