Silicoaluminophosphate Molecular Sieves with Different Silica Contents and Their Catalytic Properties in the Oligomerization of α-Methylstyrene
摘要
Silicoaluminophosphate molecular sieves SAPO‑11 were obtained from gels with different silica contents. Silicoaluminophosphates as cubic crystals with 0.5 mm diameter were obtained from gels with SiO2/Al2O3 ratio equal to 0.1, while samples with the ratio SiO2/Al2O3 = 0.5 were obtained as extended prisms with 1‑2 mm diameter. Increasing the SiO2/Al2O3 ratio from 0.1 to 0.4 leads a greater amount of acid sites and a decrease in the specific surface. The conversion of a‑methylstyrene as well as the yield of linear dimers and cyclic trimers both increase with an increasing amount of acid sites and greater external surface.