I was in my first semester of Organic chemistry and had recently synthesized aspirin when Graywolf brought THC-O-Acetate to my attention.Our research into Acetate started and we were all very impressed by the outcome of our first reaction
We have since followed this procedure many times with varied efficiency This variability was caused by and directly proportional to the amount of essential oil in the reaction.The more oil the less efficient the reaction. The maximum amount of oil I use is 20g.
When making aspirin, salicylic acid is the raw material for the reaction, Acetic Anhydride is the conjugate and Sulphuric acid (H2SO4) *is the catalyst.
The similarities between Salicylic acid and THCA are the carboxylic acid groups that direct the acetic anhydride to form an ester with the phenolic hydroxyl (OH). In fresh plant material of cannabis, most cannabinoids are present as their carboxylic acid form, known as acidic cannabinoids [Shoyama, 1975].
Since carboxylic acid and hydroxyl groups are polar and hydrophilic, small amounts of THCA are soluble in water. They can be precipitated at a higher PH and made insoluble at a low PH which can be used to our advantage. See our high purity extraction page for more details
When THCA is converted to THC-O- Acetate, the polar C-OH becomes C-O-CH2C=O-CH3. The carboxylic acid group is hydrolyzed (forms water) by the heating with the H2SO4 which reacts with excess Anhydride to produce acetic acid which reacts with regular THC at the hydroxyl group to form more THC-O-Acetate.
Simpler than it sounds, this is a highly efficient reaction, when *catalytic volumes of H2SO4 are added and a Molar excess of acetic anhydride is present.
NOTE THIS DISCLAIMER:
Do not attempt this procedure if you are not qualified or without the proper Chemical fume hood and proper personal protection equipment.
Sulfuric acid is highly corrosive, and Acetic anhydride is not only highly corrosive, but as flammable and explosive as gasoline. Not to mention Hexane is highly flammable and explosive! You should read, understand, and have ready a Material Safety Data Sheet (MSDS) for all chemicals you have.
We neither recommend this procedure or accept any responsibility if you elect to try it yourself.
- Face shield
- Chemical goggles
- Respirator with acid cartridge
- Chemical apron
- Elbow length gloves
- Fume hood
- Heated Stirrer
- Flat Bottom boiling Flask
- Alhin Reflux condenser
- 5 gal bucket of ice water
- Aquarium water pump
- Pasteur pipette’s
- Beakers of various sizes
- Graduated cylinders
- Coffee filter and funnel
- Glass separatory funnel
- Dry Ice in a foam cooler
- ½ gal 95% Ethyl Alcohol
- ½ gal Denatured alcohol
- Hexane HPLC grade
- 98% Sulphuric acid
- 98% Acetic anhydride (controlled substance)
- 2 gal distilled water
- 200g Kosher salt
- Baking soda
- Dry your extract in an oven at 220F until thoroughly dry and free of any alcohols.
- Dissolve your extract into an alkane solvent such as hexane (HPLC grade)
- In a flat bottom boiling flask combine extract in a 1:2.5 w/v ratio of oil to acetic anhydride. (1g + 2.5mL).
- In an ice and water bath; add 2.5 drops/g oil of 98% H2SO4 slowly down the side of the glass swirling gently after every couple of drops.
NOTE: This is where things can hit the fan! You should have proper PPE including a face shield, chemical resistant apron, and elbow length chemical gloves. This again should be done in a certified fume hood by qualified chemists. If you try this and it goes wrong, it’s not our responsibility.
- Once the solution has cooled place a stir bar in carefully to avoid splashes.
- Put on a stir plate and begin stirring vigorously
- Place a reflux condenser onto the top
- Begin heating until the vapor is being condensed at the second bulb. This takes a bit of adjusting to get to the perfect plate temperature versus condenser water flow.
- Start a timer for 60 min for up to 10g and add 60 min for up to an additional 10g of oil.
- Turn off the hot plate but continue to stir
- When cooled slightly add 1mL (/g oil) of distilled water drop wise against the glass.
- Vapors containing acetic acid will escape from the top. This is normal. DO NOT INHALE VAPORS!
- Pour liquid into a separatory funnel, wash flask clean with hexane and pour into funnel. Wash flask of anything left with 95% non-denatured alcohol pour into funnel.
- Prepare 2 gal of distilled water with 100g kosher salt dissolved in each.
- Once the water can be distinguished from the hexane begin draining the water.
- When you are close to the emulsion layer, stop and add salt water until the funnel is almost full.
- Cap and mix by inverting several times, uncap or the pressure will shoot the lid off.
- You should have a lower water layer an emulsion layer and an upper organic layer.
- Continue washing with salt water until both gallons are empty.
- Drain the organic layer into a clean beaker and place into an oil bath @ 250F until dry.
- Test a small drop of acetate on a watch glass with some baking soda dissolved in water. If it fizzes, re-suspend acetate in hexane and wash with baking soda and water until it stops bubbling. Re-separate water from organic in funnel.
- Dry at 250F
- Re-dissolve in 95% Ethanol and place beaker into a shallow, denatured alcohol and dry ice bath for at least 5 min.
- Pour liquid through a coffee filter
- Discard filter and dry the acetate by boiling off the alcohol.
- Wash and dry 2 more times with ethanol