Synthesis of Aspirin
Synthesis of Aspirin
Learning Goals
1. To synthesize aspirin from salicylic acid and acetic anhydride.
2. To purify the crude product by Recrystallization.
Introduction
Most drugs are chemical compounds which are described as "organic compounds" because they are comprised primarily of the elements carbon, hydrogen and oxygen. The present experiment will be the synthesis of a familiar organic compound called aspirin. The common chemical name is acetylsalicylic acid. Aspirin, the most widely used drug in the world, has an interesting history. Nearly 2500 years ago, Greeks reported that extracts of willow and poplar bark could be used to relieve pain and symptoms of illness. There are reports that American Indians, before the time of Columbus, used special teas made from the bark of willow trees to reduce fever. In 1763, the Reverend Edward Stone introduced these extracts and teas to the Europeans and in the early 1800's the active ingredient in willow bark (and in the flowers of the meadow sweet plant which had similar therapeutic characteristics) was isolated and identified as salicylic acid (from salix, the Latin name for the willow tree). Although salicylic acid could be synthesized in the laboratory and large quantities became available for therapeutic use in the mid 1800s, the compound's acidic properties caused irritation in the moist membranes of the mouth, throat and stomach. In 1875, the sodium salt was introduced and although the salt was less sour to the taste (actually it had an objectionable sweetish taste), it did not alleviate the gastric discomfort problems.
[pic]
salicylic acid sodium salicylate In 1893, Felix Hoffman Jr., a chemist working for the Bayer Laboratories in Germany, discovered a practical route for synthesizing an ester derivative of salicylic acid, acetylsalicylic acid. [pic] AcetylSalicylic Acid
Learning Goals
1. To synthesize aspirin from salicylic acid and acetic anhydride.
2. To purify the crude product by Recrystallization.
Introduction
Most drugs are chemical compounds which are described as "organic compounds" because they are comprised primarily of the elements carbon, hydrogen and oxygen. The present experiment will be the synthesis of a familiar organic compound called aspirin. The common chemical name is acetylsalicylic acid. Aspirin, the most widely used drug in the world, has an interesting history. Nearly 2500 years ago, Greeks reported that extracts of willow and poplar bark could be used to relieve pain and symptoms of illness. There are reports that American Indians, before the time of Columbus, used special teas made from the bark of willow trees to reduce fever. In 1763, the Reverend Edward Stone introduced these extracts and teas to the Europeans and in the early 1800's the active ingredient in willow bark (and in the flowers of the meadow sweet plant which had similar therapeutic characteristics) was isolated and identified as salicylic acid (from salix, the Latin name for the willow tree). Although salicylic acid could be synthesized in the laboratory and large quantities became available for therapeutic use in the mid 1800s, the compound's acidic properties caused irritation in the moist membranes of the mouth, throat and stomach. In 1875, the sodium salt was introduced and although the salt was less sour to the taste (actually it had an objectionable sweetish taste), it did not alleviate the gastric discomfort problems.
[pic]
salicylic acid sodium salicylate In 1893, Felix Hoffman Jr., a chemist working for the Bayer Laboratories in Germany, discovered a practical route for synthesizing an ester derivative of salicylic acid, acetylsalicylic acid. [pic] AcetylSalicylic Acid