Patent ID: 6608164
Filing Date: 2003-08-19
Classification: C08G

Abstract:
A method for the preparation of polycarbonate, said method comprising contacting at least one diaryl carbonate with at least one dihydroxy aromatic compound in the presence of a transesterification catalyst and optionally a co-catalyst, under melt polymerization conditions to afford a polycarbonate, said transesterification catalyst comprising at least one alkali metal or alkaline earth metal salt of a heterocyclic diol, said salt of a heterocyclic diol having structure I wherein A is independently at each occurrence an alkali metal ion or an alkaline earth metal ion; p is an integer having a value of 1 or 2; R1 and R2 are independently at each occurrence a halogen atom, cyano group, nitro group, C1-C20 alkyl group, C4-C20 cycloalkyl group, C4-C20 aromatic group, C1-C20 alkoxy group, C4-C20 cycloalkoxy group, C4-C20 aryloxy group, C1-C20 alkylthio group, C4-C20 cycloalkylthio group, C4-C20 arylthio group, C1-C20 alkylsulfinyl group, C4-C20 cycloalkylsulfinyl group, C4-C20 arylsulfinyl group, C1-C20 alkylsulfonyl group, C4-C20 cycloalkylsulfonyl group, C4-C20 arylsulfonyl group, C1-C20 alkoxycarbonyl group, C4-C20 cycloalkoxycarbonyl group, C4-C20 aryloxycarbonyl group, C2-C60 alkylamino group, C6-C60 cycloalkylamino group, C5-C60 arylamino group, C1-C40 alkylaminocarbonyl group, C4-C40 cycloalkylaminocarbonyl group, C4-C40 arylaminocarbonyl group, and C1-C20 acylamino group; andX is sulfur, oxygen or the group NR3, wherein R3is hydrogen, a C1-C40 alkyl group, a C1-C40 acyl group, C1-C40 alkoxycarbonyl group, a C4-C40 cycloalkyl group, or a C4-C40 aryl group.