Polycarbonate is synthesized by melt transesterification of diphenyl carbonate (DPC) with bisphenol A (BPA).The catalytic activity of metal acetylacetonates and the effects of the stronger or weaker bond between the catalyst and the reactant

catalyst concentration

initial monomer molar ratio

initial pressure and temprature are investigated.The logarithms of the stability constants (lg1) of dibenzoyl methane (DBM) complexes of the corresponding metal species are regarded as corresponding to the bond strength between metal species (catalyst) and benzoyl group (reactant)

which are correlated by double volcanoes-shaped relationship with the intrinsic viscosity ([]) of the PC produed with the corresponding metal acetylacetonates as catalysts.Consequently

the catalytic activity of the metal compounds is affected by the basic of acetylacetonate anion and the chelating capacity of each metal species

which is found to be very useful in forecasting the catalytic activity of the metal compound.In all the catalysts

lithium acetyacetonate (LiACAC) is the best one

by which the sample catalyzed has the lowest fries level and polydispersity index (PDI= 2.12)

besides its colorless and high molecular weight ([]= 0.710 dLg-1) .Our study exhibites that the best reagent molar ratio:nBPA∶nDPC∶nLiACAC= 1.0∶1.08∶1.510-4

the optimal initial pressure in the transesterification stage:4000 Pa and the optimal melt polymerization temperature 260℃.