Kinetic Study of the Liquid-phase Hydrogenation of 1-Butyne over a Commercial Palladium/Alumina Catalyst

ALVES J.A.; BRESSA S.P.; MARTINEZ O.M.; BARRETO G.F.

CHEMICAL ENGINEERING JOURNAL

Elsevier B. V.

Año: 2007 vol. 125 p. 131 - 138

1385-8947

Hydrorefining of C4 cuts of unsaturated hydrocarbons involves the selective removal of 1-butyne by catalytic hydrogenation. Due to its technological relevance, we investigated the hydrogenation of 1-butyne over a commercial palladium-based catalyst of the eggshell type. The experimental conditions were selected to reproduce those of industrial hydrorefining reactors: liquid-phase reaction, seven levels of temperature between 27°C and 62°C, initial concentrations of 1-butyne up to 0.6 mol/l and hydrogen partial pressure ranging from 0.8 atm to 8 atm. Under these conditions, the overall effectiveness factor of 1-butyne hydrogenation was less than 0.15. Provided that hydrogen was the limiting reactant inside the active shell, 1-butene was the only product yielded by 1-butyne hydrogenation. The regression analysis of experimental data corresponding to the hydrogenation of 1-butyne to 1-butene was restricted to experimental compositions in which 1-butyne concentration was higher than 0.07 mol/l. An intrinsic kinetic expression with reaction orders 1 and -1 for hydrogen and 1-butyne, respectively, predicts experimental data with an average deviation of 2.1%. Estimates of the activation energy and kinetic coefficient at 44°C are ( 1.55±0.06 ) 104 cal/mol and ( 4.6±0.1 ) mol/(kg s).