The kinetics of dehydrocyclization of n-hexane on rhodium and copper-rhodium films

The effect of copper present in amounts of a 0.3 and 0.5 monolayer on the c atalytic activity of a continuous rhodium film in the formation of cyclohex ane was studied in the temperature and hexane pressure ranges 560-733 K and 0.6-10 Pa, respectively. A higher activity of RhCu compared with Rh was ex plained by the formation of bimetallic active centers. The introduction of copper increased the experimental activation energy of the reaction (E-a). Depending on the conditions, the rate of the reaction either did not depend on the initial hexane pressure poor increased proportionally to p(0) on Rh and to similar top(0)(1/2) on RhCu. For RhCu (0.5 monolayer), the rate of catalyst cooling (fast or slow) after thermal treatment influenced the rate of the reaction and the E-a value.