Synthesis of SAPO-41 Molecular Sieves with Different SiO2/Al2O3 Ratios and their Catalytic Performance of n-Decane Hydroisomerization

Abstract

Using di-n-propylamine (DPA) as a template, SAPO-41 molecular sieves with SiO2/Al2O3 ratios (n) of 0.3, 0.5, and 0.7 were synthesized. Their structure, morphology and acidity were characterized by XRD, N2 physical adsorption, SEM, and Py-IR. All the synthesized samples have characteristic diffraction peaks corresponding to the AFO topological structure, which means that samples are pure phase SAPO-41 molecular sieve. The samples exhibited a highly ordered prismatic morphology with regular arrangement of individual grains, wrapped in flakes, and possessed complete channel structure. With the increase of n, the specific surface area and the amount of B acid showed a downward trend after increasing. Hydroisomerization reaction results of n-decane over SAPO-41 loaded with 0.5wt% Pd (Pd/SAPO-41(n)) showed that the higher the amount of B acid, the higher the conversion of n-decane,and high specific surface area and moderate B acid are favorable for yield of isomerization products. When the conversion of n-decane catalyzed by Pd/S41(0.3)-P was 88.9%, the yield of hydroisomerization products reached 83.3%.