反应详情

1,2-Dimethyl-3,5-diphenylpyrazolium methyl sulfate was converted by ion exchange chromatography to the pyrazolium hydroxide. This was then titrated (H2O solution) with 2,4-dichlorophenoxyacetic acid. Solid 2,4-D was added and went into solution after a very short time. The pH of the solution was monitored using a pH meter. Addition of the acid was stopped at pH 7 (initially pH was 12 to 13). This H2O solution was kept at room temperature for 48 hours. The pH was then approximately 8. An additional amount of acid was added until pH 7 was again obtained. After 24 hours, pH held at 7. ##STR6## The H2O solution was evaporated to a yellow oil and then azeotroped with toluene/acetone several times. Hexane was added with 5% to 10% dry acetone. The oil solidified to a white solid, was filtered, washed with hexane/acetone and dried. 7.0 Grams, melting point 152° C. to 154° C., of a lemon yellow solid was obtained.

1. additionSolid 2,4-D was added
2. additionAddition of the acid
3. additionAn additional amount of acid was added until pH 7
4. customwas again obtained
5. custom##STR6## The H2O solution was evaporated to a yellow oil
6. customazeotroped with toluene/acetone several times
7. additionHexane was added with 5% to 10% dry acetone
8. filtrationwas filtered
9. washwashed with hexane/acetone
10. customdried
11. custom7.0 Grams, melting point 152° C. to 154° C., of a lemon yellow solid was obtained