CARBONYLATION OF FORMALDEHYDE OVER ION-EXCHANGE RESIN CATALYSTS .1. BATCH REACTOR STUDIES

Abstract

Methyl glycolate was synthesized as a precursor to ethylene glycol from the catalytic carbonylation of formaldehyde followed by esterification with methanol. Various cation exchange polystyrene-sulfonic acid resins showed excellent activity and methyl glycolate selectivity. The perfluorinated sulfonic acid resin Nafion-H showed higher activity per proton site, yet was less effective per weight of the catalyst. The effects of process variables such as pressure, temperature, catalyst loading, and solvent were studied. High CO pressures were required to promote formaldehyde carbonylation relative to side reactions between formaldehyde. The presence of water reduced the reaction rate, yet improved the selectivity to methyl glycolate. 1,4-Dioxane was found to be the best solvent in the presence of water. At 135-degrees-C, 3500 psig, and reactant mole ratio of HCHO:H2O:H+ = 10:10:1, complete conversion of formaldehyde was achieved in 2-4 h with selectivities of methyl glycolate better than 80%. Catalysts did not show any significant deterioration in performance in repeated use up to 10 batches.