The transformations of toluene on alumina and bifunctional catalystsстатья
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Дата последнего поиска статьи во внешних источниках: 29 ноября 2015 г.
Аннотация:The activity of Pt, Rh, and Ni catalysts deposited on Al2O3 and tungsten-containing catalysts 20% H4SiW12O40/ZrO2 and 15% WOx/ZrO2 in the hydrogenation of toluene and toluene ring opening and isomerization in the presence of hydrogen was studied. Under experimental conditions (160-360 degrees C, 2.2 MPa), the main reactions on Rh/Al2O3 were the hydrogenation of toluene into methylcyclohexane, hydrogenolysis into isoheptanes, and hydrocracking into alkanes C-1-C-6. On Pt, Rh, and Ni catalysts on carriers with strong acid properties, the isomerization of the six-membered into five-membered ring followed by hydrogenolysis ( hydrocracking) of alkylcyclopentanes occurred. The yield of heptane isomers, however, did not exceed 13%. The activity of Pt and Rh catalysts on a high-acidity carrier (WOx/ZrO2) in hydrocracking was much higher than that of catalysts based on deposited heteropoly acid. The yields of hydrogenolysis ( hydrocracking) products on Ni/WOx/ZrO2 were much lower than on Pt(Rh)/WOx/ZrO2. The highest yield of ring opening products ( isoheptanes and n-heptane) was obtained with layered loading of two catalysts; it reached 58 wt% at 300 degrees C and a 2.2 MPa pressure, which was 4.5 and 2 times higher than the yield obtained on Ni-Pt/WOx/ZrO2 and 2% Rh/Al2O3 catalysts. Hydrodemethylation was not the main direction of toluene transformations on any of the catalysts studied.