Isomerization of Pentanes on Platinum/Rare Earths-Hydrogen-Zeolite Y Catalysts
1976 年 18 巻 2 号 p. 117-126
詳細
1976 年 18 巻 2 号 p. 117-126
The isomerization of pentanes in the presence of hydrogen was investigated in a flow system at total pressure ranging from 1 to 50atm and temperatures from 270 to 330°C on platinum/rare earths-hydrogen-zeolite Y catalysts. Platinum was introduced into the zeolite by ion-exchanging it with an aqueous solution of platinum ammine complex. The platinum contents of the catalysts were in the range of 0.05∼1.0wt%. It was observed that isomerization of n-pentane to isopentane and that of isopentane to n-pentane were accompanied with disproportionation to hexane and butane isomers, hydrogenolysis to lower molecular weight paraffins, and isomerization to neopentane. Based on such effects as the Pt content, the treatment of the catalyst with steam and the reaction conditions, and also based on kinetic considerations, the four reactions were considered to proceed through the following scheme. Several factors that influence the isomerization selectivity to isopentane were summarized. Finally, the mechanism of isomerization of pentanes was discussed on the basis of the present experimental results.
