The kinetics of decalin ring opening over a Ir/H-Beta catalyst

The selective ring opening of decalin over Pd/H-Y-30, Ir/H-Beta-300 and Ir/H-Beta-25 catalysts, measured in a stirred, batch reactor at 350 degrees C and 3 MPa H-2, showed that Ir/H-Beta-25 (SiO2/Al2O3 = 25) had the highest activity and yield of ring-opened products. The effect of temperature (275-350 degrees C) and pressure (3-6 MPa) on the activity and product selectivity was further investigated over the Ir/H-Beta-25 catalyst. The highest ring-opened product yield (53 mol%) was obtained at a decalin conversion of 90 mol% at 325 degrees C and 6 MPa H-2. A Langmuir-Hinshelwood kinetic model, that assumed a bifunctional catalytic process in which hydrogenation and dehydrogenation reactions occurred on metal sites and isomerization, ring-opening and cracking occurred on acid sites, was successfully applied to the data. The model included the effect of catalyst deactivation associated with the catalyst acid sites. Activation energies estimated from the model parameters showed that the ring opening of isomers had the lowest activation energy (141 kJ/mol), whereas cracking had the highest (159 kJ/mol). (C) 2012 Elsevier B.V. All rights reserved.