Process for preparing polycarbonate using sterically hindered secondary amine catalysts

An interfacial polymerization process for preparing a high molecular weight aromatic polycarbonate which comprises reacting, under interfacial polycarbonate-forming conditions, a dihydric phenol with a carbonate precursor in the presence of a catalytic amount of a sterically hindered secondary amine, or its acid addition salt, of the formula ##STR12## wherein R is selected from the group consisting of C.sub.5 to C.sub.30 linear alkyl radicals, substituted C.sub.3 to C.sub.30 linear alkyl radicals, C.sub.3 to C.sub.30 branched alkyl radicals, substituted C.sub.3 to C.sub.30 branched alkyl radicals, C.sub.5 to C.sub.30 linear alkenyl radicals, substituted C.sub.5 to C.sub.30 linear alkenyl radicals, C.sub.3 to C.sub.30 branched alkenyl radicals, substituted C.sub.3 to C.sub.30 branched alkenyl radicals, C.sub.3 to C.sub.12 cycloaliphatic radicals, substituted C.sub.3 to C.sub.12 cycloaliphatic radicals, heterocyclic ring radicals containing 3 to 12 ring carbon atoms and one atom selected from the group consisting of oxygen and sulfur, substituted heterocyclic ring radicals containing 3 to 12 ring carbon atoms and one atom selected from the group consisting of oxygen and sulfur, C.sub.7 to C.sub.20 aralkyl radicals, and substituted C.sub.7 to C.sub.20 aralkyl radicals;

• and R.sup.1 is selected from the group consisting of C.sub.1 to C.sub.30 alkyl radicals, substituted C.sub.1 to C.sub.30 alkyl radicals, C.sub.3 to C.sub.12 cycloaliphatic radicals, substituted C.sub.3 to C.sub.12 cycloaliphatic radicals, C.sub.2 to C.sub.30 alkenyl radicals, substituted C.sub.2 to C.sub.30 alkenyl radicals, heterocyclic ring radicals containing 3 to 12 ring carbon atoms and one atom selected from the group consisting of oxygen and sulfur, substituted heterocyclic ring radicals containing 3 to 12 ring carbon atoms and one atom selected from the group consisting of oxygen and sulfur, C.sub.7 to C.sub.20 aralkyl radicals, and substituted C.sub.7 to C.sub.20 aralkyl radicals.