Community Right-To-Know List. Reported in EPA TSCA Inventory.

OSHA PEL: TWA 0.25 ppm
ACGIH TLV: TWA 0.1 ppm (skin, sensitizer); Not Classifiable as a Human Carcinogen
DFG MAK: 0.1 ppm (0.41 mg/m³)
DOT Classification:  8; Label: Corrosive

For occupational chemical analysis use OSHA: #25 or NIOSH: Maleic Anhydride, P&CAM 302.

Maleic anhydride, with the CAS registry number 108-31-6, is a colourless or white solid with an acrid odour. Its IUPAC name is called furan-2,5-dione. This chemical is an organic compound with the formula C₂H₂(CO)₂O. Its EINECS registry number is 203-571-6. The substance is stable which is combustible, but incompatible with water, strong oxidizing agents, alkali metals, strong bases, amines, most common metals, polymerization catalysts and accelerators. You should keep it in a tightly closed container and store it in a cool, dry, ventilated area. In addition, Maleic anhydride should be protected against physical damage, and isolated from incompatible substances.

Properties: Maleic anhydride reacts slowly with water to form maleic acid and heat. When released into the air, Maleic anhydride is expected to exist in the aerosol phase with a short half-life. The substance is incompatible with alkali metals and alkaline earth metals. 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).

In addition, Maleic anhydride dimerizes in a photochemical reaction to form cyclobutane tetracarboxylic dianhydride (CBTA). And it will react violently with bases which contact with strong oxidizers may cause fires and explosions. Maleic anhydride hydrolyzes to form maleic acid. With alcohols, the half-ester is generated, e.g., cis-HOOC–CH=CH–COOCH₃.

Maleic anhydride undergoes violent exothermic decomposition reactions, in the presence of strong bases, alkali metals, aliphatic amines and aromatic amines at temperatures above 150 °C, to form carbon dioxide. Maleic anhydride undergoes a potentially explosive exothermic Diels-Alder reaction with 1-methylsilacyclopenta-2,4-diene at 150 °C.

Preparation: There are several mehods of producing Maleic anhydride, such as oxidation of benzene, oxidation of butene and oxidation of butane. Nowadays, oxidation of benzene is commonly used to manufacture Maleic anhydride, which use benzene as the raw material. And via catalytic oxidation, you can gain the end product. The reaction temperature is 365 °C.

C₆H₆ + 9/2 O₂ → C₂H₂(CO)₂O + 2 H₂O + 2 CO₂

Maleic anhydride was traditionally manufactured by the oxidation of benzene or other aromatic compounds. However, you can gain it use n-butane as a feedstock nowadays, the reaction equation is as the following:

2 CH₃CH₂CH₂CH₃ + 7 O₂ → 2 C₂H₂(CO)₂O + 8 H₂O

Uses: Maleic anhydride can be used to prepare other chemicals, such as 1,4-butanediol, γ-butyrolactone, tetrahydrofuran, succinic acid, alkyd resin and UPR, and in medicine and pesticide. This compound is also used in the production of polyimides and as an alignment film for liquid crystal displays. It can also be used in organic synthesis, as intermediates in synthetic fiber and as collector in metal ore-dressing industry.

When you are using Maleic anhydride, you should be very cautious about it. This chemical is corrosive and harmful if swallowed. It can cause burns and cause sensitisation by inhalation and skin contact. You must not breathe its dust. In case of contact with eyes, you should rinse immediately with plenty of water and seek medical advice. Whenever you will contact or use it, you need wear suitable protective clothing, gloves and eye/face protection. In case of accident or if you feel unwell seek medical advice immediately.

You can still convert the following datas into molecular structure:
(1)Canonical SMILES: C1=CC(=O)OC1=O
(2)InChI: InChI=1S/C4H2O3/c5-3-1-2-4(6)7-3/h1-2H
(3)InChIKey: FPYJFEHAWHCUMM-UHFFFAOYSA-N

Toxicity of Maleic anhydride: