Abstract: 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.

Key words: aluminum chloride, alumina, thiophene, olefin, alkylation, benzene