424783 Mesoporous Silica Supported Ionic Liquids Catalyst for the Alkylation of Benzene with 1-Dodecene

Wednesday, November 11, 2015: 5:15 PM
355A (Salt Palace Convention Center)
Yibo He, Qinghua Zhang, Xiaoli Zhan, Dang-guo Cheng and Fengqiu Chen, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China

Linear alkyl benzene (LAB), which is a major feedstock for synthetic detergent, is synthesized via Friedel-Craft alkylation of benezene with 1-dodecene. LAB is produced industrially over HF or AlCl3 homogenous catalyst. Yet, environmental contamination and difficulty in separation are still the concerns shared by many manufacturers. The urge to solve such problems spurred us to employ heterogeneous catalyst in this reaction.

Ionic liquids, with their fine properties, attracted much interest in recent years. In this work, ionic liquids consisted of Bis[(perfluoroalkyl)sulfonyl]imides group was synthesized, which contained "weak-coordination" anion group. For the stable and hydrophobic properties of perfluoroalkyl groups, these kinds of ionic liquids catalysts exhibited characteristics, which were more durable, safe and environment-friendly, comparing with HF or AlCl3(Figure 1 (a)). Moreover, with Ionic liquids entrapped in the channel of SiO2, ionic liquids catalyst were immobilized on ordered mesoporous silica, revealed by TEM and BET (Figure 1 (b)). After immobilization, the pore size of mesoporous silica decreases from 6.7nm to 5.5nm, and specific surface area decreases from 751m2/g to 323 m2/g. Larger specific surface area of the immobilized catalysts created a larger reaction surface which enhanced mass transfer and diffusion, led to higher catalytic activity. Such catalyst structures shared properties from both the stability of ionic liquids and high reactivity of mesoporous zeolites. The study of catalytic behavior proved the immobilized catalysts to be active and stable over the alkylation of benzene with dodecene. Dodecene conversion could reach nearly 100% in 1h with 2-LAB selectivity of more than 50%. With advances in separation and recovery combined with high selectivity and activity, these catalysts would be promising in industrial production.

Figure 1. (a) The reusability of the ionic liquid catalyst. (b) Illustration to the structure of mesoporous silica supported ionic liquids catalyst

*Corresponding author. Tel.: 86-0571-87953382, 86-0571-87952728

E-mail: qhzhang@zju.edu.cn (Qinghua Zhang)

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