Preparação de Acetaminofeno (Paracetamol)

Síntese de um analgésico por formação de ligação amida

Organic Synthesis Advanced (University) 80 min ~$18,00

Objetivo

Sintetizar acetaminofeno (paracetamol) pela acetilação de p-aminofenol com anidrido acético, demonstrando a formação de ligações amida.

Contexto

Acetaminophen is one of the world's most widely used over-the-counter analgesics. Its synthesis involves the reaction of p-aminophenol with acetic anhydride to form an amide bond. The reaction is selective for the amine group over the phenol group under mild conditions.

Avisos de segurança

  • Acetic anhydride is corrosive and has a strong odor
  • p-Aminophenol can cause skin irritation
  • Do not consume the product
  • Work in a fume hood

EPI necessário

goggles gloves lab_coat

Materiais

  • p-Aminophenol (1.5 g)
  • Acetic anhydride (2 mL)
    Corrosive
  • Distilled water (100 mL)
    Ice-cold for crystallization
  • Acetone (10 mL)
    For recrystallization

Equipamentos

250 mL Erlenmeyer flask Hot water bath Buchner funnel Filter flask Melting point apparatus Ice bath

Procedimento

1

Dissolve 1.5 g p-aminophenol in 15 mL distilled water in the Erlenmeyer flask. Warm gently if needed.

5 min Handle p-aminophenol with gloves
2

Add 2 mL acetic anhydride to the solution. Stir vigorously for 10 minutes.

10 min Fume hood — pungent vapors
3

Heat the mixture in a water bath at 70°C for 10 minutes to complete the reaction.

12 min
4

Cool the mixture in an ice bath until crystals form.

15 min
5

Collect crude product by vacuum filtration. Wash with cold water.

8 min
6

Recrystallize from hot water or acetone/water mixture. Cool slowly for larger crystals.

15 min
7

Collect purified crystals. Dry and determine melting point (pure: 168-170°C).

10 min
8

Calculate percent yield.

5 min

Resultados esperados

White crystalline solid with melting point 167-170°C. Typical yield is 70-85%. The product should be pure white; discoloration indicates impurities from p-aminophenol oxidation.

Limpeza

Do not consume the product. Dispose of organic waste properly. Rinse all glassware.

Detalhes

Categoria
Organic Synthesis
Dificuldade
Advanced (University)
Duração
80 min
Custo estimado
$18,00
Passos
8
Materiais
4

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Frequently Asked Questions

What is the objective of Preparação de Acetaminofeno (Paracetamol)?
Sintetizar acetaminofeno (paracetamol) pela acetilação de p-aminofenol com anidrido acético, demonstrando a formação de ligações amida.
How difficult is Preparação de Acetaminofeno (Paracetamol)?
This experiment is rated as Advanced (University). It takes approximately 80 minutes to complete.
What safety precautions are needed for Preparação de Acetaminofeno (Paracetamol)?
Key safety precautions include: Acetic anhydride is corrosive and has a strong odor; p-Aminophenol can cause skin irritation; Do not consume the product.
What materials are needed for Preparação de Acetaminofeno (Paracetamol)?
The main materials required are: p-Aminophenol, Acetic anhydride, Distilled water, Acetone.
What results should I expect from Preparação de Acetaminofeno (Paracetamol)?
White crystalline solid with melting point 167-170°C. Typical yield is 70-85%. The product should be pure white; discoloration indicates impurities from p-aminophenol oxidation.