3-METHYL-1H-1,2,4-TRIAZOLE

624-84-0

7170-01-6

Example 3 Preparation of 3-methyl-1,2,4-triazole: To a 20L reactor equipped with a temperature probe and overhead stirrer was added acetamidine hydrochloride (2.0 kg, 21.16 mol) and anhydrous ethanol (10.0 L). The resulting suspension was cooled to 0-5°C. Sodium methanolate (1.15 kg, 21.2 mol) was slowly added under stirring to control the reaction temperature below 20 °C. Subsequently, formylhydrazine (1.28 kg, 21.2 mol) was added. The reaction mixture was stirred at 55°C for 16 hours. After completion of the reaction, it was cooled to 20 °C and filtered to remove solids. The filtrate was transferred back to the reactor and concentrated by distillation under reduced pressure to 2.0-2.5 L. Butyl acetate (4 L) was added to the concentrate and again concentrated by distillation under reduced pressure to 2.0-2.5 L. The addition of butyl acetate (4.0 L) was repeated and the concentration was carried out until the GC analysis showed that the weight ratio of butyl acetate to ethanol was greater than 19:1. After completion of the solvent exchange the mixture was heated to 70-75 °C and held for 15 minutes, then cooled to room temperature (20-22°C) within 1 hour and stirred at this temperature for 14 hours. The suspension was further cooled to 0-5 °C, stirred for 1 h and filtered. The filter cake was washed with a solvent mixture of heptane and butyl acetate (3:1, 4.0 L, v/v), and after stripping the solution for 1 hr, it was dried at 30-35 °C under vacuum at 25 mmHg for 48 hr to afford 3-methyl-1,2,4-triazole (1.59 kg, 19.1 mol) in 90.3% yield as a pale pink solid.1H NMR (300 MHz) δ 2.53 (s , 3H), 8.03 (s, 1H), 11.52 (s, 1H); 13C NMR (300MHz) δ 156.5, 149.8, 13.5. Calculated elemental analysis (C3H5N3): C, 43.36; H, 6.06; N, 50.57. Measured value: C, 43.29; H, 6.15; N, 50.54.