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作 者:王胜平[1] 马新宾[1] 郭宏利[1] 李振花[1] 王保伟[1] 许根慧[1]
机构地区:[1]天津大学化工学院一碳化学与化工国家重点实验室,天津300072
出 处:《化学反应工程与工艺》2003年第2期188-192,共5页Chemical Reaction Engineering and Technology
基 金:国家自然科学基金(20276050);天津市科技攻关培育项目;高等学校骨干教师资助计划项目。
摘 要: 研究了Lewis酸催化剂催化苯酚和草酸二甲酯酯交换合成草酸二苯酯(DPO)反应。考察了不同Lewis酸催化剂对DPO合成反应的催化活性和Lewis酸催化剂的酸性对催化性能的影响,确定了弱酸中心促进主产物甲基苯基草酸酯(MPO)和DPO的生成,而强酸中心有利于副产物苯甲醚的生成。以弱酸TS-1分子筛为催化剂,MPO和DPO总选择性为99.2%。以强酸AlCl3为催化剂,苯甲醚选择性达到60.4%。探讨了Lewis酸催化剂催化苯酚和草酸二甲酯酯交换合成草酸二苯酯反应机理。Lewis酸催化苯酚和DMO酯交换合成MPO反应是按酰氧键断裂的反应历程进行的,DMO中和羰基相连的给电子基的-COO-基团及较大的基团体积降低了苯酚和DMO酯交换合成MPO反应的反应活性。而苯酚和DMO甲基化反应生成苯甲醚是按烃氧键断裂的反应历程进行的。Diphenyl oxalate was prepared by the transesterification of dimethyl oxalate with phenol over Lewis acid catalysts. The activities of catalysts for the transesterification of dimethyl oxalate with phenol were evaluated. The acid strength of the catalysts had a significant influence on the selectivity of products. The weak acid sites were in favor of the production of MPO and DPO, while the strong acid sites took advantage of formation of byproduct anisole. The total selectivity of methylphenyl oxalate (MPO) and DPO was up to 99.2% over TS1, which was a weak acid. When AlCl3, as a strong acid, was used for the transesterification, selectivity of anisole was 60.4%. The reaction scheme of diphenyl oxalate synthesis by the transesterification of dimethyl oxalate was proposed.
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