Synthesis
Preparation of azacrown ether: the bromine salt of compound 1,7-dioxa-4,10-tetraaza (2.6 g, 5.39 mmol) and phenol (3.04 g, 32.32 mmol) were added to 150 mL of 33% hydrogen bromide acetic acid solution. The reaction was warmed up to reflux at 80 C and stirred for 60 h. After the reaction was cooled down, the reaction solution was directly evaporated to 15 mL under reduced pressure, to which 120 mL of acetone was added, and a large amount of gray solid was precipitated immediately, and then filtered under reduced pressure, washed with acetone (330 mL), and dried in vacuum to obtain 1.1 g of the gray solid compound which was the azacrown ether.
