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Old 12-11-2017, 02:44 AM #1
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Rate of THC Decomposition to CBN

Greenfox recently brought CAT Scientific's Debunking the Myth of THC-CBN Conversion Intensity study at https://www.catscientific.com/decarboxylating-cannabis/ to my attention, and asked my read, as it appeared to fly in the face of conventional protocol. My study at:

https://thealchemistresource.thealch...g-page_10.html

Because I am familiar with the author, have tested the accuracy of the CAT Scientific hot plate, and know the Phd who tested the results, instead of simply shrugging it off, I dug deeper, starting with contacting Dr Justin Fischedick and seeking his insight on the phenomenon.

Always a delight, Dr Fischedick not only provided me with his thoughts, but provided me with three different serious scientific papers on the subject, which caused me to rewrite our own decarboxylation article and to add a couple more related threads to our TAR site.

The conflict between the CAT Scientific study and conventional protocol, was the rate of THC conversion to CBN after reaching the peak of the 70% decarboxylation curve. It showed a slower drop in THC than the plunge suggested by the generally accepted graph on the subject, provided by the Journal of Chromatography in 1990 .

Graph 1


The conventional wisdom to this point is that once 70% decarboxylation is reached, that the rate the remaining THC-a is converted to THC is lower than the rate that the existing THC is converted to CBN.

That turned out to not be so, as demonstrated by this graph, which I drew using the copyrighted graph published in Isolation of D9-THC-a from hemp and analytical aspects concerning the determination of D9-THC in cannabis products, published in Forensic Science International, on line18-Aug-2004



Insert graph 2


As you can see, what this graph shows is that by the time we've reached 70% decarboxylation, 30% of the THC has already been turned to CBN and other breakdown products. The reason that THC doesn't continue to rise above about 70%, is there is no THC-a left to convert.

That still doesn't resolve the differences between the rate of THC conversion to CBN to the right of the graph, after it has peaked around 70%, shown here:

Insert graph 3



As you can see in the CAT Scientific study, the rate of THC decomposing into CBN is radically different than the plunge demonstrated in the previous graph.

The answers to that question lay in the different reports, as well as within the keen fine minds of Dr. Fishchedick.

The issue is that the tests and graphs don't represent the same test material or conditions.

The Journal of Chromatography graph represented a dab of concentrate heated in an open glass container, while the next graph was in a closed container excluding atmospheric oxygen, and the Cat Scientific study was done suspended in oil.

Dr. Fischedick relayed yet another test he had run, testing formulation stability, where they placed the THC + formula in an oven and flooded the oven with oxygen. Even in that oxygen enriched atmosphere, he said that the degradation was slower then the first two graphs above.

He also noted that many of his clients research producing CBN under various conditions and it varies for all of them until they really find an optimized process.

In addition we routinely inject THC into the inert atmosphere of a gas chromatographs at high temperatures like those shown and we don't see any degradation in that time period.


He summarized by saying that unless you're heating a couple grams of oil on a hot plot exactly like the first graph, we shouldn't expect conversion to be close to the same.
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Old 12-11-2017, 02:48 AM #2
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Solly! Not sure what happened with all the auto bold, and I can't see an edit option to fix it.
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Old 12-11-2017, 04:36 AM #3
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The graph under criticism I've probably said a few times before does not show conversion to CBN. Neither in the scientific logic sense nor actually, since there's an explanation right under the graph for anyone who bothered to read the document, which was provided here many years ago. This should not have fallen to me to point out.
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Old 12-11-2017, 04:58 AM #4
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Originally Posted by G.O. Joe View Post
The graph under criticism I've probably said a few times before does not show conversion to CBN. Neither in the scientific logic sense nor actually, since there's an explanation right under the graph for anyone who bothered to read the document, which was provided here many years ago. This should not have fallen to me to point out. View Image
I submit that the right side of the curve does represent THC conversion to CBN, even if it is a decarboxylation graph.

The CBN doesn't rise proportionally, because its being broken down as well.
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Old 12-11-2017, 05:05 AM #5
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Cool

I have never seen this pulled off, but I've known a few to try it. None of their tests came back with CBN presence. Most of those people were doing large batches, perhaps that was the issue.

I'll be watching, been interested in this topic for awhile.
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Old 12-11-2017, 05:40 AM #6
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can someone put this into simple terms?

At what rate does THC turns to CBN in a sealed jar at room temperature and for how long?

I have notice that once you turn hash or flower into rosin it is almost like they stop aging or changing. At what rate would THC convert into CBN when THC when in oil form?

Thanks.
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Old 12-11-2017, 06:37 AM #7
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I submit that the right side of the curve does represent THC conversion to CBN, even if it is a decarboxylation graph.

The CBN doesn't rise proportionally, because its being broken down as well.
Conversion to CBN is conversion to CBN, which can only be determined by finding out how much CBN there is, not by finding how much THC you don't have. None is shown. CBN is quite stable and along with CBD suffers from none of the problems of THC distillation. The text from the second graph says At higher temperature, D9-THC is oxidised to form cannabinol. As the sum of D9-THCA-A, D9-THC and cannabinol does not reach 100%, it is assumed that polymeric material is formed also. If the time of exposure to temperature is changed, temperature needs to be adjusted to maximal conversion. With the chosen time, the maximal conversion is in the same range as it is in the injector of the GC system.

Let's analyze this statement. First, the second graph is not the authority you think, at face value, because no time is ever given. Kind of an important variable? Next, just because they say some reaction occurs, does not mean that it happens instantly or quantitatively or anywhere near.

Oh duh now I see that 8 is just a different representation of the handful of experiments in 3. So 15 minutes. They didn't mention the intermediate dihydrocannabinol even though they showed it on the stacked chromatogram figure 3. That's the better representation. That's one of the few places you'll see dihydrocannabinol mentioned much less shown on HPLC, yet they don't mention THCA converting to CBNA. They mention it as impurity in their THCA but don't show a peak for it. Anyhow it's not a ton of science being done here really, once again these are only what they are. This is an analytical not production journal.
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Old 12-11-2017, 08:20 AM #8
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Old 12-11-2017, 12:59 PM #9
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Originally Posted by G.O. Joe View Post
Conversion to CBN is conversion to CBN, which can only be determined by finding out how much CBN there is, not by finding how much THC you don't have. None is shown.

You will never reach 100% when the same process creating CBN from THC, is destroying CBN.

You lose 30% right off the top, reaching the apex of the curve, and then the THC level steadily drops until THC reaches zero.


CBN is quite stable and along with CBD suffers from none of the problems of THC distillation.



The text from the second graph says At higher temperature, D9-THC is oxidised to form cannabinol. As the sum of D9-THCA-A, D9-THC and cannabinol does not reach 100%, it is assumed that polymeric material is formed also.



If the time of exposure to temperature is changed, temperature needs to be adjusted to maximal conversion. With the chosen time, the maximal conversion is in the same range as it is in the injector of the GC system.


Let's analyze this statement. First, the second graph is not the authority you think, at face value, because no time is ever given. Kind of an important variable? Next, just because they say some reaction occurs, does not mean that it happens instantly or quantitatively or anywhere near.

Oh duh now I see that 8 is just a different representation of the handful of experiments in 3. So 15 minutes. They didn't mention the intermediate dihydrocannabinol even though they showed it on the stacked chromatogram figure 3. That's the better representation. That's one of the few places you'll see dihydrocannabinol mentioned much less shown on HPLC, yet they don't mention THCA converting to CBNA. They mention it as impurity in their THCA but don't show a peak for it. Anyhow it's not a ton of science being done here really, once again these are only what they are. This is an analytical not production journal.
Define polymophic material? Poly(Multiple) morphing (changing) into something else??? Like decomposition products for instance??

You probably skipped over the part of my write up that mentioned going straight to one of the worlds leading authorities on the subject for help sorting it out, and who does believe in the studies and provided them to me. He also relayed his own experiences as an industrial consultant on the very subject.

The point of the article is Greenfox's question of why the decomposition curves don't match, and the answer is that the processes are different.

Do you find error in that conclusion?
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Old 12-12-2017, 03:31 AM #10
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Define polymophic material? Poly(Multiple) morphing (changing) into something else??? Like decomposition products for instance??

You probably skipped over the part of my write up that mentioned going straight to one of the worlds leading authorities on the subject for help sorting it out, and who does believe in the studies and provided them to me. He also relayed his own experiences as an industrial consultant on the very subject.

The point of the article is Greenfox's question of why the decomposition curves don't match, and the answer is that the processes are different.

Do you find error in that conclusion?
The answer is the 70% figure comes with grains of salt from the start. I've had these articles for ten years and don't need an interpreter, having spoken the language for a long time.

Four (4) experiments are documented, as shown in your second graph figure 8 and my link to figure 3. Different temperatures for 15 minutes, each with half a milligram of material coating the inside of a gas tight vial. Is there plastic or unsilanized glass? They don't say, so we'll say I've found your missing THC - absorbed - if dihydrocannabinol doesn't cover it.

This 15 minutes is kind of inflexible isn't it? Maybe there would have been different results for a longer time at the lower temperature and a shorter time at the higher temperature? Obviously?

How would a large peak for CBN mean CBN is being destroyed? Plus they clearly throw in the phrase it is assumed - their assumption means jack and they would be the first to admit it. There is certainly nothing there saying it's CBN and not THC theoretically dimerizing or whatever.

No one including the authors is saying it's a definitive work that applies to anything other than what they specifically did for the purpose they did it for, so there's a bit of straw man in bringing them up at all. Did the Dr. tell you they go on to say never mind about the 70% figure unless you're analyzing hemp - did you skip over table 1? It seems that with higher D9-THCA-A concentration the decarboxylation pathway is favoured over other reaction pathways such that a higher total D9-THC can be measured than expected.
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