Pharmaceutical Analysis

Chapter 4

Diazotization Titrations

INTRODUCTION

The diazotization titration is nothing but the conversion of the primary aromatic amine to a diazonium compound. This process was first discovered in 1853 and was applied to the synthetic dye industry. The reaction mechanism was first proposed by Peter Griessin. In this method, the primary aromatic amine is reacted with the sodium nitrite in acidic medium to form a diazonium salt. This method is first used in the determination of dyes.

PRINCIPLE

The principle involved in this method is that the primary aromatic amine present in the sample reacts with the sodium nitrite in the presence of acid such as hydrochloric acid to obtain a diazonium salt.

 

R − NH₂ + NaNO₂ +HCl R − N⁺ ≡ N − Cl⁻ + NaCl + ...