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EXTRACTING CAFFEINE FROM TEA

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by

Madi Johnson

on 14 June 2013

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Transcript of EXTRACTING CAFFEINE FROM TEA

Extracting Caffeine From Tea
Extracting Caffeine from Tea Leaves
Research Question: Which type of tea leaves (white, green, and black) has the most amount of caffeine?
Background Information:
- Caffeine is an alkaloid= 1,3,7-trimethyl xanine
- Naturally occurs in tea
- Amount of caffeine depends on..
- Type of plant
- Size of the plant
- Tea leaves contain 1.4% to 4.5% caffeine by weight
- The world's most used drug


Variables
Independent Variables:
- the different types of tea leaves (white/green/black)

Dependent Variables:
- the amount of caffeine in each type of tea leaves

Controlled Variables:
- the amount of solvent
- the amount of tea leaves
- the time
- the temperature during distillation

Hypothesis
MATERIALS NEEDED
- Paulsen Pure Black Tea Leaves
- Paulsen Pure Green Tea Leaves
- Paulsen Pure White Tea Leaves
- Beakers
- Distilled Water
- Funnels
- Stirring Rods
- 3 Hot Plates
- Filter Paper
- Vacuum Pump Machine
- Conical Flasks
- Conical Flasks With Arm
- Stop Watch
- Electrical Balances
- Sodium Chloride
- Calcium Hydroxide
- Beuchner Funnel
- 1-Propanol
- Anhydrous Sodium Sulfate
- Simple Distillation Apparatus
- Water Bath
- Acetone
- Evaporation Dishes
- Bunsen Burner
- Evaporation Dishes
- Boiling Stones
Step 1: Measure 15 Grams of Tea
Step 2: Heat 200mL and 100mL
Until Boiling
Step 4: Decant tea solution, press and pour out much of water as possible
Step 3: Turn Off Heat, Add and Stir 15g of Tea Leaves to 200mL Boiling Water for 10 minutes
Step 6: Add to the combined extracts (water from tea leaves)
- 23g Sodium Chloride
- 1g of Calcium Hydroxide
Step 5: Wash tea leaves twice more with 25mL of hot water
Step 7: Heat and Stir Solution for 15 Minutes
Step 8: Pour Solution Through Filters Into Beuchner Funnels Under Vacuum
Step 9: Transfer extract to separatory funnel; Extract with 25mL 1-Propanol (extraction solvent) four times
Step 10: Wash extracts once with 25mL of 10% aqueous NaOH solution
Step 11: Transfer to Erlenmeyer Flask, dry by adding Anydrous Sodium Sulfate
PART 2:
PURIFICATION OF CAFFEINE
EXTRACTION AND PURIFICATION METHOD
Step 12: Prepare a distillation apparatus



Step 13: Distill the extraction solvent (1-Propanol) from the caffeine.








Step 14: Stop distillation before flask is dry
Step 15: Take distilled solvent (1-Propanol), measure volume, and add it to the recycled solvent
Step 16: Rinse crude caffeine residue in flask with 10ml of acetone

Step 17: Weigh an evaporation dish

Step 18: Transfer crude caffeine and residue to the evaporation dish, weigh


Step 19: Heat with a hot plate until all acetone is removed, wait for dish to cool, weigh and record
Step 20: Purify caffeine with sublimation process
PART 1:
EXTRACTION OF CAFFEINE
TABLE OF INFORMATION
GRAPH OF WEIGHT
CONCLUSION
LIMITATIONS & IMPROVEMENTS
GRAPH OF SUBLIMATION
Black Tea will have considerably more caffeine than the Green Tea and White Tea will have the lowest level of caffeine out of the three.
Weaknesses and Limitations:
Improvements:
- insufficient lab equipment
- measurements not precise
- transferring extract between several containers
- difficult method: different interpretations
- time
- test different kinds of experiments with the tea leaves
- practice trials
-repeat the experiment with more samples
The hypothesis was supported by our collected data,
However upon further research, it has been stated that factors other than tea type influence the amount of caffeine:
Leave size and
Where it is picked on the
tea plant.
Full transcript