The synthesis of 2-chloro-4-nitroaniline from aniline involves two main steps: nitration and chlorination. 1. Nitration: In this step, aniline reacts with a nitrating agent, typically a mixture of concentrated sulfuric acid H2SO4 and concentrated nitric acid HNO3 , to form 4-nitroaniline.Aniline + HNO3 4-Nitroaniline + H2OOptimal conditions for nitration:- Temperature: 0-5C to minimize the formation of undesired by-products - Time: 30-60 minutes- Concentration: Aniline 1 equivalent , H2SO4 1 equivalent , HNO3 1 equivalent 2. Chlorination: In this step, 4-nitroaniline reacts with chlorine gas Cl2 in the presence of a catalyst, such as cupric chloride CuCl2 , to form 2-chloro-4-nitroaniline.4-Nitroaniline + Cl2 2-Chloro-4-nitroaniline + HClOptimal conditions for chlorination:- Temperature: 40-60C to ensure good reaction rate while minimizing side reactions - Time: 2-4 hours- Concentration: 4-Nitroaniline 1 equivalent , Cl2 1.1-1.2 equivalents, to ensure complete reaction , CuCl2 0.01-0.1 equivalents, as a catalyst Please note that these conditions are general guidelines and may need to be optimized for specific cases. Additionally, it is important to carry out the reaction in a well-ventilated area or a fume hood, as both nitric acid and chlorine gas are hazardous.