Aspirin Synthesis

Acetylsalicylic acid, or commonly known as “Aspirin” is widely used as a pain reliever, anti-inflammatory agent, and an antipyretic (fever reducer). Aspirin is a considered one of the most versatile drugs known to modern medicine. Aspirin’s active component, Salicylic acid, was initially isolated by Edward Stone. He isolated salicylic acid from the barks of a willow tree and derived from willow bark extracts. Salicylic acid is not used like it used to be because of the irritable effects it has on the stomach. The form of Salicylic acid used today is known as “Aspirin” which is far less irritating to the stomach. Aspirin is a synthetic pharmaceutical drug that is non-steroidal anti-inflammatory. The physical appearance of Aspirin is a

Phosphoric acid was used as a catalyst in this experiment to speed up the reaction. Water will be used to quench the excess acetic acid. The product in Aspirin synthesis is not very water soluble which means that precipitate will form when the water is added. Spectroscopy is used in this experiment to determine the presence of the product or “purity” of the product.
The synthesis of Aspirin involves the chemical interaction between salicylic acid and an acetyl anhydride which causes a chemical reaction that converts salicylic hydroxyl group in to an acetyl group.
The reaction above shows the reaction that occurs between salicylic acid, phosphoric acid, and acetic anhydride. First, the phosphoric acid attacks the carbon-oxygen (C=O) of the acetic anhydride which makes it positive. This will make acetic anhydride more prone to nucleophilic attacks. The nucleophile in the reaction is salicylic acid and it was form when oxygen on the phenol group attacked the partial positive charge of a carbon from acetic anhydride. Next, the salicylic acid will attack the positively charged anhydride. The oxygen from the phenol group will now be positively charge while the carbonyl groups withhold the negative charge. This forms a tetrahedral shaped structure or intermediate. The carbon is attached to the –OH group due to it being electrophilic. The –OH group in-turn protonates the hydrogen which

The TLC performed showed an appearance of a new spot which indicates that the original substances has changed in some type of way. The TLC also showed that acetic anhydride remained due to salicylic acid working as the limiting agent which means that there is an excess of acetic anhydride. The percent yield shows that not much could be determined by the 1H NMR spectrum or the TLC analysis. The 1H NMR Graph shows the that 2.5 ppm that there is a singlet or single CH3 group. Other than that, the graph is not showing anything significant structures. The purity of the product could have yielded these poor results because some of the salicylic acid did not completely react. Combining the results from TLC analysis and IR spectrum shows that a very small amount of Aspirin was prepared and the rest could have been lost during the filtration or initial steps of the experiment. Esterification involves the transformation of a carboxylic acid into an ester which is exactly what was performed in the experiment. The esterification technique is an important and reliable technique used in organic chemistry. The experiment proved that with the execution of proper techniques, esterification is the a very efficient method regardless of the results obtained in this experiment.
The experiment demonstrated the effectiveness of the esterification through the