Paired Electrosynthesis Benzaldehyde And O-aminophenol

Chemical industry products plays a key role in improving people's quality of life,which affects people's all of the aspects.However,in actual production process will inevitably cause damage to the environment,the country's economy,society and the environment brought great pressure.In order to avoid further deterioration of the situation,green chemistry has got a wide range of national attention that is,in the production process to zero pollution emissions.The electrochemical based on electric energy as power,mainly produce hydrogen and oxygen and cause the little extent of damage to the environment in the production process,having been an important branch of green chemistry.Electrochemical was mainly used in the treatment of industrial wastewater,soil degradation and adsorption of atmospheric particles and so on.And now,more and more researchers apply the electrochemical technology to organic synthesis.Compared with the traditional organic synthesis method,this technology characteristics of easy operation control,high product purity,less by-products and higher economic advantages.Benzaldehyde and o-aminophenol both are important intermediate in organic chemical products.Benzaldehyde is one of the simplest aromatic constituents in almond and fruit and it's widely used in medicine,spices,agriculture and industry.The o-aminophenol is widely used in dye,medicine,printing and biological fields.In recent years,it has been found the o-aminophenol can also be used for the analysis of fatty acid and preparation of Schiff base.However,the traditional production process both benzaldehyde and o-aminophenol will cause relatively large damage to the environment.This experiment based on research of the literature and the previous research work of the research group found that benzaldehyde and o-aminophenol were relatively close in the tank voltage and alkaline medium in the electrolysis.This experiment decided to synthesis benzaldehyde and o-aminophenol through the green and clean technology of paired electrosynthesis,of which in process electrooxidation benzyl alcohol to benzaldehyde on the anode,electroreductive o-nitraphenol preparing o-amino phenol on the cathode,respectively.In the course,two fine chemicals with high added value were prepared simultaneously.The results are as follows:First,the anode working electrode was developed.By reviewing the literature,it was found that oxidation reaction of benzene methanol to benzaldehyde can happen on the surface of nickel foam electrode.With cyclic voltammetry analysis of the electrode,the catalytic oxidation efficiency of benzyl alcohol on the electrode is not high.In order to improve the catalytic oxidation efficiency of electrode,and get target products.This experiment prepared the NiOOH electrode based on the foam nickel through a multi-current.Comparing the cyclic voltammetry of benzyl alcohol at the same conditions,it showed that the NiOOH electrode had higher catalytic oxidation activity to benzyl alcohol..Secondly,through the review of the literature,there was no literature record the analysis method of cathode electrolysis products,which has brought inconvenience of analysis electrolytic products.Based on the literature read and the nature of o-nitrophenol and o-aminophenol,this experiment established a high performance liquid chromatography(HPLC)method for simultaneous determination of o-aminophenol and o-nitrophenol.This experiment explored the detection wavelength,column temperature,mobile phase composition and flow rate on detection results,and ultimately the optimal conditions is that: the mobile phase was pure methanol and the flow rate was 0.8min/L,the detection wavelength was 285 nm,the column temperature was 35?.It was applied to the analysis of o-aminophenol electrolysis by o-o-nitrophenol.The rates were between 93.0%~105.6% and 90.6%~106.2%,respectively.the relative standard deviations were ?3.75% and ?1.44%,respectively,showing the satisfying test results.Thirdly,with Pb as anode,Cu as the cathode,NaOH solution as electrolyte,this experiment investigated o-nitrophenol electrochemical behavior on Cu electrode surface.The experimental results show that the o-nitrophenol intermediate products generated on the Cu electrode surface,the presence of oxygen occurs with the o-nitrophenol for the electronic phenomenon.Therefore,the electrochemical reduction of o-nitrophenol to o-aminophenol used nitrogen for the protection,and through the orthogonal test,The optimum electrolysis conditions is that the ratio of the amount of o-nitrophenol added to the stoichiometric amount is 2: 1,the amount of NaOH was 3.0g,reaction temperature was 35?,current intensity was 0.3A,current efficiency was 98% or more.Fourthly,under ensuring o-nitraphenol maximum current efficiency,this experiment decide to carry out paired electrosynthesis of benzaldehyde and o-aminophenol.In the H type of electrolytic cell,NiOOH was used as anode,Cu was used as cathode,Na2SO4 solution was used as electrolyte.On the basis of keeping the cathodic electrolysis condition substantially unchangedthis,this experiment test investigated the effect of the ratio of the amount of benzyl alcohol added to the amount of matter in theory,the amount of NaOH,reaction temperature on the situation of cathode and anode current efficiency and total current efficiency.The experimental results showed that the reaction temperature is 35?,electrolytic cathode current is 0.3A,the current efficiency of electrolytic reaction could up to 156.95%.On that condition,the ratio of o-nitrophenol to the theoretical amount was 2: 1,the amount of NaOH is 3.0g in the cathode electrolytic cell;the ratio of benzil alcohol to the theoretical amount was 5: 1,the amount of NaOH is 2.0g in the anode electrolytic cell.This experiment has laid a good foundation of future industrial production.