Solvent Red 24 synthesis

Yield:85-83-6 97.23%

Reaction Conditions:

Stage #1:o-aminoazotoluene with hydrogenchloride in water at 20; for 0.5 h;
Stage #2: with sodium nitrate in water at 3; for 4 h;
Stage #3:β-naphthol in water for 3 h;Temperature;

Steps:

7.2 Step 2 Synthesis of double coupling
In a 500 ml four-necked flask with mechanical stirring and a thermometer, 15.6 g of the single coupling produced in the first embodiment was added, and 21 g of 30% hydrochloric acid was added dropwise at 20 ° C, and the mixture was dropped for 30 minutes.Cool down to 3 ° C, add 27.5 g of 20% sodium nitrate solution, and keep warm for 4 h.Then, 80.25 g of a mixed solution of 2-naphthol and 5% liquid alkali was added dropwise.Control the temperature, after 1 hour, after 2 hours,Then adjust the pH with 5% liquid alkali 20g, keep warm for 5h, retest PH=8, filter,The filter cake was washed with hot water to neutrality. The filter cake was beaten with 1% liquid alkali for 2 hours, filtered, and the filter cake was washed with hot water until neutral. The cake was then beaten with 1% hydrochloric acid for 2 hours, filtered, and the filter cake was washed with hot water until neutral. 25.11 g, purity 92.36%, yield 97.23%, DC -0.03, DH 0.11 strength 96.91.

References:

Jiangsu Daobo Chemical Co., Ltd.;Zhang Yunbing;Xu Song;Liu Xuefeng;Wang Gang CN108659569, 2018, A Location in patent:Paragraph 0016; 0031; 0034; 0035; 0036; 0037

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