Studies On Selenium-catalyzed Reduction Of DNS To DSD Acid

4,4'-Diaminostilbene-2,2'-disulfonie acid?DSD-acid?is an important fine chemicals intermediates,mainly used as the manufacture of direct dyes?fluorescent whitening agent and moth-proofing agent.At present,the common method is iron powder reduction,electrochemical method,catalytic hydrogenation reduction of 4,4'-dinitrostilbene-2,2'-disulfonic acid?DNS?prepared,but all these methods caused serious environmental pollution,and wasting resource,which restricted the further development of DSD acid.In this paper,the Se/CO/H₂O system is applied to DNS acid reduction,which is a new method of preparation of DSD acid,and more friendly to the environment and economical.Firstly,we did not to add any organic solvent,only use water as a reaction solvent in high temperature and high pressure conditions,using this system to reduction the DNS preparation of DSD acid.Then,through a lot of experiments,the reaction of the optimum experimental conditions are determined.This paper is divided into four parts.The first part is preface,which mainly introduces the DSD acid structure,properties,applications and industry main production technology,and compare their advantages and disadvantages;The second part is the experimental section,which describes the experimental process and product analysis method;The third part is for the conditions of this experiment,try to investigated the better reaction conditions based on the experimental factors;The fourth part is a conclusion.This paper give the relatively better reaction conditions by experiments:DNS 7mmol?selenium 0.064 g?sodium hydrogen carbonate 0.13 g?water 60 mL?temperature 160 ??pressure 4 MPa?reaction time 6 h.In this condition,the product of amino value more than 90%,the target product purity can be up to 92%.4,4'-Diaminodiphenylethane-2,2'-disulfonie acid below 4%and this color is light yellow.Although there is a certain gap between this purity and by-product conten and the industry standard of the current national regulations,but this experiment.provides some reliable datas and feasible method for subsequent use this system to produce DSD acid.In addition,We discover the different types and numbers of assistant catalyst alkali can influence the experiment,believe that catalyst alkali can make further optimized with the research of assistant.