反应详情

温度

60 °C

46.8 g (0.2 mol) of 1-methyl-3,5-diphenylpyrazole together with 40 g (1.25 mol) of methanol are introduced into the reaction vessel. After 22.5 g (0.22 mol) of 96% strength sulfuric acid have been added, the reaction solution is brought to 160° C. by distilling off methanol. 608 g (19 mol) of methanol are metered in below the surface of the reaction mixture in the course of 7.5 hours. After the mixture has cooled to 60° C., 10 g (0.31 mol) of methanol are added, and the mixture is cooled down to 10° C. At this temperature, the crystal slurry which has precipitated is filtered off. 68.1 g of 1,2-dimethyl-3,5-diphenylpyrazolium methylsulfate with a content of 97.3% (HPLC) of m.p. 157°-159° C. are obtained, which corresponds to a yield of 91.8% of theory.

1. customis brought to 160° C.
2. distillationby distilling off methanol
3. customare metered in below the surface of the reaction mixture in the course of 7.5 hours
4. temperaturethe mixture is cooled down to 10° C
5. customAt this temperature, the crystal slurry which has precipitated
6. filtrationis filtered off