Effects of Gel Preparation Conditions on the Crystallization of SAPO-11 Molecular Sieves

Using a combination of XRD, 27Al and 31P MAS NMR, SEM, TEM, N2 low-temperature adsorption–desorption, and IR spectroscopy of adsorbed pyridine, the effects of gel preparation conditions on the properties of the SAPO-11 molecular sieves crystallized from the gels were investigated. It was demonstrated that the crystal morphology and the characteristics of secondary pores of SAPO-11 molecular sieves can be controlled by adjusting the sequence in which the initial components are mixed during gel preparation. The synthesized micro–mesoporous SAPO-11 samples exhibited high selectivity in the hydroisomerization of n-hexadecane.