Complete the following chemical equation: How many grams of the above anhydride are needed to react with 5.0 g of cyclohexanol in the above reaction?

Synthesis of Aspirin & Methyl Salicylate
Introduction: The two compounds we will be preparing, aspirin (acetylsalicylic acid) and oil of wintergreen
(methylsalicylate), are both organic esters.
Aspirin (acetylsalicylic acid) is a common analgesic drug. It is synthesized by the acetylation of salicylic acid.
The second ester product is oil of wintergreen (methylsalicylate) is prepared by allowing salicylic acid to react with
methyl alcohol.
The Preparation of these organic esters in lab involves three steps:
1. Synthesis of aspirin & methyl salicylate
2. Isolation and purification of aspirin
3. Estimation of the purity of the final product.
1) Synthesis:
Aspirin
The synthesis involves the reaction of salicylic acid and acetic anhydride in the presence of a catalyst, phosphoric
acid, H3PO4


Methyl Salicylate
The synthesis involves the reaction of salicylic acid and methanol in the presence of a catalyst hydrochloric acid.
salicylic acid methanol methyl salicylate
2) Isolation and Purification of Aspirin
Once the aspirin is prepared it isolate it from the reaction solution and purify it by crystallization and filtration.
Although there will be some loss of product, good experimental technique will minimize the losses. Purification is
necessary to remove any unreacted salicylic acid and acetic anhydride, as well as the acetic acid product and
phosphoric acid.
The aspirin is insoluble in cold water, and can be isolated by filtering the chilled reaction solution. The acetic acid
and phosphoric acid are water soluble and can be removed by washing the aspirin with chilled water.
Salicylic acid is only slightly soluble in water and is not completely removed in the washing step. Final purification
is accomplished by the process of recrystallization. The impure aspirin is dissolved in warm ethanol. The solution is
then cooled slowly, and the aspirin crystallizes out of solution leaving the salicylic acid and other impurities behind.
If your aspirin were going to be used pharmaceutically it would require even further purification.
3) Estimation of Purity of the product
The first method you will use to determine the purity is the melting point of your product. We will use commercial
Mel-temp apparatuses to determine the temperature at which your synthesized crystals melt. If the aspirin is pure, it
will melt sharply at the literature value. If it is impure, it will be lower than the literature value by an amount that is
oughly proportional to the amount of impurity present.
A more quantitative method of determining the purity of your aspirin is to use absorption spectroscopy
4) Safety Considerations
This experiment uses salicylic acid, acetic anhydride and phosphoric acid. The salicylic acid and aspirin may cause
i
itation to your skin or eyes, but are basically not hazardous. Be sure to...