(C) To a 1000 mL four-necked flask equipped with a stirrer, thermometer, and gas introduction tube was added 400 g of MeO-DEAA obtained in step (b), followed by 6.8 g of potassium hydroxide and 0.4 g of TDA.A distillation column equipped with a packer, condenser, and distillation receiver was mounted on the flask, and a trace amount of nitrogen was passed through to act as a carrier gas. The reaction temperature was adjusted to 180 °C while stirring the reaction mixture. The system vacuum was adjusted to 60 kPa and the pyrolysis reaction was carried out for 12 hours. 307 g of crude N,N-diethylacrylamide (DEAA) (purity = 93%, yield = 92%) was obtained by collection through a water condenser. The crude DEAA was transferred to a distillation purification unit equipped with a 20 cm McMahon packing (6 mm particle size) filled column and purified by reduced pressure distillation (60 °C/0.13 kPa). The final 258 g of high purity DEAA (99.8% purity) was obtained as a colorless liquid. Examples 2-18: On the basis of Example 1, the raw materials, catalysts, solvents, polymerization blockers and reaction conditions were varied as shown in Table 1 and synthesized according to the same steps as in Example 1 to obtain the corresponding N-methyl-2-acrylamide. The results are summarized in Table 2.
