Synthesis of Aspirin Essay Sample

9 September 2017

Learning Goals
1. To synthesise acetylsalicylic acid from salicylic acid and acetic anhydride.
2. To sublimate the petroleum merchandise by Recrystallization.

Most drugs are chemical compounds which are described as “organic compounds” because they are comprised chiefly of the elements C. H and O. The present experiment will be the synthesis of a familiar organic compound called acetylsalicylic acid. The common chemical name is acetylsalicylic acid. Aspirin. the most widely used drug in the universe. has an interesting history. About 2500 old ages ago. Greeks reported that infusions of willow and poplar bark could be used to alleviate hurting and symptoms of unwellness. There are studies that American Indians. before the clip of Columbus. used particular teas made from the bark of willow trees to cut down febrility.

In 1763. the Reverend Edward Stone introduced these infusions and teas to the Europeans and in the early 1800’s the active ingredient in willow bark ( and in the flowers of the hayfield Sweet works which had similar curative features ) was isolated and identified as salicylic acid ( from Salix. the Latin name for the willow tree ) . Although salicylic acid could be synthesized in the research lab and big measures became available for curative usage in the mid 1800s. the compound’s acidic belongingss caused annoyance in the moist membranes of the oral cavity. pharynx and tummy. In 1875. the Na salt was introduced and although the salt was less rancid to the gustatory sensation ( really it had an obnoxious sweetish gustatory sensation ) . it did non relieve the stomachic uncomfortableness jobs.

salicylic acid Na salicylate
In 1893. Felix Hoffman Jr. . a chemist working for the Bayer Laboratories in Germany. discovered a practical path for synthesising an ester derived function of salicylic acid. acetylsalicylic acid.

Acetyl Salicylic Acid
Aspirin. ASA
Acetylsalicylic acid. a weaker acid than salicylic acid. was found to hold the medicative belongingss of salicylic acid without holding the obnoxious gustatory sensation or bring forthing the tummy jobs. The ethanoyl group group efficaciously masks the sourness of the drug during its consumption and after it passes into the little bowel. it is converted back to salicylic acid where it can come in the blood stream and make its hurting alleviating action. Bayer called its new merchandise “aspirin. ” the name being derived from “a” for ethanoyl group. and the root “-spir” . from the Latin name Spiraea ulmaria. the meadow sweet flower. from which salicylic acid had been isolated. It was patented by Bayer in 1899. and in 1915 Bayer Aspirin tablets became commercially available as a non- prescription drug.

The hallmark is still owned by the Bayer A. G. company in Germany. Today. acetylsalicylic acid is one of the most widely used. commercially available pharmaceutical drugs in the universe. Its belongingss make it a powerful analgetic ( trouble stand-in ) . antipyretic ( fever reducing agent ) and anti-inflammatory ( reduces swelling ) drug. Aspirin is non without its mistakes. It still causes some tummy annoyance in some persons. and it has been estimated that about 1 milliliters of blood is lost from the tummy liner for each gm of acetylsalicylic acid consumed. Aspirin is known to interfere with normal blood curdling ( which really may be a benefit in forestalling bosom jobs ) . Reye syndrome. a rare but serious unwellness has been associated with acetylsalicylic acid. and kids and adolescents should non utilize acetylsalicylic acid for grippe like symptoms before confer withing a physician. Synthesis

The salicylate ion forms the curative portion of the acetylsalicylic acid. Aspirin passes through the acidic tummy contents ad does non ionise and organize the salicylate ion until it reaches the alkalic conditions in the bowels. Here it is hydrolyzed to organize the ethanoate and salicylate ion. The latter ion is absorbed through the enteric wall. The equation picturing this reaction is given below.

The concluding measure in the commercial synthesis of acetylsalicylic acid involves the contrary of this reaction. The salicylic acid is treated with acetic anhydride. which is a more reactive compound than the acetate ion. Catalytic sums of sulphuric acid make the reaction proceed really quickly. This is the synthesis measure you will execute in this assignment.


The above reaction is an illustration of an organic synthesis called esterification. Esterification is the acerb catalyzed reaction of a carboxyl ( -COOH ) group and an -OH group of an intoxicant or phenol to organize a carboxylate ester. In the synthesis of acetylsalicylic acid the -OH group is the phenolic -OH group attached to ring of the salicylic acid. The acetyl group. -COCH3 comes form acetic anhydride. and the reaction is catalyzed by sulphuric acid. This reaction is rather simple and gives a good output of the merchandise. Aspirin. although it is soluble in hot intoxicant. is non soluble in H2O. Consequently. the concluding merchandise will be filtered from an aqueous solution. and washed with cold H2O. so air dried.

A Particular Summary ( Song )
“How to Make Aspirin Today”
Achey twenty-four hours. concern please. travel off.
And I’m acquiring a febrility. Oy vey!
Can you state me how to do. how to do acetylsalicylic acid today?
These you take. when acetylsalicylic acid you make.
Salicylic acid’s on the list

And acetic anhydride and an acerb accelerator.
Sulfuric to be exact. Blend them all and they react.
And an ester is formed. You esterify. You esterify.
On phenol. acetyl finds its end.
And from H2O. white crystals arise.
And to do them pure. from intoxicant recrystallize.
by Thomas Ott
Oakland University. Rochester MI

( Preparation of Aspirin:
1- Place 3. 0 g ( 0. 02 mol ) of salicylic acid in a 100 milliliter Erlenmeyer flask. 2- Add. with uninterrupted stirring. 6 milliliter of acetic anhydride ( fume goon ) followed by 1 milliliters of concentrated sulphuric acid. 3- Stir the mixture gently detecting the rise in temperature to 70-80 °C while the salicylic acid dissolves. Heat in a H2O bath if needed. 4- After 15 proceedingss the solution cools by itself to 35-45 °C and a solid mass of acetylsalicylic acid signifiers. 5- Pour 35 milliliter of ice-cold H2O over the contents of the flask to hydrolyse extra acetic anhydride and to finish the precipitation of acetylsalicylic acid. 6- Chill the Erlenmeyer flask in an ice bath with occasional twirling to do precipitation of the merchandise.

If no precipitate signifiers. rubing the side of the flask with a glass stirring rod may assist originate crystallisation. While the flask is chilling. fix a vacuity filtration setup
as shown at the right.

7- Collect the petroleum acetylsalicylic acid utilizing a Buchner funnel and wash with ice-cold H2O. 8- Air-dry the merchandise. weigh. and cipher the output.
( Recrystallization of Crude Aspirin:
To sublimate your synthesized acetylsalicylic acid. reassign it to a little Erlenmeyer flask and add a little sum of ethyl alcohol utilizing a fictile pipet. Warm the solution to 60 ?C. Cover the solution and let it to chill undisturbed to room temperature. Then set the beaker in an ice bath and one time once more rub the interior of the flask with a glass rod to bring on recrystallization.

Roll up the purified acetylsalicylic acid by vacuity filtration and rinse them with ice-cold H2O. Let the crystals dry for a few proceedingss before weighing them. Determine the mass of your dry purified acetylsalicylic acid.

Synthesis and Analysis of Aspirin
Report Sheet
( Give a balanced equation for the synthesis of acetylsalicylic acid from salicylic acid and acetic anhydride.

( Determine the restricting reagent in the synthesis reaction ( show computations ) .

( Preparation of Aspirin:
Theoretical output of acetylsalicylic acid ( Show computations ) .

Actual yield=
Percentage output ( show computations ) .

( Recrystallization of Aspirin:
Mass of petroleum aspirin=
Mass of recrystallized aspirin=
Percentage yield=

( Give the mechanism of the reaction in your experiment.

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