Naming Organic Compounds
L. Scheffler
Lincoln High School
IB Chemistry 3-4.
1
Naming Organic
Compounds
•
•
•
•
Originally compounds were named based
on their source or use
Many organic compounds were given
common names which are still in use
However many ambiguities resulted
With the large number of organic
compounds, a method for systematically
naming them is very important
2
IUPAC Names
•
•
•
The International Union of Pure and Applied
Chemists (IUPAC) developed a system for
naming organic compounds.
This system eliminated many of the
ambiguities that plagued earlier naming
systems
Common names for many substances are
still widely used
3
Naming Hydrocarbons
using the IUPAC System
A series of prefixes are used to designate the
number of carbon atoms in a carbon chain
meth
1C
hex
6C
eth
2C
hept
7C
prop
3C
oct
8C
but
4C
non
9C
pent
5C
dec
10 C
4
Naming Alkanes
•
•
For straight chain hydrocarbons. The prefix indicates
the number of carbon atoms.
The suffix ane is added to designate that the
compound is an alkane
5
Naming Alkanes with
branched chains
•
•
For branched chain hydrocarbons, identify the longest
consecutive (straight) chain first. Then name the side
chains or branches.
The name of the branches end in “yl” and go before
the name of the straight chain
-methylpropane
dimethyl propane
methyl butane
6
Alkenes
•
•
•
Alkenes have one (or more) carbon to carbon
double bonds
When there are 4 or more carbon atoms in a chain,
the location of the double bond is indicated by a
number.
Numbering the location of the double bond(s) takes
precedence over the location of side chains
1 butene
2-butene
methylpropene
7
Naming Compounds With
Functional Groups
Various functional groups have unique suffixes that
designate the functional group.
The functional group takes precedence in numbering
the carbon chain.
Branches to the carbon chain are named in the usual
manner.
alcohols
“ol”
Amides
“amide”
Aldehydes
“al”
Amines
“amine” or amino as a prefix
Ketones
“one”
Ethers
Ethoxy as prefix
Acids
“oic”
halohydrocarbons
Fluoro, bromo, chloro or
iodo
Esters
“oate”
8
Alcohols
1- Propanol
Suffix = “ol”
2- Propanol
2-methyl-2-propanol
9
Aldehydes and Alkanals
Suffix = “al”
Propanal
Note that the
aldeyhde group
is always on an
end carbon or
carbon 1
10
Ketones or Alkanones
Suffix = “one”
Propanone
(also known as acetone)
Butanone
(also known as methyl ethyl ketone)
2-Pentanone
(note the number is necessary
Because the C=O could be on carbon
2 or carbon 3)
11
Carboxylic Acids
Suffix = “oic”
Butanoic acid
Note that the acid
group (called a
“carboxyl”) is
always on an end
carbon or carbon 1
12
Esters
Esters
Suffix = “oate”
Ethyl butanoate
Butyl ethanoate
There are two branches.
The branch with the
carbonyl gets the suffix
13
Amides
Suffix = “amide”
butanamide
Note that the amide
group is always on an
end carbon or carbon 1
14
Amines
Suffix = “amine”
Or prefix = “amino”
Propylamine or 1-aminopropane
2-propylamine or 2-aminopropane
2-methyl-2-propylamine or
2-methyl -2- aminopropane
15
Halohydrocarbons
1-bromopropane
2 chlorobutane
prefixes =
“fluoro,
chloro,
bromo, iodo”
1,2 diiodoethane
Cis 1,2difluroethene
Trans 1,2
difluoroethene
1,1,2 trifluorothene
16
Ethers
Suffix = “oxy”on first branch
Ethoxyethane
(diethylether)
Ethoxybutane
(ethylbutyl ether)
17
Aromatic Compounds With
Functional Groups
Benzoic acid
2 hydroxybenzoic acid
3 bromobenzoic acid
18
Nitriles
Nitriles have a cyanide
group. The name is based on
the longest carbon chain that
includes the carbon atom in
the nitrile group.
19
20
21
22
23