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121.
122.
溶胶-凝胶法制备Fe2(MoO4)3超微粒子催化剂 总被引:1,自引:0,他引:1
以硝酸铁和钼酸铵为原料,采用溶胶-凝胶法和微波加热技术制备了F 2(MoO4)3超微子催化剂,使用DTA-TG,IR,XRD以及BET比表面测试等手段,考察了制备条件对复合氧化物超微粒子形成、晶相和比表面积的影响。同时测试了该样品对甲苯选择性氧化制苯甲醛的催化性能。结果表明:制备Fe2(MoO4)2超微粒子的适宜条件为:初始溶液pH=1.0,mol柠檬酸:mol(铁+钼)=0.4。在此条件下制得的干凝胶,经微波加热处理后粒子的比表面积为36.4m^2/g,粒径约为35nm。在由甲苯气相选择氧化制苯甲醛的反应中表现出较高的催化活性。 相似文献
123.
Yu-hua Shan Jun-quan Sun~ 《高分子科学》2005,(3):301-310
A neutral nickel (Ⅱ) catalyst D, { [O-(3-cyclohexyl)(5-Cl)C6H2-ortho-C(H)=N-2,6-C6H3(i-Pr)2]Ni(Ph3P)(Ph)} has been synthesized and characterized by 1H-NMR, FTIR and elemental analysis. The results indicate that Al(i-Bu)3 is an effective cocatalyst for the neutral nickel catalyst. With bis(1,5-cyclooctadiene) nickel(0) [Ni(COD)2] or Al(i-Bu)3 as a cocatalyst, the neutral nickel catalyst D is active for ethylene polymerisation and copolymerisation with polar monomers (tertbutyl 10-undecenoate(BU), methyl 10-undecenoate (MU), allyl alcohol (AA) and 4-penten-1-ol (PO)) under mild conditions.The resulting polymers were characterized by 1H-NMR, FTIR, DSC, and GPC. From the comparative studies, Ni(COD)2 is more active than Al(i-Bu)3 for ethylene homopolymerization, while Al(i-Bu)3 is more effective than Ni(COD)2 for ethylene copolymerisation with polar monomers. The polymerization parameters which affect both the catalytic activity and properties of the resulting polyethylene were investigated in detail. Under the conditions of 20 μmol catalyst D and Ni(COD)2/D = 3(molar ratio) in 30 mL toluene solution at 45℃, 12 × 105 Pa ethylene for 20 min, the polymerization activity reaches as High as7.29×105gPE.(mol.Ni·h)-1and Mηis 7.16×104g.mol-1.For ethylene copolymerization with polar monomers,the effect of comonomer concentrations was examined. As high as 0.97 mol% of MU, 1.06 mol% of BU, 1.04 mol% of AA and 1.37 mol% of PO were incorporated into the polymer, respectively, catalyzed by D/Al(i-Bu)3 system. 相似文献
124.
125.
A. Sultan Nasar S. Subramani Ganga Radhakrishnan 《Journal of polymer science. Part A, Polymer chemistry》1999,37(12):1815-1821
N-Methylaniline-, diphenylamine-, and N-phenylnaphthylamine-blocked toluene diisocyanates (TDI) were prepared and characterized by IR, NMR spectroscopy, and nitrogen content analyses. The structure–property relationship of these adducts was established by reacting with hydroxyl-terminated polybutadiene (HTPB). The cure rate of the adduct increases from the N-phenylnaphthylamine- to diphenylamine- and to N-methylaniline-blocked TDI adduct. Simultaneous TGA/DTA results also confirm this trend, and the thermal stability of the adduct decreases in the following order: N-phenylnaphthylamine–TDI > diphenylamine–TDI > N-methylaniline–TDI. The gas chromatogram of the amine-blocked isocyanate confirms that the thermolysis products are the blocking agent and isocyanate. The solubilities of the adducts were carried out in polyether, polyester, and hydrocarbon polyols, and it was found that the N-methylaniline–TDI adduct shows higher solubility than the rest and also found that the polyester polyol shows higher solvating power against the adducts than the polyether and hydrocarbon polyols. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1815–1821, 1999 相似文献
126.
127.
SimultaneousSpectrophotometricDeterminationofTracePalladiumandRhodiumwith2,4-TADATZHANGXiao-ling;andZHANGGuang(DepartmentofCh... 相似文献
128.
铈钼氧化物表面氧性质和催化性能 总被引:4,自引:0,他引:4
在甲苯选择性氧化制苯甲醛反应中,Mo基氧化物是一类重要的催化剂[1].通常的认识是反应物与催化剂表面晶格氧作用,并通过催化剂本身的还原和氧化的循环过程促使反应进行。生成产物.因此,催化剂表面不同氧物种的热脱附性能应与催化反应性能密切相关.对于Ce-Mo氧化物的TPD-MS研究,尚未见文献报导.为了能获得该方面的信息,本文应用程序升温脱附-质谱检测(TP-MS)联用技术,对Ce-Mo氧化物样品进行了表面氧TPD谱测定和动力学参量等计算,并试图与其催化性能进行关联.1实验部分1.1样品的制备和表征分别将一定质量的硝酸铈铵和仲… 相似文献
129.
T. Jaimol A. K. Pandey A. P. Singh 《Journal of molecular catalysis. A, Chemical》2001,170(1-2):117-126
The vapour phase acetylation of toluene has been catalysed by acidic H-ZSM-5, H-mordenite and REY zeolite catalysts at 453 K in a tubular reactor at atmospheric pressure. H-ZSM-5 exhibited the best results during the reaction with respect to rate of acetylchloride conversion (TOF=7.5 mol s−1 mol−1 Al×10−4), conversion of acetyl chloride (60.2 wt.%) and selectivity for 4-methylacetophenone (88.3%) compared to both H-mordenite and REY zeolites. It is revealed that the activity and selectivity of the catalyst strongly depend on the acidic properties and pore openings of the zeolites, respectively. It is observed that isomer ratio (4-methylacetophenone/2-methylacetophenone) is influenced by the reaction conditions and type of zeolite used in the reaction. With increasing reaction temperature and toluene to CH3COCl molar ratio, the conversion of CH3COCl (ACT) increases, while it decreases with the increase in reaction time, weight hourly space velocity (WHSV), Na-content and silica to alumina molar ratio of H-ZSM-5 in the acetylation of toluene. H-ZSM-5 is deactivated under the reaction conditions. 相似文献
130.
Summary To assess individual exposure to monoaromatic hydrocarbons (benzene, toluene, ethylbenzene and xylenes-BTEX) in biological
fluids, a GC-MS method was developed. Headspace sampling of BTEX was by solidphase microextraction (SPME) with a 75 μm Carboxenpolydimethylsiloxane
(PDMS) fiber. Linearity was established for concentrations up to 50 μg L−1. Detection limits, calculated both in human blood and urine, ranged 5–10 ng L−1. Repeatability was in the range 6.5–9.2% for all compounds. The method was applied to the evaluation of the internal dose
of BTEX in a group of cyclists running for 2 h within city routes. Benzene and toluene in blood, and toluene and xylenes in
urine significantly increased after exercise as compared to prerun values, such changes being consistent with airborne concentrations.
The combination of SPME with GC-MS seems to represent an appropriate analytical approach to detect changes in the concentration
of monoaromatic hydrocarbons in biological media resulting from exposure to environmental pollution. 相似文献