Adsorption and catalysis

Summary

• 1. The kinetics of the catalytic hydrogenation of cyclopentadiene and of cyclopentene in a circulation system was studied.

• 2. Cyclopentadiene hydrogenates at a lower potential than does cyclopentene, in which connection a sharp rise in the potential occurs in the hydrogenation of cyclopentadiene at the point where hydrogenation of cyclopentadiene to cyclopentene ceases.

• 3. The rate constants and values of the potential for a number of catalysts were compared.

• 4. A theory as to the mechanism observed in some “induced saturation” experiments was expressed.

• 5. The method of exhaustive hydrogenation was expanded to a study of adsorption from mixtures. The value for the adsorption of cyclopentene is greater than that for cyclopentadiene, and is smaller when adsorption is from a mixture.

• 6. It was postulated that the factor responsible for the stepwise nature of the hydrogenation of cyclopentadiene is the adsorption displacement of cyclopentene by cyclopentadiene from the surface of the catalyst, and, especially, from its active portions.