Extraction

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Extraction of Caffeine from Tea Leaves

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Simple Extraction of Caffeine from Commercial Tea

Dan Angelo Matias, Jazreel Clark Mallari, Renai Eunicia Matic, Hans Lorenzo Mercado, Celine Nicole Mindanao, Carmina Mislang

Group 6, 2C-MT, Faculty of Pharmacy, University of Santo Tomas

ABSTRACT

The study focused on the fundamentals of extraction and extraction in general. Specifically, it aimed to extract caffeine from
tea and to calculate its percentage yield.
Commercial tea (brand: Jasmine Tea) was used as the matrix from which caffeine was to be extracted. Approximately 10 g of
tea leaves was boiled in a beaker where anhydrous sodium carbonate was dissolved earlier. Dichloromethane was used as the organic
solvent which served as the extracting substance. Consequently, approximately 0.1299 g of caffeine was acquired which computed to
1.299 % yield.

INTRODUCTION
The study focused specifically on Liquid-Liquid
Extraction, which is defined as a well-established
separation technique that depends on the unequal
distribution of a solute between two immiscible
liquids. The initial feed liquid containing the solute
is brought into contact with a solvent that is selected
to have a greater affinity for the solute. The process
of extraction uses two immiscible phases: the
aqueous phase and the organic phase. Extraction
revolves mainly around the concept of polarity
where “like dissolves like”. Hence via this
principle, any organic solutes suspended in the
aqueous phase will tend to be dissolved instead in a
less polar phase. Extraction also takes advantage of
the considerable difference in the densities of the
two phases, where the denser of the two will occupy
the bottom layer, hence making use of a separatory
funnel in order to completely separate the two
phases. As for the study, extraction was
demonstrated by the use of the tea solution as the
aqueous phase and dichloromethane as the organic
phase.
Tea is defined in general both as a plant or
the beverage produced from the plant. The tea plant
has the scientific name Camellia sinensis, which is
an evergreen related to the camellia. In herbal
medicine, tea has been regarded as a dietary source
of caffeine and astringent tannins. Caffeine has the
IUPAC systematic name 1,3,7-Trimethylpurine-2,6-
dione, is used as central nervous system stimulant,
mild diuretic, and respiratory stimulant, and is the
main organic component of tea, together with
tannins.
Meanwhile, dichloromethane (or methylene
chloride, CH
2
Cl
2
) is an organic compound
commonly used to decaffeinate coffee and tea
beverages. Although immiscible in water, it is
miscible in many organic substances.
The study centered on the principles
involved in extraction, thus, its further analysis will
provide supplementary information to what has
already been known about the said process. Also, it
will shed some light on the different properties of
compounds, specifically, organic substances.
The study aimed to extract caffeine and
minute amounts of organic compounds from tea and
to compute the overall amount of caffeine obtained
by computing the percentage yield. The study also
aimed to demonstrate the extraction process in
general and to show the principles involved in the
process.

MATERIALS and METHODS
A. Sample Used
Commercial tea, specifically, the brand
Jasmine Tea, was used in the experiment
B. Procedure
Specifically, the set-up done is simple
extraction. This utilized a Bunsen burner, a
separatory funnel, Erlenmeyer flasks, glass rod,
evaporating dish, iron stand, iron ring, iron clamp,
tea bags, sodium carbonate (Na
2
CO
3
),
dichloromethane (CH
2
Cl
2
), and sodium sulfate
(Na
2
SO
4
).
Firstly, 4.4 g of anhydrous sodium carbonate
was dissolved in 100 mL distilled water in a beaker.
Ten grams of tea leaves (inside tea bags) were then
added to the sodium carbonate solution and then
heated for 10 minutes on a low flame. The tea
solution acquired was left alone for 5 minutes in
order for it to cool down and be easily filtrated
afterwards to get rid of any particles still suspended
in the solution. The solution was then extracted with
60 mL dichloromethane in a separatory funnel. This
was done by swirling the DCM-tea mixture upside
down. Any emulsion (suspension of one liquid as
droplets in another) formed is removed by stirring
the mixture gently. It was then left standing for
some time until there were two clearly visible
layers. The organic layer (the bottom DCM layer)
was then drained into an Erlenmeyer flask
containing half a spatula of anhydrous sodium
sulfate. The extract was decanted to get rid of the
visible particles suspended in the mixture. The
decanted extract was then heated on a hot plate (to
maximize evaporating rate) until only a residue can
be seen. The residue was weighed and the
percentage yield was calculated.

RESULTS and DISCUSSION
Approximately 0.1299 g of caffeine was acquired
from the whole extraction process and was
computed to be 1.299 % of the tea solution. The
results show that the commercial tea used in the
experiment (Jasmine Tea) contains the said
percentage of caffeine.

Tea Brand Jasmine Tea
Weight of Tea Leaves 10 g
Weight of Evaporating
Dish + Caffeine
121.8124 g
Weight of Empty
Evaporating Dish
121.6825 g
Weight of Caffeine 0.1299 g
Percentage Yield 1.299 %
Figure 1 Data
The above table shows the values gathered from
the experiment. These values were then used to compute
for the percentage yield.





Formula









Computation for Percentage Yield
The preceding formula and computation shows
the calculations that are done to compute for the
percentage yield of caffeine from the initial weight of tea
leaves.

Caffeine, as already been stated, is an
organic compound. Although this is true, it is still
relatively soluble in water (solubility in H
2
O:
approximately 16 mg/mL at room temperature),
because of its molecular structure (see Figure 2).
The introduction of dichloromethane, which is a
non-polar organic compound, takes advantage of
the higher solubility of caffeine in non-polar
compounds (solubility in DCM: approximately 102
mg/mL).












Aside from caffeine, tea contains other
organic compounds, such as tannins, that might
render the extract impure because tannins will also
be dissolved in dichloromethane. This is the reason
why sodium carbonate was initially introduced in
the tea solution. The action of the sodium carbonate
involves converting the tannins into their salt form,
hence, they will be ineligible for dissolution in
dichloromethane, thus, only the caffeine will be
dissolved in the said solvent.
The extraction process also utilized the
relative differences in the densities of the aqueous
phase (tea solution) and the organic phase
(dichloromethane). Dichloromethane has a density
of 1.325 g/cm
3
at 25°C, while water has a standard
density of 1.00 g/cm
3
. Due to this, the solvent,
dichloromethane, occupied the bottom layer, while
consequently, water (aqueous solution) occupied the
upper layer.
Immediately after drainage, sodium sulfate
was introduced. This further eliminates any water
molecules, hence, drying the solvent before
evaporating.






Figure 2 Molecular Structure of Caffeine
REFERENCES
Books & Encyclopedias:

(2014). Tea. The Columbia Encyclopedia, 6th ed.
Retrieved August 25, 2014 from
http://www.encyclopedia.com/doc/1E1-tea.html

Rossberg, M. et al. (2002). Chlorinated
hydrocarbons. Ullmann's Encyclopedia of Industrial
Chemistry. Retrieved August 25, 2014 from
http://onlinelibrary.wiley.com/doi/10.1002/1435600
7.a06_233.pub2/abstract

Stargrove, M. B. et al. (2007). Herb, nutrient, and
drug interactions: clinical implications and
therapeutic strategies. St. Louis, Missouri: Mosby
Elsevier. Retrieved August 25, 2014 from
http://www.google.com.ph/books?hl=en&lr=&id=4
9kLK--
eumEC&oi=fnd&pg=PR11&dq=Herb,+Nutrient,+a
nd+Drug+Interactions:+Clinical+Implications+and
+Therapeutic&ots=glefqvAvbd&sig=rn

Stevens, G. W. et al. (2001). Extraction, liquid-
liquid. Kirk-Othmer Encyclopedia Of Chemical
Technology. Retrieved August 25, 2014 from
http://onlinelibrary.wiley.com/doi/10.1002/0471238
961.120917211215.a01.pub2/abstract

Internet:

http://www.drugbank.ca/drugs/DB00201#pharmaco
logy

http://www.kentchemistry.com/links/bonding/Like
Dissolveslike.htm

http://www.khalidshadid.com/uploads/3/9/2/0/3920
808/caffeine.pdf

http://www.oehha.ca.gov/water/phg/pdf/dcm.pdf

http://www.sigmaaldrich.com/chemistry/solvents/di
chloromethane-center.html

http://xula.edu/chemistry/documents/orgleclab/14C
aff.pdf

https://www.sigmaaldrich.com/content/dam/sigma-
aldrich/docs/Sigma-
Aldrich/Product_Information_Sheet/c0750pis.pdf









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