I haven’t been in this industry for that along, and I very much appreciate the help I have received from here and elsewhere. But one thing that has baffled me has been the relationship between cannabinoids, chemistry and color… I understand pH (beam test), oxidation, temperature, potency, etc. all play into color of the oils. But I have seen wildly varying products with different colors.
For example, why is it that if you have a red/orange (ice tea color) derived oil (d8), and add terpenes to it (even 1 weight percent or less), does the oil turn gold? Is this just the result of terpenes disrupting the conjugated pi system in THC, CBD, etc. and contributing shorter conjugated pi bonds -a blue shift of sorts in the VIS? Some would say the ice tea color of the oil is due to oxidation, but if the simple addition of terpenes changes it, with no subsequent color change, that would suggest oxidation can be ruled out.
Another example: Higher potency d8 samples (95%) I have seen are more of an “ice tea” color than the lower potency (85% d8, 5% d9, 5% CBD) gold samples. But that changes once you add terpenes, or say CBD full spectrum distillate. The ice tea will turn gold.
People speak of oxidation of the oils and contribute it to dark color changes. Oxidized to what?
Is there a good comprehensive resource on cannabinoids, chemistry, and color? I see bits and pieces here on Future concerning color, but nothing specific or extensive on the topic.
I’ve personally made 400+ x 60ml mct/1g cbd isolate tinctures, all 100% clear. Only time I get a “tinge” is when I add loranne food additive flavoring.
high purity cbn I’ve produced is always a white powder. In solvents im not TOTALLY sure, but I’ve made a colorless solution in etoh and etoh with sodium ethoxide, dcm, toluene, alkanes, thf, acetone, glacial acetic, ethers, and probably others but I never seen a immediate color change.
the aromaticity of cannabinoids is really only good for wavelengths like uv, which is why you can see cannabinoids under uv light for tlc. You need larger conjugated systems for visible light. for example B-carotene, or azulenes. isolated pi systems in cannabinoids are too small for visible
And basically everything else too lol. Who is this @shattertramp dude anyway
Just quoting one of the other threads that was cited. I am not sure if his explanation is totally correct or not. I do wonder if the oils have some macroscopic optical properties depending on composition and how they were prepared.
This is all from my experience, which isn’t much. Colorless is common in alcohols. I haven’t tried much else. White CBD isolate is yellow/beige in heptane, ether, etc from what I saw -it will also be somewhat colloidal below 30 C at a 1:1 ratio. We also aren’t really discussing concentration either.
d8 reaction product I have made is pinkish after pH adjustment and washes, less pink after drying, and then gold/ice tea color after solvent recovery. And in certain instances, can be further made golden by addition of terpenes. One can also make water clear by SPD over T41 -but I lose d8 points, gain d9 points, and possibly make d10… I think anyway. I was trying to polish off the remaining d9 with T41 and I think it just non-specifically isomerized some of the d8 into d9 and d10. lol.
But I could be doing it wrong. I am really just trying to make sense of the colors.
Yeah I had fun experimenting with the d8 lol. Made some real pretty pink colors there for sure. Although the pink ones have faded sadly. Stored under Ar with parafilm so not sure if color change was caused by uv degradation or just natural.
I have noticed cool refractive properties with high purity distillates, like a diffraction grating. Maybe optical rotation with those cyclohexene stereocenters
I agree with your comments on UV-Vis. But that only matters within dilute conditions -and analytical UV measurements are very dilute solutions in which the species of interest are heavily solvated. I would have to re-read the UV fluoro thread and think for a while.
Oils in their pure form could have different optical behavior. I wonder if chemical behavior like pi-pi stacking could come into play given the planar structure of the molecule. This could elongate the absorbance pattern of the chromophore.
Polarimetry and fluorescence could be interesting avenues to explore. It could help work out impurities maybe? Or why different chemical states present the perceived colors they do?
