fumaric

Fumaric refers to fumaric acid and related salts, the trans isomer of butenedioic acid. The free acid has the chemical formula C4H4O4 and exists as a white, odorless crystalline solid. In water it is moderately soluble, and as a diacid it dissociates to form carboxylate groups in solution. The cis isomer is maleic acid, while the trans isomer is more thermodynamically stable.

Fumaric acid occurs naturally in some plants and fungi and is also produced during cellular metabolism as an intermediate in the citric acid cycle. In biochemistry, fumarate is formed from succinate by succinate dehydrogenase and is converted to malate by fumarase, linking it to energy production and metabolism.

Industrial production and forms: commercially, fumaric acid is produced on a large scale from butadiene- or benzene-derived routes, typically involving oxidation to maleic anhydride followed by hydrolysis and isomerization to fumaric acid. It is available as the free acid and as a range of fumarate salts, such as calcium fumarate and potassium fumarate, which are used as dietary supplements and chemical intermediates.

Applications: in the food industry, fumaric acid and fumarates are used as acidity regulators and flavoring aids (food additive E297). In supplements, fumarate salts provide calcium or other minerals. In medicine, dimethyl fumarate and related esters are used as drugs, notably in the treatment of multiple sclerosis, where they modulate the immune response.

Safety and handling: fumaric acid is a mild irritant to skin, eyes, and the respiratory tract; handling requires standard chemical-safety precautions. As with many organic acids, excessive exposure can be hazardous.