Instruction manual of disodium chromotropic acid

1、 Basic information

Disodium chromotropic acid

Chinese alias: sodium chromotropic acid, sodium 1,8-dihydroxynaphthalene-3,6-disulfonate, sodium 4,5-dihydroxynaphthalene-2,7-disulfonate dihydrate

English Name: 4,5-dihydroxynaphthalene-2,7-disulfonic acid, disodium salt hydrate

CAS No.: 5808-22-0

EINECS No.: 204-972-9

Molecular formula: c10h6na2o8s2 · 2H2O

Molecular weight: 400.29

Melting point: 300 ℃

Boiling point: 176-177 ℃

Flash point: 164 ℃

2、 Physicochemical properties

Disodium chromotropic acid is white to gray, beige to light brown powder, easy to change color in contact with air, easily soluble in water, slightly soluble in ethanol, the solution is light brown, irritant

3、 Purpose

Biochemical research and organic synthesis. Spectrophotometric Determination of chromium, titanium and formaldehyde. Determination of chromium, mercury, silver, titanium, chlorate, formaldehyde, nitrate and nitrite. Determination of methylene dioxy by TLC. Determination of ethylene glycol in biomaterials.

4、 Technical index

Projects

Standard value

appearance

Light grey to light brown powder

Purity%

Above 98.5

Water soluble state

pass the test

Water content%

8% - 10%

Suitability of formaldehyde analysis

pass the test

5、 Detection method

1. Purity

Potentiometric titration

Weigh 0.6g (to 0.0001g) of the dried sample, put it into a 100ml beaker, add 50ml of pure water to dissolve the sample, and titrate it with 0.1mol/l sodium hydroxide standard solution by potentiometric titrator (for determination of titration method and end point, refer to GB / T 9725)

The consumption of 0.1mol/l NaOH is 1ml, which is equivalent to 0.04003g c10h6na2o8s2 · 2H2O

2. Solubility

Weigh 5.0g of disodium chromotropic acid sample, 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. Water content

Karl Fischer titration

4. Formaldehyde analysis

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 of disodium 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.

6、 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.

7、 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.