Trimellitic Anhydride

Chemical name: 1,2,4-Benzenetricarboxylic anhydride

Synonyms: TMA, Trimellitic acid anhydride

CAS: 552-30-7

EINECS: 209-008-0

Molecular formula: C9H4O6

Molecular weight: 192.12

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Specification:

Usage:

Trimellitic Anhydride is commonly used in the production of polymers, resins, and plasticizers. It’s a key component in the synthesis of polyesters and alkyd resins, which are used in coatings, adhesives, and insulation materials. TMA is also used in the manufacture of certain kinds of inks and pigments, as well as in the preparation of some pharmaceuticals.

Packing: 25 kg per woven bag or cardboard drum; custom packaging available.

Storage: Store in a cool, dry area away from moisture and incompatible materials. Minimum shelf life: 2 years.

Related Products

• Trimesic Acid
• TMC
• Pentaerythritol
• DAU

Applications

Trimellitic Anhydride (TMA) is a key monomer in high-performance polyimide films and wire enamels used in electrical motors, transformers, and aerospace components. TMA-based polyimides offer excellent thermal stability up to 220°C for demanding engineering applications. In the coatings industry, TMA improves adhesion, hardness, and chemical resistance in polyester and alkyd coatings for automotive and industrial finishes. TMA is also used in producing TOTM (trioctyl trimellitate), a high-temperature, low-volatility plasticiser that replaces phthalates in flexible PVC cables and medical devices. Additional applications include synthesis of specialty dyes, UV-curable resins, reactive diluents for epoxy systems, and intermediates for certain pharmaceutical compounds.

Trimellitic Anhydride in Plasticiser and Coating Chemistry

Trimellitic anhydride (TMA, benzene-1,2,4-tricarboxylic anhydride, CAS 552-30-7) is a trifunctional aromatic compound that bridges the gap between phthalic anhydride and more complex crosslinking agents. Its asymmetric structure — with one anhydride group and one free carboxylic acid on the same aromatic ring — provides both reactive versatility and high thermal stability, making it a preferred building block in high-performance polymer chemistry.

Applications in Plasticisers and Wire Insulation

The dominant use of TMA is the production of TOTM (trioctyl trimellitate) and other trimellitate ester plasticisers. Trimellitate plasticisers have significantly lower volatility than phthalate alternatives (e.g., DOP/DEHP) and superior heat stability, making them the standard choice for PVC insulation in automotive wiring, aviation cables, and appliance wiring rated above 105°C. The EU RoHS directive and automotive OEM specifications increasingly mandate non-phthalate plasticisers — driving substitution toward TMA-based trimellitates. In alkyd resin synthesis, TMA is incorporated as a tribasic acid to raise the degree of crosslinking, improving hardness, chemical resistance, and outdoor durability of decorative and industrial coatings. In polyimide synthesis, TMA-derived dianhydrides and acid chlorides are used to produce high-temperature polyimide films and adhesives for aerospace and electronics applications.

Supply and Documentation

Unifarm Chemical supplies trimellitic anhydride with ≥99% purity, acid value within specification, and low colour (APHA ≤30). Full technical documentation is available: COA, MSDS, and TDS. Standard export packing is 25 kg sealed kraft bags or fibre drums. Contact our team for current pricing, minimum order quantities, and shipping terms to your destination port. Related product: Trimesoyl Chloride (TMC) for reverse osmosis membrane applications.