Synthesis of p-Nitroaniline

To a 3-neck RBF add 34 g of acetanilide and 40 mL of glacial acetic acid, then heat with stirring to about 65°C to dissolve the acetanilide, then cool down to 40°C and add 50 mL of ice-cold sulfuric acid with stirring. Connect thermometer and addition funnel to the RBF. Cool down to 5°C in an ice bath, at the same time combine 20 mL of very cold nitric acid with 30 mL of very cold sulfuric acid, cool down to 0°C pour to the addition funnel. Start adding the nitration mixture slowly, the temperature must be kept below 20°C. After addition let the solution sit for 30 minutes, then pour the solution to 200 mL of ice water, stir for 5 minutes then filter. Recrystallize from water and ethanol mixture. Crude p-nitroacetamide has been prepared now.

Combine 100 mL of conc. HCl and the crude p-nitroacetamide to in a RBF, reflux gently for 25 minutes. Then pour the solution to 150 mL of water, cool down to room temperature. Then combine 100 mL of 30% ammonia, 400 mL of water and 250 g of ice, add the refluxed mixture and stir for few times, filter. Recrystallize in ethanol, precipitate the product in a freezer. Recrystallization partially removes the ortho isomer from the product.

Source

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Heating the combined reagents

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Sulfonation and nitration in cold

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The mixture was then cooled down

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Then it was poured into the ice water solution with some stirring

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Filtration of the crude product

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Reflux with the hydrochloric acid

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Pour the mixture to the ice ammonia water

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Filter

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Recrystallize in ethanol

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Pure recrystallized p-nitroaniline

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