The production principle and technological process of scarlet sodium salt

Scarlet sodium salt is also known as 6,6'-ureylene bis(1-naphthol-3-sulfonic acid sodium salt) [6,6'-ureylene-bis(1-naph-thol-3-sulfonic acid sodium salt) ], J acid urea sodium salt, molecular formula is C ₂₁ H ₁₄ N ₂ Na ₂ O ₉ S ₂ , molecular weight is 548.
46, structural formula is

1.
Product performance

Light gray paste; easily soluble in alkali solution and soluble in water
.

2.
Production principle

After salting 2-amino-5-naphthol-7-sulfonic acid (J acid) with caustic soda, it is condensed with phosgene under alkaline conditions, and then salted out and suction filtered to obtain scarlet sodium salt
.

3.
Process flow

4.
Technical formula (kg/t)

5.
Main equipment

Salt forming pot, condensation pot, spray tower, suction filter, storage tank
.

6.
Production process

In the salt-forming pot, add 1200L of water and 180kg of 30% liquid caustic soda.
After heating to 80°C, add 330kg (100%) of J acid, add water to a total volume of 2800L, stir and mix uniformly, and all dissolve
.
The material was cooled to 30°C, and phosgene was introduced for 4 hours, and the reaction temperature was controlled at 40°C.

7.