Transition metal promoted palladium-catalyzed oxidative carbonylation of phenol to diphenyl carbonate

Abstract

Background

One-step synthesis of diphenylcarbonate (DPC) via the oxidative carbonylation of phenol can significantly improve the sustainability of polycarbonate manufacturing and aid economic potential for CO₂ utilization when coupled with the reverse water gas shift reaction. This work aims to develop active Pd-based solid catalyst by incorporating five transition metal oxide promoters individually. The impact of the transition metal oxides to the performance and stability for DPC synthesis were systematically studied.

Method

The oxidative carbonylation of phenol to synthesize diphenyl carbonate (DPC) is conducted in a high-pressure batch reactor using supported palladium catalysts. The promoted catalysts were prepared by co-precipitating Pd and the transition metal hydroxide onto the Pb-OMS-2 catalyst support followed by thermal treatment in air. Detailed materials characterization including diffraction, spectroscopic, chemisorption, and elemental analysis was implemented to aid the understanding of structure-property relations.

Significant findings

The yield of DPC exhibited a sigmoidal growth over time due to the accumulation of leached metal ions which served as promoting co-catalysts expediting the oxidative carbonylation reaction. The stability of Pd catalyst against leaching was enhanced by the incorporated transition metals with iron and nickel being most effective in the long run.