Isolation of Caffeine from Dried Tea Leaves Flashcards
It is an alkaloid and has base characteristics
Caffeine
Caffeine has the ____________, a framework that plays an important role in living systems
Purine Ring System
Caffeine is also known as:
1,3,7-trimethylxanthine
Caffeine is odorless, has a bitter taste and is ______________
Highly Soluble in Hot Water
What is the boiling point of Caffeine? (in celsius)
178°C
What is the melting point of Caffeine?
235-238°C
Caffeine acts as a ________ - are medications designed to increase the amount of water and salt expelled from the body as urine
Diuretic
Caffeine also ________ metabolism
stimulates
Caffeine also contributes to an increase in ____________ levels in the blood
Dopamine
Caffeine is also a ________ present in tea, coffee, cocoa, cola nuts and beverages.
stimulant
small doses of this chemical (blank) can** increase alertness** and reduce drowsiness and fatigue.
50-200 mg
Caffeine also affects blood circulation because the heart is stimulated and blood vessels are _____________ (vasodilation)
Relaxed
Large doses of caffeine (of over ________) can result in insomnia, restlessness, headaches, and muscle tremors.
over 200 mg
Continued, heavy use of caffeine may bring on (blank)
Physical Dependence
It is consists primarily of cellulose (the principal structural material of all plant cells)
Composition of Tea Leaves
Cellulose is insoluble in water, thus, can be separated from caffeine by ______________
Hot Water Extraction
It is a colored polyphenolic compounds of high molecular weight (500-3000 g/mol) that have acidic behavior.
Tannins
Tannins are ________ complex substances.
Water Soluble
It is responsible for astringency, color, and some flavor in tea.
Tannins
TRUE OR FALSE:
As much as 5% by weight of the leaf material in tea
plants consists of caffeine.
TRUE
It allows soluble components to be removed from solids using a solvent.
Solid-Liquid Extraction
Application of this unit operation include obtaining oil from oil seeds or leaching of metal salts from ores.
Solid-Liquid Extraction
They are readily soluble in hot water and is separated from tea leaves.
Caffeine and Tannins
It involves using a **liquid solvent to remove a liquid component ** from a liquid mixture.
Liquid-Liquid Extraction
It is known as **partitioning **
Liquid-Liquid Extraction
**TRUE OR FALSE: **
In Liquid-Liquid Extraction, the component dissolves preferably in the solvent.
True
What are the applications of Liquid-Liquid Extraction?
- Removal of Vitamins from Aqueous Solutions
- Aromatic Compounds from Crude Oil Fractions *(in chemical and mining industries and in the downstream recovery of fermentation products)
TRUE OR FALSE:
Frequently, one of the solvents is water or an aqueous
mixture (aqueous phase) and the other is a non-polar
organic liquid (organic phase).
TRUE
Liquid-Liquid Extraction comprises of two steps:
Mixing phase and phase separation
The solubility of caffeine in water is _______ ?
2g/100 g of cold water
The solubility of caffeine in dichloromethane is ______ ?
14g/100g
A procedure by which two liquids with different boiling points can be separated.
Distillation
Powerful technique for separating the component substance from a miscible fluid mixture by means of selective** evaporation** and **condensation. **
Distillation
What are the parts of Separatory Funnel?
- Stopper
- Teflon Stopcock
- Separatory Funnel Body
**PROCEDURE (Solid-Liquid Extraction) **
- What labels do you need to write in a 125 mL Erlenmeyer Flask?
Flask 1: Aqueous Layer
Flask 2: Organic Layer
- What measurements of the chemicals you need to place in a 250mL beaker with a watch glass?
- 10.0 grams of dried tea leaves
- 6.25 grams of sodium carbonate
- some boiling chips
- Pour ________ mL of Distilled Water into the beaker.
87.5
- Turn hotplate to ____. Heat the mixture to boiling for 10 minutes. (Start time when mixture starts to boil).
300°C
- ________ the liquid into a 250-mL Erlenmeyer Flask. Make sure that no solid particles will be included in the supernatant liquid.
Decant
- Cool the __________ to room temperature.
Aqueous Extract
PROCEDURE (Liquid-Liquid Extraction)
- Pour the cooled aqueous extract into a 125mL separatory funnel in the _______
fumehood
- Extract the solution with ________ of __________ . Mix by inverting the mixture in a rocking motion repeatedly. Take care not to shake the funnel too vigorously. (5 shakes by 5 sets)
15 mL of CH2CL2
- How many minutes you should let it stand the Separatory Funnel until the layers separate?
About 5 minutes
- Drain the CH2CL2 layer into a 125mL Erlenmeyer Flask #?
Flask #1
- What you should do next after draining the CH2CL2 in the Erlenmeyer flask?
- Repeat steps 2 and 3 using another 15mL of CH2CL2
- Combine the two CH2CL2 layers.
- Add a small amount of __________ to the pooled extract, and swirl the mixture for a few seconds.
Sodium Sulfate
PROCEDURE (Distillation):
- Filter the dichloromethane extract through a _________ into a ____________
cotton plug; 250mL distillation flask.
- What you should do after filtering the dichloromethane?
Assemble a distillation set-up
- ________ the evaporating dish to room temperature and weigh.
Cool
- Evaporate the dichloromethane to dryness over a ___________
Hot water bath
- Distill the dichloromethane and collect about ________. Take note of the _______
50mL; BP Range
- Transfer the remaining solution to a _____________
pre-weighted evaporated dish.
- Collect the ____________ of caffeine into a labeled vial and submit to your lab instructor
greenish-white crystals.
What is the solubility of caffeine in water?
2.17g/100mL water at 25C
What is the solubility of caffeine in a chloroform?
18.18g/100mL chloroform at 25C
The __________ is an expression of the relative preference of the solute for the solvents.
Distribution coefficient
What is the equation of a substance in each layer?
C1/C2 = Kd
What does C1 stands for?
Concentration of solute in layer 1
What does C2 stand for?
Concentration of solute in layer 2
