Changing the Si distribution in SAPO-11 by synthesis with surfactants improves the hydroisomerization/dewaxing properties

The silicoaluminophosphates SAPO-11 isodewaxing catalysts were synthesized with varying Si content following conventional methods and using a route involving the presence of surfactant. Smaller crystal size (∼80 nm) and higher external surface areas were found for the samples prepared with surfactant. This synthesis route using surfactant gives SAPO-11 samples with greater numbers of stronger acid sites than those prepared by conventional synthesis. The Si29 MAS-NMR spectra obtained for samples containing the same amount of silicon showed that SAPO-11 prepared with surfactant contains a higher relative concentration of Si (nAl, 4-n  Si), 0