The Study On Ethane Oxychlorination Reaction Catalyst Properties And Deactivation

Ethane oxychlorination reaction was studied beginning in the 20th century 90, their constraints were mainly in the low thermal stability and short life of catalysts. In this paper, we used high thermal stability double perovskite oxide as a catalyst to solve the defect, created the conditions for Large-scale industrial production.The perovskite-type composite oxides La2CuBO6 (B=Fe, Co, Ni) were synthesized by the sol-gel method and characterized by means of XRD, XPS, H2-TPR, FT-IR, BET, SEM, magnetic properties, TG-DSC and ICP-AES. Meanwhile, we investigated catalytic activities, deactivation reason and reaction condition of three catalysts with ethane oxychlorination reaction.The results showed La2FeCuO6,La2CoCuO6,La2NiCuO6 catalysts all formed the double perovskite type oxides by annealing at 900℃under air atmosphere for 4 h. Among the three kinds of catalysts, the La2FeCu06 had the highest conversion rate of ethane which reached 76.8%, the La2NiCuO6 had the highest selectivity of vinyl chloride reached 42%. And the thermal stability of three catalysts were better than traditional Cu-K-La/γ-Al2O3 catalyst. Considering the yield of vinyl chloride, we thought the activity of La2FeCu06 catalyst was the best. And from characterization results of tests, we also found the selectivity of vinyl chloride was affected by electronegativity of B site metal ions on perovskite, the ethane conversion rate was affected by oxygen vacancy concentration over catalyst.We used orthogonal test studied reaction temperature, catalyst amount, feed ratio and reaction time on the ethane oxychlorination reaction. And the results indicated that the reaction temperature and catalyst amount had significant influence to ethane conversion, the reaction temperature and HCl flow rate had significant influence to vinyl chloride selectivity.We also studied the catalyst deactivation factors. The result showed with the reaction conducted, La2FeCuO6 structure gradually collapsed, the LaOCl structure gradually formed at the same time. The catalyst were embedded by carbon deposition. Cu as the active component of the catalyst had lossed serious, which was the major constraining factor in the thermal stability of the catalyst.