Metathesis Of Ethene And Butene To Propene Upon Molybdenum And Tungsten-based Catalysts Supported On Zeolite-alumina

The metathesis between ethene and 2-butene to propene is an important technology for the increment of propene output. This dissertation focus on the invention of Mo and W based catalysts, which are highly active at relative low reaction temperatures. The influence of reaction conditions and the related mechanism aspects are also investigated.Several MoO₃ catalysts supported on zeolite-alumina are prepared, with high activity and selectivity under 60～120℃. The effects of reaction conditions, pretreatment conditions and promoter, along with the deactivation-regeneration, are investigated on MoO₃/MCM-22-Al₂O₃.On the basis of these understanding, a highly active WO₃/Al₂O₃-HY catalyst is also prepared, whose 2-butene conversion is close to the thermodynamic equilibrium value. The catalytic performance depends on the reaction conditions, especially the temperature and pressure. Under conditions of 180℃, 0.5～0.8 MPa, WHSV= 0.83 h^-1 and ethene/2-butene= 2.5～3.5 (molar ratio), the catalyst can be operated 50 hours with 2-butene conversion and propene selectivity higher than 80% and 88% respectively.By investigating the effect of HY zeolite content on the catalytic performance of 10WO₃/Al₂O₃-70HY, the Br(o|¨)nsted acidity of catalysts and the interaction between tungsten species and alumina-HY support demonstrate their important roles in the metathesis. The study of preparation methods and tungsten loading on...