Ultrafast and Continuous Flow Synthesis of Silicoaluminophosphates

作者：Liu Zhendong; Wakihara Toru; Nomura Naoki; Matsuo Takeshi; Anand Chokkalingam; Elangovan Shanmugam P; Yanaba Yutaka; Yoshikawa Takeshi; Okubo Tatsuya

来源：Chemistry of Materials, 2016, 28(13): 4840-4847.

DOI：10.1021/acs.chemmater.6b02141

Silicoaluminophosphates are a class of crystalline microporous materials that have been widely used as catalysts and adsorbents. Two representative silicoaluminophosphates, SAPO-CHA (also called SAPO-34) and SAPO-AFI (also called SAPO-5), were synthesized in a tubular reactor within 10 min and 5 min, respectively. The addition of a milled seed with small crystal size, the pretreatment of Al and Si sources by mechanical milling and the employment of high temperature condition were found to be the critical factors that contributed to the enhancement of crystallization rate of SAPO-CHA. The fast synthesized SAPO-CHA possesses only isolated Si(OAl)4 species, indicating a great potential in catalytic applications. SAPO-CHA and SAPO-AFI usually appear as a pair of competing phases during the synthesis of SAPO-CHA/SAPO-AFI because of similarities in chemical compositions and formation conditions. Here we show that owing to the feature of rapid heating, the tubular reactor demonstrated itself as a facile and precise platform to control over the phase selection between SAPO-CHA and SAPO-AFI by tuning the crystallization kinetics, which could not be realized in the conventional autoclaves. A continuous flow process was also established to synthesize these two silicoaluminophosphates with high efficiency and flexibility. These results demonstrate a comprehensive strategy to achieve the minute-order synthesis of two important silicoaluminophosphates, and could be very useful to direct the ultrafast synthesis of other crystalline materials.

• 出版日期2016-7-12