1. EXP.NO 4 :- Synthesis of Aspirin IUPAC Name 2-acetyloxybenzoic acid
The aim of the experiment is synthesis aspirin and evaluate the purity of their product This laboratory introduces students to aspects of practical organic
chemistry including synthesis, crystallization, stoichiometry, and percent yield.
Safety
The chemicals used to synthesize aspirin present a health hazard and exposure should be kept to minimum:
1) Sulfuric Acid: A highly corrosive liquid that will cause severe burns if it comes into contact with skin.
2) Salicylic Acid: Harmful by inhalation, ingestion, and through skin absorption. An irritant.
3) Acetic anhydride: Poison. Corrosive. Causes severe burns. Harmful if swallowed or inhaled. Causes severe respiratory irritation. Eye contact may cause serious irritation or burns.
4) Ferric Chloride Solution: Corrosive
5) Ethanol: Toxic and flammable

2. Molecular Formula
C9H8O4
CH3COOC6H4COOH
Melting Point is 135
 °C
The molecular mass of salicylic acid is g/ mol and the molecular mass of aspirin is g/ mol
Aspirin is used to reduce fever and relieve mild to moderate pain from conditions such as muscle aches, toothaches, common cold, and headaches. It may also be used to reduce pain and swelling in conditions such as arthritis. Aspirin is known as a salicylate and a non steroidal anti-inflammatory drug (NSAID). It works by blocking a certain natural substance in your body to reduce pain and swelling.

3. The reaction that is used for the synthesis of aspirin is shown below
The reaction that is used for the synthesis of aspirin is shown below. In this reaction, an excess of acetic anhydride (C4H6O3) is added to a measured mass of salicylic acid (C7H6O3) in the presence of a catalyst, sulfuric acid (H2SO4). The mixture is heated to form the acetylsalicylic acid (C9H8O4) and acetic acid (C2H4O2). After the reaction takes place, water is added to destroy the excess acetic anhydride and cause the product to crystallize. The aspirin is then collected, purified by recrystallization, and its melting temperature measured.
Aspirin is one of the oldest and most common drugs in use today. It is both an analgesic (pain killer) and antipyretic (reduces fever). One method of preparation is to react salicylic acid with acetic anhydride and a trace amount of acid as catalyst.
the name Aspirin, it comes from the 'A" in acetyl salicylic , the "spir" in spiraea ulmaria (the plant they derived the salicylic acid from) and the 'in' was a then familiar name ending for medicines. The synthesis of aspirin is classified as an esterification reaction. 

4. Crude and recrystallized aspirin.

5. Mechanism Of Reaction

6. Mechanism Of Reaction

7. Procedure
Place 3.00 g of salicylic acid in a 125 ml Erlenmeyer flask. Cautiously add 6 ml of acetic anhydride and then 5 drops of concentrated H2SO4. Mix the reagents and heat the flask in a beaker of water warmed to 80-90°C, for 10 minutes. Remove the Erlenmeyer flask and allow it to cool to room temperature. Add 40ml of H2O and Place the flask in an ice bath until the mixture has chilled and crystals have formed. Collect the precipitate by Buchner filtration and rinse the solid with cold distilled water. Recrystallize the crude product from distilled water , allow them to air dry overnight and weigh the product. Calculate the percent yield If you know the molecular mass of salicylic acid is g/ mol and the molecular mass of aspirin is g/ mol
A problem with this procedure is that very often crystals do not initially form. One gets a viscous oil that will eventually solidify. If you get an oil, stir it with a glass rod while it is in the ice bath. For the best results make sure that the glass rod is "scratching" the flask's surface.

8. One drawback to this synthetic procedure is that there is the possibility of some left over salicylic acid. To test for unreacted salicylic acid, add a few drops of 1% ferric chloride solution to a tube containing a few mg of salicylic acid dissolved in water. What do you observe? Do the same for a few mg of your sample dissolved in water. Is there any salicylic acid?
Ferric chloride test: ferric chloride often forms colored complexes with enols and phenols. It is therefore used as a test for enols. You should test salicylic acid, your purified aspirin and your recrystallized aspirin for the presence of any enol. Only a few mg are needed for the test!
Phenol react with FeCl3 (aq) to give a deep purple complex.
Phenol is not present in the product but in one of the reactant.
This test indicate the presence of unreacted starting material .