| production method | with 4,4 '-diaminotriphenylmethane, 1-(p-sulfophenyl)-3-methyl-5-pyrazolone as a starting material, the former is first double nitrided, and then coupled with the latter to obtain the product. The final product was obtained by filtration and drying.. 400L of water, 30% of hydrochloric acid, 131.4 and 49.4 of 4,4 '-diaminotriphenylmethane were added to the diazonium Pan, stirred and dissolved, and cooled to 0 °c. A 30% sodium nitrite solution (26.2 NaNO2) was then added over 15min. After addition, stirring was continued for 45min to obtain diazo solution. Add 300L of water and 55kg of soda ash to the coupling pan, stir and dissolve, then add 90kg of 1- (p-sulfophenyl)-3-methyl-5-pyrazolone, stir and dissolve, the temperature is cooled to below 10 ℃, and the above diazo liquid is added within 40min, and the pH value is adjusted to about 7.5 with soda ash solution at the same time. After addition, stirring was continued for 1H, and then the temperature was raised to 90 ° C., salt was added for salting out, cooled to 75 ° C., filtered and dried to obtain about 310kg of product. |