A Theory on BHO/Rosin Decarboxylation with Natural Terpene Preservation

[Dannywarbucks]

There are very few(if any) terps found in cannabis with a bp lower than 107C, so they won’t add to the.pressure much, if at all.

[Anonymouse]

@cyclopath

I suspect you neglected to use 6mol of CO2 on this second calc.

I did make the adjustment to moles and volume. Again, math is not my area. Here are my numbers for a 3kg batch:

N= 6.288 mol
R= 118.92 J/kg K
T= 383.15 K
V= 0.149 m3

PV=NRT, I still get 278 psi. Does that check out?

[Anonymouse]

@Anonymouse

As decarboxylation occurs, the CO2 gas by-product will begin fill and pressurize the headspace in the vessel, slowing down the decarb.

MEA CULPA

I did not mean to imply that the rate of decarboxylation is affected by a vacuum environment. I have never seen any empirical data to suggest otherwise and have actual experience which supports this idea. I apologize if my meaning was misinterpreted.

Again, my reasoning behind the vacuum environment during decarb is to allow ample room for the CO2 gas that will pressurize the vessel. These rough thermo calcs I did today seem to suggest that my reasoning may be accurate in that regard.

But, to repeat, vacuum will not speed up the decarb process. It’s a heat reaction that requires a specific amount of heat energy applied to break that molecular bond. It’s not a boiling point issue.

[406_Chemabis]

@Anonymouse

my reasoning behind the vacuum environment during decarb is to allow ample room for the CO2 gas that will pressurize the vessel.

The absolute volume of headspace that can be filled with the resulting CO2?! An extra 30 psi of CO2!!! if it arithmetically works linearly like that. Nonetheless, the vacuum of the headspace is a great antioxidant

[moronnabis]

[quote=“Anonymouse, post:1, topic:187315”]
The final process of degassing the oil will require much less energy “”as the butane/isobutane/propane-THC bond is much weaker than with THCA.””
(Double quotes intended to mean…a specific aspect I am referring to)
Interesting statement, The solution chemistry of THCA with alkanes is basically unknown… would you say that is a counter-intuitive notion you have arrived at. Can you elaborate a bit?

Any data or just observation is fine. …curious.

[cyclopath]

@Anonymouse

Again, math is not my area.

You and me both.

Question on How To Properly Decarb Crude

[edit: note that MW for THCA is wrong here. Used what the all-gnowing handed me without thinking…] maths?!? I’ve tried to get someone else to do this in public multiple times. guess I’ll give it a go… lets call 1 mole of THCA 315g, and use the approximation of 1g/ml to get the volume of our concentrate when we started. Call it 315ml. if we start in a 1liter container, and don’t deal with the fact that the density of our extract will change as we heat it, we can pretend we have a headspace…

I don’t buy that tripling the amount of extract in our 3.7liter container will result in such a small change in ultimate pressure.

1/4 the headspace and 3x the CO2 would have me ballpark 12x the pressure. which is consistish with the ~14x I suggested above. we are using slightly different numbers (yours being more specific to the non-ideal gas in question), so 12x vs 14x is not necessarily unreasonable.

I’ll probably dig a little harder at some point…

[Anonymouse]

@406_Chemabis

The absolute volume of headspace that can be filled with the resulting CO2?! An extra 30 psi of CO2!!! if it arithmetically works linearly like that. Nonetheless, the vacuum of the headspace is a great antioxidant

Yes, absolutely, the antioxidant properties are also another reason to perform the process in a vacuum.

@cyclopath

I don’t buy that tripling the amount of extract in our 3.7liter container will result in such a small change in ultimate pressure.

Neither do I. So I just realized this morning that we were calculating using the volume of the given number of moles at STP. We SHOULD have been calculating the actual volume of the vessel, accounting for the space occupied the oil! Lol, duh! Ha ha ha! Anyway, maybe I’ll post the math later, it’s all handwritten, here are the results. (given: 110C, 1kg bho = 1L bho, R=118.92 kg/J K)

1kg BHO, 6"x8" vessel P= 5,130 psi
3kg BHO, 6"x8" vessel P= 19,787 psi
1kg BHO, 6"x8" vessel P= 790 psi
3kg BHO, 6"x8" vessel P= 2,675 psi

@406_Chemabis

the van der waals equation maybe useful because we need to consider the intermolecular interactions between the terpenes that are most likely happening at high pressures and temperatures

I totally agree, the Van Der Waals equation is probably best suited for this calculation. At any rate, these pressures are extremely high and this process should be performed with close attention.

[cyclopath]

@Anonymouse

Neither do I. So I just realized this morning that we were calculating using the volume of the given number of moles at STP. We SHOULD have been calculating the actual volume of the vessel, accounting for the space occupied the oil!

Yep. That is a critical piece of the puzzle.

@cyclopath

as an approximation, I’m assigning 3 of the available 3.7 liters to our 3kg of extract.

@Anonymouse

At any rate, these pressures are extremely high and this process should be performed with close attention.

…and NOT performed in glass jars

[Akoyeh]

A PRV probably wouldn’t hurt, either…

[Anonymouse]

Yes! It’s in the equipment list from the write-up! Did you try it?

[Akoyeh]

We didn’t have any batches finish for decarb last week, but we’ll have more than enough to play with next week. We already perform a very similar decarb process, and we’d only be making minor changes to our current protocol. We recently had cured, decarbed product for vapes come back at just over 20% terpene content, so I know the process works. Now it is just about optimizing it.

[CuriousChemist22]

Little to no change in the before and after ratios of terpenes?

[Akoyeh]

Not from what my nose and eyes can tell. Smells just like the flower, only stronger (at least on this specific 20%er I’m referring to). Not sure I have analytics to back that up, as stuff earmarked for carts doesn’t get tested until it’s ready to go into carts.

[cyclopath]

@Akoyeh

A PRV probably wouldn’t hurt, either…

If ultimate pressure calc says you’re exceeding the value of your PRV, said prv may let some of your precious terpenes escape.

Still a requirement!!

[SCB]

Has anyone noticed if wet ethanol speeds up the kinetics of decarboxylation? From my experience things tend to decarb faster with a certain amount of water. My hunch is that it stabilizes the keto-enol intermediate which should lower the activation energy of the reaction.

Any thoughts?

[cyclopath]

They have…

@moronnabis

Has anyone thought about the catalytic effects of H2O, MeOH or EtOH on the decarb rxn? I.e., much lower temps

[406_Chemabis]

Problem is separating the EtOH without accidentally pulling out terpenes, as per the thread “preserving terpenes”

[CuriousChemist22]

If you’re using isolate, this problem doesn’t exist. Has anyone done any experiments going down that rabbit hole?

[cyclopath]

Not I.

Although I did put in a request for cannabinoids to throw down that rabbit hole only this morning… I believe the consensus was I first had to manufacture them, using other than our current production tooling, in order to earn my keep.

Which probably isn’t unreasonable given the current market.

[406_Chemabis]

Agreed, is the thread you posted applicable or is a new thread in order @cyclopath ?