AlCl_3/γ-Al_2O_3催化剂的制备及其催化脱除焦化苯中噻吩的性能

Preparation of AlCl_3/γ-Al_2O_3 Catalyst and Its Performance for Removal of Thiophene from Coking Benzene

采用气相负载法制备了AlCl3/γ-Al2O3催化剂,考察了γ-Al2O3的粒径、温度、时间、AlCl3加入量和载气流量等制备条件对催化剂上噻吩与烯烃烷基化反应活性的影响,并采用Raman光谱、X射线衍射和N2吸附-脱附等技术对样品进行了表征,用气相色谱-质谱联用仪对反应产物进行了定性分析.结果表明,AlCl3主要通过与γ-Al2O3表面–OH结合而有效负载并均匀分布于其表面,制得的AlCl3/γ-Al2O3催化剂对噻吩和烯烃的烷基化反应具有较好的催化能力,反应产物主要是烷基噻吩.在200°C,将3g的AlCl3用100ml/min的N2向10g的γ-Al2O3(0.198～0.246mm)上负载5h,制得的AlCl3/γ-Al2O3催化剂活性最高,在液剂比为20ml/g时,噻吩脱除率可达62.11%.

Thiophene and olefins are the main impurities influencing the grade and quality of coking benzene.The thiophene derivative,which can be formed by the alkylation of thiophene and olefins in benzene,is easy to be removed.A series of AlCl3/γ-Al2O3 catalyst samples were prepared by a gas loaded method and their catalytic activity for the alkylation of thiophene and olefins in benzene was measured.The effects of particle size of support,preparation temperature,preparation time,AlCl3 addition amount,and flow rate of carrier gas on the catalyst activity were investigated.Raman spectroscopy,X-ray diffraction,and N2 adsorption-desorption were used to characterize the samples,and gas chromatography-mass spectroscopy was used to analyze the reaction products.The results suggest that AlCl3 can be effectively loaded by reacting with the-OH group and the active component is uniformly distributed on the surface of γ-Al2O3.The catalytic effect of AlCl3/γ-Al2O3 for the alkylation of thiophene and 1-hexene is obvious and the main reaction product is alkylthiophene.Based on the evaluation results of the catalyst,the optimum preparation conditions of AlCl3/γ-Al2O3 are that 3 g of AlCl3 was loaded on 10 g of γ-Al2O3 with the γ-Al2O3 particle size of 0.198-0.246 mm under N2 atmosphere with a flow rate of 100 ml/min for 5 h at 200 °C,in which the removal efficiency of thiophene can reach 62.11% when the ratio of liquid to catalyst is 20 ml/g.