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采用纳米TS-1母液作为晶种,在四丙基溴化铵(TPABr)-乙胺廉价水热体系中,合成出晶粒尺寸为600nm×400nm×250nm的小晶粒钛硅分子筛(TS-1),用挤条法将其成型,得到的挤条小晶粒TS-1被用于催化固定床反应器中的丙烯环氧化反应.采用X射线衍射(XRD)光谱,傅里叶变换红外(FTIR)光谱,紫外-可见(UV-Vis)漫反射光谱及氮气物理吸附对挤条成型的小晶粒TS-1进行表征,并对丙烯环氧化的最优反应条件进行考察.其中所考察的条件包括:反应温度,压力,丙烯/H2O2摩尔比(n(C3H6)/n(H2O2)),丙烯、甲醇及H2O2的质量空速(WHSV)以及NH3·H2O浓度.在所考察的范围内,温度对环氧丙烷(PO)收率的影响较小,当反应压力为2.0MPa,n(C3H6)/n(H2O2)为4时,可以得到最高的PO收率.当丙烯、甲醇及H2O2的空速分别为0.93、2.5及0.25h-1时,PO在产物中的含量最高.较低的NH3·H2O浓度对高PO收率更有利.在优化的反应条件下,对比不同晶粒大小TS-1的催化性能,并考察了挤条小晶粒TS-1的长期运转性能,连续反应1000h,H2O2转化率及PO选择性仍能维持在95%以上.
The nanocrystalline TS-1 mother liquor was used as the seed crystal to synthesize TS-1 nanocrystals with a size of 600nm × 400nm × 250nm in tetrabutylammonium bromide (TPABr) -ethylamine cheap hydrothermal system. 1) was extruded by extruding method, and the extruded extrudate TS-1 was used to catalyze the epoxidation of propylene in a fixed bed reactor.X-ray diffraction (XRD) spectra, Fourier transform FTIR spectroscopy, UV-Vis diffuse reflectance spectroscopy and nitrogen physisorption were used to characterize the extrusion molding of small crystallites TS-1, and the optimum reaction conditions of propylene epoxidation were investigated. The investigated conditions include reaction temperature, pressure, mass ratio of propylene to H2O2 (n (C3H6) / n (H2O2)), mass space velocity of propylene, methanol and H2O2 (WHSV) The effect of temperature on the yield of propylene oxide (PO) is small, and the highest PO yield can be obtained when the reaction pressure is 2.0MPa and n (C3H6) / n (H2O2) is 4. When propylene, methanol And the space velocity of H2O2 were 0.93, 2.5 and 0.25 h-1, respectively, the content of PO in the product was the highest.The lower concentration of NH3 · H2O was more favorable for the high PO yield.Compared with the different crystal under the optimized reaction conditions Large grain Small TS-1. The continuous operation of 1000 hours, H2O2 conversion and PO selectivity can still be maintained above 95%.