SiW_(12)/MCM-41催化剂的合成及对三醋酸甘油酯反应的影响

SYNTHESIS OF SiW_(12)/MCM-41 CATALYST AND ITS PERFORMANCE IN SYNTHESIS OF GLYCERYL TRIACETATE

制备了负载H3SiW12O40(SiW12)杂多酸的SiW12/MCM-41催化剂,用XRD等方法对其结构进行了表征。以SiW12/MCM-41为催化剂对合成三醋酸甘油酯的反应进行了研究,并与其它几种分子筛催化剂HMCM-41、Hβ、BAPO-5、SAPO-5的催化性能进行了对比,筛选出合成三醋酸甘油酯的反应性能较好的负载型催化剂SiW12/MCM-41。然后在SiW12/MCM-41催化剂下通过单因素实验对SiW12的负载量、催化剂的活化温度、酸醇摩尔比等因素考察,并对冰醋酸和甘油的酯化反应进行了优化。得出最佳操作条件:SiW12/MCM-41催化剂的最佳负载质量分数为50%,催化剂焙烧温度为300℃,醇酸摩尔比为1∶5,反应温度为125℃,反应时间为4～5h。

SiW12/MCM-41 catalysts consisting of H3SiW12O40(SiW12) heteropoly acid supported on MCM-41, a mesoporous sieve, was prepared and the pore structure was characterized by XRD. The esterification reaction of TCG over loaded SiW12/MCM-41 was investigated and compared with some other kinds of molecule sieve catalysts such as HMCM-41, Hβ, BAPO-5 and SAPO-5. The novel solid heteropoly acid catalyst loaded SiW12/MCM-41 was screened, which was of better reaction performance than others for the synthesis of TCG. The esterification conditions of TCG synthesis catalyzed by loaded SiW12/MCM-41 including the loaded SiW12 quantity, activation temperature of catalyst, the mole ratio of acetic acid to glycerin, etc. were investigated and optimized by single-factor experiment of loaded SiW12/MCM-41. The optimal reaction conditions are obtained-the best quantity of supported SiW12 of the heteropolyacids: SiW12/MCM-41 catalyst is 50%, the best calcinations temperature of catalysts is 300°C, mole ratio of glycerin to acetic acid is 1:5; the reaction temperature is 125°C, the reaction time is 4-5 h.