Wang Baoyu, Wu Jianmei, Yuan Zhong-Yong, Li Niu, Xiang Shouhe
Institute of New Catalytic Materials Science, College of Chemistry, Nankai University, Tianjin 300071, PR China.
Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, PR China.
Ultrason Sonochem. 2008 Apr;15(4):334-338. doi: 10.1016/j.ultsonch.2007.07.007. Epub 2007 Aug 7.
The synthesis of MCM-22 zeolite under hydrothermal crystallization conditions has been performed by an ultrasonic-assisted aging procedure. The ultrasonic-assisted aging of the initial aluminosilicate gel can shorten the crystallization time of MCM-22, decrease the amount of hexamethyleneimine (HMI) used, and broaden the range of SiO(2)/Al(2)O(3) ratios. By using the ultrasonic aging, pure phase of high-silica MCM-22 products with SiO(2)/Al(2)O(3)>100 can be obtained. When SiO(2)/Al(2)O(3) <or= 50, high crystalline MCM-22 zeolites with the reduced average crystal sizes can be made even with low HMI/SiO(2) ratio of 0.05 under static crystallization conditions. The acoustic cavitation of the ultrasonic is believed to be responsible for these positive results due to its cracking the crystal seeds and improving the solubility of silicate species.
通过超声辅助老化程序在水热结晶条件下合成了MCM-22沸石。初始硅铝酸盐凝胶的超声辅助老化可以缩短MCM-22的结晶时间，减少六亚甲基亚胺（HMI）的用量，并拓宽SiO(2)/Al(2)O(3) 比的范围。通过使用超声老化，可以获得SiO(2)/Al(2)O(3)>100的高硅MCM-22产物的纯相。当SiO(2)/Al(2)O(3)≤50时，即使在静态结晶条件下HMI/SiO(2) 比低至0.05，也可以制备出平均晶体尺寸减小的高结晶度MCM-22沸石。据信，超声的声空化作用因其能使晶种破裂并提高硅酸盐物种的溶解度而导致了这些积极结果。
