反应详情

116 ml of sulfuric acid is introduced and mixed in portions at −15° C. with 14.70 g (95.37 mmol) of 5-fluoro-2-methylbenzoic acid. A mixture of nitrating acid (4.79 ml of fuming nitric acid and 21.8 ml of concentrated sulfuric acid) is added in drops to this mixture, specifically at −15 to −10° C. during a period of 90 minutes. After three more hours of stirring, the reaction mixture is poured into ice water and stirred vigorously for about one-half hour. The precipitated crystallizate is suctioned off, washed neutral with water and dried. The yield is 8.56 g (45.1%) of a mixture of various regioisomers and by-products. This mixture is thus incorporated into the next stage (esterification) and purified in this stage.

1. additionis added in drops to this mixture, specifically at −15 to −10° C. during a period of 90 minutes
2. stirringstirred vigorously for about one-half hour
3. washwashed neutral with water
4. customdried
5. custompurified in this stage