Studies On Selenium-Catalyzed Reduction To Prepare M Acid Under CO/H₂O System

M acid?3,5-diamino-2,4,6-trimethylbenzenesulfonic acid?is an important organic dye intermediate,which is widely demanded by the international market.At present,the main methods of industrial reduction synthesis of M acid are iron powder reduction and catalytic hydrogenation reduction.Iron powder reduction will not only generate a large amount of iron mud that is difficult to handle and thus seriously pollute the environment,but also cause the three wastes problem to be difficult to solve.The catalytic hydrogenation method requires harsher reaction conditions.When there is a sensitive sulfonic acid group in the M acid,the reaction often occurs with side reactions such as desulfonic acid,and elemental sulfur is precipitated,which makes the sulfur easily combine with the catalyst and deactivate during the catalytic hydrogenation process.This not only affects the progress of the reaction,reduces the efficiency of the reaction,but also increases the cost of the catalyst.The above methods have been restricted to a certain extent in industrial production.Therefore,a green and recyclable system is urgently needed to replace the original production process.In this experiment,we tried to apply Se/CO/H₂O reduction system to the preparation of M acid on the basis of predecessors.We selectively synthesized3-nitro-5-amino-2,4,6-trimethylbenzenesulfonic acid under normal pressure.M acid was synthesized in high yield under high pressure.Moreover,the selectivity of the two products obtained under the two conditions is close to 100%.The method has good selectivity and high yield.From the perspective of green chemistry,the reaction is green and recyclable,which is not only environmentally friendly,but also greatly reduces the cost of industrial production.In this thesis,the reduction reaction of M-acid dinitro compounds under Se/CO/H₂O system was investigated under normal pressure and high pressure.Under normal pressure conditions,we used N,N dimethylformamide as a solvent,inorganic base or organic base as a cocatalyst,and selectively generated3-nitro-5-amino-2,4,6-trimethyl Benzene sulfonic acid.Under high-pressure conditions,we use water as the solvent of the reaction to selectively generate M acid.After column chromatography and recrystallization,the pure product was obtained.The product was semi-qualitatively analyzed by liquid chromatography.Then,we analyzed and determined the structure of raw materials and products through nuclear magnetic hydrogen spectroscopy.Various control kinetics factors were explored by controlling variables.1 Atmospheric condition:1.45g?5mmol?of 3,5-dinitro-2,4,6-trimethylbenzene-sulfonic acid;0.492 g?6 mmol?of anhydrous sodium acetate;DMF:30 ml;H₂O:3ml;Se:0.0197 g?0.25 mmol?;reaction temperature:95?;reaction time:5 h.The highest purity of 3-nitro-5-amino-2,4,6-trimethylbenzenesulfonic acid is 87.9%.2 High pressure condition:3,5-dinitro-2,4,6-trimethylbenzenesulfonic acid:1.45g?5 mmol?;P_CO:4 MPa;reaction temperature:160?;Se:0.0316 g?0.4 mmol?;H₂O:10 m L;reaction time:3 h;Na₂CO₃:0.106 g?1 mmol?.The highest purity of M acid is 98.6%.The order of the influence of kinetic factors on the reaction is:temperature?water volume?pressure?selenium volume...