Síntese de Luminol

Criação de um composto quimioluminescente a partir do ácido 3-nitrofrálico

Organic Synthesis Professional (Lab) 120 min ~$30,00

Objetivo

Sintetizar luminol (3-aminoftalihidrazida) e demonstrar sua reação quimioluminescente com peróxido de hidrogênio.

Contexto

Luminol is a chemiluminescent compound used in forensic science to detect trace amounts of blood. It is synthesized by reacting 3-nitrophthalic acid with hydrazine, followed by reduction of the nitro group with sodium dithionite. When oxidized by hydrogen peroxide in the presence of a catalyst, luminol emits blue light.

Avisos de segurança

  • Hydrazine is toxic and a suspected carcinogen — handle with extreme care in fume hood
  • Sodium dithionite generates SO₂ — use in fume hood
  • NaOH is corrosive
  • Wear nitrile gloves and goggles throughout

EPI necessário

goggles gloves lab_coat

Materiais

  • 3-Nitrophthalic acid (1 g)
  • Hydrazine hydrate (10%) (3 mL)
    Toxic
  • Triethylene glycol (5 mL)
    High-boiling solvent
  • Sodium dithionite (Na₂S₂O₄) (3 g)
    Reducing agent
  • Sodium hydroxide (NaOH) (5 mL)
    10% solution
  • Hydrogen peroxide (H₂O₂) (10 mL)
    3% for chemiluminescence test
  • Potassium ferricyanide (0.1 g)
    Catalyst for glow test

Equipamentos

Round-bottom flask (50 mL) Reflux condenser Hot plate Buchner funnel Filter flask Darkened room Test tubes

Procedimento

1

Dissolve 1 g 3-nitrophthalic acid in 5 mL triethylene glycol in the round-bottom flask. Heat to 100°C.

5 min Fume hood required
2

Add 3 mL of 10% hydrazine hydrate. Attach the reflux condenser and heat at 130-140°C for 30 minutes.

35 min Hydrazine is toxic — fume hood essential
3

Cool the mixture. Add 15 mL hot water and 3 mL 10% NaOH.

5 min
4

Add 3 g sodium dithionite to reduce the nitro group. Heat at 80°C for 10 minutes.

12 min SO₂ released — fume hood
5

Acidify the solution with glacial acetic acid until luminol precipitates.

5 min
6

Collect the luminol by vacuum filtration. Wash with cold water and dry.

10 min
7

Test chemiluminescence: dissolve a small amount of luminol in 5 mL of dilute NaOH. In a darkened room, add H₂O₂ and a trace of potassium ferricyanide.

5 min
8

Observe the blue glow. Record intensity and duration.

3 min

Resultados esperados

A pale yellow solid (luminol). When tested with H₂O₂ and ferricyanide catalyst in a dark room, an intense blue chemiluminescent glow should last for 15-30 seconds. The glow confirms successful synthesis.

Limpeza

Dispose of hydrazine waste in designated hazardous waste container. Neutralize acids and bases. Rinse all glassware thoroughly. Decontaminate work area.

Detalhes

Categoria
Organic Synthesis
Dificuldade
Professional (Lab)
Duração
120 min
Custo estimado
$30,00
Passos
8
Materiais
7

Mais experimentos

Condensação Aldólica (Dibenzalacetona) 75 min Esterificação de Fischer do Acetato de Etila 90 min Extração de Cafeína do Chá 90 min Fabricação de Nylon 6,10 (Truque da Corda de Nylon) 30 min Fabricação de Sabão por Saponificação 60 min Preparação de Acetaminofeno (Paracetamol) 80 min Produção de Biodiesel a partir de Óleo Vegetal 60 min Síntese de Aspirina (Ácido Acetilsalicílico) 90 min Síntese de Óleo de Banana (Acetato de Isoamila) 90 min Síntese de Slime (PVA Reticulado) 20 min

Frequently Asked Questions

What is the objective of Síntese de Luminol?
Sintetizar luminol (3-aminoftalihidrazida) e demonstrar sua reação quimioluminescente com peróxido de hidrogênio.
How difficult is Síntese de Luminol?
This experiment is rated as Professional (Lab). It takes approximately 120 minutes to complete.
What safety precautions are needed for Síntese de Luminol?
Key safety precautions include: Hydrazine is toxic and a suspected carcinogen — handle with extreme care in fume hood; Sodium dithionite generates SO₂ — use in fume hood; NaOH is corrosive.
What materials are needed for Síntese de Luminol?
The main materials required are: 3-Nitrophthalic acid, Hydrazine hydrate (10%), Triethylene glycol, Sodium dithionite (Na₂S₂O₄), Sodium hydroxide (NaOH).
What results should I expect from Síntese de Luminol?
A pale yellow solid (luminol). When tested with H₂O₂ and ferricyanide catalyst in a dark room, an intense blue chemiluminescent glow should last for 15-30 seconds. The glow confirms successful synthesis.