The addition of propylene oxide with methanol was carried out over solid bases and a detailed mechanism of the reaction over MgO was investigated by using FT-IR method. It was found that 1-methoxy-2-propanol could be selectively synthesized on MgO, which had base sites of moderate strength, while CaO and Al2O3 showed either low activity or selectivity toward the production of 1-methoxy-2-propanol. In situ FT-IR revealed that methanol dissociation into methoxide and proton took place readily on MgO, and that propylene oxide adsorbed on MgO could generate propylene-like species via carbanion intermediates. As a result, methanol dissociated into adsorbed methoxide and reacted with the propylene-like specie in anti-Markownikov fashion, which led to the high selectivity to 1-methoxy-2-propanol on MgO. (c) 2005 Elsevier B.V. All rights reserved.