The influence of the support on activity and selectivity of nickel sulfide catalysts in the decarbonylation of stearic acid to heptadecenes

Resumo

The influence of the support nature on the performance of nickel sulfide catalyst in the decarbonylation of stearic acid to heptadecenes was investigated. The catalyst supported on silica demonstrated higher activity and selectivity in comparison with the catalyst on γ-Al₂O₃ used as a reference. The reaction schemes over these catalysts are nearly the same; however, the contributions from the side reactions of hydrogenation and oligomerization are reasonably different. Introduction of the products of decarbonylation (CO and water vapor) decreases the stearic acid conversion; and in the case of the catalyst supported on silica, the addition of CO strongly reduces the rate of hydrogenation of heptadecenes. The reasons for the observed differences were discussed. It was suggested that the dispersion of the nickel component as well as the nature of support acidity played a significant role.