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!