Studies on mechanism for homogeneous catalytic hydration of ethylene oxide: Effects of pH window and esterification

Selective hydration of ethylene oxide (EO) was investigated with several inorganic salt systems as homogeneous catalysts. By optimizing reaction conditions, the highest monoethylene glycol (MEG) selectivity of 98% was obtained with >99% EO conversion at a water/EO molar ratio = 10. The effects of pH value and anion addition–esterification on MEG selectivity were systematically studied, and a comprehensive mechanism was proposed based on the results. The conclusion should be useful in developing high performance catalysts for the manufacture of MEG by EO hydration at a low water/EO ratio.