Process for preparing polycarbonate using certain nitrogen-containing heterocyclic compounds as catalysts

An interfacial polymerization process for preparing high molecular weight aromatic polycarbonates which comprises reacting, under interfacial polycarbonate-forming conditions, a dihydric phenol with a carbonate precursor in the presence of a catalytic amount of from about 0.01 to about 10 weight percent based on the weight of said dihydric phenol of a catalyst selected from a 5 to 8 membered heterocyclic compound characterized in that (i) the ring contains only carbon and nitrogen atoms;

• (ii) the ring contains at least two nitrogen atoms and at least one carbon atom;
• and (iii) the ring is aromatic in character and contains a maximum amount of olefinic unsaturation wherein the ring members are unsubstituted or substituted with at least one substituent group selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl, alkaryl, and aralkyl radicals, with the proviso that if said substituent group is bonded to a ring nitrogen atom, said substituent group is selected from alkyl, substituted alkyl, alkenyl, substituted alkenyl, cycloalkyl, substituted cycloalkyl, and aralkyl radicals.