- Preparation method of N-phenyl-1- naphthylamino-8-sulfonic acid
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The invention discloses a preparation method of N-phenyl-1- naphthylamino-8-sulfonic acid, which comprises the following steps: 1. condensation: adding aniline into a pot, starting stirring, adding concentrated sulfuric acid, adding 1-naphthylamino-8-sulfonic acid, dehydrating, and condensing at 155+/-2 DEG C; 2. neutralization: adding a soda ash solution to perform neutralization, transferring into a neutralization pot, and regulating the material of the material to 9-11; 3. vapor distillation: regulating the volume of the material with aniline water, adding vat powder to perform vapor distillation, and carrying out extraction when the aniline content in the solution is less than 3+/-0.5%, wherein the aniline content of 2-4% in the solution is used as the switch point; 4. decolorization: starting stirring, regulating the pH value of the liquid to 6.5-7.0, adding activated carbon, and heating to 94-95 DEG C; and 5. acid precipitation: adding dilute sulfuric acid until the residual acid content of the acid precipitation solution is 1.8-2.0%, cooling, discharging to obtain the N-phenyl-1- naphthylamino-8-sulfonic acid, and washing with 1.0-2.0% acid water twice.
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Paragraph 0037; 0038; 0039; 0040; 0041; 0042
(2016/10/27)
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