Effect of Sulfiding on Deactivation Rates of Platinum and Platinum-Rhenium Catalysts in Dehydrogenation of Methylcyclohexane

Abstract

The dehydrogenation of methylcyclohexane was carried out in a differential fixed-bed reactor at 781 K and atmospheric pressure, and the deactivation rates of Pt-, PtRe-Al₂O₃ and the sulfided catalysts were compared. The presence of Re and presulfiding of the catalysts resulted in improved stability. Continuous addition of H₂S at a concentration of 50 ppm in feed was effective for maintaining the activity with Pt during only the first few hours of operation, while it caused a marked decrease in the initial activity with PtRe. The experimental results were interpreted by the ensemble effect.