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以CO2与环氧乙(丙)烷合成碳酸乙(丙)烯酯的反应为主要研究对象,对应用于环氧烷和CO2反应制备环状碳酸酯的催化剂进行比较,并对未来的发展方向进行了预测.结果发现,均相催化剂,特别是金属配合物催化剂,用于CO2和环氧烷合成环状碳酸酯反应的催化活性和选择性通常比较高,但均相催化剂与产物分离困难.与均相催化剂相比,多相催化剂易于和产物分离.但普通的多相催化剂,如金属氧化物催化剂和碱金属分子筛催化剂的催化活性较差,反应条件苛刻.将均相催化剂固载化形成具有高活性、高选择性和高稳定性的多相催化剂将是未来的发展方向. 相似文献
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采用分步浸渍法制备了MgO改性的Mg-Ni/BaTiO3催化剂,考察了MgO助剂对催化剂性能的影响,运用H2-TPR、XRD、BET等测试技术对催化剂进行表征,并与催化剂Ni/BaTiO3、Ni/γ-Al2O3比较。发现MgO的添加有利于提高催化剂的催化活性和抗积炭性能;适量的MgO助剂可以改善催化剂的性能,但过量的MgO却会对催化剂的性能产生不良影响,随着MgO含量的增加,反应活性基本呈下降趋势。同时研究了不同的制备方法对催化剂催化活性的影响,用溶胶-凝胶法制备的催化剂具有更高的催化活性。 相似文献
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Ni-Co双金属催化剂在二氧化碳重整甲烷反应中的催化活性研究 总被引:1,自引:0,他引:1
采用等体积浸渍法制备了Ni/BaTiO3、Co/BaTiO3和Ni-Co/BaTiO3催化剂,并在固定床反应装置上考察了在973~1 073 K这些催化剂对CO2重整CH4反应的催化活性,且采用程序升温还原技术对催化剂进行表征,发现与单金属催化剂相比,Ni-Co/BaTiO3双金属催化剂有更为优越的催化活性。结果表明在Ni-Co/BaTiO3催化剂中Ni和Co之间产生了一定的协同作用。同时研究了不同的制备方法对Ni-Co双金属催化剂催化活性的影响,用溶胶-凝胶法制备的催化剂具有更高的催化活性。 相似文献
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钛系催化剂对聚酯缩聚反应速度和热稳定性影响的研究 总被引:6,自引:0,他引:6
研究了K2TiF6、(C4H9O)4Ti、Sb2O33种催化剂的缩聚反应速度,并对3种催化剂合成的切片进行了热稳定性比较(Δ[η]、TG)。结果表明:钛系催化剂的催化活性明显高于常规Sb2O3,其中以(C4H9O)4Ti的催化活性最高;(C4H9O)4Ti的动力学曲线具有阶段性,其高催化活性体现在缩聚反应的中后期;对3种催化体系制得的PET切片进行热稳定性测试的结果表明:采用(C4H9O)4Ti作为催化剂配合稳定剂SI与Co2+可制得色相良好,热稳定性高的聚酯切片。 相似文献
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空气中的硫氧化物主要来源于油品中乙硫醇的燃烧,为了降低空气中的含硫化合物,必须降低油品中乙硫醇的含量。首先合成了2-硝基酞菁铝,通过元素分析、红外光谱及紫外可见光谱对2-硝基酞菁铝进行了表征,然后以2-硝基酞菁铝作为去除乙硫醇的催化剂,并和2-羧基酞菁铝及四硝基酞菁铝作为催化剂进行比较。结果表明,2-硝基酞菁铝的催化活性能达到91.6%,持续330 min,虽然没有2-羧基酞菁铝的催化活性高,但比四硝基酞菁铝的催化活性高。 相似文献
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以一种廉价的农林废弃物——松木粉为原料,首先经过炭化和活化处理,制备活性炭,再通过苯磺酸重氮盐还原法处理活性炭引入磺酸基团(—SO3H),从而制备出具有高比表面积的炭基固体酸催化剂(AC-SO3H)。其比表面积达到1364 m2/g,磺酸基密度为1.36 mmol/g。以乙酸的酯化反应考察了炭基固体酸催化剂的催化活性,并与Amberlyst-15、Nafion NR50以及Nafion SAC-13等几种固体酸催化剂进行了比较。实验结果表明,炭基固体酸催化剂的催化活性仅略低于Amberlyst-15,高于Nafion NR50和Nafion SAC-13,炭基固体酸催化剂的成本也远远低于Nafion NR50和NafionSAC-13。研究结果表明,以松木粉为原料,通过炭化、活化和磺化处理能够得到性能优异且成本低廉的炭基固体酸催化剂。 相似文献
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松木粉制备高比表面积炭基固体酸催化剂 总被引:1,自引:0,他引:1
以一种廉价的农林废弃物——松木粉为原料,首先经过炭化和活化处理,制备活性炭,再通过苯磺酸重氮盐还原法处理活性炭引入磺酸基团(—SO3H),从而制备出具有高比表面积的炭基固体酸催化剂(AC-SO3H)。其比表面积达到 1364 m2/g,磺酸基密度为 1.36 mmol/g。以乙酸的酯化反应考察了炭基固体酸催化剂的催化活性,并与Amberlyst-15、Nafion NR50以及Nafion SAC-13等几种固体酸催化剂进行了比较。实验结果表明,炭基固体酸催化剂的催化活性仅略低于Amberlyst-15,高于Nafion NR50和Nafion SAC-13,炭基固体酸催化剂的成本也远远低于Nafion NR50和Nafion SAC-13。研究结果表明,以松木粉为原料,通过炭化、活化和磺化处理能够得到性能优异且成本低廉的炭基固体酸催化剂。 相似文献
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In situ combustion synthesis of structured Cu-Ce-O and Cu-Mn-O catalysts for the production and purification of hydrogen 总被引:1,自引:0,他引:1
Joan Papavasiliou George Avgouropoulos Theophilos Ioannides 《Applied catalysis. B, Environmental》2006,66(3-4):168-174
The combustion method was employed for the in situ synthesis of nanocrystalline Cu-Ce-O and Cu-Mn-O catalyst layers on Al metal foam, without the need of binder or additional calcination steps. Copper-manganese spinel oxides have been proposed as a catalytic system for hydrogen production via methanol steam reforming, while CuO-CeO2 catalysts have been successfully examined for CO removal from reformed fuels via selective oxidation. In this work, the performance of these catalysts supported on Al metal foam has been investigated in the reactions of methanol reforming and selective CO oxidation. The Cu-Ce-O foam catalyst exhibited similar catalytic performance to the one of the powder catalyst in the selective oxidation of CO. The performance of the Cu-Mn-O foam catalyst in the steam reforming of methanol was inferior to the one of the powder catalyst at intermediate conversion levels, but almost complete conversion of methanol was obtained at the same temperature with both foam and powder catalysts. 相似文献
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Young San You Kyeong-Hwan Chung Jong-Ho Kim Gon Seo 《Korean Journal of Chemical Engineering》2001,18(6):924-929
Titania-impregnated photocatalysts supported on glass fiber (GF) were prepared and employed in the photocatalytic oxidation
of toluene. Amorphous titania sol (ATS) prepared from titanium isopropoxide was useful to impregnate titania on glass fiber
in the shape of a thin film. TiO2/GF catalysts prepared by using the ATS showed better stability against water and vibration, but lower catalytic activity
in the photo-oxidation of toluene compared to crystalline anatase powder (CAP) impregnated catalyst. Photocatalytic activity
of the ATS catalyst was considerably enhanced by the addition of hydrogen peroxide, resulting in high activity comparable
to that of the CAP catalyst. 相似文献
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以工业偏钛酸为原料,分别选取三氧化钨(WO3)、钨酸铵(ATT)、偏钨酸铵(AMT)、仲钨酸铵(APT)等4种钨盐前驱体,采用浸渍法制备了SCR脱硝催化剂载体材料钛钨粉。采用XRD、SEM(EDS)、BET等检测手段对样品进行表征,并对由钛钨粉制成的催化剂进行活性测试。实验结果表明:由偏钨酸铵(AMT)制备的钛钨粉晶粒度小,晶格畸变较小,性能比较稳定;颗粒聚集程度最低,形貌较为均一,钨的分布最均匀;比表面积最大,而比表面积在一定范围内越大对催化剂的活性越有益;且由其制备的催化剂脱硝活性最高,接近进口产品。因此,比较而言,AMT是制备钛钨粉较为理想的钨盐前驱体。 相似文献
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Surface of magnesium particles is highly reactive and may be oxidized easily during storage at ambient conditions. Coating the surface of metal particles with a layer of polymer could be a simple and efficient way to prevent oxidation. In this study, Taguchi robust design was employed as a statistical experiment design for coating of magnesium powder with azidodeoxy cellulose nitrate via solvent/non-solvent technique. FT-IR spectroscopy and scanning electron microscopy techniques were used to evaluate the surface morphology of coated particles. The effect of azidodeoxy cellulose nitrate coating on magnesium powder thermal stability has been investigated by means of thermogravimetry (TG) coupled with differential scanning calorimetry (DSC). The effects of procedure parameters, i.e., type of solvent, percent of polymer as the stabilizer, flow rate of non-solvent addition, and added non-solvent volume in the coating quality and thermal properties of magnesium powder have been studied by thermal analysis methods. Analysis of variance (ANOVA) was employed to evaluate quantitatively the effect of these parameters on thermal stability of coated magnesium particles. Thermal data showed that magnesium powder could be stabilized considerably by controlling coating process parameters including the percent of the stabilizer, flow rate of non-solvent addition, and type of solvent. Based on the ANOVA results, using of 3% stabilizer, 1 ml/min as non-solvent flow rate, and DMF as the solvent are optimum conditions for coating of magnesium particles with azidodeoxy cellulose nitrate leads to producing coated particles with higher thermal stability (567 °C); whereas, TG/DSC analysis results revealed that the main thermal oxidation of the pure magnesium powder starts at lower temperature ranges of 260 °C. 相似文献