| abstract |
A melt transesterification process for the production of polycarbonates, wherein at least one bis(aryl)carbonate is reacted with at least one dihydric phenol in the melted state, in the presence of a transesterification catalyst comprising at least one heterocyclic borate salt of the formula: n n n n M⁺B(R) n (A)⁻ 4-n (I) n n n nwhere M⁺ is an alkali metal, tetra-alkylammonium, tetra-arylammonium, tetra-alkylphosphonium and tetra-arylphosphonium ion; R is H, alkyl, aryl or aralkyl; n is an integer from 0-3; and A is an aromatic or aliphatic heterocyclic ring. |