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Experiment 2 - Extraction: BCM624L

1. This experiment aims to differentiate between simple and multiple solid-liquid and liquid-liquid extraction techniques and determine their extraction efficiencies. 2. Caffeine was extracted from tea leaves using solid-liquid extraction with sodium carbonate solution followed by liquid-liquid extraction of the aqueous extract with dichloromethane. 3. Calculations were shown to determine the solubility coefficient KD of caffeine in water and dichloromethane, and the amount of caffeine that can be extracted through single and multiple extractions using given volumes of each solvent.

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94 views15 pages

Experiment 2 - Extraction: BCM624L

1. This experiment aims to differentiate between simple and multiple solid-liquid and liquid-liquid extraction techniques and determine their extraction efficiencies. 2. Caffeine was extracted from tea leaves using solid-liquid extraction with sodium carbonate solution followed by liquid-liquid extraction of the aqueous extract with dichloromethane. 3. Calculations were shown to determine the solubility coefficient KD of caffeine in water and dichloromethane, and the amount of caffeine that can be extracted through single and multiple extractions using given volumes of each solvent.

Uploaded by

Trisha Argao
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Experiment 2 – Extraction

BCM624L

csmadarang 2021
OBJECTIVES
1. Differentiate simple and multiple extraction

2. Practice solid-liquid extraction and liquid-liquid extraction

3. Determine the efficiency of a single and multiple extraction


EXTRACTION
• Separation technique based in solubility of a substance to a solvent
• “Like dissolves like!”
• Polar functional groups:
• hydroxyl (-OH)
• carboxyl (-COOH)
• formyl (-CHO)
• carbonyl (-C=O)
• amino (-NH2)
TYPES OF EXTRACTION
BASE ON PHASE
1. Solid – Liquid Extraction
2. Liquid – Liquid Extraction

BASE ON NUMBER OF EXTRACTION


1. Single Extraction
2. Multiple Extraction
CHARACTERISTICS OF A GOOD EXTRACTING SOLVENT
1. High solubility
2. Non-reacting
3. Immiscible
4. Volatile
5. Non-toxic
TEA (Camella sinensis)
Cellulose Flavonoid
structural carbohydrate Polyheterocyclic
compounds w/c gives
tea its color
Tannins
water-soluble
polyphenolics
Chlorophyll
green pigment

ALKALOID
ALKALOIDS
• “Natural Product” (secondary metabolite)
• N-containing heterocyclic compounds
• Very weakly polar/Hydrophobic
• Favors solubility in non-polar solvent
O O
HO
O N O O
O N
N N N
N
N
N H
O HO
caffeine nicotine cocaine morphine
CAFFEINE
• Natural Product
• Purine nucleotide metabolite O
• IUPAC Names
• 1,3,7-trimethylxanthine
N
N
• 1,3,7-trimethylpurine-2,6-dione
O
• Health Effects N
• CNS acting N
• Increase BP and RR
• Diuretic caffeine
METHYLXANTHINE FAMILY
O O

N
HN NH
N
O
O N
N
N
N
xanthine theophylline O
O

HN N
N
N
O O
N N
N
N

theobromine caffeine
SOLID – LIQUID EXTRACTION
Tea Leaves
cellulose, chlorophyll, tannins
(gallotannins), flavonoids,
alkaloids (caffeine)

+ aqueous Na2CO3 solution


heat

Residue Aqueous Extract


cellulose chlorophyll, tannins, gallic
acid, flavonoids, alkaloids
(caffeine)
LIQUID – LIQUID EXTRACTION Aqueous Extract
chlorophyll, tannins, gallic acid
flavonoids, alkaloids (caffeine)
+ DCM

Aqueous Layer Organic Layer


Tannins, gallic acid, flavonoids Chlorophyll, alkaloids (caffeine)
+ anhydrous Na2SO4

Organic Layer Residue


Chlorophyll, alkaloids (caffeine) Na2SO4 + water + water soluble
impurities
evaporation

CRUDE CAFFEINE
Chlorophyll, alkaloids (caffeine)
QUANTIFYING THE COMPOUND
KD (solubility coefficient) – ratio of solute in the two solvent

Xorg
Corg Vorg
KD = =
Caq Xaq
Vaq

K D Vorg
Xorg = X0
Vaq + K D Vorg
FORMULA FOR MULTIPLE EXTRACTION
i
Vaq
Xi = X0
K D Vorg + Vaq
Xi = amount left in aqueous layer
X0 = original amount in aqueous layer
Vaq = volume of aqueous layer
Vorg = volume of organic layer
i = number of extractions
100𝑚𝑔
Corg Caffeine was extracted from 10.0 grams of tea leaves
KD = = 2.5𝑚𝐿
Caq 100𝑚𝑙 (containing 0.5% caffeine) by solid-liquid extraction
20𝑚𝑙 using 100.0 ml of water and liquid-liquid extraction
8 (60)
using DCM. Initial tests on the solubility of the caffeine
Xorg =
100𝑚𝑙 + 8 (60)
50𝑚𝑔 on the two solvents require 2.5 ml of DCM and 20.0 ml
of distilled water to completely solubilize 100.0 mg of
caffeine.
2
100 1. Compute for KD
Xi = 50𝑚𝑔
8 (30) + 100 2. How much caffeine can be extracted by single
extraction using 60.0 ml of DCM?
Xi = amount left in aqueous layer 3. How much caffeine can be extracted by two
X0 = original amount in aqueous layer successive extraction using 30.0 ml of DCM per
Vaq = volume of aqueous layer extraction procedure?
Vorg = volume of organic layer
i = number of extractions
End

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