oh, and that paper has supplemental data too that’s not in the pdf and that you can download free for additional details.
Ok so I don’t think any said why I was taught u would…
Certain things can oxidize and/or get really dark when oxygen touches it during the heating process
Will help keep lighter color and the original look more…what I was told
Hope this helps
Here is a quick study from peer reviewed literature. It is not much but nowhere are they concerned about the pressure in a study concerned with kinetics. Only time and temp and various other factors but no references to pressure itself as would be the case in a boiling temp chart.
I cannot envision how lower pressure could initiate decarboxylation the same way I can envision vacuum lowering the boiling point of a compound.
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Decarbing under vac makes sense when heading to distillate. You’re essentially combining decarb with terp strip/devolitilzation.
If decarbing for edibles or to reduce the viscosity for pens, then doing it under vac is not necessary, and in the case of pens, might well be counter productive.
ie you might even want to Decarb under pressure to retain terps?
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That’s what I’m wondering… Will decarb still happen at 250 degrees if it’s under pressure in a pressure cooker? Would this pressure keep terps from boiling off? I’ve heard mention of nitrogen or use of other blanket gas to help preserve terps
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uh huh…
is this more obvious?
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That’ll do
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turn your rotovap into an ice bath and apply vacuum. watch for bubbles?
The reaction emits carbon dioxide gas, so keep that in mind when you’re decarbing at 250 degrees in a pressure cooker. ka-boom?
There’s a few other things to consider.
Decarbing under vacuum also implies a low oxygen environment so it’s hard to separate the two factors. i’ll read the other paper which is referenced by the first and report back. There are some misconceptions floating around in here for sure.
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de-carboxylation is based upon heating not vacuum. Vacuum will not make any difference on the de-carboxylation rate
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CO2 will not combust in a pressure cooker if thats what youre implying? If you mean it will build up pressure and blow, most pressure cookers have a relief on them that open at “X” pressure.
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When it vents you’re losing terpenes and it’s not at the same pressure, the point being that the pressure is not going to be controlled. I think also you’ll find that the pressures you would need to reach to not lose terpenes when the temperature is 250 are not practical. That’s just a hunch though. It could be calculated using the max pressure of the system before the relief valve vents. That would tell you what your maximum temperature would be.
There’s also the possibility of dissolved gasses becoming insoluble during venting and your oil shooting out the valve in a process akin to muffining in a vacuum oven, only with liiquids at high temperatures. This would be more likely the more full it was. If it was very full, it would be guaranteed to happen.
I would be very very careful unless you want to have oil at 250 degrees shooting all over the room. Unless i’m very wrong, that is not a “hey let’s try it and see what happens” experiment.
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perhaps you could expand on that a little…
or give a reference that indicates that retaining or removing the CO2 actually effects the reaction rate in this case.
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started doing some back of the envelop calculations on this.
say 1kg in a 4"x12" spool (~155cu.in. 2l = 122cu.in so ~1x headspace)
with a MW of 358g/mol for THCA, one might expect 3mols of CO2.
getting three times 22.4l/mol into a ~1liter headspace is going to be problematic. on the order of 1000PSI at 275K if I did the math right. and 275k wont get you decarb. you’ll need 375K for that.
with 10x head space rather than 1x, it becomes manageble…maybe.
yet I didn’t see pressures over 150PSI when I tried it…with ~1x headspace (not sure I would have tried it if I’d done the math first!!)
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Side question would it be efficient to decarb prior to extraction? Like if I were to describe my material previous to an alcohol or butane extraction (of course letting the decarbed material cool down first before pitting I in any solvent) would it make it any better or would I be losing everything because from what I got from the comment was concentrates decarb in the vacuum oven or rotovap.
Vacuum doesn’t change the thermodynamics of breaking a bond. It lowers boiling points, which is why it is used in distillation but that is just a manipulation of vapor pressure, not breaking bonds. There is no reason vacuum would speed up decarb, thermodynamically speaking. If anything I would think it would complicate decarb by pulling off volatiles like terpenes to an excessive degree in the process.
I decarb at 110c for 30 minutes to burn off water and residual solvent then 90c for another hour and a half. That should get you full decarb without losing all of your terps.
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It’s not unusual for labs to do this when extracting with CO2 because it helps increase yield somewhat. I don’t know that it helps any with ethanol or butane though. If you’re a volume producer it would actually probably create work for you. Decarbing hundreds of pounds of biomass vs. the crude oil would make your oven requirements sizeable to say the least.
That’s hot. Decarboxylation is a continuous process. Heat speeds it up but it’s happening by itself just sitting there. 135c is where I go when I’m decarbing crude, but only because I want to burn off terps for crude. For an oil that will be used as an oil 110c for 30 minutes then 90c for an hour and a half gets you full decarb reliably and preserves a lot of the terps.
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Correct. Vacuum does not change the thermodynamics of breaking a bond.
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All reactions are an equilibrium. It just depends how far and on which side. Removing a product as it forms will drive a reaction. See Le Chatlier’s
principle.
Everyone is saying that vacuum doesn’t seem to speed it up, so the rate isn’t largely effect I guess. I’d bet you decarbing is sped up even if just a little bit though.
I think the biggest advantage however as some people have pointed out is that you remove oxygen. Heat + oxygen + time = cbn or other isomer. If you can decarb under vacuum or inert gas, that would be ideal as far as preventing degradation goes.
I’ve seen some graphs that illustrate why you shouldn’t decarb hot with oxygen. I’ll post them tomorrow if I can find them.
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I think the biggest advantage however as some people have pointed out is that you remove oxygen. Heat + oxygen + time = cbn or other isomer. If you can decarb under vacuum or inert gas, that would be ideal as far as preventing degradation goes.
I never thought of this - it seems like a great reason to decarb under vacuum… especially if you’re doing so to oil/distillate rather than biomass.
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