Cryogenic CO2-expanded ethanol (CXE) extraction

can anybody verify this patent? specifically this part " CO2 is highly soluble (up to 50% w/w and v/v) in most very cold polar solvents. The extraction method of the present invention is performed at a very cold temperature "

it has a few red flags but its also really interesting


I’ve had dry ice and solvent mixtures sitting in -86°C freezers for weeks/months at a time, and I’ve noticed the dryice disappear over time.

I assumed this was simply that the freezer had dropped below -78.5°C, and with CO2’s high vapour pressure, it had slowly sublimated into CO2 which escaped every time I opened the door.

However, I noticed one day when I pulled a beaker of what I believed to be just very cold EtOH out of the freezer … I sat it on the side, and sure enough, it started bubbling as it warmed up.

I’ve no idea how much CO2 was dissolved into the solution, but the gas given off turned moist litmus paper from blue to red, and effervescence increased seemingly proportional to temperature.

After some hours at room temperature, activity stopped and the solvent had seemingly given off all (or at least the majority) of the CO2 it had dissolved.

Refreezing the same solvent a second time, for a week or so (this time without dry ice) produced no effervescence upon removing from freezer and allowing to warm.

I’d agree CO2 is soluble in very cold polar solvents, but I’ve no idea to what extent, and how this varies with solvents and polarities. My observations were the result of laziness rather than planned experimentation, so I really couldn’t be more helpful than that.


This was actually very helpful thank you

Azoth is now openly admitting to CXE :slight_smile:

Thanks for inquiring about our Co2 extraction technologies.

I will give you a quick summary of what makes Xact Xtract different from other extraction equipment on the market.

  • We use Liquid Co2 at pressures from 400psi to 1200psi. This allows us to extract terpenes (@400psi) separately from cannabinoids (@900psi). Others claim to extract terpenes but they do so at high pressures and temperatures so the terpenes they extract are contaminated with water and

  • Our extractors use a horizontal extraction vessels with a centrifuge to eliminate channeling and allow for a toolless extraction vessel change.

  • The electric pump/compressors on the HA/LA series extractors flow over 60 liters a minute.

  • Inline filtration down to 1 micron.

  • Automatic Modifier addition allows for Carbon dioxide expanded extractions and for winterization in cycle.

  • Extraction efficiency up to 95% with CXE cycles

Vitallis said they were heading that way, but would not give any time frame.


Yea I talked to the Azores guy about buying one of his high flow co2 pump and he told me they had “solutions” if I was interested but no products directly designed for it yet. His tech is fucking sweet tho and part of the beauty of CXE is that it can be thrown in to many extracters retroactively. I was thinking of trying to sell an “upgrade kit” eventually. Especially to people who bought co2 machines and are disappointed with the process due to its numerous issues

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“8. The process according to claim 1, wherein the at least one polar solvent is present in an amount of about 50% w/w relative to the carbon dioxide, and the carbon dioxide is present in an amount of about 50% w/w relative to the at least one polar solvent.”

I have been studying and using modified Co2 since 2001 and I have yet to find a cosolvent that will stay in solution with LCo2 at concentrations over 30%. Alcohol will form a separate layer from LCo2 at concentrations over 10%.

Regardless, I have found that CXE with concentrations over 10% give you a extract that is hard to distinguish from a pure cosolvent extract.

The dilution of the cosolvent in Co2 is important to tame the power of the cosolvent. With the right ratio of modifier and Co2 you can get a extraction with the speed and power of a pure solvent extraction but with the selectively of a LCo2 extraction.


ru talking about specifically at atmospheric pressure or at elevated pressures too?

At atmospheric pressure the Co2 is dryice. I am speaking about the liquid range of Co2 (76psi to 1056psi).


I believe this patent is about co2 expanded acetone.

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what phase is the carbon dioxide in soda water? if a “gas” is dissolved in a liquid is it a gas or a metastabile liquid or does that fact that is a mixture mean that the phase diagram doesnt apply? i think this is more semantics then the physics of the chemistry. i have seen co2 referred to as a “gas” just because it’s normally thought of as a gas when its a liquid or a solid or they call it dense gas or co2 rich phase or subcritical co2 im not trying to be a smartass im just trying to get out what im thinking on the topic i kno i can come off in text overzealous sometimes
co2 and ethanol would separate initially but might still dissolve over time or with agitation. i have def got mixtures of over 10% co2 and even when they seperate both phases will act as a solvent so there’s really not much harm.

Think soda pop. CO2 crashes out of solution when the pressure is reduced by opening the cap or making it hotter.

or trying to suck it through a 15lb bed of ground cannabis :slight_smile:


I bet you could use some co2 to push it through a bed of material.

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As you know I worked as a control systems engineer designing then programming the electronics and valves, motors, motion control and sensors and such for automated machinery.

One line of machinery had been plagued for years with an unwanted solution of gas in oil. In these machines smooth movement of a grinding wheel on a slide was absolutely imperative as was the imperative that motion be stopped on a dime.

The way you do this is by pushing oil in a cylinder that pushes the grinding wheel. The trick is to push it with compressed air and this system is well known for extremely smooth operation and is known as an air over oil system. A valve on both ports of a cyclinder when closed will lock the cylinder in place instantly because oil will not compress like air will. The system benefits from the naturally smooth push from compressed air then but can stop like a hydraulic system. Very slick but…

Over the years the line was plagued with foaming oil. All sorts of things were tried and generally over the years the explanation that evolved was that the oil was becoming contaminated with water (it was) and so all efforts were towards dry air. Absolutely futile lolz. I stumbled on the fix and the simplicity of the fix was underscored by the sheer uncountable number of man hours spent by tech support over the years dealing with this. The problem was huge and relevant to this OP really as explanation. Extensive air and moisture purge procedures were introduced.

The oil WAS foaming and moisture DID make this worse but that was not the problem at all. Here is what I found and how I fixed it for a few bucks.

The systems were thought to be contaminated by atmosphere so one idea was to keep the oil pressurized when the machine was idle or shut down. If the closed system is pressurized then no atmosphere can enter it… I noticed a pattern as did the technicians. Machines that had been shut down for a long time that worked just fine before shut down would suddenly exhibit oil foaming. Foaming negates all advantages of an air/oil system. Why did those systems clearly not in use suddenly malfunction with foaming oil?

Because when not running or powered down the oil was under air constant pressure unless the factory shut down their compressors. Moreover the oil became very cold as rule when not running and fairly warm when it is running. What was actually happening was the design was forcing atmosphere into solution with the oil as it sat idle. Then when the machine began to operate again it was like releasing a soda pop cap - the oil would fizz lolz as the gas crashed out of solution. All those years they had dealt with that as a moisture problem. The moisture was being forced as a gas into the oil from factory air compressors then would precipitate into the oil when the pressure released. The oil pots acted like an air dryer (hundreds of machines)!!!

The solution was to install one valve and one wire into the machines to ensure that the oil was always unpressurized unless the main joystick was in “Auto” and the start button had been pulled. The alternative for the old machines was to send a tech bulletin advising disconnection of pressure from the machine when not in use. All oil foaming went away as did the products sold to reduce foaming heheee.

Gas is nearly without question disolved to some extent in most liquids and the pressures I am talking here with machinery is just a mere 90 psi. Not much pressure really but I have seen perfectly relaxed oil go into-foam when releasing pressure.


One time years ago i tried using co2 instead of nitrogen in my closed loop. I ended up trapping a lot of gas with the butane. I have 2 theories, co2 ice had formed, or the butane was becoming carbonated. It made some crazy High pressures after the chiller was shut down. Thank the universe for pressure relief valves. My valves crack at 60 psi, the lowest rated part of the system is the 12" spool 150 psi at 70f.


thats exactly what i was gonna say lol pressure is almost always easier then vacuum

right, but there was no lid on the vessel. I had always used vac, and the one time I dropped the dry ice in the solvent, because I was in a hurry, I couldn’t get the solvent off using the assembled equipment. totally agree pressure would work. i prefer vacuum when I can, because N2 tanks are finite, and people get distracted.

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Wow, That’s interesting for sure. What purity level was your co2?

instrument grade

Try using a Heat Exchange Unit so you can optimize your peak #CO2 flow rates. DM me if you’d like to know more information.