Patent ID: 6548623
Filing Date: 2003-04-15
Classification: C08G

Abstract:
A method of preparing polycarbonate comprising heating a mixture comprising a catalyst; at least one diaryl carbonate having structure I wherein R1 and R2 are independently C1-C20 alkyl radicals, C4-C20 cycloalkyl radicals, or C4-C20 aromatic radicals, R3 and R4 are independently at each occurrence a halogen atom, cyano group, nitro group, C1-C20 alkyl radical, C4-C20 cycloalkyl radical, C4-C20 aromatic radical, C1-C20 alkoxy radical, C4-C20 cycloalkoxy radical, C4-C20 aryloxy radical, C1-C20 alkylthio radical, C4-C20 cycloalkylthio radical, C4-C20 arylthio radical, C1-C20 alkylsulfinyl radical, C4-C20 cycloalkylsulfinyl radical, C4-C20 arylsulfinyl radical, C1-C20 alkylsulfonyl radical, C4-C20 cycloalkylsulfonyl radical, C4-C20 arylsulfonyl radical, C1-C20 alkoxycarbonyl radical, C4-C20 cycloalkoxycarbonyl radical, C4-C20 aryloxycarbonyl radical, C2-C60 alkylamino radical, C6-C60 cycloalkylamino radical, C5-C60 arylamino radical, C1-C40 alkylaminocarbonyl radical, C4-C40 cycloalkylaminocarbonyl radical, C4-C40 arylaminocarbonyl radical, or C1-C20 acylamino radical; and b and c are independently integers 0-4; and at least one dihydroxy aromatic compound; said catalyst comprising at least one source of alkaline earth ions or alkali metal ions, and at least one quaternary ammonium compound, quaternary phosphonium compound, or a mixture thereof, said source of alkaline earth ions or alkali metal ions being present in an amount such that between about 10âˆ’5 and about 10âˆ’8 moles of alkaline earth metal ions or alkali metal ions are present in the mixture per mole of dihydroxy aromatic compound employed, said quaternary ammonium compound, quaternary phosphonium compound or mixture thereof being present in an amount between about 2.5Ã—10âˆ’3 and about 1Ã—10âˆ’6 moles per mole of dihydroxy aromatic compound employed.