Allene–methylacetylene isomerization over silica-supported cobalt and iron catalysts

Abstract

Equilibrium between allene and methylacetylene was studied over iron catalyst in the temperature range of 165 to 200 °C, with allene or methylacetylene as the initial reactant. In both cases similar equilibrium product-distribution (allene 16% and methylacetylene 84%), fairly close to the calculated value, is observed.Kinetics of allene-methylacetylene isomerization was studied between 70 and 165 °C. The order of reaction was always one and temperature independent. Both activity and calculated energy of activation (11.8 and 11.2 kcal/mol over iron and cobalt respectively) were similar for the two catalysts, suggesting that active sites for the reaction were also similar. This similarity, as well as the first order kinetics, are fully explained by a reaction mechanism based on adsorbate migration.