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Fumaric acid
Chemical structure of fumaric acid
General
Common name	Fumaric acid
Systematic name	(E)-Butenedioic acid
Other names	''trans''-1,2-Ethylenedicarboxylic acid 2-Butenedioic acid Allomaleic acid Boletic acid Lichenic acid
Molecular formula	C4H4O4
SMILES	OC(=O)C=CC(=O)O
Molar mass	116.07 g/mol
Appearance	White solid
CAS number	[110-17-8]
Properties
Density and phase	1.635 g/cm³, solid
Solubility in water	0.63 g/100 mL
Solubility	Alcohols
Melting point	287 °C
Acidity (p''K''a)	p''k''a1 = 3.03, p''k''a2 = 4.44
Thermodynamic data
Standard enthalpy of formation É¢f''H''°solid	? kJ/mol
Standard enthalpy of combustion É¢c''H''°solid	? kJ/mol
Standard molar entropy ''S''°solid	? J.K−1.mol−1
'Hazards'
EU classification	Irritant ('Xi')
R-phrases
S-phrases
NFPA 704
Supplementary data page
Structure and properties	''n'', ''É√r'', etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Regulatory data	Flash point, RTECS number, etc.
Related compounds
Related carboxylic acids	Maleic acid Succinic acid
Related compounds	Fumaryl chloride Fumaronitrile Dimethyl fumarate Iron(II) fumarate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

'Fumaric acid' is the chemical compound with the formula HO₂CCH=CHCO₂H. This colorless crystalline compound is one of two isomeric unsaturated dicarboxylic acids, the other being maleic acid wherein the carboxylic acid groups are cis. It has a fruit-like taste.

Contents

Biology

Medicine

Food

Chemistry

Other uses

Safety

References

See also

External links

Biology

Fumaric acid is found in fumitory (''Fumaria officinalis''), bolete mushrooms (specifically ''Boletus fomentarius var. pseudo-igniarius''), lichen, and Iceland moss.
Related to malic acid, the ionized form of fumaric acid, fumarate, is used by cells (in the TCA cycle) to produce energy from food. Human skin naturally produces fumaric acid when exposed to sunlight.

Medicine

Fumaric acid esters are sometimes used to treat psoriasis, as it has been suggested that the condition is caused by an impairment of fumaric acid production in the skin. A starting dose is 60-105 mg daily, which may be gradually increased to as much as 1,290 mg per day. Side effects include kidney or gastrointestinal disorders, as well as skin flushing; these are mainly caused by excess intake. Decreased white blood cell counts have been reported with prolonged use.

Food

Fumaric acid is a food acidulent used since 1946 because it is non-toxic.
It is generally used in beverages and baking powders for which requirements are placed on purity, such as Welch's Grape Drink, and in Jelly Beans. It is generally used as a substitute for tartaric acid and occasionally in place of citric acid, at a rate of 1.36 g of citric acid to every 0.91 grams of fumaric acid for the same taste. It is a common component of food additives and dietary supplements, and is sometimes used as a substitute for tartaric acid in beverages or baking powder. It is also used in candy, similarly to the way malic acid is used.

Chemistry

Fumaric acid is inexpensive, so it is typically purchased rather than prepared. It was first prepared from bromosuccinic acid.^[1] A traditional synthesis involves oxidation of furfural (from the processing of maize) using sodium chlorate in the presence of a vanadium-based catalyst.^[2]
The chemical properties of fumaric acid can be anticipated from its component functional groups. This weak acid forms a diester, it undergoes additions across the double bond, and it is an excellent dienophile.

Other uses

Fumaric acid is used in the manufacture of polyester resins and polyhydric alcohols and as a mordant for dyes.

Safety

Fumaric acid converts to the irritant maleic anhydride, upon partial combustion.

References

1. Volhard, J. "Darstellung von Maleïnsäureanhydrid" Justus Liebig's Annalen der Chemie 1892, volume 268, page 255-6. DOI: 10.1002/jlac.18922680108
2. Milas, N. A. "Fumaric Acid" Organic Synthesis 1943, Collective Volume 2, page 302. http://www.orgsyn.org/orgsyn/pdfs/CV2P0302.pdf

See also

★ Dermatology

★ Photosynthesis

★ Maleic acid, the cis-isomer of fumaric acid

★ Fumarate

External links

★ International Chemical Safety Card 1173