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《Analytical letters》2012,45(2):171-175
Abstract Spectrophotometric observations, electrochemical data, esr spectrum and cryoscopic measurements in solutions of sulfur in liquid ammonia are reported. They indicate that the sulfur species present at low temperatures is S2NH3. At room temperature the predominant species is SNH3. 相似文献
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Dr. Chao Luo Dr. Gui‐Liang Xu Xiao Ji Singyuk Hou Dr. Long Chen Dr. Fei Wang Prof. Jianjun Jiang Dr. Zonghai Chen Dr. Yang Ren Dr. Khalil Amine Prof. Chunsheng Wang 《Angewandte Chemie (International ed. in English)》2018,57(11):2879-2883
Sustainable sodium‐ion batteries (SSIBs) using renewable organic electrodes are promising alternatives to lithium‐ion batteries for the large‐scale renewable energy storage. However, the lack of high‐performance anode material impedes the development of SSIBs. Herein, we report a new type of organic anode material based on azo group for SSIBs. Azobenzene‐4,4′‐dicarboxylic acid sodium salt is used as a model to investigate the electrochemical behaviors and reaction mechanism of azo compound. It exhibits a reversible capacity of 170 mAh g?1 at 0.2C. When current density is increased to 20C, the reversible capacities of 98 mAh g?1 can be retained for 2000 cycles, demonstrating excellent cycling stability and high rate capability. The detailed characterizations reveal that azo group acts as an electrochemical active site to reversibly bond with Na+. The reversible redox chemistry between azo compound and Na ions offer opportunities for developing long‐cycle‐life and high‐rate SSIBs. 相似文献
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硒代胱氨酸和硒代蛋氨酸电化学检测的比较 总被引:7,自引:0,他引:7
对硒代胱氨酸 (SeCys)和硒代蛋氨酸 (SeMet)在银电极上的电化学性质、电极反应机理及检测灵敏度等方面进行比较研究。实验表明 ,两者在pH9.5的硼砂 氢氧化钠介质中 ,于 -0 .62V和 -0 .68V(vs.SCE)处均存在一对氧化还原峰 ,电化学行为相似 ,两者具有良好的线性范围和低检出限 ,SeMet比SeCys具有更高的检测灵敏度。在相同的实验条件下 ,比较了含硫氨基酸与含硒氨基酸的电化学响应 ,含硫氨基酸的检测灵敏度远低于含硒氨基酸 相似文献
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P. W. Schenk 《Angewandte Chemie (International ed. in English)》1966,5(6):554-557
An apparatus for titrations in liquid ammonia is described. The titrations can be carried out in the absence of air, and the utility of the apparatus is demonstrated for a number of conductometric and potentiometric titrations. 相似文献
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对乙酰氨基酚在活化玻碳电极上的电化学行为及测定 总被引:2,自引:0,他引:2
应用循环伏安法,研究了对乙酰氨基酚(PCT)在活化玻碳电极上的电化学行为.在pH=4.00的HAc-NaAc缓冲溶液中,PCT的CV扫描于0.54 V左右出现一对明显的氧化-还原峰.电极反应为2电子、2质子的受吸附控制的准可逆过程.其氧化峰电流与PCT浓度在8.00×10-6~2.00×10-4mol.L-1范围内呈良好的线性关系,相关系数r=-0.99918;检出限为6.34×10-6mol.L-1.用于药物样品PCT的含量测定,结果满意. 相似文献
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Bavistin(MBC)'isatypeofveryimportantbactericides.Theanalyticalmethodsofthispesticideincludingchromatography',polarography'havebeenreported,butthereisnoreportaboutthedetendnationwithvoltanuntryonglassycarbonelectrode.Inthispaper,westudiedthevoltanunetric(CV)propertiesandthedifferentialpulsestrippingvoltanunetry(DPSV)detendnationofMBConglassycarbonelectrode.TheinstrUmentusedinthisexperimentwastheBAS-l(X)AElectroanalyser.Aglassycarbonelectrodewasusedastheworkingelectrode,aconunercialAgjA… 相似文献
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α-Carbonyl azo compounds such as diesters of azodicarboxylic acids, diacylazo compounds, and esters of arylazocarboxylic acids are highly reactive. They add e.g. to amines, aromatic compounds, olefins, CH acids, Grignard and diazo compounds, aldehydes, ketones, and ketenes. These reactions can be used for the preparation of triazanes, hydrazones, oxa-diazoline, azomethinimine, and diazetidine derivatives, etc. α,α′-Dicarbonyl azo compounds are among the strongest dienophiles known. 相似文献
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尿酸在普鲁士蓝修饰电极上的电化学行为及其分析应用 总被引:19,自引:0,他引:19
用恒电位电解法制备了普鲁士蓝修饰玻碳电极,研究了尿酸(UA)在该电极上的电化学行为,并提出了一种新的用于检测UA的方法。在 0. 1mol/L(pH5. 0 )的醋酸缓冲溶液中, 0. 100mol/LKCl作为支持电解质,UA在普鲁士蓝修饰电极上于 0. 470V处产生一灵敏的氧化峰,方波伏安法测定其氧化峰电流与UA浓度在 2. 5×10-6 ~2. 0×10-4 mol/L范围内呈良好的线性关系,相关系数为 0. 9986,检出限为 1. 1×10-6 mol/L。该电极制作简单,重现性良好,可用于UA的测定。 相似文献
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The novel method of amoxicillin (AM) determination has been developed using single-sweep polarography. The proposed method is based on the obtaining of yellow coloured azo compound due to azo coupling reaction of previous diazotized sulphanilamide (SA) (in the medium of 0.6 M hydrochloric acid) with amoxicillin at pH=9.0 with the further reduction of the formed analytical form on a dropping mercury electrode. Voltammetric determination of amoxicillin is carried out due to the reduction peak of azo group of the obtained azo compound in the presence of 0.05 mol ⋅ L−1 Na2B4O7 as a background electrolyte at the potential Ecp2=−0.55 V and potential sweep rate of 2.5 V ⋅ s−1. The developed voltammetric method has two linear ranges of the determined concentrations (0.05–2.0) ⋅ 10−5 mol ⋅ L−1 and (0.2–1.0) ⋅ 10−4 mol ⋅ L−1 and the high sensitivity: LOD without the removing of unreacted sodium nitrite is 1.1 ⋅ 10−6 mol ⋅ L−1, and 7.2 ⋅ 10−7 mol ⋅ L−1, when NaNO2 excess is removed using urea. The developed voltammetric technique of AM determination has been approved during the analyses of tablets and oral suspension. 相似文献
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The polarographic and voltammetric behaviour of 2-hydroxy-3-tert-butyl-5-methylazobenzene has been studied in aqueous-ethanol mixtures of different pH using DCP and DPP polarographic and CV and SWV voltammetric methods. The reduction of the azo linkage takes place via two electrons at pH > 7, but four electrons at pH < 7 in aqueous-ethanol mixtures. It has been determined that there is a linear relationship between the current and concentration and the lowest detection limit has been found as 1 × 10–7 M (for SWV). 相似文献
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Using NBS (N‐bromosuccinimide) and the ionic liquid (1‐butyl‐3‐methylimidazolium tetrafluoroborate) as an oxidation system, twelve unsymmetric azo compounds were efficiently prepared from hydrazo compounds for the first time. In contrast to the known methods, this novel access to azo compounds presented here is operationally simple, environmentally benign and has the advantage of enhanced atom utilization. Furthermore, the solvent and the basic catalyst used can be recovered conveniently and reused efficiently. 相似文献
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用循环伏安法、阴极溶出伏安法和电毛细管曲线测量等方法研究了卡托普利在汞电极表面的电氧化机理。实验结果表明,酸性溶液中卡托普利比较稳定,而在中、碱性溶液中卡托普利不稳定。在酸性溶液中有质子参与电极过程,卡托普利在电极表面发生单电子转移,生成汞(I)-硫化合物,该化合物在电极表面有强吸附,并进一步转化成汞(Ⅱ)-硫化合物。按照实验结果,计算了卡托普利的扩散系数和电极反应速率常数,提出了卡托普利电化学氧 相似文献
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超分子化学是当前化学领域的研究热点之一。基于环糊精和偶氮化合物的光控超分子可逆体系是近几年在超分子化学基础上发展起来的活跃领域。二者的复合物具有的优秀光学性质使其在光敏型自组装、催化、分子机器设计和智能材料领域受到极大的关注。本文综述了基于环糊精和偶氮化合物的光控超分子可逆体系的研究进展。介绍了该体系的研究背景、优势与原理; 根据该体系控制组装体的不同进行了分类总结,包括囊泡、凝胶、轮烷、催化体系、分子触手等; 最后结合现阶段的研究情况,对其前景与发展方向进行了展望。 相似文献
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蒙脱土修饰电极上某些神经递质的电化学行为 总被引:7,自引:0,他引:7
采用不同电化学方法对神经递质多巴胺(DA)在蒙脱土修饰电极上的行为进行了研究,结果发现,蒙脱土修饰膜地DA有明显的富集作用。在PH7.4时,DA强烈地富集在蒙脱土膜内,并显示完成的伏安响应而抗坏血酸(AA)和DAR的代谢产物3,4-二羟基苯乙酸(DOPAC)则无任何响应。采用计时库仑法测定了DA在蒙脱土膜内的表观扩散系数为2.3×10^-9cm^2/s,并计算了异相速率常数为2.7×10^-6cm 相似文献