Kinetic study of ethylene hydrogenation

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Journal of Catalysis; (USA)

DOI:https://doi.org/10.1016/0021-9517(91)90230-2· OSTI ID:5716807

Cortright, R D; Goodard, S A; Rekoske, J E; Dumesic, J A ^[1]

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1. Univ. of Wisconsin, Madison (USA)

Turnover frequencies and kinetic reaction orders were determined for ethylene hydrogenation over platinum catalysts at temperatures from 223 to 336 K, hydrogen pressures between 50 and 650 Torr, and ethylene pressures from 5 to 600 Torr. The hydrogen kinetic order was observed to decrease continuously from first order 336 K to half order at 248 K. Zero-order ethylene kinetics were found at ethylene pressures above 75 Torr, and the ethylene order became negative at lower ethylene pressures. The half-order hydrogen kinetics at low temperatures and the observed zero-order ethylene kinetics at higher ethylene pressures can be explained by a Horiuti-Polanyi mechanism in which hydrogen is adsorbed noncompetitively on a surface essentially covered with adsorbed hydrocarbon species. Hydrogen competes with ethylene adsorption at higher temperatures and lower ethylene pressures. A combination of the noncompetitive and competitive pathways explains the steady-state kinetics over the entire range of temperatures and pressures studied.

• OSTI ID: 5716807
• Journal Information: Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 127:1; ISSN 0021-9517; ISSN JCTLA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
ADSORPTION
ALKENES
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
ELEMENTS
ETHYLENE
HYDROCARBONS
HYDROGEN
HYDROGENATION
KINETICS
METALS
NONMETALS
ORGANIC COMPOUNDS
PLATINUM
PLATINUM METALS
PRESSURE DEPENDENCE
REACTION KINETICS
SORPTION
SURFACE PROPERTIES
TEMPERATURE DEPENDENCE
TRANSITION ELEMENTS