Electrochemistry Of Hydroxyl Compounds In Ionic Liquids

In recent years, as the various geological hazards frequent on the earth, human beings have realized this is the nature flashed out its warning. If we don't strengthen environmental protection and enhance the protection consciousness of earth, there will be unimaginable consequences. So greening requirements must be attached to these problems, People first pay attention to the chemical industry which provides various products for human decent lives. Nowadays chemical industry has to face many problems such as green chemical synthesis and the sustainable development. Green chemistry, or environmental friendly chemistry is a kind of the sustainable development that pursue to prevent the environmental pollution from the source, fundamental purpose is to save resources and energy, avoid environmental pollution.Electrochemistry is one of green synthesis rout since it carries out through use electron which is the world's most clean raw materials. In principle it accords with environmental friendly and "atom economy requirements", is a green synthesis method. Green chemical requirements all of the raw materials, the catalysts which used as much as possible are non-toxic and non-pollution, Now the ionic liquids as a kind of green reagents have already received the researchers attention and successful applied in many fields. Because the peculiar composition and structure of ionic liquids, make them have high conductivity and better electrochemical stability than general organic reagents. If as the electrolyte for electrochemical synthesis, it not only can avoid to use other supporting electrolytes, still can reduce some side reactions which because the electrolyte itself instability, and reduce product purity and conversion. Another advantage of ionic liquid as electrolyte can be recycled, to save the resources and energy. All of these advantages make that ionic liquids in electrochemical has broad application prospect.Hydroxyl compound is an important type in organic compounds, with various chemical properties, in many kinds of organic synthesis they can be used as a reaction of reactant, solvents, catalyst etc. widely application. Methanol and phenol both are belong to hydroxyl compound, but they have comparative special structure and chemical properties, and methanol and phenol are mass chemicals, industrial production and usage are quite large, so how to realize the greening applications of methanol and phenol become a hotspot research areas. Consideration question from the requirement of green chemistry, using organic electrical synthesis this greening synthesis process and ionic liquid this environmentally friendly green reagents, change methanol and phenol directly into some other important organic compounds. This method not only can reduce the use of environmental unfriendly organic reagents which in the current application of methanol and phenol, still can reduce the methanol and phenol which without reaction emissions into environment caused pollution, and can improve purity and yield of the produces, those have application value chemicals. So the research of this aspect also has environmental protection and chemical industry, economic multiplicity significance. At present about methanol electrochemical research mainly is methanol as methoxylation reagent synthetic organic carbonates and directly electro-oxidation reaction. Phenol is a special and important compound because simultaneously contains phenyl and hydroxyl, phenol has a wide range of application, such as occurs transesterification reaction with organic to preparation corresponding other organic carbonates, At present, the research of the phenol use in organic electrochemical synthesis is less.The purpose of this dissertation wants to achieve greening application of hydroxyl compound with organic electrochemical synthesis and ionic liquids which are known as green method and reagent. This research chemical reaction is to avoid the use of environmental unfriendly organic reagents and toxic materials, the purpose is to find more greening use of hydroxyl compounds, and make these have applied the prospect of large-scale industrialization produce.This thesis mainly divides into three parts studied hydroxyl compound use ionic liquid as electrolyte in organic electrochemical synthesis, and investigates the influence of the experimental condition, and also deduced synthesis mechanism.1,The electrochemical synthesis of dimethyl carbonate(DMC)Firstly use the functionalization ionic liquids which have advantage in adsorption and fixed CO2, as the electrolyte, after activation by electrochemical change into the CO2 - anion radical directly react with methanol and potassium methoxide as a catalyst, successfully synthesis of dimethyl carbonate (DMC). And the highest current efficiency of DMC reach up to 59% this is exceeds the past research about electrochemistry activation CO2 synthetic DMC. And this work avoids using virulent methyl iodide as the methylation reagent, the whole electrochemical synthesis no use harmful toxic organic reagents, accord with the green chemical concept and requirements. Meantime study on the reaction condition how to influence the electrolysis process, such as electrolytic potential, reaction temperature, electricity quantity, the catalyst types and dosage and ionic liquid types and volume. And the thesis also deduces the mechanism of synthesis DMC.2,The electrochemical synthesis of diphenyl carbonate(DPC)This paper studied successfully a new method for synthesis of diphenyl carbonate. Firstly studied in CO2 activation by electrochemical then reaction with phenol to successfully synthesized the DPC. Feeding atmospheric CO2 into ionic liquids, get CO2 anion radical from electricity chemical methods, then add phenol, use the K2CO3 as a catalyst, continue to chemical reaction process, successful synthesis of DPC Study on the electrochemical potential, reaction temperature, catalyst types and dosage, concentration of phenol, ionic liquid type and dosage et al. how to influence the current efficiency of DPC, Optimization of reaction conditions and also deduced through experiment mechanism of synthesis DPC. A brand-new preparation methods successful synthesis of DPC, the current efficiency achieved 49.7%. This method compared with the previous method of synthetic DPC, accord with green chemical requirements, and get high selectivity, the reaction system also can be repeated use.3, The electrochemical synthesis of formaldehydeIndustrial production formaldehyde by oxidation of methanol, because not only the reaction condition demanding, catalyst expensive, but also cause environmental great harm, so looking for other green chemistry required formaldehyde synthesis methods become an urgent problem. This paper using environmental friendly ecological reagent ionic liquid, as the electrolyte and solvent for electrochemical, through the electricity oxidation methanol synthesis method, efficient get the formaldehyde without water. The indirect electrochemistry oxidation of methanol uses the protonic ionic liquid methylimidazolium hydrogen sulfate as the reaction media. In this process, an initial electro-oxidation of hydrogen sulfate ion at the anode generated the active oxidative species of persulfate ion. Then oxidation of methanol with persulfate ion into formaldehyde, after the reaction this persulfate ion come back to hydrogen sulfate ion, in cathode area the hydrogen ions by reductive into hydrogen and out of the reaction system. Because the boiling point of formaldehyde is far lower than methanol and ionic liquid almost no steam pressure characteristics, the product could be separated from the electrolyte solution by the refluxing method, prompting the oxidation reaction efficiency. This paper using electricity oxidation methanol synthesis formaldehyde, this method is better than the traditional electrochemical synthesis, the advantage lies in the use of environment friendly reagent ionic liquid, also no use of equipment corrosive inorganic reagents, make the current efficiency of formaldehyde reached 89.3%. The whole reaction is the dehydrogenation oxidation, avoid a depth of oxidation methanol, and enhance the selectivity. This method avoided using any environment unfriendly reagent, with green chemistry requirements, a large-scale preparation formaldehyde, clean and efficient synthesis process line.