HEXANE ISOMERIZATION OVER A ZEOLITE CATALYST

A synthetic hydrogen-mordenite catalyst, with and without a dispersed noble metal, had the same very high hexane isomerization activity. This unique crystalline zeolite, without metal, was investigated by using the five isomeric hexanes to develop a kinetic model. Other paraffins were tested, and for n-pentane isomerization the nonmetal hydrogen-mordenite was more active than the metal-containing hydrogen-mordenite. But for n-heptane isomerization the nonmetal hydrogen-mordenite was essentially inactive while the metal-containing mordenite showed excellent isomerization and hydrocracking activity. Process-variable studies were made with n-hexane over synthetic hydrogen-mordenite by testing at various space velocities, temperatures, and pressures. The data obtained at various space velocities were correlated by using a first-order, reversible isomerization reaction model. The calculated reaction rate constants fitted an Arrhenius function of temperature with an apparent activation energy of 24.4 kcal. per mole. The effect of pressure on the reaction rate constant was consistent with the dual-site catalytic mechanism and the Langmuir adsorption isotherms. © 1969, American Chemical Society. All rights reserved.