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

Only available on StudyMode
  • Download(s) : 1133
  • Published : March 2, 2009
Open Document
Text Preview
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 the bottom layer was transferred to tube 2 using a pipette. Once in tube 2 the contents were washed with approximately 0.2 ml of ether and then the ether layer was discarded.

Extraction of Phenol
After the extraction of the Carboxylic acid, two tubes will be present one with the extracted Carboxylic acid and the other being Tube 1’ which is now a mixture of the Phenol, neutral substance, ether, and NaHCO3. Before moving on with the extraction the tube is washed with approximately 0.2 ml NaHCO3 to make sure all the Carboxylic acid has been extracted. To tube 1 (1 ml) 3M NaOH is added to separate the Phenol from the neutral substance. The bottom layer is then pipetted to a new tube (tube 3). 0.15 ml of H2O is added to tube 1’’ and the lower layer is added to tube 3. Tube 3 is washed with 0.2 ml ether and the ether layer is disposed of. The washing ensures that tube 3 is strictly phenol. Recovery of the neutral substance

Tube 1’’ is washed with saturated NaCl (0.3 ml) and the aqueous layer is discarded. To make sure all the water is removed CaCl2 drying pellets are added and the solution is transferred to a pre-weighed tube (tube 4). Tube 1’’ is rinsed 2-3 times with ether and the rinsing is placed into tube 4. Tube 4 is...
tracking img