Maleic Anhydride:Reactions,Solubility,Uses and Polymerization

Maleic Anhydride is a colorless, needle-like, crystalline (sand-like), flake, pellet or lumpy, fused mass with a strong, irritatingodor. It is used as a co-polymer in making polyester and otherresins, and as an ingredient in pharmaceuticals and pesticides.

Maleic Anhydride Solubility

The experiment results indicated that the solubility of maleic anhydride was highest in DMF and followed by methanol, acetic acid, acetonitrile, acetone, ethyl acetate, 2-propanol and n-butyl alcohol. For the temperature range investigated, the solubilities of maleic anhydride in the organic solvents increased with increasing temperature.

Maleic Anhydride Reactions

Maleic anhydride is a classic substrate for Diels-Alder reactions.

Michael reaction of maleic anhydride with active methylene or methine compounds such as malonate or acetoacetate esters in the presence of sodium acetate catalyst. These intermediates were subsequently used for the generation of the Krebs cycle intermediates aconitic and isocitric acids.

Maleic Anhydride Uses

Maleic anhydride has several uses, almost all of them related to the synthesis of other chemicals as fumaric and tartaric acids, certain agricultural chemicals (i.e., maleic hydrazide, malathion), lubricants, surface active agents, resins in different products, dye intermediates, pharmaceuticals, and more. This chemical is also used in copolymerization reactions as a comonomer for unsaturated polyester resins, preservative for oils and fats, and permanent-press resins (textiles).

Maleic Anhydride Polymerization

Maleic anhydride dimerizes in a photochemical reaction to form cyclobutane tetracarboxylic dianhydride (CBTA). This compound is used in the production of polyimides and as an alignment film for liquid crystal displays.

It is also a ligand for low-valent metal complexes, examples being Pt(PPh3)2(MA) and Fe(CO)4(MA).

Maleic Anhydride Hazards

In humans, exposure to maleic anhydride may cause irritation to the respiratory tract, eyes, exposed mucosa, and skin. It is also a skin and respiratory sensitizer.

Maleic anhydride is a low hazard profile chemical. Maleic anhydride rapidly hydrolyzes to form maleic acid in the presence of water and hence environmental exposures to maleic anhydride itself are unlikely. Maleic acid is biodegradable under aerobic conditions in sewage sludge as well as in soil and water.

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