THC Acetate

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.



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.


Materials needed:

  • 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

Basic procedure:

  • 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
  • Enjoy

Attached Photo’s

Cannabis acetate equipment

Washing with saline solution

Separatory funnel

Adding salt water

Filtering through coffee filter.

Final product

63 responses to this post.

  1. Posted by Matt on March 9, 2017 at 1:51 PM

    You rekon 97% acetic anhydride would be suffecient for this reaction?


  2. Posted by joey on September 25, 2016 at 7:54 PM

    what is the average yield percentage on this method? lets say i have a starting material of 20g @ 80% potency after dewaxing and decabing.



  3. […] THC Acetate | Skunk Pharm Research LLC – So with all the hassle and risk, was the end result worth it? THC O acetate is legal in the USA as it is unscheduled Last time I checked, which is just about 10 … […]


  4. Posted by Eric R. on March 31, 2016 at 12:30 PM

    So with all the hassle and risk, was the end result worth it? THC O acetate is legal in the USA as it is unscheduled
    Last time I checked, which is just about 10 minutes ago…


    • Posted by on January 12, 2017 at 4:46 AM

      THC is most certainly illegal at the federal level, and is subject to the Federal Analog act, which constitutes any analogous or drugs of similar psychoactive effects– the penalties, which are that of the drug it is analogous too. It is an incredibly vague bill, however it covers a whole swath of chemicals because of it.


  5. After this process do all of your oil runs come out basically the same? In strength affect and flavor does it still vary strain to strain? How many milligrams of acetate would you say is an appropriate dose? Would you recommend against making oral capsules? I am looking for a way to take a controlled dose that is the same every time with out having to vaporize the oil. My thoughts were to maybe mix the acetate oil with some food oil and put it in a capsule but I read you saying there are down sides to ingesting acetate. As you seem to be very experienced in this I would ask your recommendation on how I should administer my oil. I am also wondering how many doses I would be able to get out of a gram of oil.

    Thanks for your time


  6. what fun to see folks doing organic synthesis in the shed. this was a fun substance to make in the basement lab back in the 70’s when we did not have the high yielding strains of today. After a prosperous med chem career with big pharma I may look at all this natural product isolation and derivatization again. Do you have a TLC system to monitor the reaction and products? and ever try a spray reagent like FeCl3 that reacts with phenols to check out the reaction?
    So what I think I would like to try is the synthesis of the acetate of the THCA for a direct aspirin adduct. It will require some finness due to the molecule being so prone to decarboxylation. An old man likes to feel no pain.


  7. How to turn it into a powder form


  8. very nice info , for other article search here


  9. Posted by Hugh on September 27, 2015 at 8:06 AM

    Very close to (or maybe is) a THCA-Ester, something that the Feds fear (potency, easy conversion to effective tablet form). The FDA even authored a paper on more or less this process, available on Medline.

    For the legal questions, the Feds have a new criminal statute that looks at intent rather than a specifically listed compound. Nasty stuff, that! The safety here is medical necessity and compassionate care, but they might forget that with an ester compound.

    Really interesting work. Cheers -Hugh


  10. Posted by Brian Carroll on April 28, 2015 at 5:32 PM

    I love this stuff……& since currently I have access to 92% pure THC sans terpins I believe this stuff will be quite popular in the next 5 years.
    Its not even specifically scheduled on a federal or state level
    Outlaw life……
    For life 😉


    • Posted by King of Hemp on December 7, 2015 at 7:20 AM

      All of this is definitely illegal on the federal level. I do not mean to rain upon your parades. Cannabinoid Freedom Fighters certainly are my people. They are welcome in my castle any time. If you look hard you will see that I am correct. Even Cannabidiol is a controlled substance. Some know this,Others do not. the problem is that the federal and even state laws are so technical in their language that only those gifted with the ability of scrutinizing word meanings and legal definitions can really say so with any accuracy. I have made a point to study the language of the federal laws. This might seem subjective, but I assure you that language is everything and that even with no legal definition to be found for a specific word, one is still able to define legal relevance from even vague and nonspecific legal wording. I do not want to give any examples as they would only fuel something I do not want to fuel. Just know a good Prosecutor will find plenty of ammunition if he looks. He will likely need a chemist. I only know these things because I eat,sleep and shit in the world of chemistry. There is a difference in being able to read chemistry and do chemistry. Not everything is simple read and do. Do not let the internet fool you. The reason why you have go through legal channels for all this is not because Uncle Sam is cool. It has to do with safety. I realize this whole forum is one giant safety meeting. I do have to say that I have not observed one thing or anyone on here that even remotely done by a chemist. You basic training in organic chemistry is lacking. I see very basic chemistry training at best. You forgot some stuff in the acetate ester synth. Just saying. You also lack all the proper equipment to perform what you are doing. Suck it up and get a chemistry degree. Save your pennies, find someone with chemistry experience and then tackle your dream. Also get a really good fucking lawyer. Your going to need it. Even then you will still need the DEA permits. Prohibition ends soon, but it is not over. Do not push it. It might wreck all the hard work everyone has put into subverting the system.


      The King of Hemp


  11. Posted by Mr. Honest on February 6, 2015 at 6:59 PM

    Does this product cross any legal lines that the conventional extraction techniques do not? Is the federal monitoring of the chemicals a big concern?


    • I would encourage you to run it by your own attorney for the answer to that.

      We’ve used less than a liter of acetic anhydride in the last four years, and have only made it for medical purposes, so not sure what would happen under adult recreational, or if someone started using large quantities. It is also used to synthesize Heroin, so is indeed on the watch list.


  12. Posted by Steve-O-Acetate on February 1, 2015 at 1:34 AM

    Have you tried using butane as your alkane solvent instead? My organic chemistry classes would suggest that it would work, however butane is generally more volatile….I guess my concern is safety…Any thoughts?


  13. Posted by tehcook on October 3, 2014 at 7:03 AM


    You are speaking of converting THC to THC-acetate by using the side-product acidic acid.
    Could the THC-acetate also be made without using the acidic anhydride, by reacting THC and acidic acid with sulphuric acid as catalyst?
    I’m very curious if it could be done without the need of acidic anhydride, because it is hard to get and most people don’t like being closely monitored 😉

    Kind regards from the Netherlands


    • Posted by Steve-O-Acetate on February 1, 2015 at 2:04 AM

      Theoretically Acetic Acid can cause the esterification of THCA but this esterification reaction is far less favorable as it is reversible – you now have H2O in the equation and the presence of water will lead to hydrolysis of the THC-O-Acetate back to THCA. ….your yield is going to be low and probably not worth the trouble!….but if you are that curious give her the old college try!


    • Posted by Steve-O-Acetate on February 1, 2015 at 2:10 AM

      Oh and if you do decide to try it expect the reaction to be much much slower than with acetic anhydride….just a tip!


  14. Just curious, but isnt CBD its own analog? You mention CBD converting to THC, but as I understand CBD is created from its own synthase, using Cannabigerlolic Acid as its catalyst.


    • Posted by sharplystupid on August 21, 2014 at 9:45 PM

      Without looking into my notes, I believe CBD losses a propyl at some point and isomerizes to delta-9 (“Potency”, 1970s? see ‘isomerization’)


      • I tgought it was CBN that isomerizes into THC


        • Posted by tehcook on October 3, 2014 at 6:42 AM

          If a strong acid gets added to CBD it is converted to THC, which is what happens when the acidic anhydride gets added to the oil mixture.
          THC can turn to CBN under different conditions, but that usually only happens by extensive heating, UV-light or being in contact with oxygen for a long time.


  15. Posted by Jorge_C on July 3, 2014 at 4:12 AM

    How is the water solubility of THC-O-Acetate, any better than THC(A)? Comparable to THC-O-Phosphate?


  16. Posted by BhoDoc on July 1, 2014 at 8:40 AM

    Is acetic acid able to be used instead of the acetic anhydrous?


  17. Posted by adelina on January 8, 2014 at 9:50 PM

    I have breast tumor and lump and I heard that THC is a cancer cure.I want to buy some if you have.Thanks!


    • Officer, there is nothing for sale here! This is a non profit information based community. Ask your government for help. Good luck with your lump!


  18. Posted by Anthony Jonovich on December 21, 2013 at 3:49 PM

    What is the dry ice in the cooler used for? Is it for the ice water bath or the condenser?


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  20. Posted by tom on October 19, 2013 at 12:14 PM

    I don’t know if its the more i read the more stupid i feel? or the smarter i am getting? this is a lot of info to absorb. I think i need a safety brake.


  21. […] It is worthwhile to acetalize using sulfuric and acetic anhydride, which you might check out at Originally Posted by nocturnalreef Thank you first of for actually understanding and […]


  22. I don’t even know the way I ended up here, but I assumed this post used to be great. I don’t recognize who you are but definitely you’re going to a famous blogger when you are not already 😉 Cheers!


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  24. May I sample some, kind sir, before I take the plunge??


  25. Posted by Julian hinds on February 21, 2013 at 11:02 PM

    How to turn it into a powder form


  26. Posted by David Johnson on January 22, 2013 at 12:31 PM


    After this process do all of your oil runs come out basically the same? In strength affect and flavor does it still vary strain to strain? How many milligrams of acetate would you say is an appropriate dose? Would you recommend against making oral capsules? I am looking for a way to take a controlled dose that is the same every time with out having to vaporize the oil. My thoughts were to maybe mix the acetate oil with some food oil and put it in a capsule but I read you saying there are down sides to ingesting acetate. As you seem to be very experienced in this I would ask your recommendation on how I should administer my oil. I am also wondering how many doses I would be able to get out of a gram of oil.

    Thanks for your time 🙂


    • I would say that the variance that occurs is in yield and the taste. The more you wash it with water the better. The freshness has a huge affect on flavor. The bond that is created in this process is more susceptible to oxidation than the hydroxyl or carboxylic acid. So it starts degrading into THC and vinegar very soon after it is exposed to air. If you were to mix it into food or capsules I would suggest doing it while its fresh and mixing in an antioxidant like lemon juice or many other food additives along with an emulsifier. Otherwise be prepared to taste vinegar. Also the dosage is very hard to predict so buckle in for a ride until you get the dosage right. Batch to batch strength will also vary.


      • Posted by David Johnson on January 24, 2013 at 2:45 PM

        I was unaware until reading these comments that oxidization was something I needed to worry about, does it affect the taste when vaporized as well? What is the shelf life of THC acetate at room temperature vs. frozen? Do you have any ballpark as to dosage? How would you compare it to some good waxy BHO?


      • Posted by stephen d on September 22, 2013 at 12:47 PM

        Have you heard/read/experienced anything with propoxy ester THC? Don’t know much about it, but it’s apparently similar to this process but it uses propanoic anhydride, I just can’t find much at all on it.


  27. Posted by Bongstar420 on January 8, 2013 at 11:14 AM

    I am having a hard time seeing how you can legally use Acetic anhydride for this application or even afford to procure it with the way OMMP is set up. Isn’t it a federally regulated substance that you have to be approved of for purchase and doesn’t OMMP require no compensation for work and arn’t most OMMP card holders poor anyways? I’ve had the recipe and know how to produce sufficient extracts for years and have been limited due to regulations around chemical procurement in addition to a lack of demand for exotic cannabinoid formulations on top of the fact that an honest person cannot actually follow OMMP law unless they are rich enough to pay for most of the stuff and have enough time to do it, which I am not.

    Excellent work anyways, I commend you


    • Acetic anhydride is not illegal, nor is Cannabis Acetate any more regulated in Oregon, than any other part of the cannabis plant.

      They watch you closely when you buy it, because it can also be used to make heroin and explosives, amongst other things. We buy through our business account and keep all of our cards face up on the table. We have been open about our research and I have been publishing instructions for a couple of years now, without interference.

      It is also not horribly expensive, and it doesn’t take very much. We are still on our first liter.

      As far as compensation, no thoughts on the subject, other than there are no laws in Oregon against charging someone to process their own material and then giving it all back to them. What is illegal, is selling anything from the cannabis plant.

      Lastly, Cannabis Acetate is nothing to run shouting its accolades, or dangers through the streets, as it is probably no more potent than its parent stock, it just passes the blood brain barrier faster and arrives all at once.


      • Posted by dwalk on October 1, 2013 at 2:43 PM

        What company do you purchase through, and what type of business allows u to buy a controlled substance like AA? Sorry for the questions, I just wanna try this synthesis, I’ve been making and isomerizing oil for a few years now, this is my missing link. Please private email me if u feel in uncomfortable posting.
        Thanks so much,
        Ur friendly chemist:-)


        • We are a legal pharmaceutical research business and buy our AA in one liter lots from American Scientific Supply. It isn’t a controlled substance, just closely watched.

          You are right about us now being on a watch list, but we are not using it for the purposes that the folks that watch that sort of thing are watching for.

          It also takes very little to do what we do, so we are still on our first liter. Bet you we would have their rapt attention if we ordered a 50 gallon drum.


  28. Posted by fellowextractee on November 26, 2012 at 8:32 PM

    Is there any experience in eating the THC Acetate as well? Would you say the effort is worth the product?


    • We have vaporized and used acetate topically. Both are extremely medically effective for those methods. The down side to ingesting acetate is that it doesn’t have improved flavor over regular extract and since the ester is susceptible to oxidation into thc and acetic acid its probably best in Italian style dressings.


  29. Very interesting read. How were the effects are they up to snuff with the effects described in cannabis alchemy ?


    • Because it passes the blood brain barrier so much faster, the acetate arrives all at once, as oppose to coming on, so the effects most certainly make it seem more potent, but I’m not convinced that it is 3X, as presented in Cannabis Chemistry.

      Interestingly, despite the CBD also being isomerized into THC, the pain relieving effects when used in a topical, were also greatly enhanced. Less surprising is that the acetate form works better in e-cigarettes using glycerine or propylene glycol, than does the standard non acetate forms of oil.



      • Posted by Dankroots on February 21, 2014 at 2:30 AM

        Personally I believe the best application for this form is a inhaler type device. With the speed of the delivery i think it would rival sativix ?? second If it is a acid form at the end why can’t a basic “base to acid” salt percipitet be formed after to make a hcl form as is stage 4 as otto snow states about poppies


        • Its not an acid at the end. Its starts as an acid and ends as an acetate.


          • Posted by D. Gold on August 2, 2016 at 2:17 PM


            Maybe I can help with some input to this question. I wrote Cannabis Alchemy back in the early seventies, based on research I did in the late sixties.

            I only made the acetate three times. I had a limited supply of acetic anhydride, and used the last of it in an experiment gone awry when I accidentally inhaled the vapors from a large stainless steel pressure cooker that had about an inch of the liquid simmering in the bottom. Thought I might die for a good fifteen minutes as I tried to catch my breath. Hence, the directions for the glove-box / fume hood in the book. Please be very very careful with that stuff.

            The first acetate I made was an oil from somewhat better than average Columbian that was alcohol extracted in Columbia and shipped to the US an oil. It was rather mediocre as an oil, but its potency increased substantially on isomerization (indicating a high CBD content), and it changed dramatically again after acetylation.

            The second run was a strong Afghani hash extract from Mazar-i-Sheriff. It got substantially stronger on isomerization, but not all that much different on acetylation, and the effect didn’t change that much either.

            The best run was an oil extracted from Nepalese temple balls. After isomerization it was a good bit stronger. After acetylation, it was an effect that was just wonderfully different from any other I was familiar with at the time. Amongst the most pleasurable I have ever experienced … even to this day! (Actually, who the hell knows for sure. Fond memories from days gone past get better and better as the years progress).

            In all three cases, it seemed like it took a long time for the effects to begin. The Skunk Pharmers say that the acetate passes the blood brain barrier faster than regular THC resulting in a quicker effect. I’d go with what they say, having done the work many more times than I did, and they did it with with lab tested results.

            (While I would have loved to have the climate for research in 1969 that we enjoy now, there was something fun and exhilarating about doing the work in secret rooms dug out under Haight-Ashbury Victorian houses, trying to obtain chemicals by showing up at VW&R with two cars sans license plates … a big old Plymouth sedan being the blocker and an Austin-Healy with a Chevy engine being the getaway car, if we were lucky enough to have the purchase go through a the will-call).

            We did have good testing for a while. A company called Pharm-Chem in Palo Alto would test THC and CBD, and any other drug sent to them, for $15. Things were quite nice for underground researchers until Pharm-Chem started disclosing their findings on KSAN, the local radio station most into the San Francisco psychedelic music scene at the time. They called it the “Friday Afternoon Dope Report” and were shut down within a few months.)

            I stated in Cannabis Alchemy that Dr. Roger Adams (the true father of all cannabis alchemy) rated THC with a potency of 7.3 and THC Acetate with a potency of 14.6. I kind of accepted that to be gospel, after all, it did come from the great Dr. Adams.

            A few years after writing the book, I found an obscure report that covered Dr. Adams and his work, and discovered that his declarations of potency were based on the effects he observed after giving his extractions to his dogs. I saw pictures of the dogs, and they looked awful stoned, but not too happy.

            So, I would respectfully call into question Dr. Adams’ assigning of potency figures to the different forms of cannabinoids based on the physical appearance of his dogs. Which brings to mind a question I have had in my mind for damn near fifty years: Did Dr. Roger Adams sample his wares … perhaps in the noble manner of those eminent pioneers of modern science, Albert Hoffman and Sasha Shulgin? I would bet the answer is yes. He knew too much for just observing dogs.

            Something else I have been wondering for a long time, that perhaps somebody here knows the answer to: would it be possible to refine and concentrate white vinegar in a manner that a home alchemist might employ in order to effect the acetylation process?

            And big respect to GW and his crew for providing this forum. I hope to contribute to it from time to time.

            D. Gold

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