反应详情

A solution of 3,4-dimethylbenzoic acid (40 g) in concentrated sulphuric acid (250 ml) was cooled to 0° C., treated with a solution of potassium nitrite (27 g) in sulphuric acid (100 ml) dropwise over a period of 1 h, and stirred for 2 h. The reaction mixture was quenched with ice cooled water (100 ml). The solid precipitated was filtered, dissolved in water (2 l), basified with 2N aqueous sodium hydroxide. The solution was acidified to pH 4 with 2N aqueous hydrochloric acid and filtered to get 3,4-dimethyl-5-nitrobenzoic acid (II) (25 g) as colorless solid. The filtrate was further acidified to pH 3 and filtered get 3,4-dimethyl-2-nitrobenzoic acid (I) (13 g) as colorless solid.

1. customThe reaction mixture was quenched with ice
2. temperaturecooled water (100 ml)
3. customThe solid precipitated
4. filtrationwas filtered
5. dissolutiondissolved in water (2 l)
6. filtrationfiltered