(+/-)-trans-1,2-Diaminocyclohexane

286-18-0

1121-22-8

General procedure for the synthesis of trans-1,2-cyclohexanediamine from epoxycyclohexane (CAS:286-18-0): 1. Epoxycyclohexane (39.2 g, 0.4 mol) and 30% ammonia (1.0 mol) were added to a reaction flask. The reaction was stirred at room temperature for 1.5 hours until the solution gradually clarified, indicating completion of the reaction. 2. The reaction mixture was cooled to room temperature under reduced pressure to give a white solid. Add 35 g of water to completely dissolve the solid and then cool to 0°C. 3. Slowly add 50% aqueous sulfuric acid solution, controlling the temperature throughout the process not to exceed 30°C. After stirring, gradually heat to 80°C under reduced pressure to remove the water, the system gradually becomes viscous and solidified. Stop stirring and continue vacuuming for 4 hours. 4. The solid was removed and pulverized and continued to be dried under vacuum at 120°C for 12 h. Moisture was measured to be 0.22% by Karl Fischer titration. 5. in another reaction flask, add sodium hydroxide solution and heat to 40°C, add the above solid powder in batches, controlling the temperature not to exceed 50°C. After addition, raise the temperature to 60°C, stirring until complete clarification, the reaction was completed at pH 9-10. 6. Extraction and distillation with 1,2-dichloroethane gave 27.2 g of aziridine with a GC purity of 99.6% and a total yield of 70% in two steps. 7. Aziridine (27.2 g, 0.28 mol), 30% ammonia (0.48 mol) and inorganic boric acid (3.5 g, 56 mmol) were mixed and heated to 90-95°C for overnight reaction. 8. Upon completion of the reaction, trans-1,2-cyclohexanediamine was obtained by distillation under reduced pressure, which solidified after cooling to 28.1 g of white solid with a GC purity of 99.7% and a yield of 88%, no cis isomers were detected, and the HNMR spectrum was consistent with the literature.