A METHOD OF MELT TRANSESTERIFICATION FOR PREPARING A POLYCARBONATE

摘要

A method of melt transesterification for preparing a polycarbonate, wherein an aromatic polycarbonate is synthesized through the two stages of transesterification and polycondensation under the effect of a coordination compound of alkali metal acetylacetonate serving as the catalyst, with aromatic dihydroxy compounds and aromatic carbonate diesters being the starting material. The amount of the catalyst used is 10-7 - 10-3 mol relative to each molar of the aromatic dihydroxy compound, the reaction temperature is between 100 and 250 °C, and the reaction process is performed in stages of progressively reduced pressure. The prepared polycarbonate product has a higher viscosity-average molecular weight, no color, and a lower viscosity-average molecular weight to number-average molecular weight ratio.