preview

Separation of a Carboxylic Acid, a Phenol, and a Neutral Substance

Decent Essays
Open Document
Objective: The objective of this experiment is to use acid-base extraction techniques to separate a mixture of organic compounds based on acidity and/or basicity. After the three compounds are separated we will recover them into their salt forms and then purify them by recrystallization and identify them by their melting points.

Procedure:
Extraction of Carboxylic Acid
A pre-weighed (0.315g) mixture of Carboxylic acid, a phenol, and neutral substance was placed into a reaction tube (tube 1). tert-Butyl methyl ether (2ml) was added to the tube and the solid mixture was dissolved. Next, 1 ml of saturated NaHCO3 solution was added to the tube and the contents were mixed separating the contents into three layers. Once this was completed…show more content…
Next, add concentrated HCl drop wise until the litmus paper indicates that it is acidic. During this procedure, I added to much HCl because many CO2 gas bubbles evolved. This error in the experiment will cause the recovery % to be lower.
Recovery of Phenol by Acidification
To tube 3 a piece of litmus paper was placed into the tube. Then as is tube 2 concentrated HCl was added drop wise until the litmus paper indicated that it is acidic. No CO2 gas will evolve.
Purification of neutral substance
Tube 4 now should only have crude solid in the tube and it is then weighed. The tube is placed into a 50℃ water bath and then approximately 0.5 -1 ml of methanol is added, as well as H2O until the solution gets cloudy, once the solution is dissolved it is cooled to room temperature and then iced. The crystals are then collected using a Hirsh funnel. Next a small amount (~ 0.1g) of the crystals are placed into a melting point tube and placed into the melting point machine to record the unknown neutral substances melting point.
Purification of Carboxylic Acid and Phenol
To tube 2 and tube 3 a boiling chip is added. The two tubes are boiled to remove any residual ether. Next, the tubes are cooled to room temperature and placed into an ice bath to allow for crystallization. The solution is then removed from the solid in each tube and discarded. To tube 2 and 3 ~0.5 ml of H2O is added for recrystallization, the tubes
Get Access
Related
Get Access