Hydroisomerization of n-decane over micro/mesoporous Pt-containing bifunctional catalysts: Effects of the MCM-41 incorporation with Y zeolite

摘要

Hydroisomerization of n-decane (n-C-10) over the bi-porous Pt-containing catalysts was investigated. Two micro/mesoporous materials were respectively derived from the composition and mechanical mixing of MCM-41 and Y zeolite. This study aimed to estimate the influences of the mesoporous MCM-41 presence on catalytic performances of bifunctional catalysts during the hydroisomerization of long-chain alkanes. Compared to the Pt/Y catalyst, bifunctional catalysts with bi-porous structures were more selective to isomerized products, particularly the mono-branched isomers, which was attributed to the improved metal-acid functional balance and reduced diffusion limitations caused by the incorporation of MCM-41 with Y zeolite. Furthermore, the Pt-loaded Y/MCM-41 composite, characterized with the overgrowth of MCM-41 on Y crystals, outperformed the Pt-loaded Y/MCM-41 mechanical mixture in the regard of limiting secondary reactions. Given this fact, the migration scheme of alkene intermediates over bifunctional catalysts with bi-porous structures was proposed, and meanwhile, the differences of molecular migrations over Pt-loaded Y/MCM-41 mechanical mixture and composite were discussed.