共查询到20条相似文献,搜索用时 93 毫秒
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2-甲磺酰基-4,6-二甲氧基嘧啶的简便合成 总被引:2,自引:0,他引:2
以2-硫代巴比妥酸为原料,在相转移催化剂的作用下,超声促进与硫酸二甲酯反应,得到2-甲硫基-4,6-二甲氧基嘧啶,再经次氯酸钠氧化得到2-甲磺酰基-4,6-二甲氧基嘧啶,总收率63%。 相似文献
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成功开发一种由容易得到的2-(3,5-二甲氧基苄基)丙二酸二乙酯为原料合成5,7-二甲氧基1-茚酮的有效新方法。将原料溶解于甲磺酸中,加热到100℃反应2 h收率可以达到95%。本反应所需原料廉价、后处理简单、对设备要求不高,适用于工业化生产。另外,文中还提出了该反应可能的反应机理。 相似文献
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The plasma‐electrochemical growth of an ion‐conducting film by the oxidation of a metal in an electronegative plasma is investigated and compared with results from thermal oxidation. As model system we studied the oxidation kinetics of silver electrodes in a Cl2 rf plasma. The electrochemical control of the reaction by external currents through the product layer using the plasma as a fluid electrode was achieved. Both potentiostatic and galvanostatic control of the reaction was applied. The morphology of the product layer and its temporal evolution was investigated using SEM. A formation of silver chloride surface patterns in the oxidation process takes place if a simple stability criterion is not fulfilled. Specific surface morphologies were found under different experimental conditions. The morphology of the product layer is influenced by the external electric current and the substrate temperature. The influence of the plasma phase on the thermodynamics and kinetics of the oxidation process is discussed. The role of excited plasma species, the electrical charging of the surface and radiation from the plasma are taken into account. 相似文献
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Victor C. Diculescu Teodor Adrian Enache Paulo J. Oliveira Ana Maria Oliveira‐Brett 《Electroanalysis》2009,21(9):1027-1034
The electrochemical behavior of berberine, an isoquinoline plant alkaloid with a wide spectrum of physiological effects, was studied at a glassy carbon electrode using cyclic, differential pulse and square‐wave voltammetry. The oxidation of berberine is a quasireversible, diffusion‐controlled process and occurred in a cascade mechanism with the formation of several oxidation products. The diffusion coefficient of berberine was calculated from cyclic voltammetry studies to be D=1.69×10?6 cm2 s?1. The oxidation process of berberine is also pH dependent and the number of electrons and protons transferred was determined using differential pulse voltammetry. The formation of several oxidation products that adsorbed at the glassy carbon electrode surface was observed and their electrochemical behavior characterized. A mechanism for the oxidation of berberine at a glassy carbon electrode was proposed. 相似文献
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The electrochemical oxidation of an atrazine solution obtained from a flushing treatment of a contaminated soil was investigated. The influence of ethanol on atrazine oxidation was studied. Results show that the electrogenerated Fenton's reagent provides a complete degradation of atrazine and its main chlorinated by-products via N-dehalkylation and dechlorination. This process therefore presents an effective alternative to the chemical oxidation treatment which necessarily needs a further biological state. 相似文献
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N. I. Il'chenko Yu. I. Pyatnitskii N. V. Pavlenko 《Theoretical and Experimental Chemistry》1998,34(5):239-256
It was shown that the carbides of transition metals are effective catalysts of oxidation reactions on account of their metal-like
nature, combined with their high chemical and thermal stability. The results from systematic investigations into the catalytic
characteristics of the carbides in the oxidation of hydrogen, carbon monoxide, and ammonia and in the oxidative coupling of
methane (OCM) are examined. The first two reactions are total oxidation processes, and the oxidation of ammonia is a selective
oxidation process. The oxidative coupling of methane is a heterogeneous-homogeneous process and represents a prospective method
for the direct transformation of methane into higher hydrocarbons.
L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 252039,
Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 34, No. 5, pp. 265–281, September–October, 1998. 相似文献
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流光放电等离子体液相氧化亚硫酸铵 总被引:4,自引:0,他引:4
在氨-硫铵法烟气脱硫中, 一个关键环节是将副产物的四价硫S(IV)氧化为六价硫S(VI). 采用可规模化的流光放电液相氧化技术, 通过交直流叠加(AC/DC)电源, 激发气体放电产生等离子体对氨法脱硫高浓度的亚硫酸铵进行氧化. 实验测量了该氧化过程与溶液浓度、放电功率密度、溶液pH值、温度以及传质效率因子等各种参数的关系. 研究表明, 在亚硫酸铵摩尔浓度为3 mol·L-1时, 可以获得有实用价值的反应速率, 摩尔能耗减低到50 Wh·mol-1以下, 显示出很好的应用前景. 相似文献
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Electrocatalytic Oxidation of Hypophosphite on Nickel Electrode ──In Situ UV-Vis Spectroscopic study
ThefactthathypophosphiteisoneofthemostwidelyusedreducingagentsintheNielectrolessdepositionhasstimulatedthestudyofanodicoxidationofhypophosphiteonnicked-ic.Thisanodicreaction,whichisimportantfortheunderstandingoftheNielectrolessdepositionmechanism,isexpectedtobeoneoftheimportantreactionsintheNi-electrolessprocess.Recently,theroleandoxidationmechanismofhypophosphiteinelectrolessdepositionofNi-Palloyhavebeenstudiedindetailusingtheprobebeamdeflection',electrochemistryandinsituIR',lo.However,som… 相似文献
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采用2,2,6,6-四甲基哌啶氧自由基/Ca(ClO)2体系选择氧化甲基葡萄糖苷(简称甲苷)合成了葡萄糖甲苷酸盐,再用硫酸酸解葡萄糖甲苷酸盐,得到葡萄糖醛酸和副产物硫酸钙。考察了氧化工艺条件对葡萄糖醛酸收率的影响;用pH计监控反应过程,反应中间体和终产物用UV和HPLC检测。结果表明,该体系对甲苷伯羟基的氧化具有较好的催化活性和反应选择性,葡萄糖醛酸收率达到92%,且金属离子易于去除。和传统的淀粉HNO3氧化法工艺相比,该方法具有资源节约、环境友好的特点。 相似文献