This is incorrect. Cyclization of CBD is most certainly first order in concentration of catalyst. It is an intramolecular reaction and not governed by a “concentration” of the atomic centers forming a new bond.
I am starting to get confused. Are you aiming for d8 or d9? I assumed the latter since you talked about stopping the reaction before the shift.
Dude.
Reaction rate 1 = k1 * [CBD]
Reaction rate 2 = k2 * [D9]
Reaction rate one is pseudo first order, not actual first order.
The only thing catalyst changes is k1 and k2. Catalysts have an effect on Activation energy, not the reaction rate equation. Kinetics fuckin 101
Edit: can @roiplek, @rocksteady, or some other chemist Please come help me out here?
Edit 2: my mistake here was that catalysts have an effect on the activation energy “one time” as in the Activation Energy is not a function of the catalyst’s relative molar concentration
That is a little drastic but another quite common trait among cannabis chemists, inability to change ones mind when presented with a different way of interpreting the World around us, and overreacting.
Hold my beer while I go check my stack of cannabis papers…
I came from Pharma, I don’t mind going back if I have to.
But I am 1,000% sure that I’m right when it comes to kinetics because we have established data and have correctly predicted the outcome of such reactions many, many times both at bench and process scale.
Have you?
There are two activation energies to be considered: The first is the activation energy of protonation of the propenyl double bond. The second is the activation energy to actually form the carbon-oxygen bond, that barrier is negligible due to the intramolecular nature of the reaction.
I’ve seen people claiming d8 converting back to d9 from the heat of GC processes recently
Pharmlabs claimed they see products convert back at room temp now
This is yet another trait of cannabis chemists, many think of chemistry as a dick measuring contest.
The rate limiting factor of the cyclization is formation of the carbocation, nothing else matters.
The conversion from d8 to d9 is typically carried out below room temp, otherwise you can create other cannabinoids when de-halogenating your halogenated cannabinoid.
This another issue; replying in oranges with the other guy talks apples.
It’s not a dick measuring contest. It’s:
I am fundamentally disagreeing with your (mis)interpretation of chemistry fundamentals.
I am confident in my knowledge here because I have applied the chemistry fundamentals and successfully carried out reactions at both bench and process scales—
If im speaking with someone who hasn’t applied their misunderstanding of chemistry to see how incorrect they are, then why am I spending time discussing any more?
First you say that the reaction rate equation is based on the concentration of catalyst, then you say the rate limiting step is the cyclization.
Both of those things are red flags to me.
The rate limiting step is the formation of a catalytic complex—I.e. a transition state molecular complex—the cyclization is essentially apontaneous following the formation of such a complex.
And you saying “so common for cannabis chemists” like you know what you’re talking about.
You haven’t put out one decent piece of information in this exchange.
Just because you can correctly identify phenolic hydroxyls and tertiary carbocations doesn’t mean a goddamned thing.
Your specific interpretation of thermochemistry is way incorrect and you clearly have not attempted the chemistry yourself in any meaningful way or you’d provide data and resources that validate the claims you’re making.
I’m good on refuting the chemistry equivalent of poo-poo that you’re spewing over the forum.
Good luck with the applied chemistry, you’re going to need it unless you decide to pore through your textbooks again.
Maybe your decade in the Arrhenius facility was a decade too short.
Love,
Phil
Also, this is a bit different phenomenon.
Conversion occuring in a coated column at vacuum below 0.01 micron at temperatures around 200-250C is (in my opinion) an extenuating circumstance.
I won’t deign to know exactly what’s happening there (nor would any other chemist without formulating a hypothesis and gathering the data to corroborate it).
I did not say that. Slow down…
I said the rate-limiting step is formation of the carbocation. It is basically downhill from there. You gotta apply the breaks so you don’t end up on d8.
I think this is where this exchange is unclear…
If you want to get to d8 there’s really no “shift” to be waiting for and perfectly time.
The reaction kinetics of cyclization is governed by the ratio of catalyst:CBD and concentration of catalyst. The concentration of CBD can be expressed in terms of those two values.
I found the 97:3 paper, BTW. It is Razdan’s “Hashish - Part 26” from 1981.
Your last three responses have been about how I am a characteristically “cannabis” chemist and implies that you’re a superior chemist because you have a non-cannabis background.
Yet you’ve provided no substance to your claims, and you’ve nearly confirmed you’ve done no work in regards to this specific reaction.
You make false claims about catalysis, kinetics, reaction rate equations, thermochemistry and the influence of catalysts upon activation energy…
Am I taking crazy pills here or is there absolutely zero reason for anyone to listen to you.
And I say it’s the formation of a transition state complex.
Edit: but without explicit and accurate thermo chemical data this conversation don’t mean shit.
Edit 2: since you’re probably quite certain go ahead and draw us your reaction mechanism and I’ll draw mine.
I will not be sharing any data or kinetic models because that would violate any ND/NC I may or may not have. Sorry.
I have been doing cannabis work since 2015. I am old enough that the first Natural Chemistry book we had to digest indicated that d9 was formed non-enzymatically from CBD.
I consult on how to make stereospecific HHC, I consult on spherophorol and divarinol based cannabinoid homologs. The latest is someone’s interest in Ajulemic acid.
I have several 10k hours stints in academia, biotech, pharma. I have over two dozen peer reviewed papers to my name.
I do help people much less fortunate than myself getting it right in the hope they won’t hurt themselves in the process.
But I am picky, if they don’t have the right attitude and I can tell they will pose a danger to themselves, I will let them be.
Sure. I’ll draw something up. Might take a little while to get it nice looking, but I will try my best.
I can guarantee that I am the superior chemist.
I didn’t say you are the typical cannabis chemist, only that you perpetuate their way of talking about chemistry.
Both of you seams to be very knowledgeable in the subject. I have question about this synth:
Reaction was performed as
specified in the general procedure for protic acids.
Conditions (Table 2, entry 1): CBD (156 mg, 0.5 mmol); solvent,
H2O (1.6 mL); T = RT; HCl 37% (1.6 mL); reaction time, 72 h.
Yields: Δ8 -THC, 89 mg (57%)
https://pubs.acs.org/doi/10.1021/acs.jnatprod.0c00436?goto=recommendations&?ref=pdf
I don’t understand they add 50% H2O to the 37% HCL? Is it to slow down the reaction Or will it improve the yield?
Why not just react the CBD in 37% HCL and just skip the extra H2O?
Then clearly, since you are the superior chemist, I have a complete misunderstanding of what I’m talking about. Kinetics, thermochemistry, and the like.
Myself and three other chemists, must have been simultaneously inept enough to be incorrect about the fundamentals and to have lucked our way into figuring out these reactions and developing kinetic models with faulty understanding of chemistry and reaction engineering.
I guess it’s possible.
That is a very good paper although people have a hard time reproducing the authors’ findings. They’re doing things on very small scale and quantify by NMR.