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以乙酰丙酮钯、乙酰丙酮铜为金属前驱体,以氧化铝球为载体,采用超临界流体沉积法(SCFD)制备氧化铝球负载的平均粒径≤10 nm的钯铜纳米粒子。采用高角度环形暗场-扫描透射电子显微镜(HAADF-STEM)、X射线衍射(XRD)和称重法对钯铜纳米粒子的负载状况、粒径分布进行表征。结果表明,沉积温度与沉积压力对钯铜纳米粒子的粒径有重要影响,在65 ℃、15 MPa时,钯铜纳米粒子的平均粒径可达2.37 nm。在金属前驱体投料量一定时,沉积时间存在最佳值。助溶剂的选择影响钯铜纳米粒子的平均粒径与粒径分布,在65 ℃、15 MPa下,使用8 mL二氯甲烷作为助溶剂,钯铜纳米粒子的平均粒径降至1.81 nm。随着Pd理论负载量的增加,钯铜纳米粒子的平均粒径先降后增,当Pd理论负载量为0.50%时,出现最小值1.81 nm。 相似文献
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用三缩四乙二醇作溶剂,用硼氢化钠还原氯钯酸的方法制备了溶剂稳定的钯金属纳米颗粒,得到了分布均匀、平均粒径在1.35 nm的钯金属纳米颗粒。同时讨论了得到小颗粒的钯金属纳米颗粒的最佳条件。 相似文献
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将钯纳米颗粒负载于陶瓷膜表面制备钯/陶瓷膜催化剂,并用于对硝基苯酚催化加氢反应中,考察了陶瓷膜孔径,硅烷偶联剂KH550溶剂及其浓度和改性时间,钯盐浸渍浓度、温度及时间以及还原温度对膜催化剂催化性能的影响.结果表明,采用孔径为200 nm 的氧化铝陶瓷膜,在6g/L的硅烷偶联剂KH550溶液中浸渍48 h,然后在40℃的浓度为0.030 mol/L乙酸钯溶液中浸渍20 h,最后采用水合肼在0℃还原30 min,得到的钯/陶瓷膜催化剂在对硝基苯酚催化加氢反应中显示了较好的催化性能,其加氢速率达15.5 mol/(h·m2). 相似文献
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溶剂稳定的钯金属纳米颗粒的制备 总被引:1,自引:0,他引:1
分别用三缩四乙二醇和乙二醇作溶剂,得到了小粒径的钯金属纳米颗粒,反应条件温和,操作简单,得到的颗粒粒径小而且分布均匀,同时考察了溶剂、碱以及稳定剂PVP对粒径的影响. 相似文献
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用N,N-二仲辛基乙酰胺[N,N-di(sec-octyl)acetamide]为流动载体、聚双丁二酰亚胺(N205)为表面活性剂、磺化煤油为溶剂,硫脲溶液为内相试剂的液膜体系,提取料液中的钯。实验确定了提取Pd~(2+)的最佳实验条件和液膜组成。已成功地用于提取废催化剂和含钯资源中的钯,钯的提取(富集)率在98%以上,钯的纯度在99.9%以上,非常有实用意义。 相似文献
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以醋酸钯为前体、有机氢硅烷为还原剂开发了一种简单温和的疏水性钯纳米颗粒制备方法。通过调节前体、保护剂和还原剂的配比,在氯仿溶液中室温条件下合成了疏水性的钯纳米团簇和钯纳米球。运用透射电子显微镜(TEM)、X射线衍射(XRD)、光学接触角测试仪、循环伏安法(CV)、表面增强拉曼光谱(SERS)对这两种钯纳米材料进行了测试表征。TEM观察表明这两种钯纳米材料粒径分布均匀,分散性良好。接触角测试表明钯纳米团簇与钯纳米球均具有疏水性。CV测定结果显示这两种钯纳米材料具有良好的电催化稳定性,钯纳米团簇比钯纳米球对乙醇氧化具有更突出的电催化性能,表明钯纳米团簇结构稳定并具有更大的比表面积。SERS测试表明钯纳米团簇是一种优良的疏水性表面增强拉曼散射基底,利用这种基底对疏水性致癌物3,4-苯并芘和联苯胺进行了SERS快速检测,检测限为0.1mg/mL。 相似文献
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成小强李鹏翔冯彬白立光赵晓东 《化学推进剂与高分子材料》2022,(6):25-30
介绍了蒽醌法制备过氧化氢用钯催化剂失活的几种原因,并对其再生方法进行了讨论和总结,提出了钯催化剂的优化使用方法,针对原材料控制、操作条件优化、溶剂组分优化分别进行了阐述,以期为使用钯催化剂的过氧化氢装置稳定运行提供指导。 相似文献
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以琥珀酸二异辛酯磺酸钠(AOT)为表面活性剂,分别以抗坏血酸、硼氢化钠(NaBH4)、七水硫酸亚铁(FeSO4.7H2O)为还原剂,成功地制备了球状的钯纳米粒子。采用扫描电镜和X射线衍射仪对产物进行了表征,钯纳米颗粒的平均粒径约50~150nm。结果表明,当琥珀酸二异辛酯磺酸钠的浓度为15g/L,氯化钯的浓度为0.0025mol/L,抗坏血酸的浓度为0.05mol/L,40℃反应2h时,可制得大小均匀、粒径小、分散性好的钯纳米颗粒。 相似文献
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Expoxidized natural rubber has been selectively hydrogenated in the presence of a homogeneous palladium acetate catalyst. The hydrogenated product has been characterized by infra-red and nuclear magnetic resonance spectroscopies. No change is noted in the epoxy content of the polymer after the reaction. The catalyst is highly selective in reducing carbon-carbon double bonds in the presence of epoxy groups. Natural rubber has also been hydrogenated for a comparative study. The rate constant of hydrogenation is decreased with increase in epoxy content of the polymer. 相似文献
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醋酸钯是应用广泛的一种贵金属有机化合物,虽然在20世纪60年代就有了合成文献报道,但在国内关于醋酸钯制备的文献较少,工业生产质量不稳定,文章回顾了醋酸钯的合成研究进展,对不同的合成方法优缺点进行了比较,并指出了合成关键因素。文章主要介绍了其在药物合成中的应用。希望为国内醋酸钯的工业化生产和应用提供有益参考。 相似文献
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醋酸钯/酞菁铁催化氧化环戊烯合成环戊酮的研究 总被引:6,自引:1,他引:5
在乙腈的酸性水溶液中 ,考察了 Pd Ac2 (醋酸钯 ) /Fe Pc(酞菁铁 )催化氧化环戊烯合成环戊酮的催化活性 ,讨论了影响该反应活性的因素及其反应机理。实验结果表明 ,该催化体系对环戊烯的羰基化显示出较高的催化活性 ,反应 1 0 min,反应的平均吸氧速率为 4.2 5× 1 0 -2 mmol/min,环戊酮的收率可达 83%。在乙醇的酸性水溶液中 ,Pd Ac2 /BQ(苯醌 ) /Fe Pc催化环戊烯氧化合成环戊酮的活性高于 Pd Ac2 /Fe Pc的活性 ,反应的平均吸氧速率分别为 1 .45× 1 0 -2 mmol/min,9.0×1 0 -3 mmol/mi 相似文献
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The Surface Chemistry of Acetic Acid on Pd{111} 总被引:1,自引:0,他引:1
XPS, temperature-programmed reaction and HREELS have been used to study the adsorption and reactions of acetic acid on Pd{111}. At 170 K the adsorbed monolayer contains intact and dissociated acetic acid molecules, the latter consisting of a mixture of bidentate acetate and another species tentatively identified as monodentate acetate. The monodentate acetate appears to resemble closely the acetate species observed under reaction conditions at the surface of a pure palladium vinyl acetate synthesis catalyst. Thermal decomposition of the adsorbate yields CO2, H2O, CO, H2 and carbon. The associated processes may be rationalised in terms of two reaction channels, one due to the monodentate and the other due to the bidentate acetate. 相似文献
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Marcin Kalek Martina Jezowska Jacek Stawinski 《Advanced Synthesis \u0026amp; Catalysis》2009,351(18):3207-3216
An efficient protocol for the synthesis of arylphosphonate diesters via a palladium‐catalyzed cross‐coupling of H‐phosphonate diesters with aryl electrophiles, promoted by acetate ions, was developed. A significant shortening of the cross‐coupling time in the presence of the added acetate ions was achieved for bidentate and monodentate supporting ligands, and for different aryl electrophiles (iodo, bromo and triflate derivatives). The reaction conditions were optimized in terms of amount of the catalyst, supporting ligands, and source of the acetate ion used. Various arylphosphonates, including those of potential biological significance, were synthesized using this newly developed protocol. Some mechanistic aspects of the investigated reactions are also discussed. 相似文献
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The catalytic hydrogenation of acrylonitrile‐butadiene copolymer (nitrile rubber, NBR) using Pd(OAc)2 or RuCl2(PPh3)3 catalysts has been investigated in order to produce a totally saturated nitrile rubber. The hydrogenation of NBR is effective with both catalysts and achieved total conversion under the appropriate reaction conditions. In the case of palladium the effects of reaction parameters such as reaction temperature, pressure, time, catalyst concentration, and NBR concentration have been investigated. Even though both ruthenium‐ and palladium‐based catalysts are effective in the production of HNBR, the former requires harsh reaction conditions and has the drawback of gel formation under high conversion, motivating the migration to RuCl2 (PPh3)3 as an alternative catalyst. The degree of hydrogenation was determined by IR and NMR spectroscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献