N-methyl-2-pyrrolidone-induced conversion of USY into hollow Beta zeolite and its application in the alkylation of benzene with isobutylene
N-methyl-2-pyrrolidone-induced conversion of USY into hollow Beta zeolite and its application in the alkylation of benzene with isobutylene
复制标题
N-甲基-2-吡咯烷酮诱导USY转化为空心Beta沸石及其在苯与异丁烯烷基化反应中的应用
DOI：
10.1016/j.micromeso.2019.109944
复制
发表时间：
2020-03-01
影响因子：
5.2
通讯作者：
Xu, Longya
中科院分区：
文献类型：
--
作者：
Wang, Xinyi;Zhao, Dongpu;Xu, Longya
本文报道了一种在N-甲基吡咯烷酮（NMP）辅助下通过分子筛间转化合成中空结构β沸石的新方法。优化了合成条件，使USY沸石得到纯净中空的Beta沸石。相比之下，在不存在NMP的情况下，获得具有低收率的固体Beta沸石。USY分子筛的使用和NMP的加入是成功合成中空Beta分子筛的重要因素。通过XRD、SEM、TEM和Si-29/Al-27 MAS NMR等表征手段，对超稳Y合成中空Beta沸石的形成机理进行了探讨。USY母体晶体中的硅物种首先溶解，然后在初期生成高SiO2/Al 2 O3摩尔比的初级固体Beta晶体，最后由于初级固体Beta晶体核心中的晶体营养物的溶解-重结晶以及USY的消耗而形成中空Beta沸石。苯与异丁烯烷基化反应的催化性能表明，与由无定形二氧化硅/氧化铝合成的固体Beta相比，所得中空Beta催化剂具有优异的异丁烯转化率和叔丁基苯选择性。
A new synthetic protocol of hollow structured Beta zeolite via interzeolite conversion with the assistance of N-methyl-2-pyrrolidone (NMP) was reported in this work. The synthesis conditions were optimized to obtain the pure and hollow Beta zeolite from the USY zeolite. In comparison, the solid Beta zeolite with low yield was obtained in the absence of NMP. The important factors in successful synthesis of hollow Beta zeolite were the usage of USY zeolite and the addition of NMP. On the basis of the characterization data, such as XRD, SEM, TEM, and Si-29/Al-27 MAS NMR, a formation mechanism for the synthesis of hollow Beta zeolite from USY was proposed and discussed. The silicon species in the parent USY crystals dissolved firstly, afterwards the primary solid Beta crystals with high SiO2/Al2O3 molar ratio were generated at the earlier stage, finally, the hollow Beta zeolite was formed due to the dissolution-recrystallization of the crystalline nutriments located in the core of the primary solid Beta crystals as well as the consumption of USY. The catalytic performance of alkylation of benzene with isobutylene demonstrated that the obtained hollow Beta catalyst exhibited excellent isobutylene conversion and tert-butylbenzene selectivity against the solid Beta synthesized from an amorphous silica/alumina.