碳基固体酸催化合成环己酮甘油缩酮的研究

摘要

Amorphous carbon material prepared from expanded starch and p—toluene sulfonic acid had been examined as a novel strong solid acid catalyst. The catalytic performances were studied on condensation of cyclohexanone with glycerol and characterized by XRD, IR,elementary analysis and TGA. The effects of molar ratio of glycerol with cyclohexanone, catalyst concentration and reaction time were discussed. The results of XRD and acid— base titration indicate the incompletely carbonization of the mixtures of expanded starch and p—toluene sulfonic acid results in amorphous carbon consisting of small polycyclic aromatic carbon sheets with high density of —SO3 H groups. When the condensation reaction was carried out with n (glycerol)/n(cyclohexanone) 1.2, mass fraction of catalyst 10 ％, cyclohexane 15 mL(Accounts for 10 ％ of the total amount of liquid reactant ) and refluxe time of 120 min, the maximum yield of ketals is 99. 2％. There was very little change in the catalytic activity of the regenerated catalyst,even after eight cycles.%利用膨化淀粉与对甲基苯磺酸的部分炭化过程制备碳基固体酸催化剂,用XRD、红外光谱、元素分析和热分析进行了表征,研究了碳基固体酸催化剂在环己酮甘油缩酮合成中的催化性能,考察甘油与环己酮物质的量比、催化剂用量和反应时间等因素的影响.XRD分析和酸碱电位滴定结果表明,膨化淀粉和对甲基苯磺酸混合物的部分炭化生成含有高密度-SO3H基团的芳香碳薄层组成的无定形碳.在n(甘油)/n(环己酮)=1.2、催化剂的质量分数为10%、环己烷15 mL(占液体反应物总量的10%)和回流反应时间为120 min的条件下,环己酮甘油缩酮的收率可达到99.2%.催化剂重复使用8次后,活性下降很小.