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What is the step-by-step procedure for preparation of 2-chloro-4-nitroaniline from aniline and chlorine gas, including the appropriate reaction conditions, safety measures, and expected yield of the product?

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The preparation of 2-chloro-4-nitroaniline from aniline and chlorine gas involves a two-step process: nitration of aniline followed by chlorination of the resulting 4-nitroaniline. Here's the step-by-step procedure:Step 1: Nitration of aniline1. Dissolve 10 g of aniline in 50 mL of concentrated hydrochloric acid  HCl  to form anilinium chloride.2. Cool the solution in an ice bath to maintain a temperature below 5C.3. Slowly add a nitrating mixture of 25 mL concentrated sulfuric acid  H2SO4  and 25 mL concentrated nitric acid  HNO3  to the anilinium chloride solution, while maintaining the temperature below 5C.4. Stir the reaction mixture for 30 minutes, maintaining the temperature below 5C.5. Pour the reaction mixture into 200 mL of crushed ice and water, and allow the precipitate to form.6. Filter the precipitate and wash it with cold water to obtain crude 4-nitroaniline.7. Recrystallize the crude 4-nitroaniline from hot water to obtain pure 4-nitroaniline.Step 2: Chlorination of 4-nitroaniline1. Dissolve 10 g of 4-nitroaniline in 100 mL of glacial acetic acid.2. Cool the solution in an ice bath to maintain a temperature below 5C.3. Slowly bubble chlorine gas  Cl2  into the solution, while maintaining the temperature below 5C, until the solution turns yellowish-green.4. Stir the reaction mixture for 30 minutes, maintaining the temperature below 5C.5. Pour the reaction mixture into 200 mL of crushed ice and water, and allow the precipitate to form.6. Filter the precipitate and wash it with cold water to obtain crude 2-chloro-4-nitroaniline.7. Recrystallize the crude 2-chloro-4-nitroaniline from hot water to obtain pure 2-chloro-4-nitroaniline.Safety measures:1. Wear appropriate personal protective equipment, including gloves, goggles, and a lab coat.2. Perform the experiment in a well-ventilated area or under a fume hood, as chlorine gas is toxic and corrosive.3. Be cautious when handling concentrated acids, as they can cause severe burns.Expected yield:The yield of 2-chloro-4-nitroaniline depends on the efficiency of the nitration and chlorination steps. Typically, the yield for nitration is around 70-80%, and the yield for chlorination is around 60-70%. Overall, the expected yield for the synthesis of 2-chloro-4-nitroaniline from aniline is approximately 40-50%.
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