Maleic Anhydride

DescriptionMaleic Anhydride (MAN) is an organic compound with the chemical formula C4H203. It is the acid anhydride of maleic acid and in its pure state it is a colourless or white solid with an acrid odour. Maleic anhydride is truly a remarkable molecule in that it possesses two types of chemical functionality making it uniquely useful in chemical synthesis and applications.Maleic Anhydride is a multifunctional chemical intermediate with applications in several fields of chemical industry. Its major end use is as feedstock in the production of unsaturated polyester resins (UPR).These resins are used both in glass-reinforced and in unreinforced applications. The UPR end uses includes a wide range of applications in construction, marine and automobile industries.

UsesMaleic Anhydride is heterocyclic compound used in the manufacture of unsaturated polyester resins. It has a wide range of other applications; it is used in synthetic tensides, insecticides, herbicides and fungicides.

UsesMaleic anhydride is used in Diels-Alder syntheses (as a dienophile), manufacture of alkyd-type of resins, dye intermediates, pharmaceuticals, agricultural chemicals (maleic hydrazide, malathion), in copolymerization reactions.

General DescriptionColorless crystalline needles, flakes, pellets, rods, briquettes, lumps or a fused mass. Melts at 113°F. Shipped both as a solid and in the molten state. Vapors, fumes and dusts strong irritate the eyes, skin and mucous membranes. Flash point 218°F. Autoignition temperature 890°F. Used to make paints and plastics and other chemicals.

PreparationTo a flask equipped with a Dean-Stark trap, condenser, and mechanical stirrer is added 116 gm (1.0 mole) of maleic acid and 120 ml of tetrachloroethane. The contents are heated, the water (18 ml, 1.0 mole) distilled off as the azeotrope, and the residue distilled under reduced pressure to afford 87.7 gm (89.5%) of the anhydride, b.p. 82-84°C (15 mm), m.p. 53°C. The residue remaining in the flask consists of about 10 gm of fumaric acid, m.p. 287°C. Fumaric and maleic acids both give maleic anhydride on heating. Fumaric acid must first be heated to a higher temperature to effect its conversion to maleic acid prior to its dehydration.