沸石分子筛催化苯甲醚与苯甲酰氯的苯甲酰化反应

分别采用五种H型沸石在无溶剂条件下催化了苯甲醚与苯甲酰氯的苯甲酰化合成4-甲氧基二苯甲酮.各种沸石的酸中心分布和孔道结构各不相同,使其表现出不同的催化效果.Hβ沸石的三维孔道和集中的中强酸中心为反应提供了适宜的条件,使苯甲酰氯的转化率和4-甲氧基二苯甲酮的选择性分别可达99.5%和91.2%.Pyrid ine-FT-IR结果表明B酸中心为H型沸石主要酸中心,H+为催化活性点;NH3-TPD谱图表明中强酸中心是苯甲酰化反应的合适酸中心,据此提出了H型沸石催化苯甲醚苯甲酰基化的反应机理.

Benzoylation of Anisole by Benzoyl Chloride Over Zeolite Catalysts

Five kinds of zeolites were studied in benzoylation of anisole with benzoyl chloride for 4-methoxybenzophen one (4-MBP) without polar solvent, and showed quite different catalytic activities due to their wide acid sites distributions and various pore structures. Hβ zeolite was found to be the best in activity and selectivity ( conversion of benzoyl chloride and selectivity for 4-MBP would be 99.5 % and91.2 %, respectively) because of the nature of three-dimensional pore structure and the presence of concentrated moderate strong acid sites. The results from pyridine-FT-IR spectrometry indicated that the main acid sites of H-zeolites were Bronsted acid sites, and H + was the catalytic acid site. The results from the NH3-TPD (NH3-temperature programmed desorption) profiles showed that the moderate strong acid sites were the appropriate acid sites. The mechanism for such catalysis was proposed and discussed.