【摘要】 首次将二氯二茂钛用于碳酸二甲酯和苯酚酯交换合成碳酸二苯酯的反应,发现二氯二茂钛对该反应来讲是一种性能优良的催化剂;和钛酸酯类催化剂相比,茂钛类催化剂在空气中更稳定,从而更适合于工业化应用.同时探讨了不同种类茂钛类化合物的催化性能,发现位阻效应、环戊二烯环的电子分散效应以及取代基的吸电子效应等,都会影响中心钛原子的Lewis酸性以及相应的催化活性.总体来讲,位阻效应越小、环戊二烯环的电子分散效应越大、与中心钛原子连接的取代基的吸电子能力越强,越有利于反应的进行.更多还原

【Abstract】 Titanocene dichloride Cp2TiCl2 was found to be a novel and efficient catalyst for the transesteri- fication between dimethyl carbonate and phenol to produce diphenyl carbonate. Cp2TiCl2 is more stable in air and more convenient for industrial application than titanium esters. Various titanocene complexes were used as catalysts for the transesterification on the basis of Cp2TiCl2. It was found that titanocene catalysts modified by various substituents would strongly influence the steric and electronic properties of the catalytic centers, the stability of the transition states, and their catalytic behaviors. When the substituent was smaller and more electron withdrawing, or the substituent could make the transition state more stable, the reaction would take place with better results.更多还原