Maleic anhydride

Maleic anhydride
IUPAC name	Furan-2,5-dione
Identifiers
InChI	InChI=1/C4H2O3/c5-3-1-2-4(6)7-3/h1-2H
InChIKey	FPYJFEHAWHCUMM-UHFFFAOYAP
Standard InChI	InChI=1S/C4H2O3/c5-3-1-2-4(6)7-3/h1-2H
Standard InChIKey	FPYJFEHAWHCUMM-UHFFFAOYSA-N
CAS number	[108-31-6]
EC number	203-571-6
RTECS	UE5950000
ChemSpider	7635
SMILES	O=C1C=CC(=O)O1
Properties
Chemical 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
Structure
Hazards
Material safety data sheet (MSDS)	MSDS at J. T. Baker
EU classification	Corrosive (C)
R-phrases	Template:R22, Template:R34, Template:R42/43
S-phrases	Template:S2, Template:S22, Template:S26, Template:S36/37/39, Template:S45
NFPA 704
Flash point	102 °C
Related compounds
Other acid anhydrides	Succinic anhydride
Other compounds	Maleic acid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Maleic anhydride (cis-butenedioic anhydride, toxilic anhydride, dihydro-2,5-dioxofuran) is an organic compound with the formula C₄H₂O₃. 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

Characteristic 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.
• Maleic anhydride (MA) is an excellent ligand for low-valent metal complexes, examples being Pt(PPh₃)₂(MA) and Fe(CO)₄(MA).

External links

• International Chemical Safety Card 079907
• NIOSH Pocket Guide to Chemical Hazards 0376
• Chronic toxicity summary
• Maleic anhydride at Occupational Safety & Health Administration