Article by Travis Cesarone, Cannabis Life Network
Earlier, we discussed unknown compounds found in cannabis oil after other processes such as distillation and even decarboxylation. Don’t worry though, those unwanted side reactions can be limited with simple techniques.
What are distillation and decarboxylation?
Active cannabinoids are normally formed from acidic ones through a process known as decarboxylation. That is when the acid group falls off of the THCa molecule and leaves behind active THC, for example. But, heat is always required for this reaction.
A recommended alternative to distillation is oftentimes the decarboxylation of pure cannabinoid fractions. Yet, the number of side reactions that occur after decarboxylation compared to distillation depends on the finer points of the process. (1, 2)
CLN’s resident scientist, Dr. Markus Roggen, released a study in Chem Archive with his colleagues in November 2020 that detailed THCa and CBD-acid decarboxylation. Dr. Roggen received a Ph.D. in organic chemistry, so naturally, the paper dives deep into the technical ins and outs of the process. Their study includes an explanation as to why THCa takes far less time to decarboxylate than CBDa.
“…the hydrogen plucks the hole…”
Decarboxylation and distillation, similarities, and differences
I called Dr. Roggen for a pedestrian explanation from an expert on the nuances of cannabinoid decarboxylation. He is also the founder of CBDV (Delic Labs) a research lab licensed by Health Canada to study cannabis and psilocybin.
Can you explain how general decarboxylation differs from distillation?
So, it’s a different processing step aside from distillation. In both cases, decarboxylation and distillation, you use heat. So, from that aspect, a lot of the same things can happen, such as isomerization.
There is one big difference between decarboxylation and distillation, which is that distillation is generally done under vacuum, or reduced pressure. So, you suck out all of the air from the system. There is nothing in the gas-phase above the THC [or CBD] and other compounds in the oil because there is no gas-phase – it’s a vacuum.
Decarboxylation is not done under vacuum, or, at least, not a very good vacuum. Therefore, you still have oxygen in the atmosphere. So, that is definitely quite important because now, we not only have heat, we have oxygen. And, that can cause other reactions. So, having oxygen [in the system] oxidizes THC, and that is when THC turns into CBN (cannabinol).
Dr. Markus Roggen
You previously mentioned the use of a CO2 environment during decarboxylation to limit unwarranted side reactions.
CBN is the oxidized form of THC, which means you need oxygen in the system to go from THC to CBN. So, therefore, under decarboxylation that can happen. Therefore, you should do decarboxylation under CO2 or nitrogen.
CO2 is often cheaper and more available in production sites. But, nitrogen would be the classic set-up you would do it under. And if you want to be really sensei, then you would do it under argon. But, that is what research centers do because [argon] is expensive.
Dr. Markus Roggen