Operation manual of chromotropic acid

This product is made by treating H acid and dilute sulfuric acid under pressure. Chromotropic acid is the intermediate of dye acid medium dark blue. The dye can be used for dyeing wool fabrics and is obtained by coupling 4-chloro-o-aminophenol with Chromotropic Acid after diazotization. It is used to produce azo dyes and anthraquinone dyes. It is an intermediate of azo dyes and used as a reagent. It is used for the determination of chromium, titanium and formaldehyde, and for the determination of chromium, mercury, silver, titanium, chlorate, formaldehyde, nitrate and nitrite.

1、 Basic information

Chinese Name: 1,8-dihydroxynaphthalene-3,6-disulfonic acid

Chromotropic acid; colorimetric acid; chromic acid; 1,8-dihydroxynaphthalene-3,6-disulfonic acid; 4,5-dihydroxynaphthalene-2,7-disulfonic acid

English Name: 4,5-dihydroxynaphthalene-2,7-disulphonic acid

CAS No: 148-25-4

EINECS No: 205-712-7

Molecular formula: c10h8o8s2

Molecular weight: 320.2957

Structural formula:

2、 Physicochemical properties

Light brown to grayish green powder, soluble in water, easy to change color when exposed to air. It turns green in the presence of ferric chloride solution.

3、 Technical index

Appearance: light brown to grayish green powder

Level: analysis pure ar

Content: ≥ 99%

Solubility: qualified

Sensitivity: acceptable

Water insoluble content: below 0.01%

Specification: 500g, 25kg

4、 Detection method

1. Content

Weigh 0.1000g to 0.1500g of chromotropic acid sample powder, standard sample of chromotropic acid and standard sample of H acid with 0.0001g analytical balance, put them into three 100ml clean volumetric flasks, dilute them with mobile phase, and detect by HPLC that the purity of chromotropic acid is above 99%, and the content of H acid is below 0.1%.

2. Solubility

Weigh 5.0g sample of chromotropic acid, put it in a 250ml flask, add 100ml deionized water, and stir it in a water bath at 25 ℃ for 15min. The solution is uniform and transparent by visual inspection.

3. Sensitivity

Solution A: transfer 1ml of 35% formaldehyde aqueous solution, place it in 2000ml volumetric flask, and dilute it with deionized water.

Solution B: weigh 0.0500g chromotropic acid with analytical balance, put it in a 100ml volumetric flask, and dissolve it with 70% sulfuric acid.

Turn on the constant temperature water bath, set the water temperature at 65 ℃, after preheating, transfer 2ml of solution a and 50ml of solution B into a 250ml conical flask, and heat it in the water bath. After 10-15 minutes, the solution in the conical flask turns purple.

4. Water insoluble content

Weigh 5g chromotropic acid sample into a 500ml conical flask, measure 1500g deionized water, and filter with a flat glass sand core funnel and water filter membrane to remove impurities. Add 500ml deionized water into the 500ml conical flask and stir to dissolve.

Take a clean water filter membrane, weigh it to 0.0001g with an analytical balance, filter the solution in the conical flask with the filter membrane and a flat glass sand core funnel, and then wash it with 1000ml deionized water to remove impurities for three times. After washing, take out the filter paper, put it in a clean Petri dish, dry it in a vacuum drying oven, set the temperature at 100 ℃, vacuum at 0.06mpa, and dry it to constant weight. Then take out the filter paper and weigh it with analytical balance to 0.0001g.

Insoluble impurity content = (dry filter paper after filtration - filter paper before filtration) / sampling weight × 100%

5、 Storage and transportation

1. It should be stored in a cool and ventilated warehouse. The temperature should not exceed 37 ° C. It should be kept away from light.

2. It should be stored separately from oxidants and edible chemicals, avoid mixed storage, and keep away from fire and heat source.

3. It is easy to change color in the air. It is forbidden to be exposed in the air for a long time.

4. Transport vehicles shall be equipped with corresponding varieties and quantities of fire fighting equipment and leakage emergency treatment equipment.

5. It is strictly forbidden to mix with oxidants, edible chemicals, etc.

6. During transportation, it should be protected from sun, rain and high temperature. During stopover, keep away from fire, heat source and high temperature area.

6、 First aid measures

Inhalation: if inhaled, move the patient to fresh air.

Skin contact: take off contaminated clothes and wash skin thoroughly with soapy water and water. If you feel unwell, see a doctor.

Eye clear contact: separate eyelids, wash with flowing water or normal saline. See a doctor immediately.

Ingestion: gargle, do not induce vomiting. See a doctor immediately.