2001 Volume 59 Issue 8 Pages 790-799
New catalyst systems for the direct synthesis of diphenyl carbonate (DPC) from carbon monoxide (CO) and phenol were investigated. Palladium-tin complexes [Pd2(dPPm)2(SnCl3) Cl and Pd2(dppm)2(SnCl3)2, dppm : bis (diphenylphospino) methane] with manganese redox catalyst [Mn(TMHD)3, TMHD : 2, 2, 6, 6-tetramethyl-3, 5-heptanedionate] were found to produce DPC effectively without any addition of ammonium halide. Furthermore, palladium catalyst systems such as, palladium dinuclear complexes, palladium-diimine complexes, and palladium-6, 6'-disubstituted-2, 2'-bipyridyl complexes promoted the oxidative carbonylation of phenol more effectively in the presence of ammonium halide. Especially, the efficiencies of Pd2(Ph2PPY)2(NO2)2(Ph2PPy : 2-pyridyldiphenylphosphine) and Pd(6, 6'-Me2bpy)Cl2(6, 6'-Me2bpy : 6, 6'-dimethyl-2, 2'-bipyridyl) were highest among these palladium complexes. These palladium catalyst systems were applied for the direct synthesis of polycarbonate (PC) from bisphenol A and CO. PC with the number-and weight-average molecular weights of 5600 and 12900 respectively, was successfully obtained using Pd (6, 6'-Me2bpy) Cl2 catalyst system. These molecular weights were highest among the direct syntheses of PC by oxidative carbonylation.
