Chem2583 Organic Chemistry Laboratory
Organic Lab 2 2583-04
Instructor: Andy Szalkiewicz
The purpose of this lab is to purify solids contaminated by relatively small amount of impurities by a technique called Recrystallization. Compounds that have different solubility at different temperature usually can be recrystallized. Formulas and Structures:
Percent Recovery: Indicates how much of the active ingredient was able to recover after the purification method.
Weight of benzoic acid obtained after recrystallization % Recovered = x100 Weight of benzoic acid before recrystallization
Table of Physical Data:
Weight of Compounds before and after recrystallization
Methanol & Benzoic
Melting Point data
Benzoic Acid (°C)
Methanol & Benzoic(°C)
I had to recrystallize 0.093mg of benzoic acid from the minimum amount of water. I turned on the electrical heated sand bath and added the sold and a boiling stick to the test tube and gradually added desired hot water. After boiling begins, I continued to add water until the sold dissolved I removed the boiling stick, I corked the tube, clamped as it cooled, and observed recrystallization begin. I turned the vacuum filtration to collect the crystals.
In another reaction tube, I dissolved 0.080mg of benzoic acid in the minimum volume of hot methanol; I added drops of water to the hot solution. After the crystals form and recrystallization begin. I allowed the tube to cool slowly at room temperature, then cool in iced water and gather the crystals. Then I used the spatula to collect a tip of...
Please join StudyMode to read the full document