多级孔道纳米尺度TS-1的制备及性能评价

以四丙基溴化铵（TPABr）为模板剂、正丁胺（NBA）为碱源、可溶性淀粉作为硬模板空间填充剂，利用添加晶种且蒸汽辅助晶化的方式，制备出富含四配位Ti物种且具有多级孔道的纳米尺度TS-1，采用X射线衍射、紫外漫反射可见光谱、傅里叶变换红外光谱、电感耦合等离子光谱、N₂物理吸附-脱附及固体核磁共振等手段对所制备的样品进行一系列表征，并考察其对氯丙烯（ALC）环氧化反应的催化性能。结果表明，采用晶种辅助的方式晶粒尺寸可减小至280nm×170nm×500nm，淀粉的加入可制备出多级孔道结构且有效抑制非骨架Ti的产生；对于ALC的环氧化反应，当淀粉的添加量与SiO₂的质量比为0.4时，所制备的多级孔道TS-1催化活性最高，H₂O₂的转化率达到99.15%，环氧氯丙烷（ECH）的选择性为97.23%，并且此时ECH的收率及H₂O₂的有效利用率均较高。

Preparation of hierarchical nanosized TS-1 and its catalytic performance

Hierarchical nanosized TS-1 with abundant tetrahedrally coordinated Ti species was synthesized by steam-assisted method under seeding. Tetrapropylammonium bromide was used as template, butylamine as alkali source, and soluble starch as a hard template. The obtained samples were characterized by powder X-ray diffraction, ultraviolet visible diffuse reflectance spectra, Fourier transform infrared spectroscopy, inductively coupled plasma spectroscopy, N₂ physical adsorption/desorption and NMR. The epoxidation of allyl chloride was used as a probe reaction to evaluate the catalytic performance of the samples. The particle size of TS-1 could reduce to 280nm×170nm×500nm using the seed-assisted method, and the addition of starch could create hierarchical structure and inhibit the formation of the extra-framework Ti effectively. For the allyl chloride epoxidation, the hierarchical TS-1 prepared with the starch/SiO₂ (mass ratio) of 0.4 exhibits an outstanding activity, with a conversion 99.15% for H₂O₂ and the selectivity of epichlorohydrin of 97.23%, respectively. Meanwhile, the yield of epichlorohydrin and the utilization efficiency of H₂O₂ are also increased.