焦化苯中噻吩烷基化反应的AlCl3/硅胶催化剂的性能优化

Study on Modification Conditions and Performance of AlCl3/Silica Catalyst for Thiophene Alkylation Reaction in Coking Benzene

用盐酸溶液对硅胶的表面进行处理,以其为催化剂载体、以无水AlCl3为活性组分前驱体,采用加压负载法制备了一系列AlCl3/硅胶催化剂。采用含有1-己烯、1-戊烯或苯乙烯的噻吩-苯溶液为焦化苯模拟溶液,考察了AlCl3与硅胶载体质量比、盐酸的处理温度及时间对AlCl3/硅胶催化剂转化噻吩性能的影响,考察了烯烃的种类及含量对噻吩转化率的影响,测试了催化剂的循环利用性能。结果表明,AlCl3与载体的质量比会影响AlCl3/硅胶催化剂中活性组分的含量及存在形式,从而影响催化剂的活性。其中,硅胶于浓度为0.05 mol/L的盐酸中、15℃下浸泡12 h,AlCl3与硅胶载体质量比为0.25的条件下所制的催化剂活性最高,噻吩转化率为97.66%。模拟焦化苯溶液中烯烃的种类及含量是影响噻吩转化率的重要因素,当苯乙烯与噻吩的摩尔比为4时,噻吩的转化率较高,可达到88.30%。催化剂的再生可提高其性能,未再生的AlCl3/硅胶催化剂,在使用第5次后噻吩转化率由新鲜催化剂的97.66%降至22.96%,与之相比,再生后的AlCl3/硅胶催化剂在循环使用第5次后,噻吩转化率仍在60%以上。

The surface of silica gel was modified with hydrochloric acid solution.Then,a series of AlCl3/silica gel catalysts were prepared by pressure loading method with the modified silica gel as the carrier and anhydrous AlCl3 as the active component precursor.By using a thiophene-benzene solution containing 1-hexene,1-pentene,or styrene as a simulated solution,the effects of mass ratio of AlCl3 to silica gel carrier,hydrochloric acid treatment temperature and time on the desulfurization efficiency on AlCl3/silica gel catalyst were investigated,the effects of olefin type and content on thiophene conversion were studied,and the reuse performance of catalyst was tested.Results indicate that the ratio of AlCl3 to the carrier affected the content and form of the active component in the AlCl3/silica gel catalyst,thereby affecting the activity of the catalyst.The catalyst prepared by immersing the carrier in hydrochloric acid at a concentration of 0.05 mol/L for 12 h at 15℃,loading 2.5 g of active component AlCl3 per 10 g of carrier has the highest catalytic activity,and the conversion rate of thiophene is 97.66%.The type and content of olefins in the simulated solution are also important factors affecting the removal rate of thiophene,when the molar ratio of styrene to thiophene in coking benzene is 4,the conversion rate of thiophene reaches 88.30%.The performance of unregenerated AlCl3/silica gel catalyst reduces from 97.66%of fresh catalyst to 22.96%after the fifth use.Compared with that of the unregenerated catalyst,the thiophene conversion rate of the regenerated AlCl3/silica gel catalyst is still above 60%at fifth recycle.