|Molar mass||116.07 g·mol−1|
|Melting point||287 °C (549 °F; 560 K) (decomp)|
|4.3 g/L at 20°C|
|Acidity (pKa)||pka1 = 3.03, pka2 = 4.44|
|EU classification||Irritant (Xi)|
Related carboxylic acids
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
|what is: / ?)(|
Fumaric acid or trans-butenedioic acid is the chemical compound with the formula HO2CCH=CHCO2H. This white crystalline compound is one of two isomeric unsaturated dicarboxylic acids, the other being maleic acid. In fumaric acid the carboxylic acid groups are trans (E) and in maleic acid they are cis (Z). Fumaric acid has a fruit-like taste. The salts and esters are known as fumarates.
Fumaric acid was first prepared from succinic acid. A traditional synthesis involves oxidation of furfural (from the processing of maize) using chlorate in the presence of a vanadium-based catalyst. Currently, industrial synthesis of fumaric acid is mostly based on catalytic isomerisation of maleic acid in aqueous solutions at low pH. Maleic acid is accessible in large volumes as a hydrolysis product of maleic anhydride, produced by catalytic oxidation of benzene or butane.
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.
Fumaric acid does not combust in a bomb calorimeter under conditions where maleic acid deflagrates smoothly. For teaching experiments designed to measure the difference in energy between the cis- and trans- isomers, a measured quantity of carbon can be ground with the subject compound and the enthalpy of combustion computed by difference.
Fumarate is an intermediate in the citric acid cycle used by cells to produce energy in the form of adenosine triphosphate (ATP) from food. It is formed by the oxidation of succinate by the enzyme succinate dehydrogenase. Fumarate is then converted by the enzyme fumarase to malate. Human skin naturally produces fumaric acid when exposed to sunlight.
Fumarate is also a product of the urea cycle.
As a food additive, it is used as an acidity regulator and is denoted by the E number E297. Fumaric acid is a food acidulent used since 1946. It is generally used in beverages and baking powders for which requirements are placed on purity. 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 to add sourness, similar to the way malic acid is used. As well as being a component of some artificial vinegar flavors, such as "Salt and Vinegar" flavored potato chips, it is also used as a coagulant in stovetop pudding mixes.
In patients with relapsing-remitting multiple sclerosis, dimethyl fumarate (BG-12, Biogen) significantly reduced relapse and disability progression in a phase 3 trial. It activates the Nrf2 antioxidant response pathway, the primary cellular defense against the cytotoxic effects of oxidative stress.
Fumaric acid converts to the irritant maleic anhydride, upon partial combustion.
It is "practically non-toxic" but high doses are probably nephrotoxic after long term use.
Interactive pathway map
Click on genes, proteins and metabolites below to link to respective articles. [§ 1]
- The interactive pathway map can be edited at WikiPathways: "TCACycle_WP78".
- Record in the GESTIS Substance Database of the IFA
- Fumaric acid, PubChem
- Volhard, J. "Darstellung von Maleïnsäureanhydrid" Justus Liebig's Annalen der Chemie 1892, volume 268, page 255-6. doi:10.1002/jlac.18922680108
- Milas, N. A. "Fumaric Acid" Organic Synthesis 1943, Collective Volume 2, page 302. Online version
- British Patent No. 775,912, publicated on the May 29, 1957, by Monsanto Chemical Company.
- UK Food Standards Agency: "Current EU approved additives and their E Numbers". Retrieved 2011-10-27.
- US Food and Drug Administration: "Listing of Food Additives Status Part II". Retrieved 2011-10-27.
- Australia New Zealand Food Standards Code"Standard 1.2.4 - Labelling of ingredients". Retrieved 2011-10-27.
- Gold R., Kappos L., Arnold D.L., et al. (September 20, 2012). "Placebo-Controlled Phase 3 Study of Oral BG-12 for Relapsing Multiple Sclerosis". N Engl J Med 367 (12): 1098–1107. doi:10.1056/NEJMoa1114287. PMID 22992073.
- European Commission: "European Commission Report of the Scientific Committee on Animal Nutrition on the Safety of Fumaric Acid". Retrieved 2014-03-07.
|Citric Acid Cycle Metabolic Pathway|
|Acetyl-CoA||NADH + H+||NAD+||H2O||FADH2||FAD||CoA + ATP(GTP)||Pi + ADP(GDP)|
|+||H2O||NADH + H+ + CO2|
|H2O||H2O||NAD(P)+||NAD(P)H + H+||CO2|
|Urea cycle Metabolic Pathway|