Dicarboxylic acids

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Dicarboxylic acids are carboxylic acids that have two carboxy groups (–COOH). Carboxylic acids with only one carboxy group are called monocarboxylic acids . Dicarboxylic acids are all compounds with two acid groups without defining the structure of the remainder of the molecule.

Alkanedicarboxylic acids

Rhubarb ( Rheum rhabarbarum ) contains oxalic acid

The homologous series of unbranched saturated dicarboxylic acids, which are also called alkanedioic acids according to IUPAC , begins with oxalic acid (HOOC – COOH), followed by malonic acid with three carbon atoms and succinic acid with four carbon atoms in the main chain. Carboxylic acids important for the synthesis of polyesters or polyamides are adipic acid and sebacic acid with a chain length of six and ten carbon atoms, respectively.

If one carboxy group is on the first carbon atom and the other on the last carbon atom of an often longer (CH 2 ) n chain, the compounds are also referred to as α, ω-dicarboxylic acids.

saturated dicarboxylic acids
Chain
length		 Common name Chemical name Gross formula Occurrence Melting
point [° C]
2 Oxalic acid Ethanedioic acid HOOC-COOH Rhubarb , knotweed family 189.5
3 Malonic acid Propanedioic acid HOOC-CH 2 -COOH Sugar beet juice 135.6
4th Succinic acid Butanedioic acid HOOC-C 2 H 4 -COOH 185-187
5 Glutaric acid Pentanedioic acid HOOC-C 3 H 6 -COOH Juice of unripe sugar beet 97-98
6th Adipic acid Hexanedioic acid HOOC-C 4 H 8 -COOH Sugar beet, beetroot 153
7th Pimelic acid Heptanedioic acid HOOC-C 5 H 10 -COOH 105
8th Suberic acid , suberic acid Octanedioic acid HOOC-C 6 H 12 -COOH 142
9 Azelaic acid Nonanedioic acid HOOC-C 7 H 14 -COOH 106.5
10 Sebacic acid Decanedioic acid HOOC-C 8 H 16 -COOH Wonder tree ( castor oil ) 134.5
11 Undecanedioic acid HOOC-C 9 H 18 -COOH
12 Dodecanedioic acid HOOC-C 10 H 20 -COOH 126.5-127
13 Brassylic acid Tridecanedioic acid HOOC-C 11 H 22 -COOH 112-113
14th Tetradecanedioic acid HOOC-C 12 H 24 -COOH 125.8
16 Thapsic acid Hexadecanedioic acid HOOC-C 14 H 28 -COOH 124-124.2

Alkene dicarboxylic acids

The best-known alkene diacids that contain a C = C double bond are maleic acid and fumaric acid .

Aromatic dicarboxylic acids

Aromatic dicarboxylic acids such as terephthalic acid are used for the synthesis of plastics such as. B. PET important; the esters of isomeric phthalic acid are important plasticizers .

Other important dicarboxylic acids

Individual evidence

  1. ↑ a b Brockhaus ABC chemistry . VEB FA Brockhaus Verlag, Leipzig 1965, pp. 297-298.
  2. ↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 6: T-Z. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1988, ISBN 3-440-04516-1 , pp. 4604-4607.