Studies On Selenium-catalyzed Reduction To Prepare 2,5-dimethoxy-4-chloroaniline In CO/H₂O System

2,5-dimethoxy-4-chloroaniline is an important azo pigment intermediate. The organic chemicals are in great demand in recent years. Which is used in paint industry, coating fabric printing and dyeing, printing, printing ink, rubber, plastics, synthetic fiber and other industries. Currently the domestic industrial method of iron power reduction causes serious pollutions. Besides, recently new development of the cost of liquid phase catalytic hydrogenation reduction process is too high to be applied in practical. The purpose of this paper is to develop a highly efficient, green, low cost, simple and convenient synthetic method.On the basis of the research work that predecessor reduced aromatic nitro compounds in the preparation of aromatic amine in Se/CO/H2O system, restore system is applied to the work of 2,5-dimethoxy-4-chloronitrobenzene reduction and we explore a new method to reduce 2,5-dimethoxy-4-chloronitrobenzene.The method is compared with other methods of reduction is not only green no pollution but high efficiency, low cost.In this paper, we use 2,5-dimethoxy-4-chloronitrobenzene as reaction substrate, selenium as catalyst, organic or inorganic bases as co-catalyst. With the high temperature and high pressure, in the Se/CO/H2O catalyzed system we managed to synthesize the 1-aminoanthraquinone in one pot.Through the condition of experiment, we find out the influence of reaction conditions on reaction conversion rate:type of co-catalyst, the amount of selenium, reaction time, reaction temperature, CO pressure on the reaction, rotor speed, that all has certain effect in the reaction. As co-catalyst, inorganic base is better than organic base.The effect order of different factors for the reduction was gotten by orthogonal experiments L9(34):reaction time> reaction temperature> CO gas pressure> the amount of selenium powder.The optimum condition was obtained by experiments:ingredients 2.18 g(10mmol); Se:0.0158 g(0.2mmol); NaHCO3:0.42 g(5mmol); C6H12:40mL; H2O:2mL; reaction temperature:150℃; Pco:6.0MPa; reaction time:8 hours. 2,5-dimethoxy-4-chloroaniline yield was 98.38%, the purity of 82.89%.This paper altogether is divided into four parts:the first part is preface, mainly introduced the 2,5-dimethoxy-4-chloroaniline structure, properties, application and synthetic route and other reduction method, and compares the various route and methods; The second part is the experiment part, the paper introduces the experimental process and result analysis method; The third part is the condition of experiment, to explore the influence of various factors on the reaction and impact strength of the reaction, the optimal experimental conditions were determined. The fourth part is the conclusion.