Substitution Of Ortho/Mono-TeMo₅O₁₆ Catalysts In Propane Selective Oxidation

The storage of natural gas is rich and could be renewed from various sources in China.Propane is one of the important short chain components in natural gas and the selective oxidation of propane is promising for its potential in industrial application and academic study.However,due to the chemical stability of propane and the activity of acrolein,this reaction required a multiple functional catalyst and no great progress was made in this field.Thus,attentions should be paid on the topic,especially in the study of the catalytic process.Mo-Te-O systems are the most promising catalysts in this field,but most of the studies focus on the M1 and M2 phase and the ortho-/mono-TeMo₅O₁₆ related areas are remained unknown.In the reaction of selective oxidation of propane,the application of ortho-/mono-TeMo₅O₁₆ catalysts is based on the Mars van Krevelen mechanism. The mixed metal and multiple function reaction sites is the key factor in the catalysts and of great importance in the study.The transition metal elements with various oxidation states could be introduced into the catalysts and mortify the performance of catalysts.In order to study the relationship between the structure and properties as well as optimize the components of catalysts,the transitional elements were doped in the ortho-/mono-TeMo₅O₁₆ catalysts.The first chapter gives a brief introduction on the selective oxidation of propane into acrolein.The values of study were described in the terms of economy and academic study.The main advances in this field were introduced and the mechanism,the essential factors in the catalysts and reaction was explained. Furthermore,the topic and scope of this paper were introduced.The details of experimental method were described in the second chapter, including the synthesis of catalysts,the reevaluation and characterization of the catalysts and the relate methods to deal with the data.The third chapter studies the ortho-TeMo₅O₁₆ catalyst and its substitution. Various amounts of V,Cr and W elements were doped and those catalysts were applied in the selective oxidation of propane.The activity,selectivity and stability of catalysts were recorded.The catalysts were characterized by CH₃OH-TPSR, C₃H₈-TPSR,Raman,XPS,XRD,H₂-TPR and O₂-TG.The properties both in the surface and bulk of the catalysts were studied.Studies showed that the doped ortho-TeMo₅O₁₆ catalysts could be used in the reaction as the prospective catalysts.Similar studies were carried on the mono-TeMo₅O₁₆ catalysts with various amounts of V,Cr and W elements.The reaction was carried out in different temperature.The results showed although the subsititution also improved the catalytic peformance,the mono-TeMo₅O₁₆ catalysts were not as good as ortho-TeMo₅O₁₆ catalysts.In conclusion,the main results of this paper were that some effective catalysts were found in the research.The highest yield reaches 20%which is an outstanding number in this field.At the same time,the research showed the structure,the properties and their relationship in the doped ortho-/mono-TeMo₅O₁₆ catalysts, which would benefit the study in the partial oxidation of paraffin.