Catalyst aluminosilicate 174 --- loading

Vanadyl naphthenate (in benzene) was used to metal load aluminas and aluminosilicate gels according to an established procedure (15) the naphthenate was obtained from Pfaltz and Bauer, Inc., and contained 2.9 wt% V. Decomposition of the naphthenate was performed by calcining the impregnated materials for 10 hours at 540 C in air. All catalysts were then steam-aged for five hours with -100% steam at 760 C in a fluidized bed. 

Two main components were used in the model catalysts described in this paper. One component was a europium exchanged ammonium Y zeolite (EuNH-Y). The other component was an amorphous aluminosilicate containing about 75% Si 0 and 25% Al203 (AAA-alumina). All materials were artificially V-contaminated by impregnation with vanadyl naphthenate solutions in benzene. Tetraphenyl tin (in hot toluene) was the passivating agent used. It was added either before or after loading vanadium on the zeolite (EuNH-Y), on the gel or on a gel-zeolite mixture. 

As catalysts for the condensation reactions, two types of compounds with opposite properties show the best performances. One is hydroxides of alkali and alkaline earth metal supported on silica gel, aluminosilicate, or the like. They are generally considered to be typical bases. However, it should be noted that these hydroxides are much less active when they are not supported on a support, and that there exists an optimum value in the activity with the variation in the loading of these hydroxides. These findings led... 

The idea of this work was to obtain Sb, V and Nb containing catalysts supported on mesoporous materials. The previous study [8] indicated that MCM-41 mesoporous structure is promising for VSbOx loading. In this woik the effects of different preparation methods and conditions are studied in detail. The applied strategy is based on the introdnction of different amounts of Sb and V oxide species on NbMCM-41 material, application of different sequences of step by step impregnation, post synthesis one pot adsorption and different temperature treatment. To explain the influence of niobium additive on the properties of the SbVOx phases, the supports without Nb (sihcate - MCM-41 and aluminosilicate - AlMCM-41) are also used. 

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