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Hydroisomerization of normal pentane over a zeolite catalyst



The most active zeolite hydroisomerization catalyst found during the course of a series of screening experiments was palladium impregnated hydrogen mordenite. The high activity of hydrogen mordenite catalyst was also reported by research workers of the Shell Oil Company. (11) Typical conditions used in this study were 550°F., 450 lb./ gauge, 8 g. of n-pentane fed /h./g. of catalyst, and a hydrogen/pentane molar ratio of 3.4.

Process variable studies have shown that neither gas toparticle mass transfer, intraparticle (macro-pore) diffusion, nor the chemical reactions at the palladium sites are rate limiting. The data can be correlated by a mathematical model based on the assumptions that a first-order, reversible isomerization reaction on the mordenite acidic sites is rate-controlling, and the apparent rate constant is an Arrhenius function of thetemperature of the system.

The pressure dependency of the reaction rate constant is consistent with a dual-site mechanism and Langmuir adsorption isotherms.

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