Skeletal isomerization of n-heptane with highly selective Pt/H₃PW₁₂O₄₀/SBA–15 trifunctional catalysts

For the first time, highly selective Pt/H₃PW₁₂O₄₀/SBA–15 trifunctional catalysts were evaluated for n-heptane hydroisomerization. Both Lewis (L) and Brønsted (B) acid sites were present in these catalysts. Reduction treatment led to heteropolyacid dispersion better and Pt nanoparticles smaller. With the best 1wt%Pt/20wt%H₃PW₁₂O₄₀/SBA–15 catalyst, 100% isomerization selectivity and 56.74% n-heptane conversion were obtained at 320 °C. Among the products, the dibranched isomers concentration faction was > 50% and 2,2-dimethylpentane was predominant. Pt/H₃PW₁₂O₄₀/SBA–15 catalysts with Pt nanocrystals, proper acidity strength and a balanced ratio of B/L acid sites, and highly ordered large mesopores were chiefly responsible for the high isomerization selectivity.