N,N'-Dimethyl-1,2-cyclohexanediamine

51066-08-1

74-89-5

61798-24-1

The reaction was catalyzed by 2.5 g of inorganic boric acid with epoxycyclohexane (98.2 g, 1.0 mol) and monomethylamine aqueous solution (35%, 1.0 mol) at 50 °C for 2 hours. After the reaction was completed, it was cooled to 0 °C, and 0% sulfuric acid solution (1.0 mol) was slowly added dropwise, controlling the temperature not to exceed 40 °C during the dropwise addition. Subsequently, the temperature was raised to 110 °C to remove water under atmospheric pressure until no water flowed out and the reaction system gradually became viscous. After adding 85 mL of cyclobutanesulfone, the reaction was changed to vacuum distillation, and the temperature was gradually increased to 140 °C for 7-8 h until the moisture content was detected as 0.38%. The reaction solution was cooled to 0 ℃, aqueous sodium hydroxide was added dropwise to adjust the pH to 12-13. The temperature was slowly increased to 75 ℃, the reaction solution was gradually clarified, and the upper liquid layer was separated after cooling to room temperature 81.9 g, with a GC content of 95.2%, and the yield of the first two steps was 70%. Add the upper liquid with 35% aqueous methylamine (1.12 mol) and 1.4g inorganic boric acid into the autoclave, sealed and reacted at 90 ℃ overnight, the reaction was completed (external standard yield of 96%). After cooling, the water and pre-fraction were removed by distillation under reduced pressure to obtain pure N,N'-dimethyl-1,2-cyclohexanediamine. Combining the former fractions, a total of 88.6 g of colorless liquid was obtained in 89% yield, which was nearly white solid after cooling, with a GC purity of 99.2%.