How to Convert THC Delta 9 to THC Delta 8

by Paul on December 5, 2018

Delta-9-Tetrahydrocannabinol (THC)  is a naturally occurring isomer of THC found in cannabis plants.  It’s psychoactive effects are well known.  While delta-9-THC is the most abundant isomer of THC, there is interest in the lesser studied delta-8-THC isomer.

IUPAC Naming Convention

Detla 9 THC and other isomersThe diagram below has numbered positions on the top left ring structure.  If the double bond is at the 9 position then the molecule’s name is delta-9-THC.  If the double bond is at the 8 position the molecule’s name is delta-8-THC.

The molecule pictured is delta-8-THC for example.

The reaction

Delta-8-THC isomer can be made from Delta-9-THC in a spinning band distillation system.  Mix in 4% acidic alumina silicate with your extracted and winterized crude cannabis oil.  Distill the cannabis oil and collect the THC distillate as you normally would.  The combination of the acidic alumina silicate and boiling flask heat will catalyze the rearrangement of the THC molecule from delta-9 to delta-8-THC.

The effect

Delta-8-THC is said to give a less intense and longer lasting high than the delta-9 isomer.  Some are experimenting with different ratios of delta-8 to delta-9.  If you have tried delta-8-THC, let us know about your experience!

Warning – Lawyer Stuff

Use this information at your own risk.  Please use some common sense if you want to try this.  Find and SOP from a trusted source.  Don’t make your first attempt with a large batch of crude extract ($$$).  It may take a number of tries to perfect the technique.  Experiment with small batches that won’t break you if they fail.  Move up in batch size as your skill level and confidence increase.

Posted in cannabis-distillation

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  • Thanks for the great blog and valuable information.

    Can I trouble you for help on the brand and item number you used for acidic alumina silicate?

    This would really help me.

  • Hello,

    I’m a Army Combat Veteran with TBI, PTSD and tons of hardware now in my back. Is there any studies how it helps with TBI and PTSD?

    Also, could you please provide me with step by step instructions (recipe) on producing/extracting Delta 8 for vape pens, equipment needed, where to get the equipment, brand and item number of the solvents used?

    • Hi,

      I do not have any evidence for its efficacy for specific conditions. Delta 8 does have a measured lower psychoactivity and anecdotally I have heard/read about people claiming it produces less paranoia and the other effects of an intense high.

      If you are interested in a start to finish process, you may be best off hiring a consultant. On this topic I really only know enough to get myself in trouble. I travel to many labs (and run many distillations), but I do not do this day in day out to know all the specifics.

      Here are some places to start:


  • Hi there! Thank you for sharing! What is the *typical* conversion percentage and yield?
    Example: you start with 555g of D9 distillate at 90% thcD9 potency.
    You run the D8 rxn, filter, rotovap and distill the resulting distillate.
    How much D8 distillate do you have at the end and what is the %D8 in the distillate? 50%D8 and 40%D9 ? Higher % D8 ?
    Looking forward to hearing back from you!
    -Andrew Gumbiner
    IG: aggumbi

    • Hi,

      The after distillation yield tends to be about 90-95%. High conversions (80%+ D8) are possible on cleaner material and with better reagents. My first attempt netted me about 15% D8 and 80% D9 from 85% starting material. Minimizing side reactions is important which is why higher cannabinoid material is preferred.


  • Hello, if my cannabis oil is made from thcv, will the conversion be delta 8 thcv? Thank you.

    • Hi,

      I am willing to bet yes. There was a study I read where the goal was to make CBN-v from THC-v which was successful. The ‘v’ in THCv is far away from where the reaction is happening so it shouldn’t really have an effect.

  • Hi,
    My distalit has been converting to Delta 8, with and with out the alumina. Why would it be doing so without the alumina. I am looking to keep my distalit as delta 9. Any advice would be greatly appreciated.
    Thank you

    • Hi,

      Other than a reaction with something in your boiling flask, the other possibilities are heat and time. If your runs take 10+ hours and you need to do multiple passes, even lower temps have the potential to cause conversion.

      If your distillation machine requires temps in excess of 220-230 C, you will see much more rapid degradation. Instead of trying to increase the temperature to distill, try achieving a deeper vacuum (lower pressure). This will decrease the boiling points of everything and remove oxygen.

      • hello i work and manage a health store and had a question. Is there a particular reason Delta 9 THC it would degrade into Delta 8 THC or into CBN? I have looked and tried to do my research to understand but most articles i find say that both are just the degradation through time, heat, and or light. What is causing it to choose to convert to Delta 8 or CBN?

        I look to have a deeper understanding so i can inform/educate my customers so they are confident in what they purchase.
        Thank you for your time.

        • Delta 9 THC will not degrade on the shelf to delta 8 THC. Delta 9 THC may very slowly degrade into CBN though. This is because CBN is an oxidation product meaning that heat, light, air, and moisture exposure will contribute to forming it. Either you need a lot of time (1-2 yr+) and/or a lot of exposure to those contributors to create more than a percent or two of CBN. The problem with creating CBN is that it is in reality only one of the possible oxidation products.

          Delta 8 THC on the other hand is formed through the combination of heat and an acid. This won’t just happen sitting in a cartridge or something on a shelf. Delta 8 THC will even more slowly oxidize to CBN, but it is more resistant.

          To make high potency Delta 8 or CBN, you really need a specific reactant. Proper packing and storage will prevent your products from oxidizing to anything radically different, keeping your labels and dosing accurate.


  • Are you suggesting the use of “Aluminum Silicate” or the use of “Alumina Oxide”?

    I’m pretty sure that its Alumina Oxide because that is typically acidic/activated, just wanted to confirm this.

    • Aluminum silicate can refer to a a wide variety of compounds, often including oxygen mixed in the structure. Aluminum oxide is slightly different though.

      A big class of these compounds are called zeolites. Zeolites are often called molecular sieves because they have tiny pores which can trap molecules that are of the right size. Sometimes these pores can be “acid activated”. These acidic pores are special because they can change the conditions for some reactions. ( By adding different elements at different parts in this big crystal structure it is possible to fine tune the physical and chemical properties.

      I have not used aluminum oxide for isomerization before. I have seen many different acids at even low concentrations cause isomerization though.


  • Can delta 8 THC be converted back to delta 9 THC?

    • Not through any process currently available. In theory it could be possible. But even if you could, I am sure it would be more expensive than the actual value being created.

  • Is CBN not fully oxidized THC? I was young to make some with h2o2 and heat thinking at some point it eluded become mostly CBN and it did seem lovely compared to CBD

    • I’m screen shooting that so if you user my process I’ll have grounds for a security interest based lien, or hmu and discuss rates, if I’m right.

      • It’s literally that, no vacuum, no crazy machines, no crazy solvents, although ofc I’m curious about how that would go, but I just boiled wax and strong h2o2 in a beaker which makes for a very cheap process and it came out nice but I didn’t have lab analysis available. I did do some colorimetric also using h2o2 that did show the pink fuschia of CBN

      • Hello friends, i am producer an distiller of delta 8 thc full spectrum i want to get delta 9 thc , how i do? How i get? Thanks

        Oscar santamaria from colombia 🇨🇴

    • CBN is oxidized THC. In terms of oxidation, Delta 8 = delta 9 = delta 10. There is also CBND which is the CBD equivalent to CBN. This post briefly discusses some of the changes and potential forms.


  • Are you saying that if you vape delta 8 products, you are essentially also vaping aluminum, since it requires an acid that contains the element aluminum?

    • No.

      First, there is more than one acid commonly employed to make delta 8. The use of acidic alumina is not very widespread. The most common acid used is probably P-TSA. One of the points of this post is that some common filter aides can cause isomerization rather than to use it as a reactant.

      Second even if acidic alumina was used, aluminum isn’t part of the THC molecule. This isn’t to say that distillate or other high purity samples can’t be contaminated by metals. It is just a different cause.

      All of this isn’t to say that delta 8 products can be unsafe for a variety of other reasons though.


  • Hey Luke, if my starting material was cbd distillate or isolate and I did the same thing would the end result be a blend of d9 and d8? Is there a way to convert to mostly d8 or d9 from cbd using this method?

    • The better starting material will always be the isolate over a distillate. This mostly has to do with side reactions and unwanted/unquantifiable products. Distillate can work, but you want to make sure it is well winterized at the very least.

      Yes, it will likely be a blend. The ratio of D8:D9 will change depending on a ton of different conditions. Getting a really high yield of one over the other can be difficult.

      There are more up to date procedures now that are freely out there now. If you go looking on especially. There they even cover some of the recommended clean up steps.


  • […] Of course, there are a few methods of conversion to achieve Delta 8 THC, such as converting Delta 9 to Delta 8 THC. […]

  • […] you can even convert delta-9-THC into delta-8-THC by mixing in 4% acidic alumnia silicate with your extracted and winterize crude oil, catalyzing […]

  • […] BR Instruments notes a simpler process for the conversion of delta-9-THC. “Delta-8-THC isomer can be made from Delta-9-THC in a spinning band distillation system,” they note. Namely, 4% acidic alumina silicate is mixed with crude cannabis oil. This combination is then distilled, but the distillate will be the rearranged delta-8 molecule. […]

  • Luke
    Do you have any info or opinion on the h2o2 comments?

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