Study On The Performance Of Supported Iron-based Ethane Oxychlorination Catalysts

Vinyl chloride is the polymer of polyvinyl chloride,which is one of the world's five most commonly used plastics.At present,there are three methods to produce vinyl chloride at home and abroad,namely ethylene method,acetylene method,and ethane oxychlorination method.ethylene,the feed-stock used in ethylene process,is mainly derived from petroleum.Due to the price of oil and catalysts used in acetylene process are mainly mercury-containing catalysts.The process is easy to pollute the environment so the application of the methods are limited to a certain extent.Ethane oxychlorination method is used to produce vinyl chloride from ethane,hydrogen chloride and air.the main raw materials-ethane and air are widely used and the price is cheap.Only vinyl chloride and water,no pollution to the environment.In comprehensive consideration,ethane oxychlorination is a green and promising preparation of vinyl chloride method.The author chose ferric chloride as the active component and double perovskite La₂FeCoO₆ as auxiliaries.A series of desired catalysts ware synthesized.Finally,the catalytic performance of the catalyst was further improved by using potassium chloride as accelerator.We have explored the interaction between active components,as well as the interaction between potassium chloride,perovskite compounds and active components.The physicochemical properties of the catalysts were studied by means of XPS,H₂-TPR,FT-IR and TG etc.1.The catalysts CoCl₂/?-Al₂O₃,CuCl₂/?-Al₂O₃ and FeCl₃/?-Al₂O₃were synthesized by impregnation method.The catalysts were used to test the activity of ethane oxychlorination.The best catalyst was selected as the main active component.The experimental results show that the best catalyst is Fe-based catalyst—FeCl₃/?-Al₂O₃,and its ethane of conversion is 74.92%and vinyl chloride to conversion is 20.7%.2.we chose double perovskite La₂FeBO₆?B=Co,Cu and Mn?as a co-catalyst.On the basis of the previous chapter,we have studied the effect of B substituted type of double perovskite on the activity of catalytic reaction.Double perovskite compounds La₂FeBO₆?B=Co,Cu and Mn?were prepared by sol-gel method.They were compounded with the prepared active component by mechanical grinding.The activity test showed that the best catalyst was La₂FeCoO₆-FeCl₃-/?-Al₂O₃.its ethane of conversion is 96%and vinyl chloride to conversion is 40%.3.In order to study the effect of perovskite La₂FeCoO₆ mass percent on catalytic reaction,a series of catalysts with 10%,15%,20%,25%,30%and 35%content were prepared.The results show when the percentage content of perovskite La₂FeCoO₆ is 25%,the catalyst has the best activity.XPS analysis showed that the amount of oxygen adsorbed on the surface was higher than that of lattice oxygen,which is helpful to the reaction.4.In order to further improve the performance of the catalyst,we used potassium chloride as an additive.After adding potassium chloride,the reaction performance of the catalyst will be greatly improved.We found that the content of La₂FeCoO₆ will have a certain effect on the catalytic activity,but the effect of potassium chloride will be much greater than that of the content.H₂-TPR analysis showed the reduction peak of iron shifted to high temperature after adding potassium chloride,which indicates that the structure of the catalyst is more stable and shows that potassium chloride can inhibit the interaction among active components,auxiliaries and the support,thus improving the activity of the catalyst.