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2-amino-8-naphthol-6-sulfonic acid (2-amino-8-naphthol -6-sulfonic acid) , also known as y acid, 7-amino-1-naphthol-3-sulfonic acid, 6-amino - 4-hydroxynaphthalene-2-sulfonic acid, molecular formula is C 10 H 9 NO 4 S, molecular weight is 239.
25, structural formula is
1.
Product performance
White needle-like crystals, or off-white crystalline powder; insoluble in water, soluble in ethanol , ether and sodium carbonate solution; its alkaline solution has blue fluorescence and can be oxidized in the air; its acidic solution meets ferric chloride It is reddish brown, dark red in case of bleaching powder; poisonous
.
2.
Production principle
The potassium salt of 2-naphthol-6,8-disulfonate (G salt) is alkali-melted with NaOH and then acidified
.
The acidified product is ammoniated with ammonia to obtain 2-amino-8-naphthol-6-ammonium sulfonate, and finally the product is obtained by acid precipitation
3.
Process flow
4.
Technical formula (kg/t)
5.
Main equipment
Alkali fusion reactor, acidification pot, storage tank, ammoniation reactor, acid precipitation tank, filter
.
6.
Production process
Put 408kg of 98% sodium hydroxide into the alkali fusion reactor and heat it to melt
.
Gradually add G sodium salt solution (1194kg 70% G acid and 132kg 98% caustic soda to make 1300L) at 200～230℃, add it in 3～4h, heat up to 245～250℃, keep the reaction temperature for 4h, add the reactants Dilute in water
In the acidification pot, adjust the volume of the alkali-melted dilution to 2000L, and pass SO 2 at 60-90°C to neutralize the pH to 10 o'clock
.
Filter off the by-product sodium sulfite, and continue to neutralize to pH 6.
Adjust the volume of the acidified liquid to 2000L, add 1280L of 20% ammonia water, airtightly raise the temperature to 140℃, the pressure is close to 0.
7MPa, and ammoniated for 4h
.
In the acid precipitation tank, adjust the volume of the ammoniated solution to 5600L, add 93% sulfuric acid at 70°C until the Congo red test paper is acidic, and the released SO 2 is used for neutralization
.
Blow in air, drive off the SO 2 and filter, and the filter cake will be 2-amino-8-naphthol-6-sulfonic acid after washing
7.
Product Standard
8.
Product use
Dye intermediates, used in the manufacture of reactive dyes and direct dyes, such as direct red F, direct purple GB, direct purple N, direct dark brown M, direct gray D, direct light fast gray B, direct diazo black BH, etc.
Manufacturing
.
9.
Safety measures
(1) Toxic and highly corrosive raw materials are used in production, the equipment should be sealed, the operators should wear labor protection equipment, and the ventilation in the workshop should be strengthened
.
(2) This product is toxic.
It is packed in iron drum lined with plastic bag and stored in a cool and ventilated place to prevent sunlight and heat
.
Store and transport in accordance with toxic chemicals regulations
Related links: Production process and product standard of 2-amino-5-naphthol-7-sulfonic acid
