Deactivation mechanism of beta-zeolite catalyst for synthesis of cumene by benzene alkylation with isopropanol
Deactivation mechanism of beta-zeolite catalyst for synthesis of cumene by benzene alkylation with isopropanol
复制标题
苯异丙醇烷基化合成枯烯β-沸石催化剂失活机理
DOI：
10.1016/j.cjche.2016.11.001
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发表时间：
2017-09-01
影响因子：
3.8
通讯作者：
Chen, Rizhi
中科院分区：
文献类型：
--
作者：
Liu, Yefei;Zou, Yang;Chen, Rizhi
苯与异丙醇在β沸石上的烷基化反应是生产异丙苯的一种更具成本效益的解决方案。在苯烷基化过程中，异丙苯选择性缓慢上升，而苯转化率由于催化剂失活而急剧下降。通过对新鲜和使用过的催化剂进行表征，研究了β沸石催化剂的失活机理。XRD、SEM和TEM结果表明，在烷基化反应过程中，催化剂的晶型和粒度基本保持稳定。TG、BET、NH_3-TPD和GC-MS结果可以解释催化剂活性和苯转化率的下降。苯烷基化反应中生成的有机物主要是乙苯、对二甲苯和1-乙基-3-（1-甲基）苯，这些有机物沉积在催化剂上，严重降低了β沸石催化剂的比表面积。此外，在反应循环期间，酸度的量也显著降低。结果，发生催化剂失活。为了保持催化剂的性能，催化剂的再生是通过使用乙醇冲洗和焙烧进行。采用焙烧法可以有效地再生失活的催化剂，并获得良好的催化性能。(C)2016中国化学工业与工程学会，化学工业出版社。All rights reserved.
The alkylation of benzene with isopropanol over beta-zeolite is a more cost-effective solution to cumene production. During the benzene alkylation cycles, the cumene selectivity slowly increased, while the benzene conversion presented the sharp decrease due to catalyst deactivation. The deactivation mechanism of beta-zeolite catalyst was investigated by characterizing the fresh and used catalysts. The XRD, SEM and TEM results show that the crystalline and particle size of the beta-zeolite catalyst almost remained stable during the alkylation cycles. The drop in catalytic activity and benzene conversion could be explained by the TG, BET, NH3-TPD and GC-MS results. The organic matters mainly consisted of ethylbenzene, p-xylene and 1-ethyl-3-(1-methyl) benzene produced in the benzene alkylation deposited in the catalyst, which strongly reduced the specific surface area of beta-zeolite catalyst. Moreover, during the reaction cycles, the amount of acidity also significantly decreased. As a result, the catalyst deactivation occurred. To maintain the catalytic performance, the catalyst regeneration was carried out by using ethanol rinse and calcination. The deactivated catalyst could be effectively regenerated by the calcination method and the good catalytic performance was obtained. (C) 2016 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.