Maleic Anhydride CAS 108-31-6

What Maleic Anhydride Is

Maleic anhydride is a highly reactive cyclic anhydride sold mainly as white flakes, pastilles or briquettes, with a characteristic sharp odor. The anhydride ring opens with water to form maleic acid, so dry handling and sealed storage are essential, and the same reactivity lets it serve as a standard building block for esterification, addition and copolymer reactions. UATChem offers a 99.5% industrial grade with low molten color and moisture, the two properties resin and coating producers watch most closely. High-volume continuous plants can take molten material delivered heated, while most export orders move as solid flakes or pastilles that are easy to meter and store.

Unsaturated Polyester and Other Industries

• Unsaturated polyester resin. The largest outlet, reacted with glycols to build UPR for fiberglass composites, artificial stone, gel coats and surface coatings.
• Copolymers and water treatment. Maleic copolymers serve as scale inhibitors and dispersants in water treatment and as builders and thickeners in detergent and specialty formulations.
• Coatings, inks and lubricants. Used in alkyd and resin coating systems, printing inks and ashless lubricant dispersants such as succinimide additives.
• Other chemicals. A feedstock for BDO, THF and GBL, plasticizers, paper sizing, agrochemicals such as malathion, and pharmaceutical and food acid derivatives.

Typical Specifications

The table shows a standard 99.5% industrial lot; other assays and solid or molten forms are confirmed per order.

Packaging, Storage and Shipping

• Solid material is packed in 25 kg kraft bags or fiber drums with PE liner and in 600 kg FIBC bags; keep containers sealed, dry and cool in a ventilated warehouse, away from water, bases, amines, oxidizers and reactive metals, on a first-in first-out basis.
• For large continuous resin plants, molten maleic anhydride can be delivered in heated, insulated tank containers at 60 to 80 °C to avoid remelting; availability is confirmed against the destination and route.
• Classified under UN2215 as hazard class 8, packing group III, the dust and vapor irritate the skin, eyes and respiratory tract and can sensitize, so ventilation and PPE are required. Every lot ships with a COA covering assay, melting point, color and moisture and with SDS, samples and repeat container loads are supported, and a CIF quote needs quantity, solid or molten form, packing and destination port.

FAQ

Q: What forms of maleic anhydride does UATChem supply?

A: Solid flakes, pastilles and briquettes in 25 kg packs or 600 kg FIBC bags, plus heated molten material for large resin plants.

Q: How should maleic anhydride be stored?

A: Keep it sealed, dry and cool, away from water, bases, amines and oxidizers, as moisture turns the anhydride into maleic acid.

Q: What is the shipping classification of maleic anhydride?

A: It ships under UN2215, hazard class 8, packing group III, irritant and sensitizing, with SDS and corrosive labels each order.