III International Conference

PP-I-11OXIDATIVE DEHYDROGENATION OF ETHANE OVER MODIFIEDMULTICOMPONENT OXIDE CATALYSTS BASED ON VANADIUM ANDMOLYBDENUMBondareva V.M., Andrushkevich T.V., Maksimovskaya R.I., Dovlitova L.S.,Malakhov V.V., Plyasova L.M.Boreskov Institute of Catalysis SB RAS, Novosibirsk, RussiaE-mail: valent@catalysis.ruThe oxidative dehydrogenation of ethane and genesis of multicomponent oxide catalysts(V-Mo-Te-Nb-Me-О, where Ме - Ca, Bi, Zr, and others) have been studied using NMR, XRDand differential dissolution methods. The maximal yield of ethene 75% is achieved on thecatalyst with the composition V 0.3 Mo 1 Te 0.23 Nb 0.12 Bi 0.05 О х . The genesis of the catalystsincludes formation of the mixed oxo-, polyoxo- and heteropolyanions in solution, itscondensation into amorphous solid during drying and decomposition of the latter giving twocrystalline phases – orthorhombic (M1) and hexagonal (M2) under calcination.Nowadays the most effective catalysts for oxidative transformation of light alkanes, viz.ethane and propane are VMoTeNb-oxide compositions [1,2]. These catalysts contain twomain crystalline phases so-called M1 (orthorhombic) and M2 (hexagonal).In the present work oxidative dehydrogenation of ethane and genesis of modifiedV 0.3 Mo 1 Te 0.23 Nb 0.12 Me x -oxide catalysts have been studied. We varied the nature of theadditive (Me = K, P, Ga, Ca, Zr, Sb, Bi, Ag, Ce) and its content (x = 0.001 – 0.1).The catalysts were synthesised by the rapid evaporation of an aqueous slurry and followingcalcination according to patent procedure [3]. The raw materials were ammonium paramolybdate(APM), ammonium metavanadate (AMV), telluric acid (TA), niobium oxalate (ON) as well ascorresponding nitrates (in the case of K, Ce, Ag, Ga, Ca) or oxides (in the case of Bi, Sb, Zr) orH 3 PO 4 (in the case of P) (MeX). The chemical composition and structure of the differentcomplexes formed in solution was studied by 51 V, 125 Te, 95 Мо and 17 O NMR spectroscopy. Thechemical and phase composition of the compounds formed under thermal treatment wasdetermined by the differential dissolution method (DD) [4] and XRD accordingly.As in the case with propane, catalytic properties of VMoTeNbO catalyst in ethaneoxidative dehydrogenation are depended on M1/M2 ratio. The introduction of differentadditives into VMoTeNbO catalyst significantly affects catalytic properties. So, the additiveswith strongly different basiс and acidic properties such as Ag, K and Р decrease both activityand selectivity to ethene. Introduction of Ga, Sb and Ce is accompanied by reduction ofactivity but selectivities remain practically unchanging. Modification with Zr, Ca and Bi leads27