SELECTIVE CHLORINATION OF GLYCEROL TO 3-CHLORO-1,2-PROPANEDIOL CATALYZED BY BRØNSTED ACIDIC IONIC LIQUIDS

Abstract Brønsted acidic ionic liquids composed of 1-butyl-3-methylimidazolium, triethylbutylammonium, and 1-butylpyridinium cation counterparts and HSO4‾ and H2PO4‾ anion counterparts were used as the catalysts for the selective chlorination of glycerol with hydrogen chloride to 3-chloro-1,2-propandiol. From the perspective of the glycerol conversion and product yields, the catalytic activities of the ionic liquids containing HSO4‾ were higher than the ionic liquids containing H2PO4‾. As compared with the carboxylic acid catalysts, Brønsted acidic ionic liquids favored the catalytic chlorination of glycerol to 3-chloro-1,2-propandiol. When the glycerol chlorination was catalyzed by the Brønsted acidic ionic liquids at 110 ºC for 12 h with the catalyst loading of 0.75 mol·kg‾1 glycerol, the 3-chloro-1,2-propandiol yield was more than 81% at the complete conversion of glycerol.