Abstract: A series of SAPO-11 molecular sieves were synthesized by adjusting the n(H₂O)/n(Al₂O₃) ratio, the amount of seed crystals addition and crystallization temperature in the SAPO-11 molecular sieve synthesis process, and the effects of synthesis conditions on the physicochemical properties of molecular sieves and the catalytic performance in 1-hexene hydroisomerization were studied. The results show that the preferential growth of SAPO-11 molecular sieves can be obtained by increasing ratio of n(H2O)/n(Al2O3), thus exposing more pores and improving the catalytic performance, and the size of SAPO-11 molecular sieve can be reduced by adding heterogeneous crystal seeds. Compared with the molecular sieves synthesized under other conditions, the specific surface area, pore volume and acid content were increased. The SAPO-11-seed-200 molecular sieves synthesized at high n(H2O)/n(Al2O3) ratio, heterogeneous seeds and high crystallization temperature had the smallest particle size, the largest specific surface area and pore volume, and the highest acid amount. The catalytic activity and the skeletal isomerization selectivity of 1-hexene isomerization were better than those of other molecular sieves.

Key words: SAPO-11 molecular sieve, hydrothermal synthesis, seed crystal, 1-hexene isomerization