Synthesis of Asprin Lab Report
Preston Pegram
Lab Partner: Adam Ziegler
Niedenzu Block III
16 December 2015
Introduction: The purpose of this lab is to make a small sample of acetylsalicylic acid, commonly known as aspirin, through an esterification reaction between salicylic acid and acetic anhydride. In an esterification reaction, esters form from carboxylic acids and alcohols in the presence of acid, which acts as the catalyst. Aspirin is a mild analgesic useful in the relief of headache and muscle and joint aches. It works inhibiting the chemicals which allow blood clotting and sensitize nerve endings to pain. This experiment is important because it produces one of the most important and widely used medicines in the world.
Before Asprin was first synthesized, the chemical salicin was mainly used for pain treatment, especially arthritis. Salicin worked well, but it was really tough on the stomach and often caused more sickness than benefit. In 1853, Charles Frederic Gerhardt neutralized salicylic acid by buffering it with sodium (sodium salicylate) and acetyl chloride, creating acetylsalicylic acid, which worked much better than salicin.
Materials:
Day 1:
Safety goggles
250 mL beaker (2) thermometer
balance
dropper pipette
hot plate
ice
lab apron
boiling chip
small test tube (13x100)
salicylic acid
85% H3PO4 (phosphoric acid)
acetic anhydride
Day 2:
faucet aerator
rubber tubing
vacuum flask
funnel with rubber stopper
filter paper
balance
wash bottle w/ water
stirring rod
Day 3:
Balance
1% Iron (III) Chloride (FeCl3)
melting point apparatus
distilled water
capillary tube
Day 4:
Salicylic acid
methanol
phosphoric acid
400 mL beaker
stirring rod
thermometer
hot plate
timer
Procedure:
Day 1
The first step is to fill the 250 mL beaker about34full with H2O. Next, add a boiling chip to the beaker, put it on the hot plate and turn the heat up to level 2. Adjust the heat settings to ensure that the heat remains around 90 degrees Celsius. Using a weighing paper, measure out about 140 mg of salicylic acid record the exact measurement for later use in calculations. Put the salicylic acid into a small test tube. Then, add one small drop of the phosphoric acid to the test tube. Next, add about 0.3 mL of acetic anhydride to the test tube. This should be about 10 to 12 drops of it. Carefully mix the reactants. Heat the test tube in the 90oC water bath for 5 minutes, but be careful not to boil. Add 0.2 mL of H2O to the cooled test tube to decompose any extra acetic anhydride. When this exothermic reaction is complete, add another 0.3 mL of H2Oand allow the test tube to cool to room temperature. You should see crystals beginning to form. Continue to cool the test tube in an ice bath for at least 10 minutes.
Day 2
Write the name of your group members on a piece of filter paper using a pencil and tear off a corner of the filter paper. Record the mass of the filter paper. Pour the contents of the test tube into the filter apparatus. Rinse the test tube with