The Design of a Process

Topics: Catalysis, Hydrogen, Ribozyme Pages: 6 (2320 words) Published: February 1, 2013
Reaction mechanism of tert-butylation of phenol with tert-butyl alcohol over H-beta zeolite: An ONIOM study| 作者: Nie, XW (Nie, Xiaowa)1,3,4; Janik, MJ (Janik, Michael J.)2; Guo, XW (Guo, Xinwen)1; Liu, X (Liu, Xin)1; Song, CS (Song, Chunshan)1,2,3,4| 来源出版物: CATALYSIS TODAY  卷: 165   期: 1   页: 120-128   DOI: 10.1016/j.cattod.2010.11.070   出版年: MAY 16 2011| 被引频次: 2 (来自 Web of Science)|

引用的参考文献: 50 [ 查看 Related Records ]     引证关系图     | 摘要: Tert-butylation of phenol with tert-butyl alcohol (TBA) over H-beta zeolite was studied using the ONIOM approach with two proposed reaction paths: stepwise and concerted mechanisms. The results obtained by the ONIOM2 (B3LYP/6-31G(d,p):UFF) method reveals that the tert-butylation of phenol preferentially occurs through a co-adsorbed, concerted mechanism without prior dehydration of tert-butyl alcohol, rather than via a stepwise mechanism through dehydration to form tert-butyl carbenium ion as the first step followed by tert-butyl cation attack on the 2- or 4-position on phenol. The kinetic difference between 2- and 4-tert-butylation is more apparent in the concerted path, where 4-tert-butylation proceeds over a lower activation barrier. Decreasing the acid site strength, via substitution of Ga for Al, reduces the H-bonding interaction between the zeolitic proton and tert-butyl alcohol and increases the apparent activation barriers, which slows the overall reaction, and also lowers the selectivity to 4-tert-butyl phenol. (c) 2010 Elsevier B.V. All rights reserved.|

Vapor-Phase Alkylation of Phenol with Tert-butyl Alcohol Catalyzed by H3PO4/MCM-41| 作者: Ghiaci, M (Ghiaci, Mehran)1; Aghabarari, B (Aghabarari, Behzad)1| 来源出版物: CHINESE JOURNAL OF CATALYSIS  卷: 31   期: 7   页: 759-764   DOI: 10.1016/S1872-2067(09)60085-1   出版年: JUL 2010| 被引频次: 1 (来自 Web of Science)|

引用的参考文献: 22 [ 查看 Related Records ]     引证关系图     | 摘要: The catalytic performance of Al-MCM-41 containing 5-35 wt% H3PO4 was studied for the vapor phase alkylation of phenol with tert-butyl alcohol (TBA) from 383 to 493 K.4-Tert-butyl phenol was produced as the main product with moderate selectivity. The product distribution depends on the reaction temperature, number of acid sites, and the Bronsted to Lewis sites ratios. A lower molar ratio of reactants (TBA/phenol = 2) and a higher space velocity facilitated the production of 4-tert-butyl phenol. The influence of various parameters such as temperature, reactant feed molar ratio, feed rate, and time on stream were investigated for conversion yield and product selectivity.|

Ab initio study of the selective alkylation of m-cresol with tert-butanol catalyzed by SO3H-functionalized ionic liquids| 作者: Zhou, JX (Zhou, Jinxia)1,2; Liu, XM (Liu, Xiumei)1; Zhang, SG (Zhang, Shuguang)2; Mao, JB (Mao, Jingbo)2; Guo, XW (Guo, Xinwen)1| 来源出版物: CATALYSIS TODAY  卷: 149   期: 1-2   页: 232-237   DOI: 10.1016/j.cattod.2009.07.089   出版年: JAN 15 2010| 被引频次: 0 (来自 Web of Science)|

引用的参考文献: 16 [ 查看 Related Records ]     引证关系图     | 会议: International Symposium on Catalysis 会议地点: Seoul, SOUTH KOREA 会议日期: JUL 21-24, 2008| 摘要: Our previous work showed that for catalytic alkylation of m-cresol with tert-butanol (TBA) SO3H-functionalized ionic liquids exhibited several characteristic advantages over conventional catalysts. This work investigated the reaction mechanism of the alkylation of m-cresol with tert-butanol catalyzed by the SO3H-functionalized ionic liquid (IL) through quantum chemical calculation in combination with the experimental Studies. The experimental results showed that 2-tert-butyl-5-methyl phenol (2-TBC), 4-tert-butyl-3-methyl phenol (4-TBC) and tert-butyl-m-cresol ether (TBMCE) products were all primary products, while 2,6-di-tert-butyl-3-methyl phenol (2,6-DTBC) was a secondary product The calculation results indicated that the selectivities of the products depended on the fundamental natures of the reactive sites, including the orbital overlap, the...
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