Study On Green Nitration Process Of Phenolic Compounds

Nitrophenolic compounds are the core of organic chemistry and life sciences.They are commonly found in natural compounds,antibiotics,organic dyes,pesticides,plastics,explosives,and the pharmaceutical industry.2-sec-butyl-4,6-dinitrophenol（DNBP）has been used in the polymerization inhibition of styrene because of its good polymerization inhibition performance at high temperature.The traditional industrial production process of DNBP was nitrified by nitric acid after sulfonation,and then substituted sulfonic group by nitric acid.The large amount of highly acidic wastewater was generated.The unreacted sulfonic acid and nitric acid cannot be recycled,which leads to serious environmental problems.Therefore,it is extremely important to find a green synthetic DNBP method.In view of the above problems,a new route was designed to synthesize 2-sec-butyl-4,6-dinitrophenol.Using o-sec-butylphenol and nitric acid as s materials,using three different methods（high-pressure method,atmospheric pressure method,two-step method）to directly nitrate synthesis 2-sec-butyl-4,6-dinitrophenol.After being treated with O₃,nitric acid is mixed with concentrated nitric acid to an appropriate concentration for the next reaction.The new route eliminates the disadvantages of using a large amount of concentrated sulfuric acid in the traditional method.The atom economy is high,and the product is only the target product and water,which greatly reduces the generation of wastewater.In addition to o-sec-butylphenol,the method of this experiment is also applied to the nitration of 2,6-di-tert-butylphenol,o-tert-butylphenol,p-cresol,o-cresol,all have achieved high yield and product purity,and the reaction progress and target product content are detected by gas chromatograph（GC）.The target product was verified by nuclear magnetic resonance analysis and high-resolution mass spectrometry,and the structure was correct.