Well I was talking about THCA and CBDA
You are talking about D9 THC.
Do you have a microwave transparent container.
Some glass ware that say microwave safe, means it will not shatter in the microwave, it does not mean it wont get hot.
My home microwave oven, will heat the rotating plate to a temperature that it can not be picked up by hand in 3min.
Secondary infrared emissions from such hot plates can certainly heat you product. But I am thinking we are talking about microwave absorption.
I have not worked with THC in some timeā¦but you may be right. There are microwave transparent containers used in microwave assisted synthesis. Usually teflon-like material with special caps. I think I have zapped THC in one such containerā¦and THC does get hot. In one case we are talking about a non crystalline state of THCā¦amorphous liquid and in the other we are discussing crystalline states of THCA. Capisce?
I am saying the dehydrated, crystalline states of cannabinoic acids, CBDA and THCA do not appear to absorb in āmicrowave ovenā. (2.4 GHz machines).
Pop a diamond in and gently remove all water with short bursts of sub max power as I noted aboveā¦
Then try to zap it. Compare it to your D9. Compare to a similar amount of water.
Check out the microwave absorption spectra of liquid water
in Liquid water has a broad absorption spectrum in the microwave region, which has been explained in terms of changes in the hydrogen bond network giving rise to a broad, featureless, microwave spectrum.
Not all organic molecules in liquid state or solid state or polymer state absorb in this microwave region.
4 Likes
A one to one mole ratio of cannabinoid to water ā¦give a 5% Water signal.
MW 18
MW 358/314
So perhaps the real question is does liquid THCA absorb microwaves.?
THCA and CBDA do not appear to absorb 2.4 GHz radiation (heat up) to any great extent in the dehydrated- crystalline state under controlled conditions of a container transparent to microwaves and a proper microwave oven that doesnāt heat itself up and give rise to infrared radiation.
2 Likes
My disty is in boro media bottles, Iāve used mason jars too but i avoid microwaving those too long because they will break when heated unevenly.
I will try this i have some d9thca at my shop
Boro glass is rated as microwave safe
3 Likes
As I was pointing out ā¦microwave safe does NOT mean microwave transparentā¦
Put it in your microwaveā¦and do your usual time courseā¦and measure the empty glass tempā¦
ā microwave heating of gases and solidsā¦
ā¦is hardly possible. Gases cannot be heated under microwave irradiation since the distance between the rotating molecules is too wide. Similarly, solid materials like ice are (nearly) microwave transparent since the water dipoles are bound in the crystal lattice and cannot move as freely as in the liquid state. However, some conductive solid materials, like silicon carbide, where electrons can move freely, are excellent microwave absorbers and therefore heat very quickly.ā
Some additional details:???
5 Likes
Just leave it long enough it melts pretty nice when rotating
1 Like
Are you saying your microwave oven heats up with nothing in it?
Have you measured the air temp in the oven and the rotating glass plate temperature as a control? Long enough?
Using a Labwave9000,
I see the water disappear over a period 5 minutes pulsed modeā¦with very minimal change in crystalline state . I donāt see any boiling liquid or thc. Thatās all I can say.
Just anecdotal observationsā¦Labwave9000 machine does not have any glass plate nor does the chamber seem to heat in any noticable manner. (Large fan designed to actively remove water vapor).
If THCA adsorbed microwaves (solid crystalline THCA)ā¦it would melt , liquify, continue to boiling point , vaporize or decarb. Just put a gram of water on a plateā¦and Zap it.
Now that is a good example of absorbing microwaves. (Typical home use oven 2.45 GHz).
Donāt confuse this with THC which is liquid to begin with or mixtures of THCA/THC.
2 Likes
Get it to around 180Ā°F and leave it at that temp for 3-4 days. As soon as it stops offgassing and is totally clear of chunks itās good to go. Use a mason jar and open the lid every few hours to release gas
That describes decarb.
Although 3-4 days seems excessiveā¦even at 82C
It does not address the subject of this thread, which is āwhat is the melting temp of thcaā
Nor offer any insight re: melting thca in a microwave.
2 Likes
I mean you couldāve just answered the dudeās question like I was trying to do lol
1 Like
Which dude?
I donāt see anyone asking the question you answered (Decarb temp), and the consensus answer is that the melting temp has not been published, and will vary with purity.
I donāt have any better than ~ low to mid 70ās (C)ā¦because I donāt make THCa isolate.
Edit: if youāre referring to @moronnabis, I believe youāve misunderstood the question.
2 Likes
Your point is a good one, but heating and off gassing can be done multiple waysā¦and crude bho off gassing with a concentrate of THCA is not EXACTLY like describing the melting of a pure diamond crystal or pure chalk powder form, or hydratesā¦so the playing field is just a bit varied here. But I like your off gassing technique you describeā¦
Is this how you get your crystalline THCA? Or are you just saying that at 180 F for 3 days all the THCA crystalline material is gone and you have liquid THC? So whatever it was āyou melted itā? Rather humorous ā¦
Seriously, though I do not think that is the answer the OP was looking forā¦ā¦I once did a THCA in Pentane in a closed container at about that temp for 12 hrsā¦I was surprised at how little decarbedā¦
2 Likes
Yea I misread the question. Thanks for contributing to the conversation anyway and not being a lil hall monitor 
2 Likes
āHey, it doesnt seem like you get what the fuck folks are askingā¦ā, is not being a hall monitor.
Itās asking you if you understood the question.
You didnāt.
Now you do.
So maybe you can actually contribute.
Donāt get pissed at me because you misread missy.
There is a non-trivial number of folks reading along that donāt understand the difference between what was asked (melting) and decarb.
Should your misread be left to mislead?
See: Decarbing Diamonds if thatās what youāre here for.
4 Likes
Isolation of thca in mechanical separation (in my experiance) uses 140f to remain solid while allowing everything else to reach a liquid or gaseous state. But that assumes for some contaminant that lowers the melting point ( which seems to be everything except CBG/a. So we can safely assume its over that.
The fact that it can decarboxyate at a range of temps over times makes finding a solid number very tricky.
I feel like its going to be more of a chart of ratio of decarb %, time to reach liquidity and temperature.
Then there is physical traits of the individual thca, powders contain more gases which affect how thermal energy will move through the mass. Poweder might decarb more or less than large facets or micro crystalline within the same parameters of temp/time/% loss.
3 Likes
So whats gonna be considered the standard for pure thca? 99.9 sure. But that .01 could wreak havoc on replication.
This paper describes the temp ranges of decarbing ratio of THCa while measuring d9 formation and CBN. It also details other acidic cannabinoids decarboxylation points. Iāve succesfully mixed 20% THCa into d9 for some āliquid diamondā gimmick shit my bosses asked for and in order to dissolve the THCa I heated it at 60C for 18 hours. Only 1% decarbed.
As for your other statement about the standard for pure THCa? Depends on purification method, as HPLC or this sweet ass CPC by Gilson can achieve 99.99% or greater depending on the starting crude. If you donāt know what CPC is, this pdf describes it
1 Like
that decarb paper is interesting and it worth comparing the THCa results to those of Perrotin-Brunel, H., Buijs, W., van Spronsen, J., van Roosmalen, MJE., Peters, CJ., Verpoorte, R., & Witkamp, GJ. (2011). Decarboxylation of Āæ9-tetrahydrocannabinol: kinetics and molecular modeling. Journal of Molecular Structure, 987 (1-3), 67-73. Redirecting.
Note that the energy of activation for THCA is only about
One half the value of those of CBDA and CBGA. It will be interesting to see if the same holds true for CBCA.
Addendum @LiveResin : I am adding another Decarb study reference so that 4200 has the three best all in one spot. Lots to learn here. Mechanism and kinetics of CBDA decarboxylation into CBD in hemp | Journal of Plant Biochemistry and Biotechnology
1 Like
The authors actually reference Perrotin-Brunel et al in their paper regarding the issues using HPLC-DAD for detection, showing that the acidified species have low molar absorptivity and need to use low wavelength detection where there is more background noise. Thus, they feel the need to couple mass spec to the process. I think this is why they had definitive first order kinetics established below a certain temperature, and psuedo-first order kinetics above that temp. Super cool stuff! I could nerd out about it all day long.
this group also studied the onset of CBD decomposition which overlaps with the decarboxylation, temp and pressures and time courseā¦So the take home lesson for working 4200 when working with decarbing biomass by heat treatment:
ā We confirmed that CBDA decarboxylation is a pseudo-first order reaction resulting in an exponential decrease of CBDA and an increase of CBD mass fractions. CBD starts to degrade after a specific time at a specific temperature. The course of CBDA decarboxylation depends on time, temperature, and the chemical composition of the sample. Experimentally, the optimal conditions to turn CBDA to CBD are heating at 140 Ā°C for 30 min.ā
140C, 30minā¦.youāre done.
Now that may not hold exactly for BHO or ETOH or SC-CO2 concentrates, but it is surely a good starting point.
There is a very interesting comment on THCA-A and THCA-B decarboxylation:
(Filer CN (2021) On the reluctant decarboxylation of THCA-B, Cannabis and Cannabinoid Research 6:5, 446ā447, DOI: 10.1089/can.2021.00030 )
The author makes some interesting comments on difference between crystalline solids and biological extracts when thinking about decarb temperatures and rates. (The playing field indeed)
Or in the case above where the work was done on in situ āKiefā biomass. There is credible Raman spectrocopic data to suggest that ānanocrystalline dispersionsā exist in situ, capitate storage volumes. Sub volume elements of aqueous environments co-existing in equilibrium with terpene like non polar globules are evident from microscopic studies, suggesting a certain fraction of cannabinoic acids may be in solution as well.
Might one be able to use spectrometry to identify the range of melting observably crystalline THCa and rate of decarboxylation at the high end?
In-Situ-Fluorescence-Spectroscopy.pdf (548.8 KB)
@Bonevader , have you found the information that you were looking for?