Solvent‐Free Synthesis and n‐Hexadecane Hydroisomerization Performance of SAPO‐11 Catalyst

Abstract

SAPO‐11 catalysts are prepared by both solvent‐free and hydrothermal methods. SAPO‐11 samples prepared by the solvent‐free method have a higher density of acid sites compared with the samples obtained by the hydrothermal method. We performed 29Si NMR spectroscopy to determine the acid properties of the samples, and most Si species exist in the SAPO region. The SAPO‐11 materials were loaded with the noble metal Pt at a content of approximately 0.5 wt.‐%, and the bifunctional catalysts were applied in the hydroisomerization of n‐hexadecane. Remarkably, a higher catalytic activity and isomer yield were obtained for the catalyst synthesized by the solvent‐free method. In particular, the higher yield of multibranched isomers, including dibranched and tribranched isomers, can be ascribed to the lower nPt/nA ratio (an expression of the balance between metal and acid sites) accompanied by the longer residence of carbenium ions at the acid sites. The solvent‐free samples can produce isomer products with lower pour points and enhanced low‐temperature mobility.