Maleic anhydride

Maleic anhydride, the 2,5-furandione, the anhydride of maleic acid, is a white crystalline substance which is soluble in water to form maleic acid. The substance is also soluble in acetone and toluene. In ethanol, the substance dissolves to form esters. Maleic anhydride (molecular formula: C4H2O3) is an intermediate product of the chemical industry and is mainly used for the production of unsaturated polyesters and for the synthesis of surfactants, insecticides, herbicides, fungicides etc. With alpha-olefins MA can be converted to strictly alternating copolymers.

The maleic anhydride may have a local skin irritating effect. However, cases of genuine allergic contact dermatitis are a rarity. Inhaled exposure may cause irritation of the conjunctiva and respiratory tract. Inhalation of higher concentrations may cause bronchial irritation, rhinitis, respiratory distress and in severe cases pulmonary oedema. Maleic anhydride has a potentially sensitizing effect by inhalation. The substance can lead to allergic type I reactions of the respiratory tract ("anhydride asthma").

1. Hansen MR et al (2014) Occupational asthma caused by maleic anhydride. Ugeskr Laeger 176:37.
2. Plitnick LM et al.(2003) Identifying airway sensitizers: cytokine mRNA profiles induced by various anhydrides.toxicology 193:191-201.
3. Swinnen I et al (2012) Allergic contact dermatitis caused by C30-38 olefin/isopropyl maleate/MA copolymer in cosmetics.contact dermatitis 67:318-320.