Kinetic modeling of ethylbenzene dehydrogenation over hydrotalcite catalysts

Kinetics of ethylbenzene dehydrogenation to styrene was investigated over a series of quaternary mixed oxides of Mg3Fe0.25Me0.25Al0.5 (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 °C for reaction times of 5, 10, 15 and 20 s. Mg3Fe0.25Mn0.25Al0.5 afforded the highest ethylbenzene conversion of 19.7% at 550 °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: E1-Ni > E1-Co > E1-Mn.

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► Three different hydrotalcites based catalysts Mg3Fe0.25Me0.25Al0.5 (Me = Co, Mn and Ni) were thoroughly investigated in ethylbenzene dehydrogenation.
► Styrene was obtained as a major product in ethylbenzene dehydrogenation.
► Mg3Fe0.25Mn0.25Al0.5 displayed the highest catalytic conversion in ethylbenzene dehydrogenation.
► In ethylbenzene, styrene selectivity follows the order of Mn > Co > Ni of hydrotalcite based oxides.
► Apparent activation energies for ethylbenzene dehydrogenation followed the following order; Mn > Co > Ni of hydrotalcite based oxides.