Trimellitic anhydrides from trimellitic acid - and acetic anhydride

摘要

A mixture of the reactants, in the presence of benzene, is reacted at the b.pt. of the mixture (83-84 degrees C) at normal pressure. Pref. the benzene is used in a 6-fold esp a 2 to 3 fold excess over the trimellitic acid. Pref. the acetic anhydride is present in an excess of 10wt. % or more esp. 10-30 wt. % over the stoichiometric amount. The products high purity makes it valuable in the resin and plastics industry and for the prepn. of fibres and sheeting. The process is also useful in purifying trimellitic anhydride from other preparations, higher yields and purity are obtained.