Maleic anhydride

Maleic anhydride[1]
IUPAC name Furan-2,5-dione
Identifiers
CAS number	108-31-6 Y
PubChem	7923
ChemSpider	7635 Y
UNII	V5877ZJZ25 Y
EC-number	203-571-6
ChEBI	CHEBI:474859 N
ChEMBL	CHEMBL374159 Y
RTECS number	UE5950000
Jmol-3D images	Image 1
SMILES C1=CC(=O)OC1=O
InChI InChI=1S/C4H2O3/c5-3-1-2-4(6)7-3/h1-2H Y Key: FPYJFEHAWHCUMM-UHFFFAOYSA-N Y InChI=1/C4H2O3/c5-3-1-2-4(6)7-3/h1-2H Key: FPYJFEHAWHCUMM-UHFFFAOYAP
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
Flash point	102 °C
Related compounds
Related acid anhydrides	Succinic anhydride
Related compounds	Maleic acid
N anhydride (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Maleic anhydride (cis-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.

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-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.^[2][3]

References

1. ^ Merck Index, 11th Edition, 5586.
2. ^ 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.  edit
3. ^ Reaction conditions Horie et al 2010 reaction conditions: microreactor , mercury lamp, ethyl acetate solvent, 15 °C

External links

• International Chemical Safety Card 0799
• NIOSH Pocket Guide to Chemical Hazards 0376
• Chronic toxicity summary
• Maleic anhydride at Occupational Safety & Health Administration