Method for preparing 3-chlorophenylhydrazine sulfate
The technology of chlorophenylhydrazine and sulfate, which is applied in the field of preparation of organic compounds, can solve the problems of high impurity content, poor stability and small yield of products, and achieve the effects of improving purity, easy operation and less impurities.
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Embodiment 1
[0022] A preparation method for 3-chlorophenylhydrazine sulfate, comprising the following steps:
[0023] ⑴ diazotization
[0024] Add 50g of 3-chloroaniline and 150ml of 37% concentrated hydrochloric acid into a 1L three-necked flask, cool to 2°C with ice salt, add 85.7g of 35% sodium nitrite aqueous solution while stirring, and keep the temperature at 2°C for 1 hour.
[0025] ⑵ reduction
[0026] Add 450ml of 37% concentrated hydrochloric acid, 450ml of water and 120g of zinc powder in the reaction solution, keep the temperature at 18°C and react until the reaction is complete, the reaction solution becomes off-white, then add 20% sodium hydroxide solution until the pH value of the reaction solution is 10, After 1 hour of heat preservation at 5°C, crystals were precipitated, and 26.4 g of crude 3-chlorophenylhydrazine was obtained by filtration.
[0027] ⑶ Purification
[0028] Dissolve 26.4g of crude 3-chlorophenylhydrazine in 528g of water, heat it to 60°C to dissolve...
Embodiment 2
[0032] A preparation method for 3-chlorophenylhydrazine sulfate, comprising the following steps:
[0033] ⑴ diazotization
[0034] Add 200g of 3-chloroaniline and 600ml of 37% concentrated hydrochloric acid into a 5L three-necked flask, cool to 2°C with ice salt, add 343g of 35% sodium nitrite aqueous solution while stirring, and keep the temperature at 2°C for 1.5 hours.
[0035] ⑵ reduction
[0036] Add 730ml of 37% concentrated hydrochloric acid, 730ml of water and 195g of zinc powder to the reaction solution, keep the temperature at 18°C until the reaction is complete, the reaction solution turns off-white, then add 25% sodium hydroxide solution until the pH value of the reaction solution is 10 , kept at 5°C for 1.5 hours, crystals were precipitated, and 121g of crude 3-chlorophenylhydrazine was obtained by filtration.
[0037] ⑶ Purification
[0038] Dissolve 121g of crude 3-chlorophenylhydrazine in 2420g of water, heat to 60°C to dissolve it completely, then add an ...
Embodiment 3
[0042] A preparation method for 3-chlorophenylhydrazine sulfate, comprising the following steps:
[0043] ⑴ diazotization
[0044] Add 500g of 3-chloroaniline and 1500ml of 37% concentrated hydrochloric acid into a 10L three-necked flask, cool to 2°C with ice salt, add 857g of 35% sodium nitrite aqueous solution while stirring, and keep the temperature between 0 and 5°C for 1.5 hours.
[0045] ⑵ reduction
[0046] Add 730ml of 37% concentrated hydrochloric acid, 730ml of water and 480g of zinc powder to the reaction solution, keep the temperature at 18°C until the reaction is complete, the reaction solution turns off-white, then add 30% sodium hydroxide solution until the pH value of the reaction solution is 10 , kept at 5°C for 2 hours, crystals were precipitated, and 292g of crude 3-chlorophenylhydrazine was obtained by filtration.
[0047] ⑶ Purification
[0048] Dissolve 292g of crude 3-chlorophenylhydrazine in 5840g of water, heat it to 60°C to dissolve it completely...
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