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.摘要：本研究以由1-丁基-3-甲基咪唑鎓（1-butyl-3-methylimidazolium）、三乙基丁基铵（triethylbutylammonium）与1-丁基吡啶鎓（1-butylpyridinium）作为阳离子组分，硫酸氢根（HSO4‾）与磷酸二氢根（H2PO4‾）作为阴离子组分构建的布朗斯特酸性离子液体（Brønsted acidic ionic liquids）为催化剂，用于甘油与氯化氢的选择性氯化反应以制备3-氯-1,2-丙二醇（3-chloro-1,2-propandiol）。从甘油转化率与产物收率两方面考量，含硫酸氢根的离子液体的催化活性优于含磷酸二氢根的离子液体。相较于羧酸类催化剂，布朗斯特酸性离子液体更有利于催化甘油氯化生成3-氯-1,2-丙二醇。当采用该类布朗斯特酸性离子液体作为催化剂，在110 ℃下反应12 h、催化剂负载量为0.75 mol·kg⁻¹（以甘油计）时，在甘油完全转化的前提下，3-氯-1,2-丙二醇的收率可达81%以上。