Thermal cross-coupled dimerization of sodium acrylate/crotonate and methacrylate/crotonate binary systems in the solid state

Abstract

The solid state thermal reactions of binary crystals obtained from an equimolar mixture solution of either sodium acrylate/crotonate Na(AA/CA) or sodium methacrylate/crotonate Na(MA/CA) give cross-coupled dimers. The main product obtained in a 51.4% yield from Na(AA/CA) on heating at 250 °C for 2 h is, after conversion to a methyl ester, dimethyl pent-1-ene-3, 4-dicarboxylate, and that from Na(MA/CA) obtained in a 41.7% yield on heating at 230°C for 2 h was dimethyl hex-1-ene-2, 4-dicarboxylate. In either case. X-Ray diffraction analysis of the mixed sodium salts shows a new phase different from that of the individual salt. As dimerization proceeds, a solid solution is formed, resulting in a high selectivity of dimer formation.