Decarboxylation under Vacuum?

Agreed about the crude bit, I would never try to decarb something that had terpenes in it unless I was vaping it, haha.

If you’re trying to decarb large volumes of oil the time/temp ratios you listed simply wouldn’t do the job.

you asking me or whoever Macleod is? Either way, I know the reaction is, for all intensive purposes, not isentropic (i.e. irreversible) because you don’t observe an equilibrium between THCA and THC during decarb, it all pushes to THC eventually. That is to say, no THC reacts with CO2 (at least during typical decarb conditions, you need other reagents to achieve this) to produce THCA. Otherwise, after 10 hours of vigorous decarb you would still be seeing some amount of remaining THCA because that would be the equilibrium condition. My point is, Le Chatelier’s principle only applies to reversible reactions with dynamic equilibria, which decarb of THCA is not. So removing CO2 from the system will have no effect on the direction that the reaction proceeds. You could always attempt the corollary by decarbing at 2500 psig of CO2 and see if it goes any slower :stuck_out_tongue:

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I think regardless of vacuum or not, decarboxylation is going to require the same energy to break the bond keeping the carboxylate group attached to rest of molecule. It’s a chemical process. Decarbing under vacuum can prevent subsequent oxidation though.

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What water is being produced in decarboxylation? C22H30O4 -> C21H30O2 would only be the removal of 1 CO2

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So since we have agreed that decarboxilation is a heat reaction.who is willing to fill their miner
Bucle her up in high pressure clamps
Put in Some oil of Wich terpene content is known decarboxilate with heat and presssure say 25 bar
And test the terpene content afterwards
I would think that 6 hours at 90c gets the same decaboxilation % as 1.5 hours at 135C
And If course same oil at ambient conditions decarboxilated and a report on that
Compare what advantage decarboxilation under pressure has
I believe that live resin decarboxilated like this might make Some mighty fine vape carts😀

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Interesting I have some mighty fine. Full spectrum I would love to decarboxylate Under Pressure to preserve terpenes I could probably Cobble together a closed loop base 10 x 10 or 12 by 10 spool but I would only be able to get to about 150 to 180 PSI not 25 bar LOL then again I don’t have a GC yet so I wouldn’t be able to get Analytics on it

DECARB%20RATES

This was posted on another forum from a member named “fft” with only two posts total:

I totally agree with your comment on doing some testing in real life conditions. With HPLC pricing coming down, I’m hoping one of the labs will so some practical testing around time / temp for everyday applications like cannabutter.

In the meantime, your other comment motivated me to do some calculations using a paper I read recently on the reaction rate of THC decarboxylation. The reaction rate follows a first-order rate law, so by plugging in numbers I was able to calculate the reaction rate at a range of temperatures:

DECARB%20RATES

Sorry for the huge table. Anyway, at different temperatures I calculated the reaction rate (middle column). In the right column I compared the rates to get a relative sense of how much more time was needed to get the same results as a decarb at 230F. For example, at 212F it takes 2x longer to convert the same amount of THCA to THC as it does at 230F.

What this suggests is that while, yes, decarbing happens naturally at room temperature the rate is quite slow. At room temperature of 70F, it takes ~3000x longer to decarb as it does at 230F. This jibes at a high level with some other research that looked at how quickly the components of hash and hash extract converted/degraded at normal storage temps.

At the 115F dehydrator temperature, it takes 207x more time to get the same results as it does at 230F. Now, if I usually decarb in the 230F oven for 30 minutes, that doesnt mean it should take 207 x 30 minutes at 115F, because a good portion of that original 30 minutes is used to heat the weed to temperature. But best case it would probably take a few days in the dehydrator to get a decent decarb.

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Man i am sorry to say No in house analitics over here
But i remember back in the days When making RSO in a Rice steamer
First the solvent gets out
Then the water
And then You Could see decarboxilation by the size of bubbles and way iT “cooked”
But the Rice coocker would not pass 100C
So had to keep pressing the cook button :grinning: Eventually the decarboxilation seized
Don t remember the time frame
But My lab report came back with verylittle thca so sure iT s possible
And iT didn t seem like days

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Tread that has Some interesting similaryties

Exactly!

But we need to pull vac and add some N2 too

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Yep
I would prepare pressure chamber
With a vent valve set at maximum pressure allowed for that chamber
Pull vacuum bring to permitted pressure
With N2
Bring on the heat for the time that seems fit at the temperature that seems fit
Should not be to hard setting up this sort of rig
:grinning: So who is gooing to write history on this one :sunglasses:

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How would the pressure shift in the headspace as heat is added and co2 generated? I imagine a small prv set to just under the max your decarb vessel is rated for would be a must for this process just in case?

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Sorry the vent valve = pressure release valve😀Damn forigners

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Yes sorry prv is pressure relief valve or PSV pressure safety valve I’m in the oil and gas business so I’m used to calling them that

I would like to second this piece of information. The reaction depends on an input of a particular amount of energy per mole of material to be decarbed. The vacuum removes CO2, but would not really accelerate the reaction in any practical sense, nor would it change the activation energy required for the reaction.

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But iT avoids o2 contact !

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Did you ever find it? ty.

Only the bottom right was done in a closed reactor, but you can see the difference it made. The sum CBD content decreased by about half after 120 minutes. And just the CBD content also decreased which was not seen in the other trials. This paper was just decarbing the oil on like a glass plate or something if I remember. @Bonevader

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Hi BR, could you share the link of this test??

Thanks

@MMP_materia_labs

Citti, C.; Pacchetti, B.; Vandelli, M. A.; Forni, F.; Cannazza, G.; Analysis of cannabinoids in commercial hemp seed oil and decarboxylation kinetics studies of cannabidiolic acid, J. Pharm. and Biomedical Analysis, 2018, Vol 149. Pg 532-540