Study On The New Synthetic Process Of3,5-difluoro-4-cyanophenyl

In recent years, fluoride liquid crystal is a new synthetic performance superiorliquid crystal material, and widely favored by nation and foreign clients.3,5-difluoro-4-cyanophenyl is an important fine organic synthetic intermediate, and themajor raw materials of synthetic of fluoride liquid crystal, Its enormous market demandand broad development prospects, demand gap is great. However, many manufacturersbecause there is no good method of synthesis can not be industrialized, according tothis situation, we feel the need to find a simple and practical synthesis method insteadof the original complex process.In this paper, by querying a large number of foreign chemical information andexplore with the instructor, we design seven possible synthetic routes of3,5-difluoro-4-cyanophenyl. But some there are many side reactions, conditions, control(such as temperature, pressure) and charge order and the feedstock of uncertainty, thereaction is slow and other inadequacies in the comprehensive analysis of the varioussynthetic routes, consider select one of the best one study. Because the synthetic line islong, and research time is limited, we only study the two-step (diazotization reactionand releasing nitrogen reaction) in-depth discussions. First, we introduced the entireprocesses of preparation from aniline to phenol, through exploring and researching itsprocess to find the safety conditions of diazotization, releasing nitrogen reaction. Onthe basis， we choose different experiment programs and find out the various possiblefactors which will impact of the reaction. Through a series of single-factorexperiments，we get the best reaction condition. After we have familiared with theprocess of preparing phenol from aniline, we apply the best conditions to the process ofpreparing3,5-difluoro-4-cyanophenyl. We discuss the diazotization, releasing nitrogenreaction preliminarily and get the product of3,5-difluorophenol. We have, respectively,of phenol and3,5-difluorophenol products using high performance liquidchromatography, melting point test and IR methods to confirm the structure of theproduct. We measured the phenol of purity of99.3%,3,5-difluoro phenol purity of99.2%...