Trimellitic anhydride, chemical name: 1, 2, 4-phenyltrimethyl anhydride. The molecular formula is C9H4O5. The appearance is white flake. Melting point 168℃, boiling point 390℃, soluble in hot water and acetone, 2-J ketone, dimethylformamide, ethyl acetate, cyclohexanone. Soluble in anhydrous ethanol and reaction, slightly soluble in carbon tetrachloride, toluene.