STUDIES ON RUTHENIUM CATALYSTS .4. HYDROGENOLYSIS OF N-BUTANE ON RU AL2O3 CATALYST-DEPENDENCE OF REACTION-KINETICS ON PARTICLE-SIZE AND ON PRETREATMENT/
Gc. Bond et Jc. Slaa, STUDIES ON RUTHENIUM CATALYSTS .4. HYDROGENOLYSIS OF N-BUTANE ON RU AL2O3 CATALYST-DEPENDENCE OF REACTION-KINETICS ON PARTICLE-SIZE AND ON PRETREATMENT/, Journal of molecular catalysis, 89(1-2), 1994, pp. 221-228
Turnover frequencies (TOF) for hydrogenolysis of n-butane on Ru/Al2O3
catalysts, measured with a 10-fold excess of H-2, depend on dispersion
and on pretreatment. After a first high-temperature reduction at 753
K (HTR1), 1% Ru/Al2O3 showed high dispersion and moderate activity; ox
idation at 623 K followed by reduction at 433 K caused dispersion to d
ecrease, and rates and TOFs to increase. However, the magnitude and ev
en the sign of the effects depended on the H-2 Pressure used, because
the form of the rate dependence on H-2 PreSSUre changed significantly.
Many of the discrepancies in the literature concerning particle size
effects may originate in the use of different conditions for measuring
rates and of different pretreatments. Alterations in the form of the
dependence of rates and of product selectivities on H-2 pressure sugge
st that ''structure sensitivity'' in these systems may in fact be due
to variations in the strength of H-2 chemisorption.