An efficient catalytic system for the carbomethoxylation of ethylene oxide

Methyl β-hydroxypropionate (MHP), an intermediate to propane-1,3-diol (PDO) was produced in high yield from the carbomethoxylation of ethylene oxide (EO) using a catalytic system consisting of Co2(CO)8 and ZnX2L2 (1: L = pyridine; 2: L = phosphine; X = Cl, Br, I). The carbomethoxylation was greatly influenced by the variation of temperature and CO pressure. The increase of temperature increased the EO conversion, but decreased the selectivity to MHP. On the contrary, both the yield and the selectivity of MHP increased with increasing CO pressure. FT-IR spectroscopic studies show that Co2(CO)8 interacts with (C5H5N)2ZnBr2, affording a new ionic cobalt carbonyl species.