EXTRACTING ORGANIC
CAFFEINE
IN A SMALL ROOM
Martin the Morph-Man
Overview
Caffeine may be isolated from
coffee, tea and other aqueous
solutions by a simple acid-base
extraction procedure
Disclaimer
• It is legal to extract compounds (e.g. caffeine) from a
wide range of natural sources
• It is NOT legal to extract compounds from some other
sources, nor to possess those compounds obtained
by any means
• This talk is for your general interest only
• You are urged NOT to apply the following procedures
to any natural products
• You are encouraged to be aware of the legal
implications of any extraction procedures performed
without legal sanction
Safety
Toxic
Flammable
Corrosive
Environment
Dichloromethane
Ethers
Hydrochloric
acid
DCM
Methanol
Acetone
Sodium
hydroxide
Chloroform
Benzene
Methanol
Carbon tetrachloride
Ethanol
Benzene
Toluene
Toluene
Theory: Caffeine and Alkaloid
Chemistry
• Alkaloids are heterocyclic organic compounds - ring
containing carbon and nitrogen
• May contain (non-ring) oxygen
• N and O confer acid/base properties
• Acid/base properties influence solubility in various
solvents
Theory: Acid-Base Extractions
Generally:
• N-atoms are charged positive in acid conditions and
are neutral in basic (alkaline) conditions
• O-atoms are neutral in acid conditions and are
charged negative in basic conditions
• Charged compounds are more soluble in polar
solvents such as water & methanol
• Neutral compounds are more soluble in non-polar
solvents such as ether and toluene
Target compound
NAME :
Caffeine
CHEMICAL NAME :
3,7-Dihydro-1,3,7-trimethyl-1H-purine-2,6-dione
ALTERNATE CHEMICAL NAMES :
1,3,7-trimethylxanthine; 1,3,7-trimethyl-2,6-dioxopurine; coffeine
ALTERNATE NAMES :
thein; guaranine; methyltheobromine; No-Doz
CHEMICAL FORMULA:
C8H10N4O2
MOLECULAR WEIGHT:
194.19
APPEARANCE:
White hexagonal or needle-like crystals
MELTING POINT:
238ºC
SOLUBILITY:
Water, Ethanol, Methanol, Acetone, Chloroform
LD50 Dog:
140mg/kg oral
LD50 Rat:
105mg/kg IV
LD Low (Lethal Dose):
Human deaths reported at less than 4 grams oral.
Technique
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1) Cook up
2) Clarify
3) Remove fatty impurities
4) Make solution alkaline
5) Extract alkaloids to organic solvent
6) Separate organic from aqueous phase
7) Repeat extraction to solvent (steps 5&6)
8) Dry organic solvent
9) Evaporate organic solvent
10) Purify compound by recrystallisation, often from another
organic solvent
Equipment
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Coffee/spice mill
Pyrex or stainless steel pans
Strainers, filter papers & funnels
Separating funnel
Drying dish & dryer
Measuring cylinders, pipettes etc
Reagents
• Acid: Hydrochloric, citric, acetic
• Alkali: Sodium hydroxide, ammonium
hydroxide
• Solvents: Dichloromethane, methanol,
diethyl ether, petroleum ether (Vietti™
lighter fluid)
Precautions
• Ventilation
– toxic volatiles
• No flame
– flammable volatiles
• Protective clothing
toxic or corrosive liquids
• Be discreet
– solvent smells attract attention
- “loose lips sink ships”
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Step 1: Cook-up
Step 2: Filtration
Step 3: Defatting
Step 4: Raise pH
Step 5: Organic solvent extraction
Step 6: Separation of phases
Step 7: Rinse organic phase
Step 8: Dry organic phase
Step 9: Evaporation & crystallisation
Mission successful!
Extraction of anything in a
small room
• Be careful
• Be discreet
• Be safe
Happy extractions and
happy travelling!