Pressure accelerates the extraction?

[jump117]

The old general rule in organic chemistry is that each 10C doubles reaction rate,

Hey G.O. Joe, what is the rule for the pressure affects the rate of extraction? plz

I doubt pressure would have effects

Question about pressure rises when comparing the dynamics of the two methods of extraction with butane which I used,
tubular type with the direct flow under slight pressure in a short time,
compared with the Thermos-type long soak and stir in butane at atmospheric pressure.

(quote from http://www.edenlabs.com/ )
SUPERCRITICAL FLUID AND HIGH PRESSURE SOLVENT EXTRACTION
There are many ways of extracting with alcohol but high pressure is the best.
It is faster, does a more thorough job and requires less alcohol per volume of herb than other methods. (end of quote)

Pressure accelerates the extraction?

 

[Gray Wolf]

Ethanol becomes a supercritical fluid at 60.6 atmospheres at 513.9 degrees Kelvin, which is about 891 psi at about 241C/465F.

 

[Gray Wolf]

May I expand on this thread slightly brother Jump?

Besides turning alcohol into a super solvent by pressurizing it to 891 psi at 465F, in industry we used a system that alternately pressurized the extracting fluid with the parts immersed in it and then released the pressure.

The fluid is typically kept liquid above its boiling point under the pressure, and the pressure forces it into the pores of the medium being digested. When the pressure is released, the solvent is suddenly way above its boiling point for the pressure it is under and out gasses as steam, helping remove material from deep in its core.

That process works extremely well and is how a ceramic core autoclave works, to remove long skinny ceramic cores from deep in aerospace investment castings, using aqueous NAOH or KOH as the solvent.

In the case of cannabis, the material that we are seeking is on the surface and extracting material from deep within the plant pores, may not be to our best interests.

Most certainly that is not where the cannabinoids that we are seeking are known to reside and is where the alkaloids and other water solubles are ostensibly most concentrated.

In my own industrial experience, I found that besides elevating the temperature of the solvent to the reactive range, the partially dissolved boundary layer between the fresh solvent and the fresh surface to be dissolved, must be continuously (or at least periodically) removed for the reaction to continue.

That is because the partially reacted material protects the un-reacted material from the concentrated solvent.

I have seen leaking tanks of Nitric Hydrofluoric acid, that not only eats metal, but eats glass and other ceramics, stopped cold by a simple concrete bunker, because after the preliminary rather violent reaction between the highly base lime concrete and the acid, a boundary layer was formed and the reaction ground to a snails pace.

So as I understand the intent of some of the questions leading up to this thread, I might suggest mild heat and agitation to get the fastest most complete dissolution, but alas it would also extract some of the water solubles with it because of the heat.

The agitation would also comes the expense of creating more fines to filter out, depending on its severity.

While writing this as I simultaneously test creations, it occurred occur to me that the word pressure is relative and that if we were to put material in alcohol and simply pull a simple vacuum on it using a $15 water faucet vacuum aspirator, that it would cause the material to boil and be gently but very effectively agitated.

If you boiled it for 30 minutes and then decanted and flushed, you could speed up the process with the agitation, but of course the bad news is that unless you run the process at low temperature, you will end up with the water solubles, so setting it up in a subzero freezer might be a better idea than using warm alcohol, despite it being much faster..

With the right heat exchanger, a person could also recondense the discharge from the faucet aspirator and even recover some of the ethanol soaked in the plant material that is normally lost even with a press.

Hee, hee, hee............... Just throwing brain farts into the air, because I personally prefer a three minute frozen ethanol quick wash on dry frozen material, or extracting with butane, because of its more pristine quality and higher concentration of active ingredients.

Certainly there are processes one can take to remove non active ingredients after they are already extracted, but I have come to believe that it is more effective for to me at least, to studiously avoid most of them in the first place.

 

[dope_roor]

i believe increased pressure does allow for a more thorough extraction of the material

i've observed this difference even when spraying bho through a stainless steel mesh vs. coffee filter

because i tend to use an okief i get a sense of how much pressure is being built up (the cork on top i have to push down during the whole extraction) and generally i yield higher with greater pressure.

however, whether it be a greater yield due to a higher level of THC i cannot be certain, the added mass may be other plant constituents (i think that was the jist of what GW was saying?)

 

[G.O. Joe]

Question about pressure rises when comparing the dynamics of the two methods of extraction with butane which I used,
tubular type with the direct flow under slight pressure in a short time,
compared with the Thermos-type long soak and stir in butane at atmospheric pressure.

My quotes were in response to an unclear question from out of the blue:

Hey G.O. Joe, what is the rule for the pressure affects the rate of extraction? plz

It still isn't clear what you're talking about. You are comparing a static system to a flow-through system, which doesn't have much to do with supercritical fluids. If only fresh solvent is coming in, this is always better extraction than a static system.

Not very surprising that ethanol is a better solvent at 241C than otherwise. Doesn't sound like something very selective.

 

[Rednick]

So many variables, it is impossible to give a straight answer.
SCFs are used in the botanicals industry extensively, decafination of coffee, cleanup of contaminated soil (superfund sites, ect.).
Eden Labs uses multiple designs depending on how deep your pockets are:
Flow Through @ HP, saturation brought up to HP at Temp, Francionating distillation, fractionating flow through,...the list goes on.

Crystals are found throughout the flower, so pressure would probably facilitate penetration of the fibers at a faster rate than chromotography (saturation?).

As far as impurities go, the chemical makeup of the solvent is most important. Next the state the solvent is in. And last the contact time with the solvate.

As far as purity would go, the less time contact time spent would result in the easiest to gather (contact) solvates.

The whole theory behind sample preparation with SCF is that at these higher temps and pressures the gas does not become a liquid (with its inherent molecular friction, relatively), instead it becomes a 'dense gas' (with the increased solvating power of more molecules per unit of volume, yet still retains the molecular friction of a gas). Less molecular friction means the solvent can travel more freely through the material.

 

[jump117]

Thank you for your participation!

May I expand on this thread slightly brother Jump?
-
The fluid is typically kept liquid above its boiling point under the pressure, and the pressure forces it into the pores of the medium being digested … may not be to our best interests.
-
the partially dissolved boundary layer between the fresh solvent and the fresh surface to be dissolved, must be continuously (or at least periodically) removed for the reaction to continue.

That is because the partially reacted material protects the un-reacted material from the concentrated solvent.

You are welcome anytime Gray Wolf! Thanks for the explanation, I think exactly the same.

i've observed this difference even when spraying bho through a stainless steel mesh vs. coffee filter
-
however, whether it be a greater yield due to a higher level of THC i cannot be certain

I used ½ “ and ¾” DIY metal tubes with coffee filter and steel mesh то hold the filter from outside. Sure the samples may differ.

It still isn't clear what you're talking about. You are comparing a static system to a flow-through system, which doesn't have much to do with supercritical fluids. If only fresh solvent is coming in, this is always better extraction than a static system.

You’re absolutely right, I’m totally confused my question, lumped together butane, overheated ethanol and SCF.
Excuse me for I was not in focus in recent days of Russian Christmas holidays.

Supercritical and High Pressure do not interest me at all, I had to post these words in the title of the cited article to find it on the site.
The point was in compare thermos and tube extractors.

I understand the obvious logic of washing with fresh solvent, it removes the saturated layer from the surface of dissolving trichome heads. In static system this layer slows extraction which rate depends on concentration dissolved. With stirring, the concentration in boundary layer is constantly aligned with an average concentration throughout the volume, grows and slows extraction.

I tried to compensate this with elongation the time of extraction, the last time it was two runs both for one hour (1h+1h) with excessive amount of butane in both rounds and stirring every ten minutes.
The quality of the two runs was the same, amount ratio 70%+30%, I washed the leftovers in ethanol and it also wasn’t empty.

Less molecular friction means the solvent can travel more freely through the material.

Does it mean the lower pressure the faster extraction?

 

[jump117]

I wonder how much pressure is formed in a tubular extractor when it is full and dense loading?

 

[strictlybongz]

was trying to devise a system to measure the pressure in a tubular extractor yet with no formal engineering background I wasn't sure which measurement instrument was appropriate. WOuld we be measuring the gas pressure or the flow rate of the liquid butane, because as I understand it the back pressure causes a temperature drop and phase change within the tube from gas to liquid.

 

[G.O. Joe]

The pressure inside a sealed container containing a pure liquid and little else, at a certain temperature, is most easily determined from a chart as above. An expanded version follows. There is no reason not to extract with warmed butane; 10 bar is in easy reach with hardware store pipe and teflon tape. It would not be difficult to engineer a standard flowing system with 3 pipes on end, 2 caps, a screen and 2 valve joints. And heating tape or other safe heating method if you want to see what happens above room temp. It might not be easy to tell if any increase in yield is from THC or the other stuff. A closed, heated system is very likely to be a butane miser if you want it to be.

 

[budbasket]

I was reading on another chemistry forum and the members were discussing the variable polarity of C02 dependent on temperature and pressure. I know this thread is about butane specifically as a solvent but I am wondering, could be possible to change the pressure/temp of bottled c02 when doing extractions so that varying cannabinoids/terpenes are extracted?
I think eventually the pharma companies will be looking to extract individual cannabinoid profiles and perhaps combining them to produce a compound which more emulates the active "high" in marijuana. I have heard one reason there hasn't been a mmj medicine put out (besides sativex and marinol) is because the companies have never been able to recreate synthetically the effects/exact compounds found naturally in cannabis. What if the medical benefits is because of the combination of chemicals found naturally in cannabis? Not just CBD/CBN/THC individually but varying levels of all cannabinoids?
It seems to me for any real research to be done, first the cannabinoids must be extracted/isolated/examined. Then work on creating as many compounds of the chemicals as possible searching for the "right one". Then after correct combinations are found, work will need to be done creating a synthetic version which could be easily produced/controlled under lab conditions.
Sorry about this weird rant that went way off topic... fairly medicated myself this morning, stay safe all-basket

 

[Hashmasta-Kut]

its moreso the terpenes that effect the psychoactive profile, as opposed to ratios of cannabinoids.

 

[budbasket]

That just opens the door for further research of isolating specific terpenes in addition to the cannabinoids, I focused on the topic of cannabinoids mainly because I believe those to possess the most pharmaceutical potential such as non-lethal EFFECTIVE treatments of cancer, hell even tumors, as opposed to chemo/radiation. I could be completely wrong, it could be the terpenes or a combination of both.What would be the most effective solvent/extraction process for terpenes?
I think there are the chemicals in this plant which will someday result in the perfect anti-depressant/stress relief without leaving users forgetting what they did this morning. And also other chemicals that will produce a cancer treatment as common as taking a Tylenol. This is why I like the conversation into the topic as well as the potential for actual research to be done. I know there are many in the community who despise what the pharmaceutical/agribusiness companies are rumored to be doing, but in a realistic world, I believe they will be the only ones producing real medicine derivatives from the cannabis plant.
-basket

 

[Gray Wolf]

The pressure inside a sealed container containing a pure liquid and little else, at a certain temperature, is most easily determined from a chart as above. An expanded version follows. There is no reason not to extract with warmed butane; 10 bar is in easy reach with hardware store pipe and teflon tape. It would not be difficult to engineer a standard flowing system with 3 pipes on end, 2 caps, a screen and 2 valve joints. And heating tape or other safe heating method if you want to see what happens above room temp. It might not be easy to tell if any increase in yield is from THC or the other stuff. A closed, heated system is very likely to be a butane miser if you want it to be.

I haven't tested an open extraction tube to see what pressure is achieved, but I have experimented with closed butane systems at ambient. I know that my first sealed system ran at around 25psi, but I didn't record ambient.

I think it is therefore safe to say that the open ended extraction tube operates at less than 25psi.

My current closed system has seen up to 40 psi when I opened the column dump valve, without the valve to the recovery pump being open, and the butane hit the heated bottom of the lower collection vessel.

As I pre-evacuate my entire system to -28.5 in/Hg before backfilling the column with liquid butane, it is mostly butane pressure, as opposed to entrapped air.

What I have found thus far, is that my new soak/recycle system produces more green pigment in the oil processing at an ambient temperature of between 50 and 60F, than a single pass by the plant material in a packed column at those temperatures.

Still a light green, but nere the less more green, which I attribute in part to the slight solubility of the short chain N-Butane in water, which as ya'll know, are not an issue with the next longer chains and above.

Here are the first three cycles on five extraction and recovery cycles of prime bud, and a picture of the last two combined in a jar. The first four cycles were of 3 minute duration, and the last was 5 minutes. Compare the color of that jar to the accompanying jar picture of BHO extracted using a simple flow though 1" X 36" column.

 

[Gray Wolf]

Well now, I was able to delete a mislabled photo, but not repost the new one, so here they are again.

The first is the forth and fifth 3 & 5 minute soak extraction cycles vis a vis BHO extracted using a conventional flow through tube.