Gas phase base-catalyzed dehydrogenations of cyclic hydrocarbons over a KOH/Al₂O₃ catalyst

Potassium hydroxide impregnated on a γ-alumina support, KOH/Al₂O₃, was found to be an active catalyst for the base-catalyzed dehydrogenation of cyclic hydrocarbons such as cycloolefins, cycloparaffins and alkyl aromatics. Among reactions studied were the dehydrogenation of cyclohexene, pK_a 36, and cyclohexane, pK_a 45, to benzene, and ethylbenzene to styrene. The reactions proceeded with high conversions and selectivity at temperatures above 500 °C. Cracking reactions were suppressed and the catalyst was stable to deactivation over long time periods. Comparison of γ-Al₂O₃ with other common supports showed it was the most effective and selective.