甲基磺酰氟Simons电化学氟化过程特性和机理研究

选择CH₃SO₂F电化氟化制备CF₃SO₂F过程为研究系统,研究了电化氟化过程操作电压和反应时间的关系、操作条件对氟化产物组成的影响规律以及Ni电极在电化氟化过程的变化情况. 实验结果表明,Simons电化学氟化过程主要由三个步骤组成：F-在阳极发生电化学氧化反应生成F,该步骤是Simons电化学氟化过程的控制步骤;在Ni电极上生成的F与Ni或NiF₂反应生成高价NiF_n (n≥3),NiFn为Simons电化学氟化过程的氟化剂;NiF_n可以在电极/电解液界面与有机物发生氟化反应生成氟化产物,也可以发生分解反应生成游离F²,NiF_n与有机物发生氟化反应的机理与用CoF₃等为氟化剂氟化有机物的机理相同. 但NiF_n的反应活性比CoF₃高,且在实验条件下极不稳定.     

Photochemical and Electrochemical Carbon Dioxide Utilization with Organic Compounds

In the last few years, photochemical and electrochemical CO₂ transformations have attracted increasing attention in response to topical interest in renewable energy and green chemistry. The present minireview offers an overview about the current approaches for the photochemical and electrochemical carbon dioxide fixation with organic compounds. Valuable products, including carboxylic acids and heterocyclic compounds, are accessible through carboxylation and carboxylative cyclization, respectively. In photochemical and electrochemical processes, photo‐ or electro‐induced radical ions or other high‐energy organic compounds are considered as key intermediates to react with CO₂. Besides, activation of CO₂ to produce radical anion has also been reported.     

Redox transformations in desorption electrospray ionization

Redox changes occur in some circumstances when organic compounds are analyzed by desorption electrospray ionization mass spectrometry (DESI-MS). However, these processes are limited in scope and the data presented here suggest that there are only limited analogies between the redox behavior in DESI and the well-known solution-phase electrochemical processes in standard electrospray ionization (ESI). Positive and negative ion modes were both investigated and there is a striking asymmetry between the incidence of oxidation and of reduction. Although in negative ion mode DESI experiments, some aromatic compounds were ionized as odd-electron anion radicals, examples of full reduction were not found. By contrast, oxidation in the form of oxygen atom addition (or multiple oxygen atom additions) was observed for several different analytes. These oxidation reactions point to chemically rather than electrochemically controlled processes. Data is presented which suggests that oxidation is predominantly caused by reaction with discharge-created gas-phase radicals. The fact that common reducing agents and known antioxidants such as ascorbic acid are not modified, while a saturated organic acid like stearic acid is oxidized in DESI, indicates that the usual electrochemical redox reactions are not significant but that redox chemistry can be induced under special experimental conditions.     

Relevance of gaseous flows in electrochemically assisted soil thermal remediation

Treatment of polluted soil is one of the priorities in the search of a more sustainable planet. Electrochemically assisted soil remediation has been considered a good option for removing organic contaminants contained in soil, including the removal of volatile organic compounds, associated with gaseous streams produced during the treatment. Also, recently, electrochemical gas treatment technologies have been appointed as promising for the treatment of volatile organic compounds. In this work, we review the current opinion about the most recent studies in both areas. The first section focuses on the production of gaseous compounds during soil remediation by conventional and electrochemical systems. The second section describes the recent progress in the integration of adsorption and absorption with electrochemical processes. Finally, we discuss the holistic application of assisted electrochemical technologies in soil remediation, considering also emerging processes recently published in the literature.     

The effect of organic nitrogenous compound content and different pretreatments on agricultural lignocellulosic biomass characterization methods

Considering the diverse compounds contained in lignocellulosic biomasses, especially in agricultural biomass, and the complexity of the different chemical and physical structural connections between these compounds, appropriate analytical methods must be used to characterize these biomasses. In this study, two extraction processes and two analytical methods were used to characterize the main compounds in corn stover residue before and after different pretreatments. The results of this study suggest that pretreatment and organic nitrogenous compound content greatly affect the most common extraction processes and analytical methods used for biomass characterization. For raw corn stover biomass residue, the extraction process using neutral detergent fiber solvent removed more extractives and more organic nitrogenous compounds (18.5 and 2.4%, respectively) than the combination of extractions using water and ethanol (13.4% of extractives and 1.8% of organic nitrogenous compounds). This study also showed that the different pretreatments improve the efficiency of both extraction processes and that these processes seem to be more effective with the neutral detergent solvent extraction than the combination of extractions with water and ethanol. Organic nitrogenous compounds represent a significant proportion of agricultural biomasses; therefore, insufficient organic nitrogenous compound extraction can cause interference with different characterization methods. It was observed that, for the same analytical method and with the raw biomass, the value of insoluble lignin after the extractions with water and ethanol was higher than that obtained after the extraction with the neutral detergent solvent 16.1 and 13.2%, respectively. This can be explained by the fact that there are more organic nitrogenous compounds in the samples after the extraction with water and ethanol than in the samples after the extraction with the neutral detergent solvent. This result was also observed for the pretreated samples. These results, therefore, show that the extraction step is very important because it can remove more organic nitrogenous compounds before the main compounds are characterized (lignin, carbohydrates).     

Electrochemical oxygen transfer reactions: electrode materials,surface processes,kinetic models,linear free energy correlations,and perspectives

This work summarizes progresses achieved in electrochemical oxygen transfer reactions from water to organic pollutant molecules on metal oxide electrodes during the past two decades. Fundamental understanding of the dynamics of the electrochemical oxygen transfer reaction is of crucial importance for the development of key concepts of electrocatalytic processes, leading to the implementation of environmental electrochemistry wastewater treatment schemes with rational design of the suitable electrocatalytic systems. We discuss the current knowledge on the electrochemical oxygen transfer reaction, emphasizing the importance of surface processes in order to generalize mechanistically the experimental results obtained on different electrode materials, describing also the practical kinetic models developed and their implications. From the information gathered in this review, it is apparent that explanations for the kinetics of the reactions in relation to the structure of the organic compounds involved is lacking, hence that new information about structure-reactivity relationships is needed. We show in particular that the open circuit decay of the concentration of radical cations, obtained from spectroelectrochemical data, allows correlating the structure of adsorbed states with reactivity during oxygen transfer reactions, pointing as well to research efforts required to understand the catalytic performance of metal oxide electrodes in decomposing organic compounds strongly adsorbed on their surfaces. Finally, some perspectives for future research in this area are briefly commented.     

Synthesis and properties of novel hole-transporting materials with triphenylamine units

Two novel organic hole-transporting materials have been synthesized by combination of triphenylamines(TPA) viaπ-conjugated bonds using Wittig reaction.The structures were characterized by NMR,FT-IR and HRMS.The optical,electrochemical and thermal properties of the materials were studied in detail.The results show that these two compounds have blue emission,proper HOMO levels and high thermal stability.Furthermore,a quantum chemical calculation on electron distribution of the two compounds was performed, which suggests the current synthesized materials would be promising candidates for hole-transporting materials.     

Electroscrubbers for removing volatile organic compounds and odorous substances from polluted gaseous streams

The treatment of waste gaseous streams has become an important topic of environmental concern. One promising technology is electroabsorption which combines two important treatment processes into a single unit. In this sense, this review compiles the information available in the recent literature showing the hybridization of absorption units with electrochemical cells for treatment of gases polluted with volatile organic compounds and odorous substances. This approach is compared with other competing technologies, paying special attention to the technology readiness level. Although from the laboratory tests, it appears to be a promising methodology for the degradation of volatile organic compounds and environmental odorous gases; this critical review points out that more research is needed to raise the technology readiness level of this treatment technology in a context in which the society is demanding more and more sustainable technologies.     

Efficient Fixation of Carbon Dioxide by Electrolysis Facile Synthesis of Useful Carboxylic Acids

Electrochemical fixation of atmospheric pressure of carbon dioxide to organic compounds is a useful and attractive method for synthesizing of various carboxylic acids. Electrochemical fixation of carbon dioxide, electrochemical carboxylation, organic halides, organic triflates, alkenes, aromatic compounds, and carbonyl compounds can readily occur in the presence of an atmospheric pressure of carbon dioxide to form the corresponding carboxylic acids with high yields, when a sacrificial anode such as magnesium or aluminum is used in the electrolysis. The electrochemical carboxylation of vinyl bromides was successfully applied for the synthesis of the precursor of nonsteroidal anti-inflammatory agents such as ibuprofen and naproxen. On the other hand, supercritical carbon dioxide （scCO2） has significant potential as an environmentally benign solvent in organic synthesis and it could be used both as a solvent and as a reagent in these electrochemical carboxylations by using a small amount of cosolvent.     

水溶液中噻吩的电化学聚合成膜

本文研究水溶液中噻吩的电化学聚合。高酸度水溶液中噻吩先经历化学低聚反应,低聚合物可在较负的电位阳极氧化成膜。     

Organic mixed-valence compounds: a playground for electrons and holes

Mixed-valence (MV) compounds are excellent model systems for the investigation of basic electron-transfer (ET) or charge-transfer (CT) phenomena. These issues are important in complex biophysical processes such as photosynthesis as well as in artificial electronic devices that are based on organic conjugated materials. Organic MV compounds are effective hole-transporting materials in organic light emitting diodes (OLEDs), solar cells, and photochromic windows. However, the importance of organic mixed-valence chemistry should not be seen in terms of the direct applicability of these species but the wealth of knowledge about ET phenomena that has been gained through their study. The great variety of organic redox centers and spacer moieties that may be combined in MV systems as well as the ongoing refinement of ET theories and methods of investigation prompted enormous interest in organic MV compounds in the last decades and show the huge potential of this class of compounds. The goal of this Review is to give an overview of the last decade in organic mixed valence chemistry and to elucidate its impact on modern functional materials chemistry.     

A review of electrochemical reduction processes to treat oxidized contaminants in water

The purpose of this review is to provide a short overview of electrochemical reduction processes for oxidized contaminants in water. The major parameters affecting the electroreduction mechanisms and the impact of electrode choice are discussed with reference to both inorganic and organic pollutants that are either regulated or emerging (e.g., nonmetal oxyanions, perfluoroalkyl and polyfluoroalkyl substances). To conclude, a discussion is presented on the future directions and challenges that must be addressed to develop these electrochemical reduction processes at a larger, commercialized scale.     

Transition Metals in the Synthesis and Functionalization of Indoles [New Synthesis Methods (72)]

The use of transition-metal complexes as reagents for the synthesis of complex organic compounds has been under development for at least several decades, and many extraordinary organic transformations of profound potential have been realized. However, adoption of this chemistry by the practicing synthetic organic chemist has been inordinately slow, and only now are transition-metal reagents beginning to achieve their rightful place in the arsenal of organic synthesis. Several factors contributed to the initial reluctance of synthetic organic chemists to use organometallic reagents. Lacking education and experience in the ways of elements having d electrons, synthetic chemists viewed organometallic processes as something mysterious and unpredictable, and not to be discussed in polite society. Organometallic chemists did not help matters by advertising their latest advances as useful synthetic methodology, but restricting their studies to very simple organic systems lacking any serious functionality (e.g., the “methyl, ethyl, butyl, futile” syndrome). Happily, things have changed. Organometallic chemists have turned their attention to more complex systems, and more recently trained organic chemists have benefited from exposure to the application of transition metals. This combination has set the stage for major advances in the use of transition metals in the synthesis of complex organic compounds. This review deals with one aspect of this area, the use of transition metals in the synthesis of indoles.     

Studies in the field of electrochemistry of organic compounds in 2000–2006

This review presents the author’s views on the state-of-art in the electrochemistry of organic compounds, based on the analysis of the data published from 2000 to 2006. The number of publications that consider to one or another extent the electrochemical reactions involving organic compounds constantly increases. The range of problems studied is intimately related with the demands of new technologies. The largest number of publications are devoted to the electrochemical polymerization and the properties of polymeric films on the electrode surface and also to the mechanism of electrode reactions of metal-complex compounds and their properties. The directions such as electrochemistry of nanomaterials and the methods of modification of electrodes are largely associated with the use of electroactive polymers. Fine organic electrosynthesis including the technological developments in the destruction of organic compounds, e. g., for cleaning of waste water, fade to the background. A new direction in this field is the development of amperometric sensors that employ modified electrodes based on electrochemically activated polymeric films.     

Electrochemical technologies for the treatment of pesticides

Pesticides are used worldwide in large quantities to increase yield in agriculture. On the other hand, they are in general toxic/persistent organic pollutants presenting strong adverse effects to the environment and human health, including acute and chronic toxicity. Consequently, water polluted by pesticides should be treated efficiently before its release into receiving water bodies to protect the natural aquatic environment. Different methods have been used for the treatment of water contaminated by pesticides. Among them, electrochemical technology seems to be very efficient in removing pesticides from water. Therefore this review aims to provide an overview of the recent works on the treatment of pesticide wastewater using electrochemical technology with a special focus on electrochemical advanced oxidation processes that demonstrated high efficiency in the removal of various types of pesticides from contaminated water.     

Liquid–Liquid Extraction of Organic Compounds into a Single Drop of the Extractant: Overview of Reviews

Single-drop microextraction (SDME) and hollow-fiber membrane microextraction (HFME) belong to methods of the liquid-phase microextraction preconcentration of organic compounds. These methods are characterized by the low consumption of organic solvents, high preconcentration factors, simplicity, low cost, ease of combination with various chromatographic methods; processes of preconcentration and sample injection are combined in a single device. Since the emergence of SDME (1996) and HFME (1999), a large number of versions have been developed that differ in the preconcentration technique, nature of the extractants used, and combinations with methods for the subsequent determination of the preconcentrated substances. The popularity of these methods among the analysts is evidenced by many reviews that we have summarized in this publication.

     

Analytical applications of electrochemiluminescence: an overview

The chemical transformations of electrogenerated ion-radicals of a number of complex organic compounds may be accompanied by emission of photons. An electrochemiluminescence (ECL) quantum contains information both on the kinetics of the heterogeneous electrode processes and on the subsequent homogeneous chemical reactions in the solution. Application of ECL to solution analysis provides advantages in comparison to electrochemical methods. Using ECL for electrode surface analysis allows information to be obtained on the rate of an electrochemical process simultaneously at all points of the electrode under analysis in real time, and that is the main difference between this method and the point-by-point testing specific to electrochemical methods. The potential of ECL for analytical chemistry is examined concerning the homogeneous ECL-analysis of solutions and the heterogeneous ECL-analysis of electrode surfaces. Received: 6 April 2000 / Revised: 23 June 2000 / Accepted: 27 June 2000     

有机电化学合成简谈

本文简要介绍了有机电化学合成的体系,研究方法和技术及主要特征。以C=C类物质为例介绍了有机电化学合成中的各类反应,并以己二腈的电合成为例介绍了相应的工业化应用。试图以CO2的电化学固定利用为例介绍了有机电化学合成的研究动向。     

Emerging Lithiated Organic Cathode Materials for Lithium-Ion Full Batteries

Organic electrode materials have application potential in lithium batteries owing to their high capacity, abundant resources, and structural designability. However, most reported organic cathodes are at oxidized states (namely unlithiated compounds) and thus need to couple with Li-rich anodes. In contrast, lithiated organic cathode materials could act as a Li reservoir and match with Li-free anodes such as graphite, showing great promise for practical full-battery applications. Here we summarize the synthesis, stability, and battery applications of lithiated organic cathode materials, including synthetic methods, stability against O₂ and H₂O in air, and strategies to improve comprehensive electrochemical performance. Future research should be focused on new redox chemistries and the construction of full batteries with lithiated organic cathodes and commercial anodes under practical conditions. This Minireview will encourage more efforts on lithiated organic cathode materials and finally promote their commercialization.     

Electrochemistry at High Pressures: A Review

High pressure electrochemical studies are potentially dangerous and less immediately implemented than conventional investigations. Technical obstacles related to properties of the working electrode material, preparation of its surface, availability of suitable reference electrodes, and the need for specially designed high pressure equipment and cells may account for the relative lack of experimental data on electrochemistry at high pressures. However, despite the stringent requirements for system and equipment stability, significant developments have been made in recent years and the combination of electrochemical methods with high hydrostatic pressure has provided useful insights into the thermodynamics, kinetics, and other physico‐chemical characteristics of a wide range of redox reactions. In addition to fundamental information, high pressure electrochemistry has also lead to a better understanding of a variety of processes under non‐classical conditions with potential applications in today's industrial environment from extraction and electrosynthesis in supercritical fluids to measurement of the pH at the bottom of the ocean. The purpose of this article is to detail the experimental pressurizing apparatus for electroanalytical measurements at high pressures and to review the relevant literature on the effect of pressure on electrode processes and on the properties of aqueous electrolyte solutions.