Diazonium compounds are formed by disintegrating primary aromatic amines into diazo compounds. The synthetic dye industry used this process for the first time in 1853. Peter Griessin is credited with proposing the mechanism of this process. An aromatic amine reacts to form a diazonium salt in an acidic medium by reacting with sodium nitrite. Dye is the first substance to be measured using this technique.
R − NH2 + NaNO2 +HCl🡪 R − N+ ≡ N − Cl− + NaCl + H2O
A solution of amine is added to an acid solution at 0-5 °C accompanied by the addition of sodium nitrite. A reaction between the amine and nitrous acid results in the formation of nitrosamine, followed by tautomerization, which results in the water being lost. In diazonium, positive charges are displaced at ortho and para positions to stabilize the ions.
C6H5NH2 + NaNO2 + HCl C6H5N = NCl + NaCl + H2O
Theory
The reaction between sodium nitrite and hydrochloric acid produces sodium chloride and nitrous acid.
NaNO2 + HCl NaCl + HNO2
As a result of the reaction between the nitrous acid and the aromatic amine, the diazonium salt is obtained. In addition to nitrous acid, ammonium sulfate solution is added to remove excess nitrous acid.
R − NH2 + HNO2🡪 R − N = NH + H2O
Starch iodide paper produces a blue color when it comes into contact with the endpoint. To prepare this solution, mix starch mucilage with potassium iodide and soak the filtered paper in it.
2. Weigh a sample of 1 mg of sulphonamide accurately and dissolve it in 4ml of concentrated HCl and 10ml of distilled water. The 0.1 M Solution of Sodium Nitrite solution is then titrated with this solution after cooling to 15 °C. After one drop of the solution has been streaked on the starch iodide paper, until the blue color appears, you know you have reached the endpoint. Based on the following equation, the percentage content of the sulpha drug is determined:
3. Applied to the determination of chlorpheniramine.
4. To the five ml of HCl and the fifty ml of distilled water, the accurately weighed sample is added. After cooling the solution to 15°C, it is absorbed. Using starch iodide paper as an indicator, the solution is then titrated with the sodium nitrite solution at 0.1 N.
5. This is used to determine the amount of dopamine in a sample.
6. Procaine is determined with this substance.
7. Amphetamine is determined by using this reaction.
8. Procaine is determined by using this test.
9. For determining ephedrine.
10. This test is used in determining how much P-amino benzoic acid (vitamin B4) is present in food.
11. Method: Add 3 ml of HCl to 5 ml of distilled water after the accurately weighed sample is weighed. This solution is then cooled to 15 degrees Celsius. After the solution has been slowly titrated with sodium nitrite solution, starch iodide paper is used as an indicator to evaluate the titration.
12. The salt nitrate solution of 0.1 N with 0.01371 g of vitamin B4 is equal to 1 ml
Principle
This method involves reacting sodium nitrite with the aromatic primary amine in the sample to turn it into diazonium salt.R − NH2 + NaNO2 +HCl🡪 R − N+ ≡ N − Cl− + NaCl + H2O
A solution of amine is added to an acid solution at 0-5 °C accompanied by the addition of sodium nitrite. A reaction between the amine and nitrous acid results in the formation of nitrosamine, followed by tautomerization, which results in the water being lost. In diazonium, positive charges are displaced at ortho and para positions to stabilize the ions.
C6H5NH2 + NaNO2 + HCl C6H5N = NCl + NaCl + H2O
Theory
The reaction between sodium nitrite and hydrochloric acid produces sodium chloride and nitrous acid.
NaNO2 + HCl NaCl + HNO2
As a result of the reaction between the nitrous acid and the aromatic amine, the diazonium salt is obtained. In addition to nitrous acid, ammonium sulfate solution is added to remove excess nitrous acid.
R − NH2 + HNO2🡪 R − N = NH + H2O
Starch iodide paper produces a blue color when it comes into contact with the endpoint. To prepare this solution, mix starch mucilage with potassium iodide and soak the filtered paper in it.
KI + HCl KCl + HI
2HI + 2HNO2🡪 I2 + 2NO =2H2O
I2 + starch mucilage 🡪 blue colour end pointMethods
Following the transfer to the standard flask, the sample is weighed and processed as described above. Secondly, distilled water is added, followed by concentrated hydrochloric acid and potassium bromide. A standard solution is thereby formed. Pipette the standard solution out at the appropriate volume and maintain the temperature between 0 and 5 degrees Celsius. A sodium nitrite solution is then added to the solution and titrated until the starch iodide paper turns blue. Another procedure involves immersing the platinum electrodes after maintaining the flask's temperature. Once the electrodes are connected to the potentiometer, sodium nitrite solution is titrated slowly until a permanent deflection can be observed at the endpoint.Applications
1. Sulphonamides are determined using this method.2. Weigh a sample of 1 mg of sulphonamide accurately and dissolve it in 4ml of concentrated HCl and 10ml of distilled water. The 0.1 M Solution of Sodium Nitrite solution is then titrated with this solution after cooling to 15 °C. After one drop of the solution has been streaked on the starch iodide paper, until the blue color appears, you know you have reached the endpoint. Based on the following equation, the percentage content of the sulpha drug is determined:
3. Applied to the determination of chlorpheniramine.
4. To the five ml of HCl and the fifty ml of distilled water, the accurately weighed sample is added. After cooling the solution to 15°C, it is absorbed. Using starch iodide paper as an indicator, the solution is then titrated with the sodium nitrite solution at 0.1 N.
5. This is used to determine the amount of dopamine in a sample.
6. Procaine is determined with this substance.
7. Amphetamine is determined by using this reaction.
8. Procaine is determined by using this test.
9. For determining ephedrine.
10. This test is used in determining how much P-amino benzoic acid (vitamin B4) is present in food.
11. Method: Add 3 ml of HCl to 5 ml of distilled water after the accurately weighed sample is weighed. This solution is then cooled to 15 degrees Celsius. After the solution has been slowly titrated with sodium nitrite solution, starch iodide paper is used as an indicator to evaluate the titration.
12. The salt nitrate solution of 0.1 N with 0.01371 g of vitamin B4 is equal to 1 ml
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