Formate Ester Is Not a Decisive Intermediate in the Low-Temperature Synthesis of Methanol from Carbon Dioxide Dissolved in Diethylaminoethanol

Abstract

Alcohols are often discussed as suitable solvents for the low-temperature methanol synthesis. In particular, 2-(diethylamino)ethanol is seen as a promising solvent in this regard because it is already used as a carbon dioxide scrubbing agent. Often observed intermediates in the low-temperature methanol synthesis are alcohol formate esters. This study investigates the formation of 2-(diethylamino)ethanol formate ester and its conversion. Kinetic investigations with 2-(diethylamino)ethanol formate ester as the starting material reveal that the reduction of this ester to methanol is not the only reaction under typical reaction conditions. Two-thirds of the ester decomposes to carbon dioxide and hydrogen, while only one-third is reduced to methanol. Furthermore, it is shown that methanol is also produced in the related hydroxyl-group-free triethylamine. Hence, the formation of formate esters seems to be not a strict requirement for the low-temperature methanol synthesis.