CM134-1L/CM134-02L-A21 Organic Chemistry Laboratory
1st Quarter AY 2023-2024
MAPUA UNIVERSITY
School of Chemical, Biological, and Materials Engineering Sciences
Liquid-Liquid Extraction
Group No. 5
Rosales, Dominique
Roxas, Juan Carlos B.
ABSTRACT
One of the common purification techniques that is done in most laboratory applications is
the liquid-liquid extraction. The liquid-liquid extraction relies on the different solubilities of
the compounds found in every mixture that is immiscible to the water organic phase. As
such, to understand the extraction process, it will understand the effect of salting-out. It is a
purification method that utilizes reducing the solubility of certain molecules in a solution with
a high ionic strength. In this experiment, it will be done through a titration process to
visualize easily to determine the distribution coefficient and percentage yield of extraction for
the solution needed. As such, it will visualize the separation process of the organic
compounds through extraction.
1. INTRODUCTION
Separation processes are used to separate the organic components from a
mixture of chemicals. A simple exam of this is when someone is brewing coffee or
tea. This example works because tea leaves are not soluble in water but the teabags
which contain “tea” are soluble in the water. This is an example of a solid-liquid
extraction (Nichols, 2022). But in the laboratory a liquid-liquid extraction is often
used, which is a separation process by using a “separatory funnel”.
This liquid-liquid extraction is commonly used when they are immiscible, like oil
and water. In oil and water even when mixed thoroughly they wouldn’t mix with each
other. This will separate the mixture into different phases, in which oil is above the
water because of its density which is lower than water (JoVE, n.d.).
The same
happens in the process of the liquid-liquid extraction, in which the solvent that is
heavier will sink to the bottom of the funnel and the solvent that is lighter will be in the
upper region. The two solvents are simply shaken for the two solvents to intermix
with each other (CU Boulder, n.d.).
CM134-1L/CM134-02L-A21 Organic Chemistry Laboratory
1st Quarter AY 2023-2024
In the extraction process, the stopcock is slowly opened, enabling the lower layer
to flow out. The liquid that is released is the extract, and the liquid that is recovered is
the raffinate (Akinsunmade, 2022). After the extraction, the distribution (or partition)
coefficient (KD) is simply the ratio of the concentration in the organic phase to that in
the aqueous phase (Qureshi, 2014).
2. METHODOLOGY
In this experiment, it is divided into two parts: Salting-out Effect, and the
Determination of a Distribution Coefficient and Percentage Yield of Extraction. The
materials include the following: Erlenmeyer Flask, Pipet, Micro Test Tubes, Quick Fit
Funnel, and the reagents that are being observed.
In the first part of the experiment which is named Salting-out Effect, two micro test
tubes are filled with 3 mL of distilled water. A drop of 0.003 M aqueous crystal violet
and 0.50 mL of n-amyl alcohol has been added to each test tube. After the test tubes
are shaken, one of the test tubes is added with sodium chloride. The test tubes are
then compared and observed.
In the second experiment which is named Determination of a Distribution
Coefficient and Percentage Yield of Extraction, 10 mL of 10% adipic acid is added
with a drop phenolphthalein and is titrated with 0.05M NaOH up to a light pink end
point. The volume of the titrant is recorded. 10 mL of adipic acid is added in the
separatory funnel in which it is mixed with 10 mL of ether before extracting the acid.
The aqueous layer is then added with a drop of phenolphthalein and is titrated with
0.05M NaOH. the volume of the titrant is then recorded. The organic content is then
drawn off into a bottle labeled “Ether Extract”.
The next process is the double extraction, in which the same process is repeated
twice with the use of 5 mL of ether with the same amount of adipic acid. The results
of the experiment are recorded in the laboratory, including the calculations, and the
measurements.
3. DATA AND RESULTS
A. Salting-out Effect
In the observation in the actual experiment, the mixture was composed of
n-Amyl Alcohol, Crystal Violet, and water. The N-amyl alcohol is slightly soluble to
CM134-1L/CM134-02L-A21 Organic Chemistry Laboratory
1st Quarter AY 2023-2024
water compared to the crystal violet, whereas it shows that the component is
slightly dissolving. The color of the mixture is dark violet while shaking and the
n-Amyl alcohol stays on top. When adding the NaCl to the mixture, it creates a
new layer that separates each component. One layer is composed of violet
colored mixture, while the other layer is composed of a slightly cleared liquid with
remaining pigments left on the mixture itself.
In various reports and existing literature, adding salt to the bulk solution
decreases the solubility of the organic non-electrolyte to the solution. As the salt
concentration increases to the mixture, it creates an attraction to the ions that are
free to react to the charged part of a protein. It could cause an increasing demand
in the solvent that the interaction on both proteins will get stronger than the
interaction between the solvent and the solute. It will eventually form a two visible
immiscible layer of liquids due to the coagulation of the protein molecules through
a formation of hydrophobic layers.
B. Determination of a Distribution Coefficient & Percentage Yield of Extraction
Table 1.a. Liquid-Liquid Extraction (Volume of NaOH used for Titration
Original 1% sample
30.5 mL
Solution extracted once
22.7 mL
Solution extracted twice
10.12 mL
Table 1.b Weight of Adipic Acid
Original solution
0.1114 g
Solution extracted once
0.0829 g
Solution extracted twice
0.0370 g
Table 1.c Distribution Coefficient
SIngle Extraction
0.3438
Double Extraction
6.6919
CM134-1L/CM134-02L-A21 Organic Chemistry Laboratory
1st Quarter AY 2023-2024
1.d Percentage Yield
SIngle Extraction
25.58 %
Double Extraction
66.79 %
Table 1.a shows the experimented data from the titration process that is done
on the extraction process and the weight of the adipic acid is also determined as
seen in Table 1.b. Whereas, it will serve as a given to determine the partition
coefficient for both single and double extraction. It refers to the distribution
coefficient where the ratio is given with the solubility of the concentrated organic
solvent and the solubility of water. The percent yield was also determined since
the starting material for both extraction was also given.
Formula Used For This Experiment:
𝐾 =
𝐴
𝐵
where:
K - Distribution Coefficient
A - solubility of the concentration of organic solvent
B - solubility concentration of water
𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝑌𝑖𝑒𝑙𝑑 =
𝑎𝑐𝑡𝑢𝑎𝑙 𝑦𝑖𝑒𝑙𝑑
𝑠𝑡𝑎𝑟𝑡𝑖𝑛𝑔 𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙
* 100%
After determining both the distribution coefficient and the percentage yield, the
double extraction obtained the higher yield compared to the single extraction as
seen in Table 1.c & 1.d. Considering the distribution coefficient is a ration, it will
only reside on the organic layer in a single extraction. In comparing both
extractions, it interprets that extracting the solution twice will potentially acquire
the right amount of acid needed for the mixture than the one that is extracted
once. As the number of extraction increases, the percentage yield and the
distribution coefficient also increases, where the data that is collected in Table
1.c and Table 1.d showcases that second extraction is around 6.6919 of its
coefficient and 66.79% of its yield which is recorded as the highest.
CM134-1L/CM134-02L-A21 Organic Chemistry Laboratory
1st Quarter AY 2023-2024
CONCLUSION
The conducted experiment was successful in both processes. The Salting-out effect
showcases the increasing amount of ionic strength and the decreasing of the solubility of
the solute found in the mixture itself. Considering that the solute used for this experiment is a
weak organic that is found on the non-electrolyte substance from the solvent.
In the extraction process, it shows that the double extraction is much more efficient than
the single extraction where both the distribution coefficient and percentage yield will increase
depending on the number of extraction. The objective of the experiment was meant as
expected, but the execution and the calculation for the experiment will surely have a slight
discrepancy from previous reports. Overall, it gave an understanding about the potential
applications in the extraction process.
REFERENCES
Akinsunmade, O. (2022). How does liquid liquid extraction work? The Engineer’s
Perspective.
https://www.theengineersperspectives.com/how-does-liquid-liquid-extractionwork/
CU Boulder. (n.d.). Extraction. Retrieved October 15, 2023, from
https://www.orgchemboulder.com/Technique/Procedures/Extraction/Extraction
.shtml
JoVE. (n.d.). Extraction [Video]. JoVE. Retrieved October 15, 2023, from
https://www.jove.com/science-education/11198/extraction-liquid-liquid-and-aci
d-base-extraction-concept#:~:text=A%20common%20example%20of%20extr
action,water%20into%20the%20liquid%20phase.
Nichols, L. (2022). 4.2: Overview of extraction. Chemistry LibreTexts.
https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Organic_Chemistr
CM134-1L/CM134-02L-A21 Organic Chemistry Laboratory
1st Quarter AY 2023-2024
y_Lab_Techniques_(Nichols)/04%3A_Extraction/4.02%3A_Overview_of_Extr
action
Qureshi, N. (2014). Integrated processes for product recovery. In Elsevier eBooks
(pp. 101–118). https://doi.org/10.1016/b978-0-444-59498-3.00005-1
Libretext (n.d.) Salting Out Retrieved From:
https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry
_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemis
try)/Thermodynamics/Real_(Non-Ideal)_Systems/Salting_Out
APPENDIX
A. Preliminary Data
CM134-1L/CM134-02L-A21 Organic Chemistry Laboratory
1st Quarter AY 2023-2024
CM134-1L/CM134-02L-A21 Organic Chemistry Laboratory
1st Quarter AY 2023-2024
CM134-1L/CM134-02L-A21 Organic Chemistry Laboratory
1st Quarter AY 2023-2024
B. Calculations
Original solution
𝑀 = 30. 5 * 0. 05 *
1
2
* 146. 14 *
1
1000
= 0. 1114 𝑔
Solution extracted once
𝑀 = 22. 7 * 0. 5 * 0. 05 *
1
2
* 146. 14 *
1
1000
= 0. 0829 𝑔
Solution extracted twice
𝑀 = 10. 12 * 0. 5 * 0. 05 *
1
2
* 146. 14 *
1
1000
= 0. 0370 𝑔
Distribution Coefficient (Solution extracted once)
𝐾 =
0.1114−0.0829
10
0.0829
10
= 0. 3438
Distribution Coefficient (Solution extracted twice)
𝐾 =
0.1114−0.0370
5
0.0370
10
= 6. 6919
Percentage Yield (Single Extraction)
𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝑌𝑖𝑒𝑙𝑑 =
|0.0829−0.1114|
0.1114
* 100% = 25. 38%
Percentage Yield (Double Extraction)
𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝑌𝑖𝑒𝑙𝑑 =
|0.0370−0.1144|
0.0370
* 100% = 66. 79%