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 共查询到18条相似文献，搜索用时 59 毫秒
1.
梁永光  杨水金 《分子催化》2001,15(6):475-477
首次报道了新型催化剂TiSiW12O40/TiO2催化酯化合成葡萄五丁酸酯,考察了糖酸比、催化剂用量、反应时间、反应温度诸因素对产率的影响。实验表明,TiSiW12O40/TiO2是合成葡萄糖五丁酸酯的良好催化剂。最佳反应条件为：糖酸摩尔比1：6,催化剂的用量为反应物料总量的2.0%,酯化反应时间为2.0h,反应温度90-95℃。反应产率可达85.4%。  相似文献   

2.
TiSiW12O40/TiO2催化合成苹果酯   总被引：33，自引：0，他引：33  
以固载杂多酸盐TiSiW12O40/TiO2为多相催化剂,通过乙酰乙酸乙酯和乙二醇反应合成了苹果酯,探讨TiSiW12O40/TiO2对缩酮反应的催化活性,较系统地研究了原料量比,催化剂肜量,反应时间诸因素对产品收率的影响,实验表明：TiSiW12O40/TiO2是合成苹果酯的良好催化剂,在n(乙酰乙酸乙酯）：n(乙二醇）＝1：1．5,催化剂用量为反应物料总质量的1．0％,环己烷为带水剂,反应时间50min的优化条件下,苹果酯的收率可达84．1％。  相似文献   

3.
TiSiW12O40/TiO2催化合成丙酸乙酯   总被引：5，自引：0，他引：5  
余新武  王建  赖国松 《合成化学》2003,11(4):366-367,370
以自制的固载杂多酸(盐)TiSiW12O40／TiO2为复相催化剂，通过丙酸和无水乙醇反应合成了丙酸乙酯，探讨了诸因素对酯化率的影响，结果表明，在最佳反应条件下，收率可达78．1％。  相似文献   

4.
TiSiW12O40/TiO2催化合成乙酸环己酯   总被引：10，自引：0，他引：10  
孙婷  吴长增 《合成化学》2003,11(5):453-454
以固载杂多酸TiSiWl2O40／TiO2催化乙酸和环己醇合成了乙酸环己酯。实验确定最佳反应条件为：n(乙酸)：n(环己醇)=1．0：1．1,TiSiW12O40／TiO2用量为乙酸质量的5％,反应时间1．5h,酯化率达95．5％。  相似文献   

5.
TiSiW12O40/TiO2催化合成丙酸异戊酯   总被引：15，自引：0，他引：15  
丙酸异戊酯是一种具有菠萝或洋梨果香味的无色液体 ,可作食用香料及多种工业溶剂。传统工业采用浓硫酸催化丙酸和异戊醇合成丙酸异戊酯[1 ,2 ] ,但原料利用率及产率较低 ,环境污染严重。近年来 ,有关杂多酸及其盐类的催化作用的研究发展迅速[3～ 7] 。我们合成了杂多酸盐ＴｉＳｉＷ1 2 Ｏ40 /ＴｉＯ2 催化剂 ,研究其对丙酸异戊酯的催化合成反应 ,取得了较为满意的结果。1　实验1 1　仪器试剂ＰＫＷ 型电子节能控温仪 ;Ａｂｂｅ折光仪 ;ＩＭＰ41 0红外光谱仪 (ＫＢｒ压片 ,40 0～2 0 0 0ｃｍ- 1 ) ;Ｄ/ＭＡＸ ⅢＣ自动Ｘ射线衍射仪 (Ｃｕ靶 …  相似文献   

6.
TiSiW12O40/TiO2催化合成己酸异戊酯   总被引：6，自引：0，他引：6  
报道了以固载杂多酸盐TiSiW12O40/TiO4为多相催化剂,通过己酸和异戊醇反应合成了己酸异戊酯,探讨了TiSiW12O40/TiO4对酯化反应的催化活性,较系统地研究了醇酸摩尔比,催化剂用量,反应时间诸因素对收率的影响,实验表明：TiSiW12O40/TiO4是合成己酸异戊酯的良好催化剂,在n(醇）：n(酸）＝1．6：1,催化剂用量为反应物总质量的1．5％,反应时间45min,使用环己烷为带水剂的适宜条件下,己酸异戊酯的收率可达91．9％。  相似文献   

7.
杨锦飞 《应用化学》2003,20(2):201-0
催化剂;TiSiW12O40/TiO2催化合成磷酸三-(β-氯乙基)酯  相似文献   

8.
制备了新型固载杂多酸盐TiSiW12O40/TiO2环境友好催化剂,并以丁酸丁酯的合成作为探针反应,系统考察了原料H4SiW12O40@xH2O与TiO2摩尔比、焙烧温度、焙烧时间等制备条件对TiSiW12O40/TiO2催化活性的影响.实验表明:制备催化剂的适宜条件为原料H4SiW12O40@xH2O与TiO2摩尔比为0.47,焙烧温度为350℃,焙烧时间为3.0 h.利用该条件下制备的催化剂TiSiW12O40/TiO2合成丁酸丁酯,正丁醇与正丁酸的投料摩尔比n(醇):n(酸)=1.3:1,催化剂的用量占反应物总投料质量的1.3%,反应时间为1 h,丁酸丁酯的产率为97.2%.该催化剂TiSiW12O40/TiO2用于制备其它丁酸酯类(如乙酯、丙酯、戊酯、异戊酯)时同样取得了好的结果.  相似文献   

9.
固载杂多酸盐催化合成苯甲酸正戊酯   总被引：2，自引：1，他引：2  
首次报道了以固载杂多酸盐TiSiW12 O4 0 /TiO2 为多相催化剂 ,对以苯甲酸和正戊醇为原料合成苯甲酸正戊酯的反应条件进行了研究 .实验表明 :TiSiW12 O4 0 /TiO2 是合成苯甲酸正戊酯的良好催化剂 .最佳反应条件为 :醇酸物质量比为 4∶1,催化剂用量为反应物料总量的 1.5 % ,反应时间为 2 .5h .上述条件下 ,苯甲酸正戊酯的产率可达 96 .7% .  相似文献   

10.
微孔多金属氧酸H3PW12O40/SiO2催化合成丙烯酸正丁酯   总被引：4，自引：3，他引：4  
通过溶胶－凝胶技术将Keggin型杂多酸H3PW12O40负载于SiO2基质上，在含氧极性溶剂中得到不溶脱，易分离，可重复使用的具有大表面积（350．5m^2/g)的微孔催化材料（孔径为0．57nm)，利用UV，ICP，TGA，BET吸附等手段对该催化剂进行了表征，以H3PW12O40／SiO2做催化剂用丙烯酸和正丁醇合成丙烯酸正丁酯，催化活性高于H3PW12O40和H2SO4，当酯化反应2．5h时，丙烯酸的转化率可达97．6％，催化剂重复使用3次，其催化活性依然很高。  相似文献   

11.
体相及SiO2负载磷钼杂多酸铜盐的性质   总被引：3，自引：0，他引：3  
张昭良  杨锡尧 《分子催化》2000,14(5):359-362
采用ＴＧ－ＤＴＡ、ＦＴ－ＩＲ、ＸＲＤ、ＢＥＴ比表面积等方法,研究了体相及ＳｉＯ２负载磷钼杂多酸铜盐的性质,并与磷钼酸作了对比。结果表明,磷钼酸铜盐的热稳定性稍高于磷钼酸,且铜盐的部分结晶水更稳定;但是它们的最后分解产物相同。ＳｉＯ２负载的磷钼酸铜盐以非晶形态高度分散在ＳｉＯ２表面,但它们确实保持了Ｋｅｇｇｉｎ结构,热稳定性也提高约４５℃。  相似文献   

12.
《Electroanalysis》2003,15(8):695-701
The electrochemical properties of PW12O (abbreviated as PW12) anion in poly(ethylene glycol) (PEG) have been studied by cyclic voltammetry, complex impedance and FT‐IR spectroscopy. The PW12 anion in PEG‐LiClO4 electrolyte shows reasonable facile electrochemistry, and the diffusion coefficients of PW12 were measured with microelectrode. It is shown that ionic conductivity of polymer electrolytes based on low molecular weight PEG can be improved by the addition of PW12. The increase of conductivity is coupled with decrease of transient cross‐links density of polymer chains which is evidenced by the downshift of C? O? C stretching mode. The phenomena are explained in view of ion‐ion and ion‐polymer interactions.  相似文献   

13.
《Electroanalysis》2005,17(7):579-587
Organic/inorganic hybrid films of poly(new fuchsin) and phosphomolybdate (PMo12O ) have been prepared in acidic aqueous solutions. These new combination films are stable, electrochemically active, and can be produced on glassy carbon, platinum, gold, and transparent semiconductor tin oxide electrodes. An electrochemical quartz crystal microbalance along with cyclic voltammetry and UV‐visible absorption spectroscopy were used to study the in situ growth of the hybrid films. The hybrid poly(new fuchsin) and PMo12O films showed four obvious redox couples, and when transferred to various acidic aqueous solutions, the formal potentials of the four redox couples were found to be pH dependent. The electrocatalytic reduction of ClO , BrO , IO , SO , S2O , H2O2, and NO by the hybrid poly(new fuchsin) and PMo12O films was achieved in acidic aqueous solutions. In an aqueous solution at pH 1.5, a hybrid poly(new fuchsin) and PMo12O film showed a higher electrocatalytic reduction activity of IO than BrO or ClO , and the order of electrocatalytic activity was IO >BrO >ClO . The order of electrocatalytic reduction of SO , S2O , H2O2, and NO by hybrid poly(new fuchsin) and PMo12O films in an aqueous solution at pH 1.5 was NO >H2O2>S2O and SO . The electrocatalytic reactions of the poly(new fuchsin) and PMo12O films were investigated using the rotating ring‐disk electrode method.  相似文献   

14.
采用空间和时间分辨的四极质谱法了３５５ｎｍ脉冲激光  相似文献   

15.
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The development of begin{document}$rm{Bi}_2$end{document}Wbegin{document}$rm{O}_6$end{document}-based materials has become one of research hotspots due to the increasing demands on high-efficient photocatalyst responding to visible light. In this work, the effect of high energy radiation (begin{document}$gamma$end{document}-ray) on the structure and the photocatalytic activity of begin{document}$rm{Bi}_2$end{document}Wbegin{document}$rm{O}_6$end{document} nanocrystals was first studied. No morphological change of begin{document}$rm{Bi}_2$end{document}Wbegin{document}$rm{O}_6$end{document} nanocrystals was observed by SEM under begin{document}$gamma$end{document}-ray radiation. However, the XRD spectra of the irradiated begin{document}$rm{Bi}_2$end{document}Wbegin{document}$rm{O}_6$end{document} nanocrystals showed the characteristic 2begin{document}$theta$end{document} of (113) plane shifts slightly from 28.37begin{document}$^{rm{o}}$end{document} to 28.45begin{document}$^{rm{o}}$end{document} with the increase of the absorbed dose, confirming the change in the crystal structure of begin{document}$rm{Bi}_2$end{document}Wbegin{document}$rm{O}_6$end{document}. The XPS results proved the crystal structure change was originated from the generation of oxygen vacancy defects under high-dose radiation. The photocatalytic activity of begin{document}$rm{Bi}_2$end{document}Wbegin{document}$rm{O}_6$end{document} on the decomposition of methylene blue (MB) in water under visible light increases gradually with the increase of absorbed dose. Moreover, the improved photocatalytic performance of the irradiated begin{document}$rm{Bi}_2$end{document}Wbegin{document}$rm{O}_6$end{document} nanocrystals remained after three cycles of photocatalysis, indicating a good stability of the created oxygen vacancy defects. This work gives a new simple way to improve photocatalytic performance of begin{document}$rm{Bi}_2$end{document}Wbegin{document}$rm{O}_6$end{document} through creating oxygen vacancy defects in the crystal structure by begin{document}$gamma$end{document}-ray radiation.  相似文献   

16.
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Photocatalytic reduction of CObegin{document}$_2$end{document} into various types of fuels has attracted great interest, and serves as a potential solution to addressing current global warming and energy challenges. In this work, Ag-Cu nanoparticles are densely supported on N-doped TiObegin{document}$_2$end{document} nanowire through a straightforward nanofabrication approach. The range of light absorption by N-doped TiObegin{document}$_2$end{document} can be tuned to match the plasmonic band of Ag nanoparticles, which allows synergizing a resonant energy transfer process with the Schottky junction. Meanwhile, Cu nanoparticles can provide active sites for the reduction of CObegin{document}$_2$end{document} molecules. Remarkably, the performance of photocatalytic CObegin{document}$_2$end{document} reduction is improved to produce CHbegin{document}$_4$end{document} at a rate of 720 begin{document}$mu$end{document}molbegin{document}$cdot$end{document}gbegin{document}$^{-1}$end{document}begin{document}$cdot$end{document}hbegin{document}$^{-1}$end{document} under full-spectrum irradiation.  相似文献   

17.
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Hydrogen evolution reaction (HER) is the major cathodic reaction which competes begin{document}${rm C}rm{O}_rm{2}$end{document} reduction reaction (begin{document}${rm C}rm{O}_rm{2}$end{document} RR) on Pt electrode. Molecular level understanding on how these two reactions interact with each other and what the key factors are of begin{document}${rm C}rm{O}_rm{2}$end{document} RR kinetics and selectivity will be of great help in optimizing electrolysers for begin{document}${rm C}rm{O}_rm{2}$end{document} reduction. In this work, we report our results of hydrogen evolution and begin{document}${rm C}rm{O}_rm{2}$end{document} reduction on Pt(111) and Pt film electrodes in begin{document}${rm C}rm{O}_rm{2}$end{document} saturated acid solution by cyclic voltammetry and infrared spectroscopy. In solution with pH > 2, the major process is HER and the interfacial pH increases abruptly during HER; begin{document}${rm C}rm{O}_rm{ad}$end{document} is the only adsorbed intermediate detected in begin{document}${rm C}rm{O}_rm{2}$end{document} reduction by infrared spectroscopy; the rate for begin{document}${rm C}rm{O}_rm{ad}$end{document} formation increases with the coverage of UPD-H and reaches maximum at the onset potential for HER; the decrease of begin{document}${rm C}rm{O}_rm{ad}$end{document} formation under HER is attributed to the available limited sites and the limited residence time for the reduction intermediate (begin{document}$rm{H}_rm{ad}$end{document}), which is necessary for begin{document}${rm C}rm{O}_rm{2}$end{document} adsorption and reduction.  相似文献   

18.
    
Hybrid density functional theory calculations on the structures, vibrational frequencies, electron binding and dissociation energies, and bonding properties of CuO$_{3}^{-}$ and CuO3 species have been carried out. Stable isomers containing an O3 subunit and composed of O2 bound to CuO have been located on the potential energy hypersurfaces of CuO$_{3}^{-}$ and CuO3. The isomers formed by O2 bonded to CuO in side‐on and end‐on coordination are more stable than those containing an O3 subunit. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 81: 162–168, 2001  相似文献   

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