Palladium-doped sulfated zirconia: Deactivation behavior in isomerization of n-hexane

摘要

The deactivation and regeneration behaviors of palladium doped sulfated zirconia was studied in the n-hexane isomerization. Results indicated that sulfate reduction is the major catalyst deactivation reason. Sulfate leakage also contributed to the deactivation but not the predominant cause. Since the appearance of hydrogen, the amount of carbon deposition is very low, and it plays a positive role in the reaction: covering part of high active sites, avoiding cracking. Reduced sulfite can be re-oxidized into sulfate under high temperature at the atmosphere of air, but accompanied by the gasification loss of sulfate and carbon deposition. Although the effect of nitrogen on oxidizing sulfites is not as good as air, nitrogen can inhibit the gasification loss of sulfate and carbon deposition, and finally the catalyst regenerated under nitrogen at 400 degrees C reflects superior performance even than fresh catalyst.