Compounds of antimony and germanium as catalysts for melt polycarbonate

A method for the preparation of bisphenol A polycarbonate said method comprising contacting at least one diaryl carbonate with bisphenol A in the presence of a transesterification catalyst and optionally a co-catalyst, at a temperature in a range between about 180° C. and about 310° C. and a pressure in a range between about 760 and about 1 torr to afford a product polycarbonate, said transesterification catalyst comprising at least one alkali metal or alkaline earth metal salt of antimony or germanium, said salt having structure I

• (MOn)m(A)p(R1)q I
• wherein M is antimony or germanium, n is an integer in a range from 0 to 4, m is an integer in a range from 1 to 2, A is independently at each occurrence an alkali metal ion or an alkaline earth metal ion, p is an integer in a range from 1 to 4, R1 is an organic ligand having structure III
• and q is an integer in a range from 1 to 2.

A method for the preparation of bisphenol A polycarbonate, said method comprising contacting bisphenol A with diphenyl carbonate at a temperature in a range between about 180° C. and about 310° C. and a pressure in a range between about 760 torr and about 1 torr in the presence of a catalyst having structure IV,

• and tetrabutylphosphonium acetate, said diphenyl carbonate being present in an amount corresponding to between about 0.9 and about 1.2 moles diphenyl carbonate per mole of bisphenol A, said catalyst having structure IV being present in an amount corresponding to between about 1×10−8 and about 2.5×10−4 moles catalyst IV per mole bisphenol A employed, said tetrabutyl phosphonium acetate being present in an amount corresponding to between about 1×10−6 and about 1×10−2 moles tetrabutyl phosphonium acetate per mole bisphenol A employed.