from first principles PP-I-1

PP-III-92Effects of Nanostructuring of Ti-MCM-41 by Supporting of VanadiumOxide on the Process of Dehydrogenation of PropaneRedkina A.V., Konovalova N.D., Khomenko K.N.Institute of Sorption and Problem Endoecology of NASU, Kiev, Ukrainetoniamail@rambler.ruIn connection with the considerable increase of demand on clean propylene, research ofpossibility of increase of propylene yield in the endothermic process of catalyticdehydrogenation (DH) of propane and development of exothermic process of its oxidativedehydrogenаtion (ODH) becomes an actual task presently. It was shown that a greater yield ofpropylene has been reached on catalysts supported on porous supports with the developedactive surfaces. It is known also, that the system of unidimensional pores of меsoporoussilicon dioxide can be used as solid-phase nanoreactor for the synthesis of well-organizedarrays of unidimensional nanostructures of connections of transitional metals. Thus thereactionary zone limited to the walls of pores creates terms for the synthesis of nanophases.In this work vanadium oxides supported on mesoporous system Ti-MCM-41 wereinvestigated as catalysts of processes of DH and ODH of propane. This system has beenobtained by hydrothermal template, alkaline synthesis from pyrogenic titanairosil (TAS),which contains Ti ions only in the form of isomorphic replacement of Si ions by its in SiO 2matrix. Its quantity corresponded ~ 2,5 wt. % TiО 2 . Catalytic activity of the receivedsupported systems has been measured in a flowing quartz reactor with length of 30 sm in andinternal diameter of 0,5 sm, using particles in the size of 0,25-0,5 mm, not filling an inactivepacking the empty volume of a reactor before and after a layer of the catalyst. The reactionmixture contained 7 vol.% С 3 Н 8 in Ar (DH) or 7 vol.% С 3 Н 8 and 3,5 vol.% О 2 in He (ODH).The time of contact of the reaction mixture with the catalyst – 2,5 s. It is established that theobtained mеsoporous system contains isolated strong acidic sites and shows comparativelylarger catalytic activity in the processes of dehydrogenation of propane to propylene atpresence and absence of oxygen in the reaction mixture. The yield of propylenewas ~ 20 mol. % at 650-675 o C.The vanadium oxides were supported on surface H-Ti-MCM-41 by impregnation its watersolution of vanadium oxalate complex or a solution of acetylacetonate vanadyl in acetonitrilewith the subsequent drying and calcination in an air atmosphere. Systems containing 5÷25 wt.% V 2 O 5 / Н-Ti-MCM-41 and 2÷30 wt. % VOх / Н-Ti-MCM-41 were obtained, accordingly. It was250