Kinetic studies on high-pressure methylation of 2-methylnaphthalene over MTW-type zeolite with different crystal sizes
Kinetic studies on high-pressure methylation of 2-methylnaphthalene over MTW-type zeolite with different crystal sizes
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DOI：
10.1016/j.cej.2016.11.139
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发表时间：
2017-03
影响因子：
15.1
通讯作者：
G. Watanabe;Y. Nakasaka;Taichi Taniguchi;T. Yoshikawa;T. Tago;T. Masuda
中科院分区：
文献类型：
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作者：
G. Watanabe;Y. Nakasaka;Taichi Taniguchi;T. Yoshikawa;T. Tago;T. Masuda
采用间歇式反应器在高压条件下进行了2-甲基萘（2-MN）在MTW型沸石（Si/Al = 100）上的甲基化反应。与宏观尺寸的MTW型分子筛相比，纳米尺寸的MTW型分子筛具有更高的2-MN转化率和二甲基萘（DMN）选择性。此外，焦炭形成的催化剂上可以抑制由于提高所产生的DMN的溶解度，通过增加体相压力，这使得动力学分析的2-MN甲基化超过MTW型沸石。对不同晶粒尺寸的MTW型沸石上2-MN甲基化反应进行了动力学分析，得到了MTW型沸石上2-MN甲基化和异构化反应的速率常数和活化能。减小MTW型沸石的晶粒尺寸可以降低扩散阻力，从而提高2-MN甲基化反应的表观速率常数。此外，2-MN甲基化的有效因子估计的基础上的2-MN甲基化的速率常数和MTW型沸石的晶体尺寸。结果表明，2-MN的甲基化达到反应限制条件所需的MTW型沸石（Si/Al = 100）的晶体尺寸低于240 nm。
Methylation of 2-methylnaphthalene (2-MN) under high-pressure reaction conditions over MTW-type zeolites (Si/Al = 100) was carried out using a batch-type reactor. Compared with macro-sized MTW-type zeolites, nano-sized MTW-type zeolites exhibited higher 2-MN conversion and dimethylnaphthalene (DMN) selectivity. In addition, coke formation on the catalyst could be suppressed due to improvement of the produced DMN solubility by increasing the bulk phase pressure, which enabled kinetic analysis of 2-MN methylation over MTW-type zeolites. Kinetics analysis of 2-MN methylation over MTW-type zeolites with different crystal sizes was successfully carried out, and reaction rate constants and activation energies for methylation and isomerization of 2-MN over MTW-type zeolites were obtained. The apparent reaction rate constants of 2-MN methylation were improved by decreasing MTW-type zeolite crystal size due to decrease in diffusion resistance. Moreover, the effectiveness factors for methylation of 2-MN were estimated based on the rate constants of 2-MN methylation and crystal sizes of the MTW-type zeolites. As a result, it was revealed that the crystal size of MTW-type zeolite (Si/Al = 100) required for methylation of 2-MN to achieve the reaction-limiting condition was below 240 nm.