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Bromination of Acetanilide Precautions: Ethanol is flammable. Sodium hypochlorite is an oxidizing agent (handle in the fume hood) Acetic acid is corrosive and harmful if inhaled (handle in the fume hood). Safety goggles are required. Gloves are recommended. Purpose To convert acetanilide to p-bromoacetanilide using in situ generation of bromine. A reaction that demonstrates “green” chemistry. Typically bromination is carried out using bromine and a Lewis Acid catalyst (such as FeBr3) for electrophilic aromatic substitution to afford a brominated aromatic ring. Here, instead of starting with a large quantity of bromine, which is toxic, we are generating it in situ. By this method, there will be small amounts of bromine in the reaction mixture that should be consumed upon reaction until the reaction is completed. Bromine is generated by a series of redox reactions involving acetic acid, bleach and sodium bromide. Please see supplemental material at the end of the lab manual taken from “Laboratory Techniques in Organic Chemistry” by Mohrig, et al. p 22-24. Reaction Scheme: [structure] NaBr, NaClO -> [brominated product] EtOH/CH3COOH Procedure: Place 95% ethanol (6 mL) and acetic acid (5 mL) in a 125 mL Erlenmeyer flask. Add acetanilide (7.4 mmol) and sodium bromide (1.8 g); swirl until both dissolve. Place the reaction flask in an ice bath (at least 5 °C) for 5 minutes (keep this reaction in the hood). Add sodium hypochlorite (8.3 mmol) by addition of household bleach; leave the reaction flask in the ice bath approximately 5 min. Remove the flask from the ice bath and place a watch glass over the opening, allow the reaction mixture to come to room temperature over 15 minutes. Place the reaction flask into the ice bath and quench the unreacted bromine by the addition of both 5 mL of sodium thiosulfate solution (1 g/5 mL solution) and 5 mL sodium hydroxide solution (1 g/5 mL solution); collect the product by suction filtration. Recrystallize the brominated product from ethanol. Due to variation of solvent, you will need to select a solvent for recrystallization (see Laboratory Techniques in Organic Chemistry). To purify the product, test the solubility of your compound in small amounts of various solvents in test tubes using a water bath to heat organic solvent. Remember to use a spatula with the size of the tip of a matchstick. NEVER heat organic solvents directly on a hot plate. Collect the pure product by filtration.

Bromination of Acetanilide

Precautions:
Ethanol is flammable.
Sodium hypochlorite is an oxidizing agent (handle in the fume hood)
Acetic acid is corrosive and harmful if inhaled (handle in the fume hood).
Safety goggles are required. Gloves are recommended.

Purpose
To convert acetanilide to p-bromoacetanilide using in situ generation of bromine. A reaction that demonstrates “green” chemistry. Typically bromination is carried out using bromine and a Lewis Acid catalyst (such as FeBr3) for electrophilic aromatic substitution to afford a brominated aromatic ring. Here, instead of starting with a large quantity of bromine, which is toxic, we are generating it in situ. By this method, there will be small amounts of bromine in the reaction mixture that should be consumed upon reaction until the reaction is completed. Bromine is generated by a series of redox reactions involving acetic acid, bleach and sodium bromide.

Please see supplemental material at the end of the lab manual taken from “Laboratory Techniques in Organic Chemistry” by Mohrig, et al. p 22-24.

Reaction Scheme:

[structure] NaBr, NaClO -> [brominated product]
EtOH/CH3COOH

Procedure:
Place 95% ethanol (6 mL) and acetic acid (5 mL) in a 125 mL Erlenmeyer flask. Add acetanilide (7.4 mmol) and sodium bromide (1.8 g); swirl until both dissolve. Place the reaction flask in an ice bath (at least 5 °C) for 5 minutes (keep this reaction in the hood). Add sodium hypochlorite (8.3 mmol) by addition of household bleach; leave the reaction flask in the ice bath approximately 5 min. Remove the flask from the ice bath and place a watch glass over the opening, allow the reaction mixture to come to room temperature over 15 minutes. Place the reaction flask into the ice bath and quench the unreacted bromine by the addition of both 5 mL of sodium thiosulfate solution (1 g/5 mL solution) and 5 mL sodium hydroxide solution (1 g/5 mL solution); collect the product by suction filtration. Recrystallize the brominated product from ethanol. Due to variation of solvent, you will need to select a solvent for recrystallization (see Laboratory Techniques in Organic Chemistry). To purify the product, test the solubility of your compound in small amounts of various solvents in test tubes using a water bath to heat organic solvent. Remember to use a spatula with the size of the tip of a matchstick. NEVER heat organic solvents directly on a hot plate. Collect the pure product by filtration.

Bromination of Acetanilide

Precautions:
Ethanol is flammable.
Sodium hypochlorite is an oxidizing agent (handle in the fume hood)
Acetic acid is corrosive and harmful if inhaled (handle in the fume hood).
Safety goggles are required. Gloves are recommended.

Purpose
To convert acetanilide to p-bromoacetanilide using in situ generation of bromine. A reaction that demonstrates “green” chemistry. Typically bromination is carried out using bromine and a Lewis Acid catalyst (such as FeBr3) for electrophilic aromatic substitution to afford a brominated aromatic ring. Here, instead of starting with a large quantity of bromine, which is toxic, we are generating it in situ. By this method, there will be small amounts of bromine in the reaction mixture that should be consumed upon reaction until the reaction is completed. Bromine is generated by a series of redox reactions involving acetic acid, bleach and sodium bromide.

Please see supplemental material at the end of the lab manual taken from “Laboratory Techniques in Organic Chemistry” by Mohrig, et al. p 22-24.

Reaction Scheme:

[structure] NaBr, NaClO -> [brominated product]
EtOH/CH3COOH

Procedure:
Place 95% ethanol (6 mL) and acetic acid (5 mL) in a 125 mL Erlenmeyer flask. Add acetanilide (7.4 mmol) and sodium bromide (1.8 g); swirl until both dissolve. Place the reaction flask in an ice bath (at least 5 °C) for 5 minutes (keep this reaction in the hood). Add sodium hypochlorite (8.3 mmol) by addition of household bleach; leave the reaction flask in the ice bath approximately 5 min. Remove the flask from the ice bath and place a watch glass over the opening, allow the reaction mixture to come to room temperature over 15 minutes. Place the reaction flask into the ice bath and quench the unreacted bromine by the addition of both 5 mL of sodium thiosulfate solution (1 g/5 mL solution) and 5 mL sodium hydroxide solution (1 g/5 mL solution); collect the product by suction filtration. Recrystallize the brominated product from ethanol. Due to variation of solvent, you will need to select a solvent for recrystallization (see Laboratory Techniques in Organic Chemistry). To purify the product, test the solubility of your compound in small amounts of various solvents in test tubes using a water bath to heat organic solvent. Remember to use a spatula with the size of the tip of a matchstick. NEVER heat organic solvents directly on a hot plate. Collect the pure product by filtration.

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