Studies Of The Selective Oxidation Of Propane(Propene) To Acrolein Over V(Mo)TeO Catalysts Prepared By Precursor Method

The selective oxidation of propane to acrolein has attracted much attention due to its ecnomic and scientific terms.For the partial oxidation of propane to acrolein,it needs to transfer six electrons,consists of several steps,such as:dehydrogenation of propane to propene,insert oxygen to ally etc.To satisfy activity and selectivity,the active sites have to be well controlled and a catalyst system has to be well designed. For this reason,not only optional composition,but also elaborate procedures are often desired for the preparation of effective catalysts for this reaction.In the present work,V₂Te_0.5O/SBA-15 catalysts were prepared by MDD methods,which showed good catalytic performance for the selective oxidation of propane to acrolein.By use of the optimum catalyst calcined at 600℃,the acrolein yield of 9.3%was achieve with 29.2%conversion of propane and 31.7%selectivity of acrolein under the reaction condition(C₃H₈/O₂/N₂=1.2/1/4,3000 ml·g^-1·h^-1,500℃). The effects of the catalyst composition,preparation conditions and preparation method on the VTeO/SBA-15 catalysts were studied.And,a detailed characterization of catalysts was performed using XRD,N₂ adsorption,H₂-TPR,Py-IR,XPS measurements.Characterizations revealed that the well-organized mesoporous structures of SBA-15 is sustained after the introduction of V by MDD method, furthermore,moderate Broensted acid sites,facile reducibility,highly dispersed V active sites which were probably the main reasons for its good catalytic behavior in the selective oxidation of propane to acrolein.Otherwise,TeMo₃O and TeMo₆O catalysts prepared by decomposition of (NH₄)₆TeMo₆O₂₄·Te(OH)₆·7H₂O and(NH₄)₆TeMo₆O₂₄·7H₂O were used for propene selective oxidation to acrolein.The catalytic performances were compared with catalysts prepared by Solid-Reaction and Sol-Gel methods.The result showed samples obtained from(NH₄)₆TeMo₆O₂₄·Te(OH)₆·7H₂O calcined in air at 400℃have relatively high activity and selectivity in the selective oxidation of propene to acrolein. The acrolein yield of 74.6%was achieve with 80.4%conversion of propane under the reaction condition(C₃Hs/O₂/N₂=1.2/1/4,3000 ml·g^-1·h^-1,400℃) Characterization results of SEM,XRD and IR revealed that good catalytic performances of TeMo₃O catalysts obtained from(NH₄)₆TeMo₆O₂₄·Te(OH)₆·7H₂O calcined at 400℃in air resided in effective cooperation effect between MoO₃ and Te₂MoO₇ and its large surface area.