电合成间苯氧基苯甲酸

以Nafion417作隔膜,Pb-PbO2作阳极,Pb作阴极,电解氧化Cr(Ⅲ)为Cr(Ⅵ),然后以Cr(Ⅵ)为氧化媒质,氧化间甲基二苯醚为间苯氧基苯甲酸.研究了在Nafion417隔膜槽中影响Cr(Ⅲ)电氧化的因素,并进一步探究优化电合成间苯氧基苯甲酸的工艺条件.     

A green method for the electroorganic synthesis of new 1,3-Indandione derivatives

This is an environmentally friendly method in the field of electroorganic reactions under controlled potential electrolysis, without toxic reagents at a carbon electrode in an undivided cell which involves the (EC) mechanism reaction and comprises two steps alternatively; (i) electrochemical oxidation and (ii) chemical reaction. In particular, the electrochemical oxidation of 4-tert-butylcatechol, 4-methylcatechol and 2,3-dihydroxybenzoic acid in the presence of 2-phenyl-1,3-indandione has been studied in a water-acetonitrile (90 : 10) mixture. The research includes the use of a variety of experimental techniques, such as cyclic voltammetry, controlled-potential electrolysis, and spectroscopic identification of products (FT-IR, (1)H-NMR, and MS spectrometry).     

Recycling ZnTe, CdTe, and other compound semiconductors by ambipolar electrolysis

The electrochemical behavior of ZnTe and CdTe compound semiconductors dissolved in molten ZnCl(2) and equimolar CdCl(2)-KCl, respectively, was examined. In these melts dissolved Te is present as the divalent telluride anion, Te(2-), which was found able to be converted to elemental metal by electrochemical oxidation at the anode. ZnTe-ZnCl(2) melts were studied at 500 °C by standard electrochemical techniques. On the basis of these results, electrolysis was performed, resulting in the simultaneous extraction of phase-pure liquid Zn at the cathode and phase-pure liquid Te at the anode. This new process, involving the simultaneous deposition of liquid metals at electrodes of opposite polarity, is termed herein as ambipolar electrolysis. A melt consisting of CdTe dissolved in equimolar CdCl(2)-KCl was processed by ambipolar electrolysis, resulting in the production of liquid Cd at the cathode and liquid Te at the anode. Ambipolar electrolysis could enable new approaches to recycling compound semiconductors and semiconductor devices, such as CdTe solar cells.     

Alternating-current electrolysis for the production of phenol from benzene

Works both ways: phenol was produced by both anodic and cathodic benzene oxidations over the V(x)O(y)-Sn(0.9)In(0.1)P(2)O(7) electrode in an electrochemical cell, thus allowing the use of AC electrolysis for phenol production. AC electrolysis was found to be more efficient and selective toward phenol production than DC electrolysis.     

Cr2O3粉末在CaCl2熔盐中直接电化学还原的金属通腔电极研究

应用金属通腔电极研究Cr2O3粉末于熔盐中的电化学行为,验证了900℃下Cr2O3粉末在含镁量<0.005%氯化钙熔盐中的分步还原机理,估算其电化学还原动力学参数;并由扫描电镜观察产物形貌,分析电解电位和时间对金属颗粒尺寸的影响.     

电化学合成纳米材料和小分子材料在电解制氢领域的应用

氢气是一种清洁、高效、可再生的新型能源,并且是未来碳中和能源供应中最具潜力的化石燃料替代品。因此,可持续氢能源制造具有极大的吸引力与迫切的需求,尤其是通过清洁、环保、零排放的电解水方法。然而,目前的电解水反应受到其缓慢的动力学以及低成本/能源效率的制约。在这些方面,电化学合成通过制造先进的电催化剂和提供更高效/增值的共电解替代品,为提高水电解的效率和效益提供了广阔的前景。它是一种环保、简单的通过电解或其他电化学操作,对从分子到纳米尺度的材料进行制造的方法。本文首先介绍了电化学合成的基本概念、设计方法以及常用方法。然后,总结了电化学合成技术在电解水领域的应用及进展。我们专注于电化学合成的纳米结构电催化剂以实现更高效的电解水制氢,以及小分子的电化学氧化以取代电解水制氢中的析氧共反应,实现更高效、 增值的共电解制氢。我们系统地讨论了电化学合成条件与产物的关系,以启发未来的探索。最后,本文讨论了电化学合成在先进电解水以及其他能量转换和储存应用方面的挑战和前景。     

Electrosynthesis and Microanalysis in Thin Layer: An Electrochemical Pipette for Rapid Electrolysis and Mechanistic Study of Electrochemical Reactions

Electrochemistry represents unique approaches for the promotion and mechanistic study of chemical reactions and has garnered increasing attention in different areas of chemistry. This expansion necessitates the enhancement of the traditional electrochemical cells that are intrinsically constrained by mass transport limitations. Herein, we present an approach for designing an electrochemical cell by limiting the reaction chamber to a thin layer of solution, comparable to the thickness of the diffusion layer. This thin layer electrode (TLE) provides a modular platform to bypass the constraints of traditional electrolysis cells and perform electrolysis reactions in the timescale of electroanalytical techniques. The utility of the TLE for electrosynthetic applications benchmarked using NHPI-mediated electrochemical C−H functionalization. The application of microscale electrolysis for the study of drug metabolites was showcased by elucidating the oxidation pathways of the paracetamol drug. Moreover, hosting a microelectrode in the TLE, was shown to enable real-time probing of the profiles of redox-active components of these rapid electrosynthesis reactions.     

Nomenclature, symbols and definitions in electrochemical engineering (IUPAC Recommendations 1993)

This document treats performance parameters in electrochemical engineering. Nomenclature and definitions for electrochemical engineering together with the respective symbols are given. Parameters to account for electrochemical reactions in electrolysis as well as for electrochemical power sources (electrochemical energy generators) are included in this document.     

Indirect Electrochemical Oxidation of 4-Amino-dimethyl-aniline Hydrochloride

Introduction4Amino dimethyl anilinehydrochlorideisoneof themaincomponentsofthewastewaterresultedfrom vanillinproduction[1]whichinhibitsthenormalactivity ofthemicroorganismsofmicrobialpopulation,thereby affectingthebiologicaltreatmentprocessofvanillin.Comm…     

电化学还原和羧化肉桂酸乙酯的研究

在一室型电解池中,以MeCN为溶剂,Mg为牺牲阳极,成功地实现了肉桂酸乙酯的电化学还原和羧化。直接电还原生成相应的氢化二聚物和饱和酯。而在CO2氛围下,可以实现相应的电羧化反应,反应的总产率和选择性受各个反应条件的影响,例如电极材料、电解电位、底物浓度和反应温度。在最佳条件（阴极为Ni,电位为-1.7 V,底物浓度为0.1 mol·L-1,温度为-10 ℃）下可以得到78 ％的羧酸化产率。     

Paired Electrochemical Reactions and the On‐Site Generation of a Chemical Reagent

While the majority of reported paired electrochemical reactions involve carefully matched cathodic and anodic reactions, the precise matching of half reactions in an electrolysis cell is not generally necessary. During a constant current electrolysis almost any oxidation and reduction reaction can be paired, and in the presented work we capitalize on this observation by examining the coupling of anodic oxidation reactions with the production of hydrogen gas for use as a reagent in remote, Pd‐catalyzed hydrogenation and hydrogenolysis reactions. To this end, an alcohol oxidation, an oxidative condensation, intramolecular anodic olefin coupling reactions, an amide oxidation, and a mediated oxidation were all shown to be compatible with the generation and use of hydrogen gas at the cathode. This pairing of an electrolysis reaction with the production of a chemical reagent or substrate has the potential to greatly expand the use of more energy efficient paired electrochemical reactions.     

Progress in Convergent Paired Electrolysis

Convergent paired electrolysis combines both anodic and cathodic reactions simultaneously in an electrochemical transformation. It provides a highly energy-efficient and divergent approach to conventionally challenging and useful structures. However, the physical separation of the two half-electrode reactions makes it extremely difficult to couple the intermediates arising from the two electrodes. In this concept article, four strategies used in convergent paired electrolysis will be discussed from the perspective of the reaction mechanism: a) metal-catalyzed convergent paired electrolysis, b) convergent paired electrolysis enabled by persistent radical effects, c) microfluidic chemistry applied to convergent paired electrolysis, and d) alternating current electrolysis.     

Self-supported ultrathin Co3O4 nanoarray enabling efficient paired electrolysis of 5-hydroxymethylfurfural for simultaneous dihydroxymethylfuran (DHMF) and furandicarboxylic acid (FDCA) production

Production of value-added chemicals and fuels from biomass via electrochemical methods has been of emerging interest in light of the increasing environmental, economic, and political challenges. Paired electrolysis, with anodic oxidation and cathodic reduction reactions pairing in a single electrochemical cell, offers an effective way to produce desired products in both electrodes, thus achieving complete electron economy. In this work, an efficient 5-hydroxymethylfurfural (HMF) paired electrolysis system is developed over a self-supported ultrathin Co₃O₄ nanoarray electrocatalyst for simultaneous production of value-added 2,5-dihydroxymethylfuran (DHMF) and 2,5-furandicarboxylic acid (FDCA). The as-designed paired electrolysis cell achieves a high HMF conversion and DHMF/FDCA selectivity at both anode and cathode without external hydrogen and oxygen input. A near-quantitative yield (95.7%) of FDCA and 78.8% yield of DHMF can be achieved in the paired electrolysis system, with a total Faradaic efficiency of 127%. This work will open up new opportunities in designing efficient electrochemical devices to simultaneously produce building-block chemicals from biomass-derived molecules in both anode and cathode.     

Characterisation of spatial and temporal changes in pH gradients in microfluidic channels using optically trapped fluorescent sensors

This paper demonstrates the use of micron sized beads, modified with fluorescent dyes, as non-invasive sensors to probe the local changes in pH, within a microfluidic channel. To achieve this, amine modified polystyrene spheres (either 3 microm or 6 microm in diameter) were functionalised with the pH sensitive fluorochrome SNARF-1 to produce point sensors. The modified beads were trapped at defined positions close to a pair of integrated planar gold microelectrodes within the channel, using optical tweezers. Both transient and steady-state electrochemical potentials were applied to the microelectrode pair in order to generate changes in the local pH, associated with electrolysis. The functionalised beads indicated the pH changes in the channel, measured as a change in the fluorescence signal, generated by the immobilised pH sensitive dye. Responses were measured with temporal resolutions of between 1 and 200 ms, whilst the spatial resolution of the pH gradients was limited by the size of the beads to 3 microm.     

Electrochemical oxidation of pentafluorophenol in hydrogen fluoride and superacid media

The electrochemical behaviour of pentafluorophenol was examined by means of Classic and Cyclic Voltammetry at a platinum electrode in strongly basic (KF) and strongly acidic (SbF₅) media in HF as solvent.It was shown that the first electrochemical step is the formation of a radical which is chemically stable in strongly acidic media probably because of the protonation of pentafluorophenol. The products formed by controlled potential electrolysis were analysed by GCMS. The main products of electrolysis are perfluorocyclohexadienone and dimers of the radical pentafluorophenol. The yield of the various products was evaluated as a function of the acidic level.     

Electrochemical synthesis of α,β-(E)-unsaturated esters in undivided cell (Horner–Emmons reaction)

The known electrochemical synthesis of α,β-(E)-unsaturated esters (Horner–Emmons reaction) was modified in order to achieve the electrolysis in an undivided cell using magnesium as the sacrificial anode. The undivided cell procedure showed advantages over the traditional two-compartment cell methodology. The best yield using undivided cell methodology for the synthesis of aliphatic α,β-(E)-unsaturated esters was 85–86%, which is almost the yield obtained by means of the homogenous chemical reaction. This electrochemical methodology presented some limitations when aromatic aldehydes or base sensitive products were used.     

Extraction of neodymium from other fission products by co‐reduction of Sn and Nd

High temperature processing is an important method for recovering long‐lived elements from spent nuclear fuel. Electrolysis is the key technology for high temperature processing. The electrochemical behaviors of Sn²⁺, Nd³⁺ and the mechanisms of Sn‐Nd alloy formation were investigated on a Mo electrode at 873 K by conducting a series of electrochemical techniques. The results showed the deposition of Nd on inert electrode is a two‐step process in LiCl‐KCl‐SnCl₂ (2.0 wt.%) melt system. Subsequently, the electrochemical extraction of Nd from molten chlorides were carried out on the Mo electrode at temperature of 873 K by the potentiostatic electrolysis at ?1.2 V for 40 hr. Besides, the extraction efficiency is 97.6%. A series of potentiostatic electrolysis were carried out at potential range between ?1.0 and ? 1.4 V. The NdSn₃ alloy was obtained by electrolysis at ?1.2 V. This deposition potential is consistent with the predicted results of the mathematical model. The micro‐chemical analysis and morphology analysis of the deposits was characterized by energy dispersive spectrometry (EDS) with scanning electron microscopy (SEM) equipped. The composition of the deposits was analyzed by X‐ray diffraction (XRD) and inductive coupled plasma atomic emission spectrometer (ICP‐AES).     

Dy(Ⅲ)离子在LiCl-KCl熔盐中的电化学行为及Dy-Ni金属间化合物的选择性制备

采用循环伏安、方波伏安和开路计时电位等电化学方法研究了Dy(Ⅲ)离子在LiCl-KCl 共晶盐中的电化学行为及Dy-Ni 合金形成的电化学机理. 循环伏安和方波伏安法研究表明, Dy(Ⅲ)离子的电化学还原过程为三个电子转移的一步反应. 与惰性W电极相比, Dy(Ⅲ) 离子在Ni 电极上的循环伏安曲线多出了三对氧化还原峰,是由于Dy与Ni 形成了合金化合物, 导致Dy(Ⅲ)离子在活性Ni 电极发生了欠电位沉积. 采用X射线衍射(XRD)和扫描电子显微镜(SEM)附带能量散射谱(EDS)对恒电位(-1.6, -1.8 和-2.0 V)电解制备的Dy-Ni 合金进行分析, 分别获得了DyNi₅, Dy₂Ni₇和DyNi₂金属间化合物. 实验结果表明, 通过控制电位进行恒电位电解可以有选择性地制备不同的金属间化合物.     

煤沥青的电化学加氢：Ⅱ.精制沥青的电化学加氢

在隔离式是电解中，用泡沫铅作用阴极，铂作阳极，饱和甘汞电极做参考电极，对太原钢铁公司焦化厂煤沥青经溶剂萃取后所得的精制沥青进行了电化学加氢的研究，考察了电解体系工艺条件对加氢效果的影响。     

Enantiomeric separation of D,L-tryptophan and D,L-kynurenine by HPLC using pre-column fluorescence derivatization with R(-)-DBD-PyNCS

The enantiomeric separation of d ,l ‐tryptophan (Trp) and d ,l ‐kynurenine (KYN) was investigated by high‐performance liquid chromatography using pre‐column fluorescence derivatization with a chiral fluorescent labeling reagent, R(−)‐4‐(3‐isothiocyanatopyrrolidin‐1‐yl)‐7‐ (N,N‐dimethylaminosulfonyl)‐2,1,3‐benzoxadiazole [R(−)‐DBD‐PyNCS]. Using an octadecylsilica column, namely, an Inertsil ODS‐3 column (250 × 2.0 mm; i.d., 3 µm), four fluorescence peaks of D‐ and l ‐Trp as well as d ‐ and l ‐KYN derivatized with R(−)‐DBD‐PyNCS were clearly observed, and their chemical structures were confirmed by HPLC–time‐of‐flight–mass spectrometry. Simultaneous separation was achieved under the mobile phase condition of 1.5% acetic acid in H₂O–CH₃CN (60:40), and the separation factors of d ,l ‐Trp and d ,l ‐KYN derivatized with R(−)‐DBD‐PyNCS were 1.22 and 1.19, respectively. Fluorescence detection was carried out by setting the emission wavelength at 565 nm, and the excitation wavelength at 440 nm, and the detection limits were approximately 0.3–0.5 pmol (signal‐to‐noise ratio of 3). Copyright © 2010 John Wiley & Sons, Ltd.