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Bulk Subzero Ethanol Extraction

duke0fdank

New member
The dry ice is bubbling CO2 through the ethanol and saturates it.

-50C is a minimum and when chilling ethanol directly with dry ice, the temperature is typically closer to -70C. Unless the column of material is at -70C or below, the temperature won't stay that low once the flow starts.

Attached is a chart showing dielectric constant of ethanol at temperature.

i understand but Im talking about making a co2-expanded ethanol. i could get it to -70c and saturate with co2, then add the material then seal the vessel if necessary. this patent asserts this could work at atmospheric pressure but im not entirely convinced but even not it will still be relatively low pressure (<1000psi) which i can handle.

it should also 2x the volume of the ethanol which saves expensive ethanol
and under the right conditions, it could be better than straight ethanol for purity
 

duke0fdank

New member
couple excerpts from some sources ive found
In
"CXLE, lipids can be extracted with any appropriate liquid solvent,
just like in PLE, and mass transfer rate is increased in the presence
of compressed CO2 rather than by increasing the temperature. This
ought to be an attractive methodology for lipids sensitive to heat,
such as certain fat-soluble vitamins and carotenoid pigments, as
well as for lipids of high vapor pressure like certain essential oils."

it also says this tho is certainly not a definite at this point

"There are only a few publications describing
CO2-expanded liquid extraction (CXLE), for instance the
extraction of γ-linolenic acid from Arthrospira platensis (Spirulina)
algae by CO2-expanded ethanol [6]. Obviously, much research is
remaining, considering for instance the lack of knowledge on solubility
of lipids in CXLs, also including CXLs at one-phase liquid
condition, as well as knowledge on mass transfer limitations in
CXLE. Just as described above for EFLC and UPC2, what is the
actual density, viscosity, diffusivity, compressibility and surface
tension, in addition to solvent properties like polarisability, acidity
and basicity, of different CXLs? How can a certain molar ratio of
CO2/solvent at a certain pressure and temperature be accurately
produced and used in analytical chemistry applications?"
 

Gray Wolf

A Posse ad Esse. From Possibility to realization.
Mentor
ICMag Donor
Veteran
couple excerpts from some sources ive found
In
"CXLE, lipids can be extracted with any appropriate liquid solvent,
just like in PLE, and mass transfer rate is increased in the presence
of compressed CO2 rather than by increasing the temperature. This
ought to be an attractive methodology for lipids sensitive to heat,
such as certain fat-soluble vitamins and carotenoid pigments, as
well as for lipids of high vapor pressure like certain essential oils."

it also says this tho is certainly not a definite at this point

"There are only a few publications describing
CO2-expanded liquid extraction (CXLE), for instance the
extraction of γ-linolenic acid from Arthrospira platensis (Spirulina)
algae by CO2-expanded ethanol [6]. Obviously, much research is
remaining, considering for instance the lack of knowledge on solubility
of lipids in CXLs, also including CXLs at one-phase liquid
condition, as well as knowledge on mass transfer limitations in
CXLE. Just as described above for EFLC and UPC2, what is the
actual density, viscosity, diffusivity, compressibility and surface
tension, in addition to solvent properties like polarisability, acidity
and basicity, of different CXLs? How can a certain molar ratio of
CO2/solvent at a certain pressure and temperature be accurately
produced and used in analytical chemistry applications?"

Suggest searching for SCFE CO2 with co-solvents. They are a common way to tweak SCFE CO2 extraction to a specific product.

Here is are a couple links discussing SCFE CO2 solubility with and without co-solvents, one being Ethanol.

Do any of ya'll readers have an account at either?

https://www.sciencedirect.com/science/article/pii/S0378381203000220

https://pubs.acs.org/doi/pdf/10.1021/jf0345550
 

duke0fdank

New member
i do own a CO2sfe lol
but im talking about more than half ethanol by weight which would make it more of a co2 expanded ethanol then ethanol as an entrainer for sc co2
 
Hi everybody,

What is pros & cons of subzero extraction with ethanol vs pentane, if subsequent processing of the extract involves only DCVC separation (pentane-ethyl acetate)?

Is winterization needed prior to separating with DCVC?

Thank you all
 

Gray Wolf

A Posse ad Esse. From Possibility to realization.
Mentor
ICMag Donor
Veteran
Hi everybody,

What is pros & cons of subzero extraction with ethanol vs pentane, if subsequent processing of the extract involves only DCVC separation (pentane-ethyl acetate)?

Is winterization needed prior to separating with DCVC?

Thank you all


Alcohol is less explosive and easier to hold on to. It also doesn't have to be subsequently winterized, like Pentane does.
 

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