Fumaric acid
- Trans - butenedioic
- Trans - ethylene dicarboxylic acid
- (E)- butenedioic
- E 297
D05AX01
White, almost odorless, crystalline powder
Fixed
1.64 g · cm -3
287 ° C (closed capillary)
200 ° C.
< 0.1 Pa ( 20 ° C)
- PKS1 = 3.0; 3.02
- PKa2 = 4.5; 4.38
Poorly in water ( 4.9 g · l -1)
Attention
-811.7 KJ / mol
Template: Infobox chemical / molecular formula search available
Fumaric acid is the trivial name of a naturally occurring organic chemical substance. It is an unsaturated dicarboxylic acid with the IUPAC name trans - butenedioic, also called trans - ethylene dicarboxylic acid. Its salts are called Fumarate. Cis isomeric form is maleic acid.
History
In 1937, Albert Szent- Györgyi was awarded the Nobel Prize in Medicine for his biochemical work among other things, for fumaric acid.
Occurrence and production
Fumaric acid is present in larger amounts in various plants, fungi and lichens. It took its name from the ordinary Fumitory ( Fumaria officinalis ), which contains larger amounts of the acid.
Synthetic fumaric acid is produced by isomerization of maleic acid; This is done by heating at about 150 ° C, by UV irradiation or catalytically in aqueous solution.
It occurs in all organisms (for example, in several genera of the Mucorales ) on various biochemical pathways:
- As an intermediate in the citric acid cycle by oxidation of succinic acid in the presence of the enzyme succinate dehydrogenase ( oxidoreductase );
- In the urea cycle, by cleavage of the arginine succinate;
- In the biosynthesis of purine nucleotides (for aspartate );
- In nucleotide metabolism in the preparation of adenosine monophosphate from inosine monophosphate;
- By hydrolytic degradation of amino acids such as phenylalanine, tyrosine
- By deamination of aspartic acid
Properties
Fumaric acid has no melting point under atmospheric pressure, but is sublimated from about 200 ° C. It forms white, almost odorless, flammable crystals at room temperature. The aqueous solution is strongly acidic: 1 liter of water with dissolved 4.9 g of fumaric acid has a pH of 2.1, the dibasic acid has a PKS1 of 3.0 and a pKa2 of 4.5.. The compound dissolves only slightly in water. At 15.5 ° C water dissolve in 100 g of only 0.428 g of fumaric acid, at 100 ° C the solubility increases to 9.97 g per 100 g of water.
Use
Fumaric acid is approved as a food additive E 297 and is used as an acidulant. In the synthesis chemistry used for polyester production. In biotechnology, ammonia is stereoselectively attached to the carbon-carbon double bond is formed enzyme-catalyzed L- aspartic acid. Many - particularly amino- - pharmaceutically active substances are administered as salts of fumaric acid. Fumaric acid esters such as dimethyl fumarate and fumarate are used to treat psoriasis and, since March 2013, the relapsing- remitting multiple sclerosis.
In pig rearing fumaric acid is used as a feed supplement for piglets to avoid coli infections caused by so that the pH is maintained sufficiently low in the intestine.