A new synthetic method: pyromellitic dianhydride preparation by Ni–Mo/ZrO2 catalytic oxidation

Abstract

A new method was designed and optimized for the synthesis of pyromellitic dianhydride (PMDA). PMDA was oxidatively synthesized in a fixed bed with 1,2,4-trimethylbenzene and dichloroethane as feedstock and aluminum chloride as alkylation reagent, supported by a Ni–Mo/ZrO₂ catalyst. The catalyst achieved a final yield of approximately 73.7% and demonstrated good cycling performance. Density functional theory (DFT) calculations of the first reaction mechanism were carried out to demonstrate the reaction trend of the intermediate.