乙酰丙酮氧钛催化苯酚和碳酸二甲酯的酯交换反应

Transesterification of Phenol and Dimethyl Carbonate Catalyzed by Titanium Oxide Acetylacetonate Catalyst

首次将乙酰丙酮氧钛用于苯酚和碳酸二甲酯的酯交换反应合成碳酸二苯酯,显示出较好的催化活性和很高的酯交换选择性,催化剂经180℃热处理后,苯酚转化率可达45.8%,转化数(n(苯酚)/n(Ti))为96,高于有机钛类均相催化剂.结果表明,当乙酰丙酮氧钛用量为0.2g以上,开始有副产物苯甲醚生成,酯交换选择性随催化剂用量的增加而降低.该催化剂重复使用5次后,苯酚转化率仍可达40%以上,酯交换选择性为99.9%,表现出较高的重复使用性能.

Titanium oxide acetylacetonate（TiO（acac） 2） was found to be a novel and efficient heterogeneous catalyst for the transesterification of phenol and dimethyl carbonate（DMC） to diphenyl carbonate（DPC）.The conversion of phenol was 45.8% on the TiO（acac）2 pretreated at 180 ℃,and the turnover number reached 96,which was better than the more common organic titanium catalyst.The effect of the amount of catalyst on the catalytic performance was investigated.The transesterification selectivity decreased with catalyst loadings over 0.2 g per 100 ml reactants.At the optimized amount of catalyst the conversion of phenol was 42.4%,and no anisole was detected.In particular,the TiO（acac） 2 catalyst proved reusable,and catalytic activity of the recovered TiO（acac） 2 was almost the same as that of the fresh catalyst.The conversion of phenol 40.0% was attained from TiO（acac） 2 recovered for the fifth time.