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Hermann-JosefMiddeke 《电镀与涂饰》2005,24(3):34-38
在非导体表面化学沉积金属的开始,首先必须要有一种合适的引发剂,即是今天所谓的活化剂。从含有亚锡的酸性溶液中制取的胶体钯是活化剂的主要成分。总的来说,胶体钯催化剂的制备虽然简单,但要符合一些质量要求,就必须收集有关催化剂结构的详细数据。胶体钯催化剂的结构对胶体与被镀表面的反应及其活性均有影响。目前大多数催化剂是与加速剂联合使用,以引发化学镀镍溶液中金属的沉积。在直接镀工艺中,使用大量的催化剂所带来的导电性有利于后续的电镀。 相似文献
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壳聚糖席夫碱钯对碘代苯与丙烯酰胺反应生成肉桂酰胺的催化性能 总被引:2,自引:0,他引:2
水杨醛与壳聚糖反应制得壳聚糖席夫碱配体,该配体与PdC l2反应得到壳聚糖席夫碱钯催化剂。研究了该催化剂对碘代苯(PhI)与丙烯酰胺(AM)反应生成反式-肉桂酰胺的催化性能。考察了不同反应因素(原料量比、缚酸剂种类及用量、反应温度、反应时间、催化剂用量、溶剂)对该反应的影响,得到了最佳反应条件:PhI 10mmol,以三丁胺(Bu3N)为缚酸剂,n(PhI)∶n(AM)∶n(Bu3N)=1∶1.3∶1.8,催化剂用量为0.10 g,2 mL DMF为溶剂,氮气中110℃反应1 h,产率高达91.1%。该催化剂经过滤分离、溶剂洗涤,循环使用7次仍有较高的催化活性,产率为87.5%。该催化剂对取代碘苯与丙烯酰胺的反应也有较高的催化活性,产率均在86.7%以上。 相似文献
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Palladium is generally active in the catalytic decomposition and synthesis of methanol. The activity of palladium is largely affected by its support. Cerium oxide is an effective support especially when the catalyst is prepared by the coprecipitation or depositionprecipitation method which leads to a strong interaction between palladium and the support. Cationic palladium species formed in the catalyst are probably active species for both decomposition and synthesis while formation of Pd-O-Ce bonding is rather important in the synthesis reaction. 相似文献
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2-ethylhexanal (2EH) was directly synthesized from n-butyraldehyde and hydrogen at 1 atm and 150°C using the catalysts prepared
by supporting tetraamine palladium(II) chloride on the potassium ion-exchanged zeolite X (Pd/KXW) and on the potassium ion-added
zeolite X (Pd/KXU). The latter catalyst contains a larger amount of potassium ion and exhibits higher activity and very high
selectivity of 2EH (>93%) due to its greater basicity. The main reaction path possibly starts from self-condensation of n-butyraldehyde
on the catalyst basic sites to form 2-ethyl-3-hydroxyhexanal followed by dehydration to 2-ethyl-2-hexenal which was then hydrogenated
on the metallic Pd sites to 2EH.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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制备了SiO2负载壳聚糖席夫碱钯催化剂,利用X-射线衍射,红外光谱和热重等方法对其进行了表征。以苯乙炔和碘代苯为反应物,研究了该催化剂的催化性能,同时考察了不同反应条件(反应时间,反应温度,催化剂用量等因素)对该反应的影响。最终得出了最佳反应条件:碘代苯4mmol,苯乙炔4mmol,K2CO3用量8mmol,催化剂0.1g(Pd质量分数为3.8%),乙醇16ml,N2气保护下80℃反应9h,产率达95.40%。该催化剂经过滤分离,溶剂洗涤,重复使用3次仍有较高的催化活性。 相似文献
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Miyake T. Hattori A. Hanaya M. Tokumaru S. Hamaji H. Okada T. 《Topics in Catalysis》2000,13(3):243-248
Benzylacetate synthesis from toluene, acetic acid and oxygen on Pd–Bi binary catalyst was studied in the liquid phase. By
incorporation of Bi with Pd, both the activity and selectivity were improved. Especially better stability was obtained with
the catalyst having Pd/Bi = 3. Deactivation of the catalyst was investigated in detail by XRD, XPS, TEM, elemental analysis,
EPMA and so on. Comparing the used catalyst with the fresh one, it was indicated that the main cause of deactivation was the
dissolution of Pd into the reaction mixture from the most outer surface of the catalyst. By adopting proper reaction conditions
to prevent the Pd dissolution, the catalyst having Pd/Bi = 3 was suggested to be used as an industrial catalyst.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Liquefied petroleum gas (LPG) fuel was directly synthesized from syngas over a hybrid catalyst which contained a methanol synthesis catalyst and zeolite. The new hybrid catalyst composed of (Pd–Ca/SiO2) and β-zeolite, showed a high activity and selectivity for LPG production. X-ray diffraction (XRD) characterization of the catalyst was used to analyze the deactivation of (Pd–Ca/SiO2)/β-zeolite. 相似文献
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Three different vanadium-modified Pd/Al2O3 catalysts were prepared and tested as catalysts for the deep oxidation of methane. Vanadium was added to the palladium catalyst by incipient wetness of palladium catalyst in order to modify its properties and improve its thermal stability and thioresistance. The behaviour of vanadium-modified catalysts depends on the concentration of this compound, being 0.5 wt.% the optimum amount. However, when strong catalyst poisons are present in the gas (SO2), these modified catalysts do not show a better performance than unmodified catalyst. Bimetallic catalysts were tested with and without further reduction, being observed that reduced bimetallic catalysts perform worse than the non-reduced ones. 相似文献
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以Pd Cl2和Co(NO3)2为原料,采用分步乙二醇还原法制备了多壁碳纳米管负载Pd-Co复合纳米催化剂Pd-Co/CNT。利用TEM、XRD和XPS对催化剂的结构进行了表征,考察了其甲醇电氧化性能。结果显示,Co的引入使Pd催化剂的分散性得到改善,其电化学表面积可达39.7 m2/g。循环伏安测试表明,当Pd∶Co物质的量比为1∶0.2时,Pd-Co/CNT的甲醇氧化峰电流密度约为Pd/CNT的2.7倍。计时电流结果表明,Co的添加使催化剂的活性衰减比例由Pd/CNT的63.8%降至54.2%,显示出较强的抗中毒能力。Pd-Co复合催化剂性能的改善归因于Pd与Co之间的协同相互作用。 相似文献
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分析了不同厂家生产的对苯二甲酸精制用钯炭催化剂载体活性炭的各种物性指标。实验结果表明,各种活性炭比表面相同时,其吸附量基本相近,但孔结构有较大差异,尤其是中孔孔容相差较大。中孔孔容增大,有利于钯炭催化剂分散度的提高和热稳定性增强.活性炭的表面基团对催化剂分散度也有影响,表面酸性基团含量增加,值化剂分散度提高. 相似文献
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以2-氯吡嗪为反应底物,氯化钯为催化剂,在四丁基溴化铵和N,N-二异丙基乙基胺的作用下合成了2,2’-联吡嗪,分析了催化剂、碱、溶剂对反应产率的影响,得到了合成2,2’-联吡嗪较为优化的反应工艺。 相似文献
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从催化氧化法葡萄糖酸钠废催化剂中回收氯化钯的研究 总被引:6,自引:0,他引:6
本文介绍了从催化氧化法葡萄糖酸钠废催化剂中回收氯化钯的原理和步骤 ,试验钯的回收率可达99 0 %以上 ,回收后的氯化钯可以返回再用来制备Pd/C催化剂 ,能减低葡萄糖酸钠产品成本 10 %。 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