Looking for a fresh set of eyes on a problem we’ve been dealing with:
We’re seeing mid-high conversion of our D9 to D8. Starting crude is 78% TAC ND D8. Distillate ends at 80% D9 5%D8 5%MISC.
CO2 extracting, 200proof ETOH winterization, Hochstrom Filter, Roto
We’ve stopped filtration through media (AC,Celtie) and cleaned all glass. It’s happened more than once after stopping filtration so hesitant to think it’s something in the crude. Can media stick to BF that long? Would PH imbalance in etoh cause this?
I ran into this a few years ago. My blind, ignorant guess was residual water interacting with co2 and acting as a lewis acid or “base”.
Drying the material out and starting with fresh gas seemed to resolve it. But I was only at the facility teaching distillation. So wasn’t onsite long. But they said it stopped coming up after that
I had a buddy who dealt with this problem for a while and said that he figured out it was heavy metals being extracted by the co2 then causing isomerization in the crude upon distillation. You should check for the presents of hhc IMO
What is likely happening is that you’re creating acidic conditions from CO2 interaction with residual water in the biomass to form carbonic acid during extraction. It’s pressure dependent (~7.4MPa). So, if the resulting crude has indeed been acidified (in this case, a number of species in the crude has been protonated), all you need is excess heat to facilitate conversion from D9->D8, and/or CBD-> D8. Thus, a boiling flask at 220C for an extended period of time will easily cause conversion. In my state, I see this happening with scCO2 extracted distillate, and 5% D8 is pretty average. I’d wager that 5% misc are isomerized compounds testing labs aren’t looking for (d8-iso-thc, etc.). You could find out with an extended cannabinoid panel, but your local regulators will be pissed if they find out and you’d be under scrutiny for “intentional” synthetic formation.
Drying out biomass completely, and a gentle decarb + distillation will reduce your final D8. Getting a diffusion pump in addition to your roughing pumps will reduce the temp at which you distill D9.
