overheads chem 122
TRANSCRIPT
Organic Chemistry:
Organic Chemistry- That branch of
chemistry which centres on carbon and its
compounds.
Greek Prefixes:
mono
1
hexa
6
di
2
hepta
7
tri
3
octa
8
tetra
4
nona
9
penta
5
deca
10
Alkanes:
Alkanes: A hydrocarbon(compound
containing only carbon and hydrogen) in
which all carbon-carbon bonds are single
bonds.
n
Compound
Name
1 CH4 methane
2
CH3CH3
ethane
3
CH3CH2CH3
propane
4
CH3CH2 CH2CH3
n-butane
5
CH3(CH2)3CH3
n-pentane
6
CH3(CH2)4CH3
n-hexane
7
CH3(CH2)5CH3
n-heptane
8
CH3(CH2)6CH3
n-octane
9
CH3(CH2)7CH3
n-nonane
10
CH3(CH2)8CH3
n-decane
Line Notation:
The end of each line represents a carbon atom
and the appropriate number of hydrogens.
Isomers:
Isomers- Compounds with the same
molecular formula but different arrangement
of atoms.
C C HC
HH
C
HH
H
H
H H H
C C H
H
C
CH
H
H
H H
H
H H
n-butane
Isobutaneor methylpropane
C5H12 has 3 isomers.
C6H14 has 5 isomers.
C7H16 has 9 isomers.
C10H22 has 75 isomers.
C30H62 has 4 BILLION isomers.
Isomers cont...:
Naming Alkanes: Remove a H from CH4(methane) to get a methyl
group
C
H
H
H
methyl C C
HH
H
H
H
ethyl
C C
H
C
HH
H
H
H H
n-propyl
Naming:
prefix - parent - suffix
Identify the longest chain of C atoms.
Identify alkyl and/or side groups and
location.
Cycloalkanes:
Ring structures that contain only C-C
single bonds.
C
C
C
H
H
H
H
H H
cyclopropane
C
C C
CH
H H
H
H
H H
H
cyclobutane
General Formula CnH2n
Alkenes:
Alkenes are hydrocarbons which have a
carbon-carbon double bond somewhere in the
structure.
Alkenes have the general formula CnH2n
where n = 1, 2, 3, …
Name derived from the corresponding
alkane, except the ending is changed from
"ane" to “ene."
H H
CC
HH
H H
CC
HH
HH
ethane ethene
Naming Alkenes:
Alkenes cont…
For alkenes containing more than 4 carbon
atoms, the position of the double bond must
be indicated. Ex:
CH2=CHCH2CH3 1-butene
CH3CH=CHCH3 2-butene
5-methyl-2-hexene
In naming alkenes the largest chain is
numbered to give the lowest number to the
double bond.
Ex:
Alkenes cont…
6 4 2
5 3 1
Cis-trans Isomers:
Alkenes also exhibit geometric
isomerization. Due to restricted motion of
double bond. Not found in alkanes.
Consider ethane. Free rotation about C-C
single bond.
H3C CH3
CC
HH
H CH3
CC
HH3C
cis-2-buteneB.P. = 1ºC
B.P. = 2.5ºCtrans-2-butene
Restricted motion in 2-butene results in two
stereoisomers.
Alkynes:
Hydrocarbons that contain atleast one
carbon-carbon triple bond. When naming,
the ending "ane" of the corresponding alkane
is replaced with the ending "yne.“
HCCH ethyne. Also known as
acetylene.
Position of the triple bond must be indicated.
HCCCH2CH3 1-butyne
CH3CCCH3 2-butyne
Aromatic Hydrocarbons:
C
C
C
C
C
C
H
H
H
H
H
H
C
C
C
C
C
C
H
H
H
H
H
H
Benzene ring may berepresented as follows.
Substituted Benzene:
Ex: dimethyl substituted benzene.
Use ortho(o), meta(m), and para(p) for
disubstituted benzenes. CH3 CH3 CH3
CH3
CH3
CH3
2-xylene
o-xylene
3-xylene
m-xylene
4-xylene
p-xylene
These are groups of atoms which give
hydrocarbons characteristic chemical and
physical properties.
Functional Groups:
Examples:
-OH: Alcohols
-NH2: Amines
-COOH: Carboxylic Acids
Some Benzene Compounds: CH3
toluene
NH2
aniline
OH
hydroxybenzeneor
phenol
CH3
m-chlorotoluene
Cl
NH2
o-chloroaniline
Cl
Alcohols:
Hydrocarbons that contain a -OH group.
Alcohols are named by taking the name of the
parent alkane and replacing the ending "ane"
to "anol."
Numbers are used to indicate the position of
the substituents, lowest number assigned to
the carbon containing the -OH group.
Alcohols cont…:
H C
H
H
C HC
HH
H
C
HH
H
H C
H
H
C OHC
HH
H
C
HH
H
primary alcohol1-butanol
n-butane
Ethers: Ethers have the general structure R-O-R.
R can be an alkyl or aromatic group.
CH3OCH
3
dimethyl ether
CH3 OCH2CH3
ethyl methyl ether
Naming Aldehydes:
H C
O
H
To name aldehydes, take the name of the
parent alkane and replace the ending "e"
with "al."
methanal
or
formaldehyde
ethanal
or
acetaldehyde
CH3 C
O
H
Aldehydes cont…
For larger aldehydes, #'s are used to indicate
position with C=O carbon given the lowest
number of one.
NOTE: Do not have to indicate position of
aldehyde carbon.
Ketones:
In a ketone, the chain is numbered to give the
C=O carbon the lowest number. Replace the
"e" of the parent alkane with "one."
R C
O
R ketone
R: alkyl or aromatic group.
Carboxylic Acids:
Carboxylic acids contain the -COOH group.
C
O
OH
Named by dropping the "e" of the parent
alkane and replacing it with "oic acid." The
carbon on the carboxyl group is numbered
one.