Kinetic modeling of ethylbenzene dehydrogenation over hydrotalcite catalysts

Kinetics of ethylbenzene dehydrogenation to styrene was investigated over a series of quaternary mixed oxides of Mg(3)Fe(0.25)Me(0.25)Al(0.5) (Me = Co, Mn and Ni) catalysts prepared by calcination of hydrotalcite-like compounds and compared with commercial catalyst. The study was carried out in the absence of steam using a riser simulator at 400, 450, 500 and 550 degrees C for reaction times of 5, 10, 15 and 20 s. Mg(3)Fe(0.25)Mn(0.25)Al(0.5) afforded the highest ethylbenzene conversion of 19.7% at 550 degrees C. Kinetic parameters for the dehydrogenation process were determined using the catalyst deactivation function based on reactant conversion model. The apparent activation energies for styrene production were found to decrease as follows: E(1-Ni) > E(1-Co) > E(1-Mn). (C) 2011 Elsevier B.V. All rights reserved.