3,3',4,4'-Benzophenone tetracarboxylic dianhydride

3,3’,4,4’-Benzophenone tetracarboxylic dianhydride (BTDA) is chemically, an aromatic organic acid dianhydride. It may be used to cure epoxy-based powder coatings. It has the CAS Registry Number of 2421-28-5 and a European Community number 219-348-1. It is REACH and TSCA registered. The formula is C17H6O7 with a molecular weight of 322.3.

Uses
Its use in epoxy powder coatings is slightly unusual in that many epoxy coatings are designed to be fairly close to a stoichiometric curing ratio. BDTA cured materials benefit from having the stoichiometry closer to 0.65 rather than 1. It is also used to synthesize polyimides. These have good flexibility because of the carbonyl and keto groups which increase the molecular distancing between the imide rings. This improves the solubility. The resultant product when combined with nano-technology produces composites with enhanced heat stability properties. BTDA has also been used to synthesize other molecules and is thus a reactive ingredient in its own right.