A method for the production of a polyestercarbonate comprises (i) providing at least one dihydroxyaromatic compound (ii) providing a carbonate precursor and (iii) providing at least one solid, biosynthetically derived, aliphatic alpha-omega dicarboxylic acid having about 10 to about 22 carbon atoms and having a nitrogen content of not more than about 55 ppm, and reacting interfacially in the presence of a base said dihydroxyaromatic compound, said carbonate precursor and said dicarboxylic acid.