Modification And Catalytic Performance Of SO₄^2-/M_xO_y Solid Superacid

SO2-4/MxOysolid superacid is a new catalytic material developed in recent years, thecomposite carrier SO2-4/ZrO2-WO3solid superacid has many advantages such as simplepreparation, high activity, less polution and repeatable use, especially for paraffinisomerization has good catalytic effect, also has broad prospects in the field of petrochemicalindustry.In the present study, we focus on the effects of synthesis methods and rare earth metal onthe structure and catalytic behavior of SO2-4/ZrO2-WO3catalysts, and the hydrogen in then-heptane isomerization reaction for the model to investigate the performance of catalyst.Hydrothermal method were used to sythesize the Ni-SO42-/ZrO2-WO3catalysts. Thehydrothermal treatment can enhance the pore structure of the catalyst, imporve the thermalstability of the catalyst, and inhibit the growth of ZrO2in the process of roasting, whileincreasing the specific surface area and pore size of the catalyst. In the n-heptaneisomerization reaction, the coversion and selectivity of n-heptane can reach31.3%and64.5%when the concentration of sulfuric acid is0.5mol/L, calcination temperature is600°C,hydrothermal temperature is110°C, hydrothermal time is24h, and the cotent of Ni was4%,the reduction temperature is400°C, the reduction time is4h, the reaction temperature is240°C.The Ni-SO2-4/ZrO2-WO3-La2O3catalysts was prepared by impregnation method. Thecatalysts were characterized by XRD, IR, BET. The catalytic performance of the samplesunder different conditions was studied. The results showed that La can stabilize the tetragonalphase of ZrO2, increasing the specific surface area of the sample, and the isomerizationperformance improved significantly. When lanthanum zirconium ratio is0.04, sulfuric acidconcentration is0.5mol/L, calcination temperature is650°C, and the and the cotent of Ni was6%, the reduction temperature is400°C, n(H2)/n(C7H16) is12, the reduction time is4h, thereaction temperature is260°C, MHSV is6.8h-1, the coversion and selectivity of n-heptane canreach22.5%and77.3%.