物理化学学报
物理化學學報
물이화학학보
ACTA PHYSICO-CHIMICA SINICA
2013年
1期
183-190
,共8页
左轶%宋万仓%王梦丽%徐永海%王祥生%郭新闻*
左軼%宋萬倉%王夢麗%徐永海%王祥生%郭新聞*
좌질%송만창%왕몽려%서영해%왕상생%곽신문*
丙烯环氧化%TS-1%H2O2%反应条件%表征%固定床反应器
丙烯環氧化%TS-1%H2O2%反應條件%錶徵%固定床反應器
병희배양화%TS-1%H2O2%반응조건%표정%고정상반응기
Epoxidation of propylene%TS-1%H2O2%Reaction condition%Characterization%Fixed-bed reactor
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600 nm×400 nm×250 nm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2.0 MPa, 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0.25 h-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1000 h, H2O2转化率及PO选择性仍能维持在95%以上.
採用納米TS-1母液作為晶種,在四丙基溴化銨(TPABr)-乙胺廉價水熱體繫中,閤成齣晶粒呎吋為600 nm×400 nm×250 nm的小晶粒鈦硅分子篩(TS-1),用擠條法將其成型,得到的擠條小晶粒TS-1被用于催化固定床反應器中的丙烯環氧化反應.採用X射線衍射(XRD)光譜,傅裏葉變換紅外(FTIR)光譜,紫外-可見(UV-Vis)漫反射光譜及氮氣物理吸附對擠條成型的小晶粒TS-1進行錶徵,併對丙烯環氧化的最優反應條件進行攷察.其中所攷察的條件包括:反應溫度,壓力,丙烯/H2O2摩爾比(n(C3H6)/n(H2O2)),丙烯、甲醇及H2O2的質量空速(WHSV)以及NH3·H2O濃度.在所攷察的範圍內,溫度對環氧丙烷(PO)收率的影響較小,噹反應壓力為2.0 MPa, n(C3H6)/n(H2O2)為4時,可以得到最高的PO收率.噹丙烯、甲醇及H2O2的空速分彆為0.93、2.5及0.25 h-1時, PO在產物中的含量最高.較低的NH3·H2O濃度對高PO收率更有利.在優化的反應條件下,對比不同晶粒大小TS-1的催化性能,併攷察瞭擠條小晶粒TS-1的長期運轉性能,連續反應1000 h, H2O2轉化率及PO選擇性仍能維持在95%以上.
채용납미TS-1모액작위정충,재사병기추화안(TPABr)-을알렴개수열체계중,합성출정립척촌위600 nm×400 nm×250 nm적소정립태규분자사(TS-1),용제조법장기성형,득도적제조소정립TS-1피용우최화고정상반응기중적병희배양화반응.채용X사선연사(XRD)광보,부리협변환홍외(FTIR)광보,자외-가견(UV-Vis)만반사광보급담기물리흡부대제조성형적소정립TS-1진행표정,병대병희배양화적최우반응조건진행고찰.기중소고찰적조건포괄:반응온도,압력,병희/H2O2마이비(n(C3H6)/n(H2O2)),병희、갑순급H2O2적질량공속(WHSV)이급NH3·H2O농도.재소고찰적범위내,온도대배양병완(PO)수솔적영향교소,당반응압력위2.0 MPa, n(C3H6)/n(H2O2)위4시,가이득도최고적PO수솔.당병희、갑순급H2O2적공속분별위0.93、2.5급0.25 h-1시, PO재산물중적함량최고.교저적NH3·H2O농도대고PO수솔경유리.재우화적반응조건하,대비불동정립대소TS-1적최화성능,병고찰료제조소정립TS-1적장기운전성능,련속반응1000 h, H2O2전화솔급PO선택성잉능유지재95%이상.
A smal-crystal titanium silicalite-1 (TS-1) with a size of 600 nm × 400 nm × 250 nm was synthesized using a nano-sized TS-1 mother liquor as the seed in a tetrapropyl ammonium bromide (TPABr)-ethylamine hydrothermal system, and was extruded with silica sol. The obtained TS-1 extrudate was characterized by X-ray powder diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-Vis) diffuse reflectance spectroscopy, and nitrogen physisorption. The reaction conditions, including temperature, pressure, molar ratio of propylene/H2O2 (n(C3H6)/n(H2O2)), the weight hourly space velocities (WHSVs) of propylene, methanol and H2O2, and the concentration of NH3·H2O, were systematical y studied to identify ideal conditions for propylene epoxidation over smal-crystal TS-1 extrudate. The reaction temperature had little effect on the propylene oxide (PO) yield under the conditions examined. The highest PO yield was obtained when the pressure was 2.0 MPa and the n(C3H6)/n(H2O2) was 4. The PO content in the product was maximized when the WHSVs of propylene, methanol and H2O2 were 0.93, 2.5, and 0.25 h-1, respectively. A low concentration of NH3·H2O was beneficial for a high PO yield. Under the optimized condition, we compared catalytic performances of TS-1 with different crystal @@@@sizes and performed a long-term test over the smal-crystal TS-1. The tests indicated that H2O2 conversion and PO selectivity could both reach 95%, even after 1000 h on stream.
