Preparation of Cyclic Urethanes from Amino Alcohols and Carbon Dioxide Using Ionic Liquid Catalysts with Alkali Metal Promoters
نویسندگان
چکیده
Several ionic liquids were applied as catalysts for the synthesis of cyclic urethanes from amino alcohols and pressurized CO2 in the presence of alkali metal compounds as promoters. A comparative study was made for the catalytic performance using different ionic liquids, substrates, promoters, and pressures. The optimum catalytic system was BMIM-Br promoted by K2CO3, which, for 1-amino-2-propanol, produced cyclic urethane in 40% yield with a smaller yield of substituted cyclic urea and no oligomeric byproducts. For other amino alcohols, cyclic urethanes, cyclic ureas, and/or undesired byproducts were produced in different yields depending on the substrates used. Possible reaction mechanisms are proposed.
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