Rate multiplicity in hydrogenation of ethylene on platinum catalyst

Abstract

Hydrogenation of ethylene on 0.05% platinum-boehmite catalyst was investigated. The reaction was carried out in a kinetic region. It is demonstrated that the reaction proceeds by Langmuir-Hinshelwood mechanism. Rate hysteresis due to kinetic instability was observed. Adsorption study of hydrogen and ethylene was carried out and multilayer chemisorption of ethylene was observed. A hypothetical mechanism that ethylene is chemisorbed to form multilayer and the difference of reactivity of each layer results in the rate maximum and the rate hysteresis phenomena is suggested and discussed.