Synthesis method of 2,2'-Azobis(2-methylpropionitrile): (1) Put 1 part of hydrazine hydrate and 3.6 parts of acetone into the reaction kettle, heat to reflux temperature with stirring, continue heating and reflux for 4-6 hours, then cool down to 60 ° C. The condensation reaction produces a azine (acetone with nitrogen).
(2) A 70% sulfuric acid solution is put into the reactor, and then a 25% to 30% aqueous solution of sodium cyanide is added under stirring to produce hydrogen cyanide.
(3) The generated hydrogen cyanide gas is introduced into the produced azine (acetone-nitrogen), and the cyanation temperature is controlled to 55 to 60 ° C, and the reaction is carried out for 5 hours. After cooling, the temperature was lowered to 25 to 30 ° C, and the reaction was carried out for 2 hours. Then, the layer was allowed to stand, and the wastewater was separated to obtain diisobutyronitrile.
(4) Cooling the diisobutyronitrile to a temperature below 10 °C, while stirring, while introducing chlorine gas from the bottom of the kettle, the temperature will rise slightly, and it should be controlled below 20 °C. The tail gas is absorbed by water and alkali. After the oxidation reaction is completed, the precipitate is allowed to stand, filtered, and the filtrate is recycled. The filter cake is washed with water, and the water is separated to obtain a crude azobisisobutyronitrile.
(5) The product is refined by recrystallization. The crude azobisisobutyronitrile was dissolved in ethanol and filtered. The filtrate is crystallized at a low temperature, suction filtered, and the filtrate ethanol can be recycled, and the filter cake is dried at a low temperature to obtain a finished product.
(6) A condensation reaction is carried out by hydrazine hydrate with acetone at a reflux temperature to form a azine (acetone nitrogen). Hydrogen cyanide is produced by reacting 70% sulfuric acid with 25% to 30% sodium cyanide. Then, the obtained hydrogen cyanide gas is reacted with a azine (acetone nitrogen) at 55 to 60 ° C, and then cooled and cooled to continue the reaction to obtain diisobutyronitrile. The diisobutyronitrile is reacted with nitrogen at a temperature below 20 ° C, then left to settle, filtered, and the filtrate is recovered. The filter cake is washed with water and water is removed to obtain a crude 2,2'-Azobis (2-methylpropionitrile). The crude 2,2'-Azobis(2-methylpropionitrile) was dissolved and filtered with ethanol, and the filtrate was subjected to low-temperature crystallization, suction filtration, and dried at a low temperature to obtain 2,2'-Azobis (2-methylpropionitrile).
Synthesis method of 2,2'-Azobis(2-methylpropionitrile)
