Carbonylation of Formaldehyde Catalyzed by Copper(I) and Silver Carbonyls

Abstract

Carbonylation of formaldehyde by CO (1atm) was carried out at room temperature using [Cu (CO)n ]+ or [Ag (CO)₂]+ in strong acids as a catalyst. Glycolic acid or its ester was obta ined in high yield without side reaction. Rate constants of carbonylation increased 30 times in the presence of the catalysts (Fig.3∼6). The sufficient concentrations of the copper ( I ) and silver compounds were 0.2 and 0.4 mol/l, respectively, in sulfuric acid, and 0.05 mol/l in boron trifluoride hydrate to carry out carbonylation rapidly. The CO concentration in the catalyst solution decreased in the order:
The rate of carbonylation decreased in the same order at the same molar concentration of the copper ( I ) or silver compound. The rate decreased with the decrease of the acid concentratio n in each system. Carbonylation hardly proceeded in solutions less concentrated than 84.5%H₂SO₄, and H₂O/BF₃= 2. After the reaction, methyl glycolate was separated by vacuu m distillation and the catalyst solution was used again.