Chem2273A Lab Report
CHEM2273A ORGANIC CHEMISTRY 1
EXPERIMENT 2: EXTRACTION AND RECRYSTALLIZATION
Objective: The main goal of this experiment is to first isolate benzoic acid and Ethyl 4-
aminobenzoate (benzocaine) from a mixture of benzoic acid (organic acid), benzocaine (organic
base) and 9 Fluorenone (neutral compound) by using liquid-liquid extraction and then removing
unwanted impurities to get an accurate melting point for identification of the compound by using
recrystallization.
Introduction: Extraction is the most common process that is utilized to isolate different
components from a mixture. The isolation depends on the type and nature of component present.
The main principle by which isolation occurs is the phase distribution. The component itself
distributes itself into aqueous or organic layers. One of the phases, that is the component itself
will be liquid or solid and the second phase is always a liquid. The distribution of components
between different layers depends on the relative solubility of the component among the two
solvents that are immiscible. In the first part of the experiment; in order to dissolve acid, base
and neutral compounds, the solvent (diethyl ether) is used to perform liquid-liquid extraction
technique. HCl and NaOH is added to extract the organic base and acid, respectively. The
mixtures did not dissolve and separated into two layers. The liquid at the bottom has a higher
density.
Recrystallization is a process that is performed to pure a chemical substance. In this process the
solvent is heated and a saturated solution of the compound is formed. The selection of solvent for
this purpose is very essential for this purpose. Such solvent is selected in which the impurity is
relatively soluble as compared to the desired compound (when the temperature increases, the
solubility increases as well).When the solvent is cooled down the desired compound precipitates
out and then is separated out from impurities.
Procedure: Procedure of this experiment can be found on the lab manual.
Wisner, J. Department of Chemistry, The University of Western Ontario. CHEM 2273A Organic
Chemistry 1 Laboratory Manual, Fall 2022, pp 102-104,106.
, Lal Guner Chem2273A 10/13/2022
Chem2273A Lab Report
Extraction Flow Chart
Results
Mass of the crude before extraction and recrystallization (g): 1.004
Mass of each component = 0.335 g
Mass of neutral- 9 Mass of organic base- Mass of organic acid-
Fluorenone (g) benzocaine (g) benzoic acid (g)
After extraction 0.273 0.585 0.101
After recrystallization 0.120 0.004 0.003