Fumaric acid
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Surname | Fumaric acid | ||||||||||||||||||
other names | |||||||||||||||||||
Molecular formula | C 4 H 4 O 4 | ||||||||||||||||||
Brief description |
white, odorless crystals |
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properties | |||||||||||||||||||
Molar mass | 116.07 g mol −1 | ||||||||||||||||||
Physical state |
firmly |
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density |
1.64 g cm −3 (20 ° C) |
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Melting point |
287 ° C (closed capillary) |
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Sublimation point |
200 ° C |
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Vapor pressure |
<0.1 Pa (20 ° C) |
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pK s value |
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solubility |
poor in water (4.9 g l −1 at 20 ° C) |
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safety instructions | |||||||||||||||||||
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Thermodynamic properties | |||||||||||||||||||
ΔH f 0 |
−811.7 kJ / mol |
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As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . |
Fumaric acid is the common name of a naturally occurring organic chemical substance. It is an unsaturated dicarboxylic acid with the IUPAC name trans -butenedioic acid , also called trans -ethylene dicarboxylic acid. Their salts are called fumarates . The isomeric cis form is called maleic acid .
history
In 1937 Albert Szent-Györgyi received the Nobel Prize for Medicine for his biochemical work, including on fumaric acid.
Occurrence and manufacture
Fumaric acid is found in large quantities in various plants, fungi and lichens. It got its name from common earth smoke (Fumaria officinalis) , which contains large amounts of acid.
Fumaric acid is produced synthetically from maleic acid by isomerization . This is done by heating to over 150 ° C, by UV radiation or catalytically in an aqueous solution.
It arises in all organisms (e.g. in several genera of the Mucorales ) on different biochemical metabolic pathways:
- as an intermediate in the citric acid cycle through oxidation of succinic acid in the presence of the enzyme succinate dehydrogenase (an oxidoreductase )
- in the urea cycle by splitting arginine succinic acid
- in the biosynthesis of purine nucleotides (from aspartate )
- in nucleotide metabolism in the representation of adenosine monophosphate from inosine monophosphate
- by hydrolytic breakdown of amino acids such as phenylalanine and tyrosine
- by deamination of aspartic acid
properties
Fumaric acid does not have a melting point under normal pressure, but sublimes from around 200 ° C. At room temperature it forms white, almost odorless, flammable crystals. The aqueous solution is strongly acidic: 1 liter of water with 4.9 g of fumaric acid dissolved in it has a pH value of 2.1. The biprotonic acid has a pK s 1 of 3.0 and a pK s 2 of 4.5. The compound dissolves only slightly in water. At 15.5 ° C, only 0.428 g of fumaric acid dissolves in 100 g of water; at 100 ° C, the solubility increases to 9.97 g per 100 g of water. The flash point of fumaric acid is 273 ° C, the decomposition temperature is> 350 ° C and the ignition temperature is 375 ° C.
use
Fumaric acid is approved as a food additive E 297 and is used as an acidulant . In synthetic chemistry it is used for the production of polyester . In biotechnology, ammonia is stereoselectively attached to the carbon-carbon double bond, and enzyme-catalyzed L - aspartic acid is formed . Many pharmaceutically active substances - especially those containing amino groups - are administered as salts of fumaric acid. Fumaric acid esters such as dimethyl fumarate and monoethyl fumarate are used to treat psoriasis and, since March 2013, relapsing-remitting multiple sclerosis .
In pig rearing, fumaric acid is used as a feed additive for piglets to prevent coli-related infections by keeping the pH value in the intestine sufficiently low.
It has been proven that fumaric acid as a feed additive in lambs can reduce their methane production by up to 70%.
Fumaric acid is also used in cosmetic products. It is used there as a buffer substance and stabilizes the pH value of the cosmetic.
Web links
Individual evidence
- ↑ Entry on FUMARIC ACID in the CosIng database of the EU Commission, accessed on December 28, 2019.
- ↑ Entry on E 279: undefined in the European database on food additives, accessed on August 6, 2020.
- ↑ a b c d e f g h i j k l Entry on fumaric acid in the GESTIS substance database of the IFA , accessed on December 16, 2019(JavaScript required) .
- ↑ a b c A. Reichert: Potentiometric titrations in theory and practice. ( Memento from April 1, 2007 in the Internet Archive )
- ↑ a b chem.wisc.edu: pKa Data , Compiled by R. Williams (PDF, 78 kB).
- ↑ Entry on Fumaric acid in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
- ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-25.
- ↑ K. Lohbeck, H. Haferkorn, W. Fuhrmann, N. Fedke: Maleic and Fumaric Acids. In: Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH Verlag, Weinheim 2012. doi : 10.1002 / 14356007.a16_053 .
- ↑ German Multiple Sclerosis Society: Green light for fumaric acid and teriflunomide for the treatment of relapsing multiple sclerosis. ( Memento from May 25, 2013 in the Internet Archive ) March 23, 2013.
- ↑ Scientists look to cut cow flatulence m.phys.org, March 21, 2008, accessed November 30, 2019
- ↑ Marina Bährle-Rapp: Aleurites moluccana . In: Springer Lexicon Cosmetics and Body Care . 4th edition. Springer, 2012, ISBN 978-3-642-24688-3 , pp. 221 ( limited preview in Google Book search).