एल्डोल संघनन (डाइबेंजेलएसीटोन)

सनस्क्रीन में उपयोग किए जाने वाले UV-अवशोषक यौगिक का संश्लेषण

Organic Synthesis Advanced (University) 75 मिनट ~$18.00

उद्देश्य

कार्बन-कार्बन बंध निर्माण प्रदर्शित करते हुए, बेंजेल्डिहाइड और एसीटोन के बीच एक क्रॉस एल्डोल संघनन के माध्यम से डाइबेंजेलएसीटोन का संश्लेषण करें।

पृष्ठभूमि

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.

सुरक्षा चेतावनियाँ

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

आवश्यक PPE

goggles gloves lab_coat

सामग्री

  • 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

उपकरण

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

प्रक्रिया

1

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

3 मिनट Fume hood — benzaldehyde is an irritant
2

Add 1.5 mL acetone to the flask and stir.

2 मिनट
3

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

5 मिनट NaOH is corrosive
4

Stir the mixture at room temperature for 30 minutes.

30 मिनट
5

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

10 मिनट
6

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

10 मिनट
7

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

10 मिनट
8

Calculate the percent yield.

5 मिनट

अपेक्षित परिणाम

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.

सफाई

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

Frequently Asked Questions

What is the objective of एल्डोल संघनन (डाइबेंजेलएसीटोन)?
कार्बन-कार्बन बंध निर्माण प्रदर्शित करते हुए, बेंजेल्डिहाइड और एसीटोन के बीच एक क्रॉस एल्डोल संघनन के माध्यम से डाइबेंजेलएसीटोन का संश्लेषण करें।
How difficult is एल्डोल संघनन (डाइबेंजेलएसीटोन)?
This experiment is rated as Advanced (University). It takes approximately 75 minutes to complete.
What safety precautions are needed for एल्डोल संघनन (डाइबेंजेलएसीटोन)?
Key safety precautions include: NaOH is corrosive; Benzaldehyde is an irritant with a strong almond odor; Acetone is flammable.
What materials are needed for एल्डोल संघनन (डाइबेंजेलएसीटोन)?
The main materials required are: Benzaldehyde, Acetone, Sodium hydroxide (NaOH), Ethanol, Distilled water.
What results should I expect from एल्डोल संघनन (डाइबेंजेलएसीटोन)?
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.