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CAS 108-31-6|C₄H₂O₃

Maleic Anhydride

Reactive cyclic anhydride — primary feedstock for unsaturated polyester resins (UPR), alkyd coatings, and styrene-maleic anhydride copolymers.

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Flash Point

102 °C (216 °F)

Melting Point

52.8 °C (127 °F)

DOT Class

8 — Corrosive Solid

Packaging

Bags / Drums / Molten

Physical Properties

Molecular FormulaC₄H₂O₃
Molecular Weight98.06 g/mol
CAS Number108-31-6
Boiling Point202 °C (396 °F)
Melting Point52.8 °C (127 °F)
Flash Point102 °C (216 °F) — Combustible
Density (solid)1.48 g/cm³ at 20 °C
Vapor Pressure0.02 kPa at 20 °C
Solubility in WaterReacts — forms maleic acid
SublimationSignificant at room temperature
Auto-ignition Temp.477 °C (891 °F)
Dust ExplosionCombustible dust — Class II
Maleic Anhydride (2,5-Furandione)OOOC₄H₂O₃ | MW 98.06 g/mol | CAS 108-31-6

Grades & Packaging

IndustrialMolten GradeBriquette/Flake
50-lb Bags500-lb DrumsBulk (molten)

Industrial Applications

Unsaturated Polyester Resins

Primary feedstock for unsaturated polyester resins (UPR) used in fiberglass composites, marine, construction, and automotive applications.

Alkyd Resins

Modifier in alkyd resin synthesis to improve hardness, drying speed, and chemical resistance in oil-based coatings.

Maleic Acid & Fumaric Acid

Hydrolysis produces maleic acid; isomerization produces fumaric acid — both used in food, pharmaceutical, and polymer applications.

Copolymers & Adhesives

Comonomer in styrene-maleic anhydride (SMA) and vinyl acetate-maleic anhydride copolymers for adhesives, coatings, and dispersants.

Agricultural Chemicals

Intermediate in synthesis of malathion insecticide and other organophosphate agrochemicals.

Lubricant Additives

Feedstock for succinic anhydride derivatives used as dispersants and detergents in engine oil additive packages.

Safety & Regulatory

NFPA Health3 — Serious hazard (corrosive)
NFPA Flammability1 — Slight hazard
NFPA Reactivity1 — Slight hazard
OSHA PEL (TWA)1 ppm (4 mg/m³)
ACGIH TLV (TWA)0.1 ppm
DOT Hazard Class8 — Corrosive Solid
UN NumberUN 2215
Packing GroupIII
Dust HazardCombustible dust — Class II

Corrosive Solid — Respiratory Sensitizer

Maleic anhydride dust and vapors are corrosive to the respiratory tract and skin. Use respiratory protection and chemical-resistant gloves. SDS available upon request.

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Flake, briquette, and molten bulk delivery across Texas and the Gulf Coast.

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