SAPO-11分子筛的粒度调控

摘要

In the presence of hexadecyl trimethyl ammonium bromide (CTAB) or fluoride ions (HF), superfine SAPO-11 was obtained via steam-assisted conversion method. The samples were characterized by SEM, XRD, IR, MAS NMR, TPD, TEM, TG-DSC and Nitrogen adsorption-desorption. The introduction of CTAB or HF can not only decrease the particle size, but also control the framework, morphology, pore structure and acid properties of SAPO-11 zeolites. The surfactant (CTAB) promotes the incorporation of Si atoms into the framework and leads to the increase of acid sites. The rod-like SAPO-11 monocrystal with 500 nm can be obtained in the presence of HF. F- ions could contribute to the higher thermal stability of the sample, while they inhibit Si atoms to incorporate into the framework of the zeolite, which causes a significant decrease of acid sites.%采用干凝胶法,通过向合成体系中添加适量的十六烷基三甲基溴化铵(CTAB)或氟化氢(HF)控制SAPO-11分子筛的粒度.采用SEM、XRD、IR、MAS NMR、TPD、TEM、TG-DSC以及低温N2吸附脱附对产物进行表征.结果表明,CTAB或HF的加入不仅能够减小分子筛的粒度,而且能调控分子筛骨架元素组成、表观形貌、孔道结构及酸性质等.其中,CTAB的加入有利于Si进入分子筛骨架.增加产物的酸量；HF的加入使样品由不规则的微米级颗粒调控为500 nm左右的棒状单晶,增强了分子筛的稳定性.但阻止了硅进入骨架,降低产物的酸量.