Study On Nitro-derivates Of Trifluoromethylbenzene

The nitro-derivates of trifluoromethylbenzene are intermediates of finechemical industry and pharmaceuticals. They are important raw material for manufacture of medicines, agrochemicals, dyes and so on. Synthesis of nitro-derivates of trifluoromethylbenzene is significant to promote the development of correlative industries of our country and satisfy the requirement of the international market.The synthesis of its nitro-derivates using trifluoromethylbenzene as starting material is improved in the article. ①3-nitro-trifluoromethylbenzene (Ⅰ) was prepared via nitration with a mixture of sulfuric acid and nitric acid. The reaction conditions recommended are that the molar ratio of sulfuric acid to nitric acid is 1.5:1, the molar ratio of nitric acid to trifluoromethylbenzene is 1.2:1, the temperature of adding is about 2℃, followed by rising temperature to 45℃ and reacting for 1.0h, and the yield is 92.26%; ②hydrogenation of (Ⅰ) gave 3-trifluoromethyl-aniline(Ⅱ). The yield of the reaction is 96.8%; ③ niflumic acid was prepared by condensing (Ⅱ) with 2-chloronicotinic acid in xylene. The reaction conditions recommended are that the molar ratio of 2-chloronicotinic acid to (Ⅱ) is 1:1.6, the reaction temperature is 130℃, reaction time is 1.5h, the volume of xylene is 4 mL, and the yield is 75.4%.