Yield:569-61-9 70%

Reaction Conditions:

with hydrogenchloride in water at 140; for 5 h;Reagent/catalyst;Temperature;

Steps:

26
The preparation method of alkaline pay magenta is that methylene diphenylamine and aniline are catalyzed by catalytic oxidation in air using the catalyst, which comprises the following steps:(1) A mixture of methylene diphenylamine and aniline in a weight ratio of 20: 1 was placed in a four-necked flask to obtain a mixture A; four ports in a four-necked flask were provided with a condenser, a water separator, a thermometer and an air Introduction tube, four-necked flask with a stirrer;(2) mixing the mixture A with stirring in a concentration of 30% HCl to obtain solution B; wherein the weight of 30% HCl used is 0.77 times the weight of methylene aniline;(3) adding a catalyst to solution B to obtain solution C, the weight of which is 1% to 4% by weight of methylene aniline; the catalyst is cesium vanadate;(4) to the side of the solution C while heating into the air, to be heated to 140 when the temperature and continue to pass into the air for 5 hours until no moisture generated, the end of the reaction to get the material D;(5) the material D for azeotropic distillation to remove and recover excess aniline, get the crude, the crude material poured out of the four-necked flask, the crude will cool brittle;(6) grinding the crude product and stirring with a dilute hydrochloric acid solution to obtain a solution E of pH ≤ 1;(7) The solution E is continuously stirred for 6.5 hours and then filtered through celite. The filtrate is filtered to obtain solution F;(8) the solution F with 0.4mol / L NaOH solution and to PH = 5, the temperature is 24 , filter and filter cake after the filtrate to get the material G;(9) The material G was dissolved in boiling water of PH = 4, cooled to room temperature for 16 hours to crystallize, and finally filtered. The solid product was alkaline quasi-red crystals with a yield of 70%.

References:

SHANGYU RIYUEXING TECHNOLOGY CHEMICAL CO LTD;Zhang, Yongjian;Chen, Zengmao;Shi, Yufeng;Gu, Yaofu;Jin, Heixia CN105936752, 2016, A Location in patent:Paragraph 0323 - 0333

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