Methods of Diazotisation titration
Diazotization titration is a type of titration in which a primary aromatic amine is converted to its corresponding diazonium salt using nitrous acid (HNO2). The diazonium salt is then titrated with a suitable titrant to determine the concentration of the primary aromatic amine.
There are two commonly used methods for diazotization titration:
- Sandmeyer method: In this method, the primary aromatic amine is first treated with a mixture of sodium nitrite (NaNO2) and hydrochloric acid (HCl) to form the diazonium salt. The diazonium salt is then treated with copper (I) chloride (CuCl) to form the corresponding aryl chloride, which is a stable product that can be weighed or titrated. This method is used for the determination of primary aromatic amines such as aniline, toluidine, and naphthylamines.
- Kjeldahl method: In this method, the primary aromatic amine is first treated with excess sulfuric acid (H2SO4) and potassium permanganate (KMnO4) to oxidize the amine group to nitrogen gas (N2) and water. The liberated nitrogen gas is then measured using a suitable apparatus, and the amount of primary aromatic amine is determined from the volume of nitrogen gas evolved. This method is used for the determination of primary aromatic amines in the presence of other nitrogen-containing compounds.
Both methods have their advantages and disadvantages, and the choice of method depends on the specific requirements of the analysis. Diazotization titration is a useful method for the determination of primary aromatic amines, which are commonly used in the manufacture of dyes, pharmaceuticals, and other organic compounds.
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