Fumaric acid, also known as corylic acid or lichenic acid, is equivalent to fumaric acid. It is a colorless, flammable crystal and a carboxylic acid derived from butene. Its chemical formula is C4H4O4. Burning fumaric acid will release pungent maleic anhydride smoke. Fumaric acid is fruit-like in nature and can be found in Fumaric, Boletus, Lichen and Iceland Nori.
There are many industrial methods to produce fumaric acid. Its main source is the oxidation of benzene (or butene) to maleic acid (or maleic anhydride) in the presence of a catalyst, which is then obtained by isomerization. Benzene (or 80% of butene) and excess air are oxidized in a fluidized bed or fixed bed reactor to generate maleic anhydride, which is absorbed into maleic acid by the circulating acid solution. After decolorization and filtration, maleic acid is isomerized under the action of thiourea catalyst, and the reactant is filtered, washed, and dried to obtain fumaric acid. The isomerization catalyst also uses ammonium persulfate-ammonium bromide mixture or metal salt, amine salt, mercaptan and 10-20% hydrochloric acid. Carbohydrates such as sucrose, glucose, and maltose can also be fermented by black rhizobacteria to produce fumaric acid.
Due to the fumaric acid properties, fumaric acid is used in the production of unsaturated polyester resins. This type of resin is characterized by good chemical resistance and heat resistance; the copolymer of fumaric acid and vinyl acetate is a good binder, which is compatible with styrene Copolymer is the raw material for manufacturing FRP. The plasticizer made by fumaric acid is non-toxic and can be used for vinyl acetate latex in contact with food. This product is a fine chemical intermediate such as medicine and optical bleaching agent. It is used in the production of antidote dimercaptosuccinic acid in the pharmaceutical industry. The fumaric acid is neutralized with sodium carbonate to obtain sodium fumarate ([17013 -01-3]), and then replaced with ferrous sulfate to obtain ferric fumarate, which is a drug used to treat small red blood cell anemia with iron enrichment. As far as the properties of fumaric acid are concerned, it can also be used as a food additive - sour agent. Because fumaric acid is like fruit, it is generally used in refreshing beverages, fruit candy, jelly, ice cream, etc., mostly used with sour agent citric acid, fumaric acid and sodium hydroxide reaction to produce monosodium salt, also used as a sour seasoning, also used as an intermediate for synthetic resins and mordants.