Indirect Electro-oxidation Synthesis Of 2 - Methyl-1 ,4-naphthoquinone,

This paper is based on the industrial application-synthesis of 2-methyl-l,4-naphthoquinone(2-MNQ) with indirect electrosynthesiso The oxidation course of chromium sulfate(main reaction)and the electrolysis water (vice reaction) in the Sulfuric acid medium were measured with exact decomposed stable polarization curves which used three anodes by constant density .The influence on main and vice reaction's current efficiency of total current density ,chromium sulfate concentration , Cr6+ concentration as well as sulfuric acid concentration which were analysed by polarization curves were investigated and its credibility was also testified by the invariable current electrolysis experiments . We also measured the active component on the surface of Pbo2 /Ti anode which comes from the factory and Pbo: /Pb anode which we made ourselves with XRD ,further more we observe the external of the two anodes with SEM.. In optimizing synthesis of 2-MNQ ,the circle times of chromium sulfate solution is very important ,to improve the oxidation efficiency of 2-MNQ and the average current efficiency, we studied the effect of circle times . The optimal craft term of synthesis of 2-MNQ which raw material is 2- methyl-naphthalene(2-MN) and Crr>" was decided.The main contents of thesis is divided into four parts: One :The research of the oxidation course of chromium sulfate: The main reaction of the oxidation course of chromium sulfate:The vice reaction of the oxidation course .of chromium sulfate:According to thermodynamics principle , while the main reaction isproceeding , the electrolysis water reaction is inevitable .To gainthe exact anode polarization curves, we have used the method of decomposedstable polarization curves to get hold of the oxygen volume .The currentefficiency of the main reaction and vice can be gained . The influence onmain and vice reaction's current efficiency of chromium sulfateconcentration , sulfuric acid concentration, as well as current density could beeduced from the anode polarization curves. Conclusion as follows:CD When the anode Electric potential is constant, the currentdensity of separated oxygen ( which is also called the separatedoxygen reaction speed) enlarge with the rising of chromiumsulfate concentration, on the contrary , the current density of mainreaction (which is also cal led the main reaction speed)descend .(2) When the chromium sulfate concentration is constant , the current efficiency of separated oxygen enlarge with the the rising of total current density ,contrary ,the current efficiency of the main reaction decrease.(3) When the Cr6+ concentration(Cr6+and Cr6+ were both amount to Cr6+)was constant, The current efficiency of separated oxygen in the chromium sulfate solution which contain more Cr6+is higher ;with the rising of total current density ,it will happen that the main and vice reaction current efficiency were equal , then the main will grow higher that vice.(4) The Sulfuric acid is both medium and supporting electrolyte,itsconcentration is a optimum data.Two :To testify the above rules , we arrange a series of constant electrolysis experiments to review the influence on main and vice reaction's current efficiency of total current density and chromium sulfate concentration .the current density as follows, 750A/m2, 575A/m2,350A/m2, 200A/m2, 300 A/m2, 450 A/m2.the results show that the above rules is credible and it can guide the industrial application . The electrolysis experiments also compared the pbo2 /Ti anode which comes from the factory with Pboi /Pb anode which we made ourselves.the results show the different influence on the electrolysis efficiency .Three : in The synthesis of 2-methyl-l,4-naphthoquinone(2-MNQ) which raw material is 2- methyl-naphthalene(2-MN), The chromium sulfate solution is circled. We have got the best craft term of the synthesis of 2-methyl-l ,4-naphthoquinoneIn this proc...