2. WHAT ARE CARBOXYLIC ACIDS?
• A carboxylic acid is an organic compound that contains a carboxyl group
(C(O)OH).The general formula of a carboxylic acid is R-C(O)OH with R referring
to the rest of the (possibly quite large) molecule.
• Carboxylic acids are the acids found in organic molecules, the carbon based
compounds necessary for life. The term “carboxylic” is derived from carbonyl
and “hydroxyl”, the two structures which make an organic acid.
STRUCTURE CHEMICAL FORMULA
RCOOH/CH3COOH
3. Common Compound
Straight-chain, saturated carboxylic acids
Carbon
atoms
Common name IUPAC name Chemical formula
Common location
or use
1 Formic Acid Methanoic acid HCOOH Insect stings
2 Acetic Acid Ethanoic acid CH3COOH Vinegar
3 Propionic Acid Propanoic acid CH3CH2COOH
Preservative for
stored grains
4 Butyric Acid Butanoic acid CH3(CH2)2COOH Butter
5 Valeric acid Pentanoic acid CH3(CH2)3COOH Valerian
6 Caproic acid Hexanoic acid CH3(CH2)4COOH Goat fat
7 Enanthic acid Heptanoic acid CH3(CH2)5COOH
8 Caprylic acid Octanoic acid CH3(CH2)6COOH
Coconuts and bre
ast milk
9 Pelargonic acid Nonanoic acid CH3(CH2)7COOH Pelargonium
10 Capric acid Decanoic acid CH3(CH2)8COOH
Coconut
and Palm kernel
oil
5. NAMING CARBOXYLIC ACIDS
• count number of carbons in the longest carbon chain containing the –COOH group
• replace the –e with the suffix –oic acid
• compound containing multiple -COOH groups do not drop the –e but add a di- or tri-
to the ending – carboxylic acid or add a di- or tri- to the suffix –oic acid.
Example:
6. Here is an important list of rules to follow:
• 1. The carboxyl group takes precedence over alkyl groups and halogen substituents,
as well as double bonds, in the numbering of the parent chain.
• 2. If the carboxyl group is attached to a ring the parent ring is named and the suffix
-carboxylic acid is added.
• 3. When both double bonds and carboxyl groups are present, the -en suffix follows
the parent chain directly and the -oic acid suffix follows the -en suffix (notice that
the e is left off, -en instead of -ene). The location of the double bond(s) is(are)
indicated before the parent name as before, and the -oic acid suffix follows the -en
suffix directly. Remember it is not necessary to specify the location of the carboxyl
group because it will automatically be carbon #1. See below for examples. Again,
the carboxyl gets priority in the numbering of the parent chain.
7. • 4. There are several common names which are acceptable as
IUPAC names. They are shown in the examples at the end of this
list butat this point these names will not be accepted by the
computer. Eventually they will be accepted.
• 5. If there is a choice in numbering not previously covered, the
parent chain is numbered to give the substituents
the lowest number at the first point of difference.
