Maleic anhydride
| Maleic anhydride[1] | |
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Furan-2,5-dione |
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| Identifiers | |
| CAS number | 108-31-6  |
| PubChem | 7923 |
| ChemSpider | 7635 |
| UNII | V5877ZJZ25 |
| EC-number | 203-571-6 |
| ChEBI | CHEBI:474859  |
| ChEMBL | CHEMBL374159 |
| RTECS number | UE5950000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C4H2O3 |
| Molar mass | 98.06 g/mol |
| Appearance | White crystals |
| Density | 1.48 g/cm3 |
| Melting point |
52.8 °C, 326 K, 127 °F |
| Boiling point |
202 °C, 475 K, 396 °F |
| Solubility in water | Reacts |
| Hazards | |
| MSDS | MSDS at J. T. Baker |
| EU classification | Corrosive (C) |
| R-phrases | R22, R34, R42/43 |
| S-phrases | (S2), S22, S26, S36/37/39, S45 |
| NFPA 704 |
 1
3
1
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| Flash point | 102 °C |
| Related compounds | |
| Related acid anhydrides | Succinic anhydride |
| Related compounds | Maleic acid |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Maleic anhydride (butenedioic anhydride, toxilic anhydride, 2,5-dioxofuran) is an organic compound with the formula C2H2(CO)2O. It is the acid anhydride of maleic acid and in its pure state it is a colourless or white solid with an acrid odour.
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Production [edit]
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.
In both cases, benzene and butane are fed into a stream of hot air, and the mixture is passed through a catalyst bed at high temperature. The ratio of air to hydrocarbon is controlled to prevent the mixture from catching on fire. Vanadium pentoxide and molybdenum trioxide are the catalysts used for the benzene route, whereas vanadium and phosphorus oxides are used for the butane route.[2]
- 2 CH3CH2CH2CH3 + 7 O2 → 2 C2H2(CO)2O + 8 H2O
Reactions [edit]
The chemistry of maleic anhydride is very rich, reflecting its ready availability and bifunctional reactivity. It hydrolyzes, producing maleic acid, cis-HOOC–CH=CH–COOH. With alcohols, the half-ester is generated, e.g., cis-HOOC–CH=CH–COOCH3.
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).
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.[3][4]
References [edit]
- ^ Merck Index, 11th Edition, 5586.
- ^ Kurt Lohbeck; Herbert Haferkorn; Werner Fuhrmann; Norbert Fedtke (2005), "Maleic and Fumaric Acids", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a16_053
- ^ Horie, T.; Sumino, M.; Tanaka, T.; Matsushita, Y.; Ichimura, T.; Yoshida, J. I. (2010). "Photodimerization of Maleic Anhydride in a Microreactor Without Clogging". Organic Process Research & Development 14 (2): 100128104701019. doi:10.1021/op900306z.
- ^ Reaction conditions Horie et al 2010 reaction conditions: microreactor , mercury lamp, ethyl acetate solvent, 15 °C
