Maleic anhydride
history
| RTECS = UE5950000
| InChI = 1/C4H2O3/c5-3-1-2-4(6)7-3/h1-2H
| StdInChI = 1S/C4H2O3/c5-3-1-2-4(6)7-3/h1-2H
| InChIKey = FPYJFEHAWHCUMM-UHFFFAOYAP
| StdInChIKey = FPYJFEHAWHCUMM-UHFFFAOYSA-N
| ChemSpiderID = 7635
| EC-number = 203-571-6
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| Section7 = , ,
| SPhrases = , , ,
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| FlashPt = 102 °C
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Maleic anhydride (cis-butenedioic anhydride, toxilic anhydride, dihydro-2,5-dioxofuran) is an organic compound with the formula C2H2(CO)2O. In its pure state it is a colourless or white solid with an acrid odour.
Maleic anhydride was traditionally manufactured by the oxidation of benzene or other aromatic compounds. As of 2006, only a few smaller plants continue to use benzene; due to rising benzene prices, most maleic anhydride plants now use n-butane as a feedstock: :2 CH3CH2CH2CH3 + 7 O2 → 2 C2H2(CO)2O + 8 H2O
Reactions
The chemistry of maleic anhydride is very rich, reflecting its ready availability and bifunctional reactivity.
It hydrolyzes, producing maleic acid, cis-HO2CCH=CHCO2H. With alcohols, the half-ester is generated, e.g., cis-HO2CCH=CHCO2CH3.
Maleic anhydride is a potent dienophile in Diels-Alder reactions. It is also a ligand for low-valent metal complexes, examples being Pt(PPh3)2(MA) and Fe(CO)4(MA).
MA dimerizes in a photochemical reaction to cyclobutane tetracarboxylic dianhydride CBTA. This compound is used in the production of polyimides and as an alignment film for liquid crystal displays Reaction conditions Horie et al 2010 reaction conditions: microreactor , mercury lamp, ethyl acetate solvent, 15 °C.
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References