एस्पिरिन (एसिटाइलसैलिसिलिक अम्ल) का संश्लेषण

दुनिया की सबसे आम दवाओं में से एक बनाना

Organic Synthesis Advanced (University) 90 मिनट ~$15.00

उद्देश्य

एसिटिक एनहाइड्राइड के साथ सैलिसिलिक अम्ल के एसिटाइलेशन द्वारा एस्पिरिन (एसिटाइलसैलिसिलिक अम्ल) का संश्लेषण करें, और गलनांक निर्धारण द्वारा शुद्धता का आकलन करें।

पृष्ठभूमि

Aspirin synthesis is a classic organic chemistry experiment. Salicylic acid reacts with acetic anhydride in the presence of a phosphoric acid catalyst to form acetylsalicylic acid and acetic acid. The product is purified by recrystallization and verified by melting point (135°C for pure aspirin).

सुरक्षा चेतावनियाँ

  • Acetic anhydride is corrosive and has a pungent odor — work in fume hood
  • Phosphoric acid is corrosive
  • Do not consume the synthesized aspirin
  • Wear gloves and goggles

आवश्यक PPE

goggles gloves lab_coat

सामग्री

  • Salicylic acid (2 g)
  • Acetic anhydride (5 mL)
    Corrosive, pungent
  • Phosphoric acid (H₃PO₄) (5 drops)
    85%, catalyst
  • Distilled water (100 mL)
    Ice-cold for crystallization
  • Ethanol (10 mL)
    For recrystallization

उपकरण

Erlenmeyer flask (125 mL) Hot water bath (beaker) Buchner funnel Filter flask Vacuum pump Melting point apparatus Thermometer Ice bath

प्रक्रिया

1

Weigh 2.0 g of salicylic acid into the Erlenmeyer flask. Record the exact mass.

3 मिनट
2

In a fume hood, add 5 mL of acetic anhydride and 5 drops of phosphoric acid catalyst.

3 मिनट Acetic anhydride is corrosive and pungent
3

Heat the flask in a water bath at 70-80°C for 15 minutes, swirling occasionally.

15 मिनट
4

Remove from heat and carefully add 20 mL of cold water to decompose excess acetic anhydride.

3 मिनट Exothermic — add water slowly
5

Cool the flask in an ice bath until crystals form. Scratch the flask wall with a glass rod to initiate crystallization.

10 मिनट
6

Collect the crude product by vacuum filtration using the Buchner funnel. Wash with cold water.

10 मिनट
7

Recrystallize: dissolve the crude product in 5 mL warm ethanol, add 15 mL warm water, then cool slowly in ice bath.

15 मिनट
8

Collect purified crystals by vacuum filtration. Dry and determine the melting point.

10 मिनट
9

Calculate the percent yield. Pure aspirin melts at 135°C.

5 मिनट

अपेक्षित परिणाम

White needle-like crystals with a melting point of 134-136°C (pure aspirin is 135°C). Typical yield is 70-90%. A depressed or broad melting range indicates impurities (likely unreacted salicylic acid).

सफाई

Dispose of organic waste in designated containers. Do not consume the product. Rinse all glassware.

Frequently Asked Questions

What is the objective of एस्पिरिन (एसिटाइलसैलिसिलिक अम्ल) का संश्लेषण?
एसिटिक एनहाइड्राइड के साथ सैलिसिलिक अम्ल के एसिटाइलेशन द्वारा एस्पिरिन (एसिटाइलसैलिसिलिक अम्ल) का संश्लेषण करें, और गलनांक निर्धारण द्वारा शुद्धता का आकलन करें।
How difficult is एस्पिरिन (एसिटाइलसैलिसिलिक अम्ल) का संश्लेषण?
This experiment is rated as Advanced (University). It takes approximately 90 minutes to complete.
What safety precautions are needed for एस्पिरिन (एसिटाइलसैलिसिलिक अम्ल) का संश्लेषण?
Key safety precautions include: Acetic anhydride is corrosive and has a pungent odor — work in fume hood; Phosphoric acid is corrosive; Do not consume the synthesized aspirin.
What materials are needed for एस्पिरिन (एसिटाइलसैलिसिलिक अम्ल) का संश्लेषण?
The main materials required are: Salicylic acid, Acetic anhydride, Phosphoric acid (H₃PO₄), Distilled water, Ethanol.
What results should I expect from एस्पिरिन (एसिटाइलसैलिसिलिक अम्ल) का संश्लेषण?
White needle-like crystals with a melting point of 134-136°C (pure aspirin is 135°C). Typical yield is 70-90%. A depressed or broad melting range indicates impurities (likely unreacted salicylic acid).