Aspirin Lab

CHEM 30475, Summer 2023
Ibrahim Alghuzaili 06/20/2023
ESTERS OF SALICYLIC ACID LAB
Purpose: The objective of this experiment was to synthesize acetylsalicylic acid through the
acetylation of salicylic acid and characterize the synthesized product.
Introduction: Acetylsalicylic acid, commonly referred to as aspirin, is a widely used

nonsteroidal anti-inflammatory drug (NSAID). It exhibits analgesic, antipyretic, and anti-
inflammatory properties and is commonly used for pain relief, fever reduction, and antiplatelet
effects. Aspirin is synthesized through the acetylation of salicylic acid, where the hydroxyl group
(-OH) of salicylic acid is replaced with an acetyl group (-OCCH3). This chemical modification
increases its bioavailability and reduces its irritant properties.
Reaction Scheme:
Procedure: A hot water bath was prepared using a crystallizing dish, and it was heated to a
temperature of approximately 60°. Additionally, an ice bath was prepared, and a beaker
containing approximately 75 mL of deionized water was placed in the ice bath to cool. 2.99 g of
salicylic acid was obtained, and the weight was recorded to three decimal places. The salicylic
acid was placed into a 125 mL Erlenmeyer flask equipped with a stir bar, and 5 mL of acetic
anhydride was added. It should be noted that both acetic anhydride and concentrated sulfuric
acid were highly corrosive. Five drops of concentrated sulfuric acid were added, and the mixture
was gently swirled. The flask was placed in the water bath and monitored to ensure it maintained
a temperature of 60°C. After 30 minutes, the flask was taken out from the water bath and
allowed to cool down to room temperature. Then, 50 mL of ice-cold deionized water was added
to the flask. Subsequently, the reaction flask was placed in an ice bath and left undisturbed for
crystal formation. Meanwhile, an IR spectrum of the starting material could be obtained.
The Buchner flask and funnel were prepared with a piece of filter paper. The crystalline solid
was collected using vacuum filtration. The solid was washed with a small amount of COLD
deionized water. A few crystals of the crude aspirin were retained for the purpose of determining
the melting point, which would be compared with the recrystallized aspirin. 1.54 g of the
remaining aspirin product was scraped off the filter paper and subjected to recrystallization from
95% ethanol. For this, approximately 2 mL of 95% ethanol was added to the solid in a small
Erlenmeyer flask. The flask was warmed in a water bath. Drops of 95% ethanol were gradually
added to the solid until it JUST dissolved, while maintaining the warmth of the flask. Dropwise
the addition of water was done until the solution became cloudy. The flask was warmed again to
dissolve the cloudiness and then cooled first to room temperature and subsequently in an ice bath
to complete recrystallization. The crystals were filtered using a Buchner funnel, washed with a
small quantity of ice-cold distilled water, and subjected to suction for several minutes. The
aspirin was left to dry before obtaining a melting point, as the crystals were likely not
sufficiently dry until the next day. If the crystals were left until the following day, they were left
uncovered for the purpose of drying. An IR spectrum of both salicylic acid and the synthesized
acetyl salicylic acid was obtained. The spectra were compared to confirm the successful
transformation as intended.
Discussion: The synthesis of acetylsalicylic acid was successful, yielding a white, crystalline
solid product. The melting point of the pure sample was found to be 130°C, which closely
matched the reported melting point of acetylsalicylic acid (134°C-136°C). The melting point of
the crude sample was found to be 110°C, which closely matched the reported melting point of
acetylsalicylic acid (122°C-123°C). This indicates the purity of the product. Infrared
spectroscopy was performed to confirm the presence of characteristic functional groups. The IR
spectrum showed a strong absorption peak at 1250 cm-1, corresponding to the carbonyl group
(C=O) in the acetyl moiety. The absence of the hydroxyl group absorption peak at 3000 cm-1
confirmed the successful acetylation of salicylic acid. The yield of the synthesized acetylsalicylic
acid was calculated by comparing the actual mass obtained to the theoretical yield. The
percentage yield was determined to be 78.8%, indicating a satisfactory result.
Calculation:
Conclusion: The synthesis of acetylsalicylic acid (aspirin) was successfully carried out
through the acetylation of salicylic acid. The synthesized product was characterized by its
melting point and infrared spectroscopy, confirming its purity and the successful acetylation
reaction. The yield obtained was within an acceptable range. The synthesized aspirin can be
further used for various applications in the pharmaceutical industry.

Aspirin Lab

Uploaded by

Copyright:

Available Formats

Aspirin Lab

Uploaded by

Document Information

Original Description:

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Aspirin Lab

Uploaded by

Copyright:

Available Formats

CHEM 30475, Summer 2023

Ibrahim Alghuzaili 06/20/2023

ESTERS OF SALICYLIC ACID LAB

Introduction: Acetylsalicylic acid, commonly referred to as aspirin, is a widely used

You might also like