A coworker did a DSC analysis with crystalline THC-A 99.98%. Hopefully this can help better define the melting and decarb dynamics of THC-A Isolate.
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I believe the kinetics of THCA decarboxylation (and other acid cannabinoids) has been well described in the following paper which may be considered comparatively recent:
Cannabinoid-Decarboxylation-A-Comparative-Kinetic-Study.pdf (2.4 MB)
Edit: Oops. I didnāt realize I had already discussed this quite a bit above. At least this paper is a bit newer with some cool graphics.
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@ Ganjineert710 , thatās the bombā¦please file that as a small clip on the references pageā¦as āDifferential thermal analysis : DSC THCA .ā There is no other reference than 4200! That funny transition at about 130 to 138 may be the dissociation of the dimer to monomer, assuming that crystalline material is as reported dimer. It is nice to see some original data here. @cyclopath @Liveresin @Lowkeyalchemy @MagisterChemist @Lincoln20XX @roiplek ā¦etc
That is what I call a contribution.
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Props to your colleague, at least heās good for something
Thank you!
We were discussing that transition as well. A little background, I used cold butane extracted crude and did a 2x recrystallization in Pentane to make the isolate. I have the GC and HPLC data buried somewhere and can fish it out if needed.
My colleague was generous enough to donate her time for my āmake future4200 great againā request. How do I add the clip to the references page?
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Open a new discussion topic in ādata dump.ā
Give it the name I suggested.
Then just upload those two figures with a brief description of what they are. Just copy and past if you like. Put a time stampā¦and call it aāpresentationā at 4200 open forum.
There are a number of similar studies for salicylic acid, and its anionic saltsā¦all the way to decomposition.
Are you currently at a university?
there is an enormous amount of work to do on just the cannabinoic acids. Have you followed some of the work of the Australian group? They have a whole Team of Ph.D.s working on the cannabinoic acids. CBDA is a little trickier to work withā¦the rescorcinolic hydroxyl somehow interacts differently the the āsalicylic acid moietyā than the THCA ester of the secondary ring.
The key element is the 6 membered intramolecular h-bonded ring .(formed by the salicylic acid moiety) This āh-bonded ringā behaves differently when comparing the physical natures of both CBDA and THCA in various solvents. āLong storyā. If you really want to āunderstandā the cannabinoic acids and their conjugate bases just look at their elution order from a standard C18 RP HPLC separation.
Regardsā¦
I just got a call from a friend
Telling me that his thc-a did NOT melt in a vacuum oven set at 125C after 2 hours in only a real small portion decarboxilated like 2%
If it was not for the info given by
@Ganjineer710 i would have been baffled thank you by the way
So I told him to set the oven at 150C
To be continued
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have you considered that the temperature in the vacuum oven is not the same temp as the oil? Was it sitting on a directly heated shelf or one suspended by 4 small points? You need to consider that heat does not transfer well in a vacuum. Iād be willing to bet that the THCa never hit 125C. How do you think a thermos stays hot or cold for so long? Itās not from good insulation material. Itās from the lack of it.
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Agreed I gave instructions to make sure the temperature ramping is also creating good conductivity of heat
Since it does sound strange to me
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It may be a useful tip to suggest to this person that they can get away with adding the bulk of the energy to the system at atmo on a hotplate or some such.
crystalline thca is durable as hell, and generally wonāt do anything one doesnāt want it to with oxygen till it becomes less of a solid.
Spread it like 3/8 of an inch thick on a pyrex flat dish, set on a hotplate cranked up to 150c or more, since all youāre doing at this stage is energy dumping.
Once you begin to see the faintest beginnings of melt-action, toss it in the vac oven youāve been preheating and pull a vac.
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Iām happy to hear that and glad to have helped!
I think its important to consider time and volume as well. Thereās a bit over overlap between decarb and melting.
If you are working with nearly pure THC-A, the melting dynamics are different than mixtures with terpenes/other compounds(such as in the case of sugar, budder, etc.)
Sorry for being elusive, but you can melt THC-A based mixtures(e.g. sugar) by exploiting methods traditionally used on thixotropic mixtures employed by pharma research and food processing industries. Heat is not the way. 
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Not in Uni. but fortunate to work around talented people in R&D. Iām not a chemist, just an engineer who worked in weed too long.
This gives me flash-backs(pun intended).A poorly designed ventilation system resulted with me getting methanol poisoning. It is the only time a doctor will tell you to drink grain alcohol to get better.
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Another route is:
Put the tray in the oven. Pull vac, replace with inert gas, then heat it up in there close to atmospheric pressure. Then pull vac once it starts melting.
This leaves less room for dropping/spilling things and negates the oxidation almost completely.
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Forgot about the oleā safety blanket, thanks for the reminder!
So I went and did this with around 200g~ of THCa tested 99.9%.
-Vac oven preheated to 130-140c, material spread and packed into a thin-ish cake in a pyrex, set upon a shelf.
- Vacuumed down, then backfilled with nitrogen to assist with thermal transfer.
- Once signs of melting began I opened it up and stirred it all, packed it back down again, and repeated earlier steps.
- Once a desired consistency is achieved, remove from oven, add zest to taste, and manipulate as one desired.
Thereās a trick to clarity, but itās definitely possible. It all takes longer if you donāt energy-dump first, for sure, but just tossing it in an oven was certainly less involved.
Also, lol, be careful if using PTFE sheets during your manipulations. I had some fairly delicate material that became unintentionally charged sufficiently that it jumped off the table to stick to the wall above the bench about a foot away! 
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Can you provide any additional details? Was it THCA powder, a melt ā¦.Can you provide any info on how the THCA was prepared before the jump? Thanks
Also, is US 2023/0182037A your patent by any chance?ā¦just update that Melting Point to take into account the numbers posted above.
Patent says use 170F=77C
Numbers above say 138C.
Anyone know anything about the isomers of THCa and their respective melting points?
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Now to breed a plant that produces significant quantities of isomeric THCa, thatād be a funny!
Tho, I wonder, Iāve certainly had a batch or two go through the ringer for decarboxylation and the data kept saying it wasnāt done yetā¦ Grape something or other.
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I own no patents, and arrive at most (we all have our imaginations :D) of my conclusions through data driven means. The data I leverage is generated in-house, from experiment designs informed by any number of the references and citations I catalogue in my almost 30-page citations document.
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iv never taken it passed 120c and get full decarb in under 24 hrs