Dicarboxylic acid
From Wikipedia, the free encyclopedia
Dicarboxylic acids are organic compounds that are substituted with two carboxylic acid functional groups. In molecular formulae for dicarboxylic acids, these groups are often written as HOOC-R-COOH, where R is usually an alkyl, alkenyl, or akynyl group. Dicarboxylic acids can be used to prepare copolymers such as nylon and polyethylene terephthalate.
In general, dicarboxylic acids show the same chemical behaviour and reactivity as monocarboxylic acids. The ionization of the second carboxyl group occurs less readily than the first one. This is because more energy is required to separate a positive hydrogen ion from the doubly charged anion than from the single charged anion.
A mnemonic to aid in remembering the order of the common nomenclature for the first six dicarboxylic acids is "Oh my, such great apple pie!" (oxalic, malonic, succinic, glutaric, adipic, pimelic).
When one of the carboxy groups is replaced with an aldehyde group, the resulting structure is called a "aldehydic acid".
[edit] Examples
| Common name | IUPAC name | Chemical formula | Structural formula |
|---|---|---|---|
| Oxalic acid | ethanedioic acid | HOOC-COOH |  |
| Malonic acid | propanedioic acid | HOOC-(CH2)-COOH |  |
| Succinic acid | butanedioic acid | HOOC-(CH2)2-COOH |  |
| Glutaric acid | pentanedioic acid | HOOC-(CH2)3-COOH |  |
| Adipic acid | hexanedioic acid | HOOC-(CH2)4-COOH |  |
| Pimelic acid | heptanedioic acid | HOOC-(CH2)5-COOH |  |
| Suberic acid | octanedioic acid | HOOC-(CH2)6-COOH |  |
| Azelaic acid | nonanedioic acid | HOOC-(CH2)7-COOH |  |
| Sebacic acid | decanedioic acid | HOOC-(CH2)8-COOH |  |
| Phthalic acid | benzene-1,2-dicarboxylic acid o-phthalic acid |
C6H4(COOH)2 |  |
| Isophthalic acid | benzene-1,3-dicarboxylic acid m-phthalic acid |
C6H4(COOH)2 |  |
| Terephthalic acid | benzene-1,4-dicarboxylic acid p-phthalic acid |
C6H4(COOH)2 |  |
