here are a couple of good reads on the subject, from my dropbox

https://www.dropbox.com/...28bookfi.org%29.pdf?dl=0
https://www.dropbox.com/...28bookfi.org%29.pdf?dl=0

for those that missed it, here is the complete parts list
https://www.dmt-nexus.me...&m=678821#post678821

that's what I used to put together a reliable SFE, to safely handle pressure up to 124 bar (1800 psi).
(note: all connections on the high-pressure side should be consistently sized, i.e. 1/4" NPT throughout. don't use reducing/enlarging adapters).

the 1000cc sample cylinder can probably hold a half-kilo of dried plant material.

https://www.researchgate...f50fe964609129000000.pdf

for dealing with free base alkaloids, see page 7 (pp. 420)

Thank you for sharing the links B.
Though some texts are hard to wrap my non chemist head around

Instead of increasing the polarity of CO2 to get the alkaloid salts in plant matter, we might beforehand mix plant material with a base, wet, then dry, like is done in the dry-teks, and work with pure CO2 without polarity modifier?

it really depends on the overall polarity of the molecule. in the case of DMT, a polar entrainer probably isn't necessary, whereas with mescaline, it would be advised.

I'd add KOH in methanol, to do a basification of the dried plant material, prior to applying the supercritical CO2. the SS sample cylinder and collection vessel can handle strong base with no issues.

or, if the basification is done as you mentioned, 95%ethanol added with the SC-CO2.
again, this is necessary for some of the more polar alkaloids, ones which contain functional groups containing oxygens (hydroxy, methoxy groups, etc,)

ok, so I've run 5 experiments so far, four on pecans, one on 75 dried ghost peppers with everclear as the entrainer.
no issues except for very small leaks twice, this is due to improper taping/swaging (tightening)

The tank needed 60C to maintain 1100-1150 psi in the latter extraction done most recently. mind you, this is a 10lb cylinder.

thus, it would behoove one to use a storage tank with a siphon (the guys at the gas supply shops call it a diptube) installed.
this will allow you to get the most use out of your tank. I took my original 20# tank to get one installed.

I don't know exactly what freeze precipitated out, but it doesn't look very nice

next on the to-do list, san pedro. stay tuned..

I know that this is an old thread, but because I am trying to do this I am reading all threads here. I want to compliment you Benz for all of the work you have presented here and the personalized help you have given me. I have all sorts of goodies coming here to start experimenting with this in the coming weeks.

thanks, and no problem.
I got very nervous the first couple of runs, but I “designed” it to be very safe.
Put over 20 extractions on it, with no issues other than small leaks due to improper taping.

I understand the nervousness. When I first starting building 'dangerous things' I was nervous at first too. I learned that thinking through every little detail and double checking everything is essential. I find that that process allows me to think of every assembly detail and remember it... all things properly tightened, sealants applied, gaskets installed, voltages correct, and more. I first started with building vacuum tube amplifies in the mid 1970's. The first ones started with 150 volt power supplies and the last one had almost 600 volts at 1 amp available speaking of dangerous. Then it was building at the time high horsepower V8 engines up to 400 horsepower. I have built from the bottom end up about 8 engines and all have lived for more than a decade before having to tear them down again. Each and every detail needs appropriate attention. In this case it is all high pressure plumbing operation at 1800 PSI or so. Teflon tape sealant are to be applied everywhere, all joints tightened appropriately, lower test pressures (175 PSI) applied and leak checking will be done before putting the system to its full pressure. It's better to be a little nervouse and cautious than risk life and limb.

'twas asked if I've ever successfully extracted DMT with a SC-CO2 extraction.

No.

there are a couple reasons I never attempted it: in plant cells, it is observed/theorized that DMT exists as a tannate salt. To extract it out of cells, and break that salt bond, we use acid/base, or base extractions. Neither acid nor base is used in SFE.
Hypothetically, ethanol may be used as an entrainer solvent with CO2, to pull from MHRB powder. The caveat is that CO2 is very effective at pulling plant lipids and oils. Whatever is pulled, will need to be cleaned with liquid-liquid extraction (sep funnel workup).

can it be done? perhaps... but not as effectively/efficiently and quickly as an A/B extraction.