preparation method of 3-nitrophenylhydrazine hydrochloride_kain industrial additive

background and overview^[1][2]

3-nitrophenylhydrazine hydrochloride is an aromatic organic compound and an important pharmaceutical intermediate. the existing technology uses m-nitroaniline as raw material, undergoes diazotization reaction, sodium sulfite reduction, hydrolysis, and salt formation to prepare the hydrochloride of m-nitrophenylhydrazine. the reaction time is long, and the generally required yield is only 63-72%, and the production cost is high.

structure

preparation method^[1-2]

a method for preparing 3-nitrophenylhydrazine hydrochloride, which uses m-nitroaniline as a starting material, undergoes diazotization reaction, reduction reaction, and hydrolysis to prepare m-nitrophenylhydrazine, which is formed with hydrochloric acid. the salt is obtained to obtain 3-nitrophenylhydrazine hydrochloride. the reduction reaction uses sodium metabisulfite as the reducing agent at 10-35°c and a ph of 7-9. the temperature of the reduction reaction is preferably 20°c, and the ph is preferably 7. the specific steps are as follows:

1) add 110ml of water to an 800ml beaker, stir, add 126.5ml of 10n hydrochloric acid and 60g of m-nitroaniline, heat to 90°c to dissolve them all, then slowly cool the solution to 0°c, quickly add submersible sodium nitrate solution (made up of 30 grams of sodium nitrite and 15 ml of water) is added. adjust the ph of the system to 1-2. control the temperature of the reaction system to 5°c-7°c. after 30 minutes of reaction, stop the reaction, filter and keep it. filtrate.

2) add 250ml of water to a 2000ml beaker, add 128g of sodium metabisulfite and 143g of sodium hydroxide while stirring. at this time, the ph of the solution is 7 and the temperature of the solution is 35°c. after the solution cools to 18°c, slowly add the above filtrate. when the addition is complete, the solution temperature is 20°c and the ph is 7. continue the reaction for 30 minutes. warm the reaction system to 30-40°c, stir, add 80.5ml of hydrochloric acid, continue to heat to 75-80°c, and after reacting at this temperature for 1.5-2 hours, 40 grams of sodium chloride was added, the system was cooled to 20°c, filtered to retain the filter cake and dried to obtain the product. the purity measured by high performance liquid chromatography was 98.42%.

main reference materials

[1] cn200710135393.7 apreparation method of 3-nitrophenylhydrazine hydrochloride