ZrO2—Dy2O3／SO^2—4—HZSM—5催化剂合成柠檬酸三丁酯的研究

研制了分子筛复合超强酸催化剂ZrO2-Dy2O3/SO^2-4-HZSM-5，以柠檬酸和正丁醇的酯化合成为模型反应，考察了制备条件对催化剂性能的影响。运用AES和XRD分别对催化剂的失活原因和物相组成进行了初步探讨。结果表明，催化剂ZDSH具有良好的催化活性和稳定性。能使柠檬酸的转化率达到97.67％，反复使用5次后活性只下降4.41%；焙烧温度和（NH4）2SO4用量对催化活性有显著的影响；Dy2O3的添加，明显提高了催化剂的稳定性；催化剂的失活主要是由于表面积炭引起的；催化剂中ZrO2主要以T晶相存在。

Preparation of ZrO2-Dy2O3/ SO42--HZSM-5 and its catalytic properties for the synthesis of tri-n-butyl cetricate

A new composite superacid/zeolite catalyst ZrO2-Dy2O3/SO42--HZSM-5(called catalyst ZDSH for short) is prepared. The esterification of citric acid with n-butanol is regard as a model reaction. This paper studied the effect of preparation conditions on catalytic properties. The mechanism of deactivation and phase structure are also analyzed by AES and XRD respectively. The results reveal that the catalyst has high activity and good stability. It makes the conversion of citric acid amout to 97.67% and only decrease by 4.41% after five runs. The catalyst activity can be prominently affected by calcination temperature and the quantity of (NH4)2SO4.The adding of Dy2O3 increased the stability significantly. The main cause of deactivation of catalyst was the carbon deposition and tetragonal crystal system predominated in ZrO2.