HYDROISOMERIZATION PERFORMANCE OF SMALL SIZE SAPO-11MOLECULAR SIEVE SYNTHESIZED BY SILYLANIZATION OF SEED CRYSTAL

The SAPO-11seed crystal was first silylanized using n-propyltriethoxysilane(Pr-TES)in synthesis process and the SAPO-11molecular sieve with small particle size(H-SAPO-11-S)was then synthesized by crystallization in cyclohexane-1-butanol system.Samples were analyzed by XRD,SEM,nitrogen adsorption-desorption and Py-IR.Characterization results show that pure phase SAPO-11molecular sieve is obtained by silylanizing seed crystal.The mean particle size for H-SAPO-11-S molecular sieve is much smaller than normal SAPO-11molecular sieve(H-SAPO-11-N)synthesized by conventional method,reducing from 8.0μm of H-SAPO-11-N to 1.0μm of H-SAPO-11-S.Compared with H-SAPO-11-N molecular sieve,H-SAPO-11-S molecular sieve possesses much more external specific surface area,larger pore volume and more suitable acid amount and acid strength.The results of n-hexadecane hydroisomerization show that the catalyst Pt/H-SAPO-11-S exhibits much better activity and higher isomers selectivity than that of the Pt/H-SAPO-11-N catalyst.