Condensación Aldólica (Dibenzalacetona)

Síntesis de un compuesto absorbente de UV usado en protectores solares

Organic Synthesis Advanced (University) 75 min ~$18,00

Objetivo

Sintetizar dibenzalacetona mediante una condensación aldólica cruzada entre benzaldehído y acetona, demostrando la formación de enlaces carbono-carbono.

Antecedentes

The aldol condensation is one of the most important carbon-carbon bond-forming reactions in organic chemistry. Dibenzalacetone is formed by the double aldol condensation of benzaldehyde with acetone under basic conditions. The bright yellow product absorbs UV light and was once used in sunscreen formulations.

Advertencias de seguridad

  • NaOH is corrosive
  • Benzaldehyde is an irritant with a strong almond odor
  • Acetone is flammable
  • Work in a fume hood

EPP requerido

goggles gloves lab_coat

Materiales

  • Benzaldehyde (5 mL)
    Fresh, not oxidized
  • Acetone (1.5 mL)
  • Sodium hydroxide (NaOH) (25 mL)
    10% solution
  • Ethanol (20 mL)
    95%
  • Distilled water (100 mL)
    Ice-cold

Equipamiento

250 mL Erlenmeyer flask Buchner funnel Filter flask Vacuum pump Melting point apparatus Ice bath Magnetic stirrer

Procedimiento

1

Dissolve 5 mL benzaldehyde in 20 mL ethanol in the Erlenmeyer flask.

3 min Fume hood — benzaldehyde is an irritant
2

Add 1.5 mL acetone to the flask and stir.

2 min
3

Slowly add 25 mL of 10% NaOH while stirring. A yellow precipitate should begin forming.

5 min NaOH is corrosive
4

Stir the mixture at room temperature for 30 minutes.

30 min
5

Cool the flask in an ice bath for 10 minutes to maximize crystallization.

10 min
6

Collect the yellow crystals by vacuum filtration. Wash with cold water.

10 min
7

Dry the product and determine the melting point (pure dibenzalacetone: 110-112°C).

10 min
8

Calculate the percent yield.

5 min

Resultados esperados

Bright yellow crystals with a melting point of 109-112°C. Typical yield is 60-80%. The product absorbs UV light strongly, which can be confirmed if a UV lamp is available.

Limpieza

Dispose of organic waste in designated containers. Neutralize NaOH waste. Rinse all glassware.

Detalles

Categoría
Organic Synthesis
Dificultad
Advanced (University)
Duración
75 min
Costo estimado
$18,00
Pasos
8
Materiales
5

Más experimentos

Esterificación de Fischer del Acetato de Etilo 90 min Extracción de Cafeína del Té 90 min Fabricación de Jabón por Saponificación 60 min Fabricación de Nylon 6,10 (Truco del Hilo de Nylon) 30 min Preparación de Acetaminofén (Paracetamol) 80 min Producción de Biodiésel a partir de Aceite Vegetal 60 min Síntesis de Aceite de Plátano (Acetato de Isoamilo) 90 min Síntesis de Aspirina (Ácido Acetilsalicílico) 90 min Síntesis de Luminol 120 min Síntesis de Slime (PVA Entrecruzado) 20 min

Preguntas frecuentes

What is the objective of Condensación Aldólica (Dibenzalacetona)?
Sintetizar dibenzalacetona mediante una condensación aldólica cruzada entre benzaldehído y acetona, demostrando la formación de enlaces carbono-carbono.
How difficult is Condensación Aldólica (Dibenzalacetona)?
This experiment is rated as Advanced (University). It takes approximately 75 minutes to complete.
What safety precautions are needed for Condensación Aldólica (Dibenzalacetona)?
Key safety precautions include: NaOH is corrosive; Benzaldehyde is an irritant with a strong almond odor; Acetone is flammable.
What materials are needed for Condensación Aldólica (Dibenzalacetona)?
The main materials required are: Benzaldehyde, Acetone, Sodium hydroxide (NaOH), Ethanol, Distilled water.
What results should I expect from Condensación Aldólica (Dibenzalacetona)?
Bright yellow crystals with a melting point of 109-112°C. Typical yield is 60-80%. The product absorbs UV light strongly, which can be confirmed if a UV lamp is available.