Direct synthesis of diphenyl carbonate by oxidative carbonylation of phenol using Pd-Cu based redox catalyst system

A catalyst system was designed for direct synthesis of diphenyl carbonate b y oxidative carbonylation of phenol. Besides Pd carbonylation catalyst, ino rganic and organic redox cocatalysts were included in the catalyst system f or in situ regeneration of active Pd species. Copper(II) acetate was used a s inorganic redox cocatalyst and hydroquinone was found to give good result s as organic redox cocatalyst. Efficiency of various bases, effect of a dry ing agent, and optimum reaction conditions for achieving high catalytic act ivity were also investigated in detail. Using suitable components of cataly st system and under optimum reaction conditions, a Pd turnover number of 25 0 could be obtained. (C) 1999 Elsevier Science B.V. All rights reserved.