Study On The Synthesis Of Benzoic Acid-like Fine Chemical Intermediates

The industry of fine chemical intermediates is one of the most vigorous focus fields in today's chemical industry as well as the important component of new medicines and new materials.Fine chemical intermediates are various in kind,high value added,widely used and with high industry relevancy,which directly serves for many industries in our national economy and fields of high technology.Therefore,the research on the synthesis of some common fine chemical intermediates has very important practical and social significance.In this article,it is mainly introduced that two benzoic acid-like intermediates—2-amino-5-nitrobenzoic acid,5-nitrosalicylic acid and an dichlorocyclopropane-like intermediate—1,1-dichloro-2-phenylcyclopropane were synthesized,the influences of some factors were studied and final product were analyzed and characterized.The main research work and results are as follows:1)P-nitroaniline and isatin were respectively used as raw materials of route one and route two for the synthesis of 2-amino-5-nitrobenzoic acid. The reaction mechanism of route one was presumed and the effects of some factors on the yield of route two were investigated.After recrystallization and testing,the melting point of 2-amino-5-nitrobenzoic acid was 267～268℃and the optimum yield of refined product was 61.1%.The structure of the product was confirmed by IR and ~1H NMR.2)Under the irradiation of microwave,acetic acid and acetic anhydride were used as mixed solvent,concentrated nitric acid was used as nitrating agent to synthesize 5-nitrosalicylic acid with one-step method in ice bath.The effects of some factors such as reaction time,reaction temperature and irradiation time on the yield were investigated.After recrystallization and testing,the melting point of 5-nitrosalicylic acid was 230～232℃and the optimum yield of refined product was 82.6%.The structure of the product was confirmed by IR and ~1H NMR.3)Using styrene and chloroform as raw materials,and 1,1-dichloro- 2-phenylcyclopropane can be obtained from the addition reaction between styrene and dichlorocarbene which is formed at the existence of concentrated alkaline and phase transfer catalyst.The effects of some factors such as reaction temperature,reaction time,amount of chloroform, sorts and amount of catalyst on the yield were investigated.After separation,purification and testing,the boiling point of 1,1-dichloro-2-phenyl cyclopropane was 124～126℃/-0.095MPa,the density was 1.219g/ml,the n20/D was 1.5983 and the optimum yield of refined product was 65.7%.The structure of the product was confirmed by IR and ~1H NMR.