Synthesis
Acetylsalicylic acid is an acetyl derivative of salicylic acid which appears as a white and crystalline and a weakly acidic substance with a melting point of 135°C and is also known to be aspirin. It is one of the most widely used drugs that can lower fever and is used as a painkiller.
According to (Escobel, 2011), Aspirin is synthesized through the reaction of salicylic acid with acetyl anhydride that causes a chemical reaction that turns salicylic acid's hydroxyl group into an acetyl group, (R—OH → R—OCOCH3). An inorganic acid such as phosphoric acid is used as a catalyst.
Set-ups
Figure 1.1. Steam bath
Figure 1.2. Cold bath
Figure 1.3. Suction filtration set-up
Figure 1.4. Melting point apparatus
List of Necessary Chemicals
Name and Structure of the Compound
Function in the Exercise
Physical Properties
Hazards
Precautions
Salicylic acid
C7H6O3
Ultrasal-ER is flammable. Keep away from fire or flame. Keep bottle tightly capped when not in use.
Ultrasal-ER is for external use only. Do not permit Ultrasal-ER to contact eyes or mucous membranes. If contact with eyes or mucous membranes occurs, immediately flush with water for 15 minutes. Ultrasal-ER should not be allowed to contact normal skin surrounding the wart site, since localized irritation may occur. Treatment should be discontinued if excessive irritation occurs.
Acetic anhydride
85% Phosphoric acid
95% Ethanol
Commercial Aspirin
II. DATA
Table 1. Observation of chemical compounds used in the preparation of Acetylsalicylic acid (Aspirin)
NAME OF THE COMPOUND
DESCRIPTION
Table 2. Observation on the crystallization of crude sample
SAMPLE
OBSERVATIONS
Mixture of crude sample and solvent
Mixture on steam bath
Mixture on a ice bath Suction filtration
a. filtrate
b. residue
Air dried crystals
Table 3. Determination of percent yield of aspirin weight of sample +