Maleic acid

Maleic acid is an organic compound that is a dicarboxylic acid, a type of acid that contains two carboxyl groups. Its chemical formula is HO2CCH=CHCO2H. Maleic acid is the cis-isomer of butenedioic acid, whereas fumaric acid is the trans-isomer. It is mainly used in the manufacture of polyester resins, coatings, antirust products, and agricultural products.

History

Maleic acid was first described by Swedish chemist Carl Wilhelm Scheele in 1785. It was isolated from apple juice by hydrolysis of maleic anhydride.

Properties

Maleic acid has a molar mass of 116.072 g/mol. It is a white crystalline compound that is soluble in water, ethanol, and acetone. Its melting point is 130-131 °C, and it decomposes before boiling. Maleic acid is a weak diprotic acid. It has a strong, unpleasant odor.

Production

Maleic acid is produced by the oxidation of benzene or butane. The process involves the reaction of these substances with oxygen in the presence of a vanadium pentoxide catalyst.

Uses

Maleic acid is used in the production of polyester resins and coatings. It is also used in the manufacture of antirust products and agricultural products. In addition, it is used in the synthesis of other chemicals, such as fumaric acid, tartaric acid, and certain amino acids.

Health effects

Exposure to maleic acid can cause irritation to the eyes, skin, and respiratory tract. It can also cause nausea, vomiting, and diarrhea if ingested. Long-term exposure can lead to kidney damage and respiratory problems.

See also

• Fumaric acid
• Dicarboxylic acid
• Organic compound
• Carboxyl