extracting organic caffeine in a small room martin the morph-man
TRANSCRIPT
EXTRACTING ORGANIC CAFFEINEIN 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• 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
• 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”
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!