Example 1: A solution of N-ethylmethylamine (100 g, 1.69 mol) in dichloromethane (1.5 L) was slowly added dropwise to a suspension in dichloromethane (2 L) containing sodium bicarbonate (284 g, 3.384 mol) and triphosgene (332 g, 1.117 mol), the temperature was maintained at a controlled level of 10-15°C, and the dropwise process lasted for 2 hours. After completion of the dropwise addition, the reaction mixture was continued to be stirred at room temperature for 3 hours. Upon completion of the reaction, the resulting sodium chloride was removed by filtration and the filtrate was concentrated under reduced pressure to afford 189 g of N-methyl-N-ethylcarbamoyl chloride, the product being a light yellow oil (yield: 92%). Example 3: The procedure of Example 2 was repeated, only the solvent was changed to methylene chloride, and the rest of the reaction conditions remained unchanged. The experimental results are shown in Table 2, the yield consistently exceeded 98%.
