Effect of template content on the physicochemical characterization and catalytic performance of SAPO-11 for the hydroisomerization of n-tetradecane
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摘要: 采用水热合成法,以二正丙胺(DPA)和二异丙胺(DIPA)混合物为模板剂合成SAPO-11分子筛,考察了模板剂用量和混合模板剂中DPA和DIPA配比对所得产物的影响,并通过XRD、N2吸附、NH3TPD和29Si MAS NMR等手段对样品进行了表征。结果表明,改变模板剂用量和配比不仅可以调节SAPO-11结晶度,还会改变Si在分子筛骨架上的分布,从而调节SAPO11的酸性。当模板剂用量比为1.5,模板剂中DPA的质量分数为66%时,样品的Si区面积最小,Si(n Al)(0 < n < 4)结构最多。因此,分子筛酸性和对正十四烷异构活性也最高。
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关键词:
- SAPO-11分子筛 /
- 水热合成 /
- 模板剂用量 /
- 模板剂配比 /
- 29Si MAS NMR /
- 临氢异构
Abstract: Different SAPO-11 have been synthesized hydrothermally using the mixed template of di-n-propylamine (DPA) and di-iso-propylamine (DIPA) by varying the template content or the ratio of DPA/DIPA. Products were characterized using X-ray diffraction (XRD), N2 adsorption, NH3temperatureprogramed desorption (TPD) and 29Si MAS NMR, and evaluated towards n-tetradecane skeletal isomerization. The results indicated that the template had strong influence on the crystallinity, the Si distribution and thus the acidity of SAPO11. The sample prepared at template content of 1.5 and w (DPA) of 66% possessed small silicon domains and large amount of Si(n Al)(0 < n < 4) sites, and the catalyst obtained with this method performed highest catalytic activity in the hydroisomerization of n-tetradecane due to the high acidity.
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