tailieunhanh - Oxidative dehydrogenation of n butane on vanadiummagnesium oxides system: the influence of orthovanadate phase on butadiene selectivity

Vanadium – Magnesium mixed oxides used for the oxidative dehydrogenation were synthesized by impregnation method. Characterization of catalysts was determined by serial model techniques such as XRD and N2 physisorption. The result of XRD showed that V2O5 phase was inhibited in the V-Mg-O mixed oxides prepared with impregnation method. Catalyst test performance showed high selectivity for the oxidative dehydrogenation of n-butane to butene and butadiene. | Journal of Chemistry Vol. 45 Special issue P. 154 -157 2007 OXIDATIVE DEHYDROGENATION OF n-BUTANE ON VANADIUMMAGNESIUM OXIDES SYSTEM THE INFLUENCE OF ORTHOVANADATE PHASE ON bUTADIENE SELECTIVITy Received 15 October 2007 NGUyEN ANH vu NGUyEN THI MINH HIEN Petrochemical and Catalysis Materials Laboratory Hanoi University of Technology summary Vanadium - Magnesium mixed oxides used for the oxidative dehydrogenation were synthesized by impregnation method. Characterization of catalysts was determined by serial model techniques such as XRD and N2 physisorption. The result of XRD showed that V2O5 phase was inhibited in the V-Mg-O mixed oxides prepared with impregnation method. Catalyst test performance showed high selectivity for the oxidative dehydrogenation of n-butane to butene and butadiene. I - INTRODUCTION The oxidative dehydrogenation reaction is on excellent way to synthesize alkenes. 2CnH2n 2 O2 2CnH2n 2H2O Q The products are stable compounds as water CO2 which are due to very thermodynamically advantage 1 . In addition the presence of oxygen in reaction inhibits coke and carbon deposition 2 8 9 . Catalysts with chemical composition of V-Mg-O have been proposed activity available for ODH of n-butane propane ethyl-benzene 3 7 . The purpose of present study is to evaluate the n-butane directly conversion ability to butadiene on V-Mg-O catalysts. II - EXPERIMENTAl Mg OH 2 was prepared by precipitation from MgCl2 solution with NH4OH at pH 10 80oC with magnetically stirring. The product was filtered dried at 120oC for 12h and after that calcinated in air to MgO at 600oC for 6h. 154 V-Mg-O systems were prepared with various vanadium loadings by conventional impregnation using ammonium vanadate NH4VO3 solution of different concentrations. III - CATAlysTs CHARACTERIzATION Pore size and pore distribution were determined by nitrogen adsorption method in an ASAP 2010 instrument Micromeritics USA. XRD patterns were obtained from D8 Advance Bruker Diffractometer Germany with