Super critical co2 is also used for caffeine extraction in coffee, and its safer solvent for cannabis extracts and concentrates. I would never buy cbd products unless they are lab tested with a GC for contaminates and extracted with co2.

Look into USP-grade acetone-extracted cannabinoids. Acetone is 100% VOC so it will evaporate away cleanly without needing a vacuum purge (I'd still heat it to 135F to boil off the acetone which boils at ~133F) and your body naturally produces it in small amounts, so a tiny bit of contamination isn't going to be likely to cause damage. It is cheap to obtain vs. compressed CO2 (the cost of the equipment required for CO2 extraction represents the bulk of the cost of the extract) so you'll also save money.

Many places that do CO2 extraction also don't use a closed-loop system, so many are just venting the CO2 directly into the atmosphere.

Take a look at the USP Acetone specification, it does not indicate definite ideal suitability for the task:

https://greenfield.com/wp-content/uploads/2018/11/Spec-Sheet...

This fungible specification has no specific limit for Diacetone Alcohol content, a common impurity and one which increases during storage.

Diacetone Alcohol is an industrial solvent with properties of its own, not nearly as low-boiling as Acetone. Clean Diacetone Alcohol will also show negligible Residue After Evaporation and Non-Volatile Residue under conditions of the tests, which report mostly solids content along with many higher-boiling liquid impurities but not components as moderately volatile as Diacetone Alcohol itself.

However Diacetone Alcohol can still be a significant component of the extract once the bulk Acetone has fully evaporated, depending on the conditions of the processing. Rotovap would help a lot and more than 135F would reduce residual solvent better from a viscous matrix.

The USP Purity minimum of 99.5 basically means that the water content plus any other chemical impurities such as Iso-Propyl Alcohol & Methanol (specified) and implying things like Diacetone Alcohol or Benzene, etc (but unspecified) must not add up to more than 0.5 percent.

You might even prefer to explicitly specify a maximum limit For some other target toxins, less than some low detectable amount if you were picky.

Some legitimate laboratories may not be able to detect the difference between Acetone which contains unlisted impurities and that where it is negligible.

Take a look at the associated weaselwords from legal:

https://greenfield.com/wp-content/uploads/2018/11/OVI-Residu...

Which references this as the closest applicable guideline, even though it was intended to apply to the residual solvent content of pharmaceutical products not solvents themselves:

https://www.uspnf.com/sites/default/files/usp_pdf/EN/USPNF/g...

Better than nothing but not as cautious as it could be. You may want fewer impurities than marginal drug companies anyway, you're allowed to do that. This particular supplier does look nicely better than marginal, which is good, with typicals looking well better than the limit.

Regardless with two lots of USP Acetone having apparently identically suitable certificates, one may result in its Diacetone Alcohol or other not-so-volatile components comprising a significant portion of the extract, while the other lot would not, under the same solvent-removal conditions which are excellent for the latter batch of Acetone having only the lighter impurities such as IPA & Methanol.

I would still want to test it myself first.

Source: pioneered laboratory techniques which some other testers and chemical plants eventually adopted years later, still state-of-the-art today, including this particular material. Certified billions of dollars worth of commodities like this, single-handedly more than some single petro-chemical companies can manufacture. Less than a year ago deployed a further advanced system with two backups for 100 percent uptime in a 24hr staffed operation, for when a big oil/chemical client has their ships come in, and it was Acetone. There is still no adequate publication within ASTM, been at it since dirt was rocks, and Acetone has been around even longer. Documentation not found elsewhere.

It's also being used as a solvent to make high quality cannabis concentrates and extracts in place of butane or alcohol that's more commonly used now. I haven't tried them, but I know the CO2 extracted products are being used more in edibles as toxic solvents aren't used in the extraction process.

Such extracts are too pure imo. Especially for edibles, I'd rather have an ethanol extract that got a run of related chemicals and some other stuff that came along for the ride... aka "flavor".

Super pure extracts that then have added back flavorings, or even blended concertos of specific chemicals, miss the charm and much of the value of taking the "light oils" off the plant. Flower is hard to fake, home extracts are easy to do, and who knows what's in that commercial oil, really?

Ah yeah, the terpenes in the strains do more than add flavour too. Different terpenes in different strains have been found to have different effects in combination with the cannabinoids in the strain. I doubt re-adding terpenes and flavouring after the fact has the same effect. I suppose I have tried CO2 extract, I have tried the prefilled oil carts with the added flavour. I don't like them. The high from them feels weird and the taste isn't great.

Yes. The advantage as I've heard is that the extract is flavourless.

CO2 is also the best substance to inject into oil fields for enhanced oil recovery. It becomes supercritical at the pressures involved in the oil bearing formations and is more effective at sweeping recoverable petroleum than water or steam. The problem is sourcing enough CO2 near a field.

It's also a very convenient way for oil and gas companies to suck all the renewable subsidy money in the name of "carbon sequestration", when the reality is they're developing new ways to get even more oil and gas out...

I assure you, the decision is entirely economic on the production side. CO2 is fungible, no? (in regards to sequestration subsidies)

CO2 is indeed fungible. I simply suspect that a lot of companies are requesting government money to research and develop something that they would choose to research anyway even without government money. (because it increases oil production).

They get away with that because many governments don't have good tech advisers.

CO2 injection is not R&D, but established operating procedure. Its use can count to what determines recoverable reserves.