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Getting the Green and Waxes Out Afterwards

Gray Wolf

A Posse ad Esse. From Possibility to realization.
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Public opinion appears to be split on the salubriousness of including chlorophyll and other plant water solubles in our extracted oils, so this is written not to stir controversy, but specifically for those of ya'll whom do not wish ingredients other than cannabis in your extracts.

Those whom wish to preserve those ingredients are invited to please ignore this posting, rather that debating whether it is a mistake or even a crime against sweet Mary's natural wholeness.

In a nutshell, many of those non cannabinoid ingredients came along for the ride because there was water present and they are water soluble. It is easier to use a process that minimizes their extraction in the first place, but what if that is a moot point, because you already have an extraction with excessive non-active ingredients and wish to remove them?

Next best to a process that doesn't pick up many water soluble ingredients, is one to take them out, so let's talk about a couple processes that we use at skunk pharm:

If the extraction just needs final polishing, we may simply re-dissolve it in 190 proof (~95.5% azeotropic) ethanol and stick it in the freezer overnight at 0F, for the waxes to coagulate and the excess water solubles to precipitate out.

We then carefully decant and filter the alcohol mixture, to remove the coagulated waxes, as well as the chlorophyll, and plant alkaloids which precipitated out as sludge in the bottom of the container.

We routinely use this step to clean up extractions using Isopropyl or Methanol, because they are far more aggressive than ethanol in stripping everything, and much of the non active ingredients fall out when re-dissolved in hot ethanol and subjected to the above step.

It also works well to remove the minor water solubles picked up in a butane extraction, but has its limitations because alcohol is polar and 190 proof is still almost 5% water.

As far as filtering, I prefer a 0.45 micron or a 0.2 micron syringe filter, but got good results with a coffee filter until Joe turned us on to syringe filters. We have picked both the syringes and filters up off of E-bay, as well as from our local scientific supply store.

Now, if we really need to clean up an extraction, we have had good results by re-dissolving the oil in a hot highly non-polar solvent such as hexane and repeatedly washing the solution with saturated salt water until it is mint quality.

You can even skip the re-dissolve step, by just mixing the alcohol extraction with the highly non-polar solvent before evaporating it off, and the alcohol will leave with the first water wash, after the non-polar solvent has stolen away sweet Mary's succulent and titillating charms.

Salt water washing is easy, easier with a separatory funnel, but you can even do it with a few gallon Ziploc bags in pinch, or any number of ways to siphon off, blow off, etc., to achieve that purpose.

To use a Ziploc bag, simply hang by one corner, and clip off the lower corner to drain, pinching to control flow and shut off point.

The way we do it is to start out by making four or five liters of saturated salt water in glass (or ceramic) containers, by mixing sodium chloride (table salt) in hot tap water with a hand mixer until no more will dissolve. We buy the salt cheap by the bag, using salt intended for water softener use.

The magic trick if the alcohol from extraction is still present, is that because the saturated salt water readily accepts the alcohol, but no longer has any room for the water solubles due to its salt saturation, they fall out of solution and are filtered off in bottom sludge or left stuck to the sides of the funnel. If the alcohol has already been removed, the water solubles simply do not dissolve in the Hexane.

The rest of the magic is just as predictable when you mix the polar solvent holding sweet Mary's charms and the lustful non-polar solvent that covets them deeply, given that because of her own polarity, sweet fickle Mary herself lusts after the new suitor, so participates willingly and with a passion.

The alcohol and water are left giggling like idiots and the sludge is probably left puzzled.

To perform the salt water wash of the hexane mixture, simply pour the salt water and hexane into the separatory funnel together in about equal parts and shake well, before allowing the mixture to separate out into layers.

After carefully bleeding off the bottom layer of water, alcohol, and sludge, we replace the salt water that we bled off and shake up the mixture again to mix well. After bleeding that salt water, et al, again, and repeating the procedure several times, the hexane mixture becomes pristine and bell clear.

At that point we stop washing and evaporate off the hexane. While we use HPLC grade hexane from the local science store, naphtha will also work for this process.

To get rid of the hexane, we first evaporating off the visible liquid hexane, and then add 190 proof ethanol to the extracted oil and boil that off. We repeat that procedure several times, until there is no discernible taste or odor of hexane left.

That means that the remaining hexane is below about 30 ppm, which is (~) our sensory threshold perception level. What does that mean as far as our health means?

For starters, because it is a simple Alkane and relatively non toxic, hexane is used extensively in food extraction, but should not be viewed as being as salubrious as mother's milk.

The first clue of course, is that it doesn't come in nearly as attractive a container, and the second is the MSDS information which tells us, that in excess, N-Hexane attacks our nervous system.

OH MAHGAWD, but do check out at what levels this is so and note that oxygen in a breathing atmosphere greater than 75% pure will kill us dead! Poison is in the dosage, so leave us please keep N-Hexane's potential nature in perspective, which includes never losing sight of it!!!!!!

Despite our worst terrors, a review of the hexane Material Safety Data Sheet shows that the oral rat LD50: is relatively high at 25000 mg/kg. At that rate it would take about 4.5 pounds to kill 50% of a population of 180 lb men.

Acute toxicity of the gas (LC50 rat): was 48000 ppm using 4 hours exposure data and the Threshold Limit Value for an 8 hour weighted average in breathing air is 500 ppm with a Permitted Exposure Limit of 1800 mg/M3 (~ppm).

The good news is that if you are out of the stink or taste, you are less than about .01% of TLV, but the bad news (?) is that although it is relatively non toxic, hexane still tastes like lighter fluid below toxicity levels, with our sensory threshold far below the Threshold Limit Value.

Not an unexpected taste treat, because as many of ya'll know, lighter fluid is in point of fact light naphtha, which is a blend of pentane (5 carbon atom chain) and hexane (6 carbon atom chain).

Most of skunk pharm oil goes into oral or topical medications, though some is vaporized. Both the oral and the vaporization applications require residual hexane below human discernable (threshold) perception levels, so out of practicality, we standardized on zero perceptible solvent content on all our oils as just a matter of policy.

Lawrd knows that there are enough people kissing and licking at least some of the more provocative foxes and hunks in our folds all over, that we voted to use the same taste standard for topicals as orals.

The last issue, is of course residue and color, when using topicals! Besides undesirable taste, and non-active bulk in your extractions, there is the pregnant issue of how much residue they leave behind on the skin and how badly they stain our clothes.

Yet another reason to take care in extracting and subsequently processing our topicals, despite the ostensible threshold perception standards being lower.

We could also add that after we have removed the bulk of the non-active ingredients, our oil is more uniform and so our mixing ratios in our menstruums will be more precise and the results more uniform, as a bonus to not leaving a mess on our skin and clothes!
 

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Blue Tail

New member
Sensei Gray Wolf,

Many thanks for this timely post.

I am pulling my big old extraction unit out of storage. Many years ago... I did my primary extractions with Petroleum Ether, as, at the time, it was purported to be a more selective solvent for the MJ properties we are after.

What is your experience with PE as to the Wax and Chlorophyll content of the primary extract? And, would you still recommend the further purification steps you describe in this post?

Perhaps it may even be better to just do the primary extract with 190 proof ethanol, and proceed per this post.

Any advice would be very much appreciated.

Best Regards,

Blue Tail
 

!!!

Now in technicolor
Veteran
Great post. I just started toying with hash just this morning. Currently messing with hashetone simply because acetone evaporates quickly and cleanly. The result is nasty tasting and dark green. I'll get the separatory funnel out later this week and begin working on a cleaner product.
 

Gray Wolf

A Posse ad Esse. From Possibility to realization.
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ICMag Donor
Veteran
Sensei Gray Wolf,

Many thanks for this timely post.

I am pulling my big old extraction unit out of storage. Many years ago... I did my primary extractions with Petroleum Ether, as, at the time, it was purported to be a more selective solvent for the MJ properties we are after.

What is your experience with PE as to the Wax and Chlorophyll content of the primary extract? And, would you still recommend the further purification steps you describe in this post?

Perhaps it may even be better to just do the primary extract with 190 proof ethanol, and proceed per this post.

Any advice would be very much appreciated.

Best Regards,

Blue Tail

Petroleum ether is typically mostly pentane, which is a simple non polar alkane and should make a pretty clean extract all by its self.

I would probably use the PE for the extraction and the alcohol to remove the remains of the petroleum ether.

As you may know, pentane is five carbons in a chain with 12 hydrogens attached, and hexane is six carbons with 14 hydrogens. They are otherwise identical.
 

spurr

Active member
Veteran
Hey Graywolf,

Long time no see, I know you from TCC, this is gojo :wave:. This thread comes at a perfect time for me and a buddy, thanks.

It also works well to remove the minor water solubles picked up in a butane extraction, but has its limitations because alcohol is polar and 190 proof is still almost 5% water.
Have you tried using 3A molecular sieve to make 100% pure EtOH from ethanol azeotrope, such as 190 proof Everclear? That is what I am planning in the near future for a method that I and a buddy have been PMing about (incl. using oil-free diaphragm vacuum pump, manometer, Nalgene vacuum chamber, etc.). One can make a column style molecular sieve for < $100 incl. cost of the 3A zeolite (~$60 for 10 lbs of 3 angstroms pore diameter 3A that is 2.5-4.5 mm bead size). Or just using the tub method, not a column, should also work. However, using the tub method seems less ideal due to issues like possibility of fines from the zeolite beads getting into the EtOH when removing the zeolite beads.


I have a few questions for you, if you don't mind, please and thank you:


1. From everything I have read, using 2.4-4.5 mm 3A beads seems to be common practice to break the ethanol azeotrope and remove the water for 100% EtOH. However, it seems to me using 1.5-2.5 mm might work better (or at least more efficiently); thoughts?


2. I was thinking about using a sub-micron syringe filter from Whatman for filtration like you are doing (not sure if you're using Whatman brand, though). Do you find it's an efficient method?

I ask because when I make poppy extracts for CFO (cooked flake opium) I use filter bags made from nylon monofilament to filter the water/opiate extract to remove coagulated waxes and particulate. I use filter bag sizes from 25 micron to 10 micron to 5 micron and I have also used down to 1 micron. I use them in 'steps', from one to the next, to the next.

Due to the success I found using that method, I was thinking about using a 10 micron or a 5 micron or even a 1 micron filter bag for the cannabis concrete re-dissolved into EtOH; to filter out the coagulated lipids (like waxes). The only concern I have is the size of the bags, they are 7" wide at mouth x 32" long. I looked into Whatman filter paper and glass filters, but they are small and not easy to work with; not to mention non-pressurized filtration time is slow for sub-micron filters. So when I read you have used sub-micron syringe filters I got a bit excited; I already have a bunch of 0.2 micron Whatman syringe filters for other projects. What size syringe do you use and what brand/model filter?

Re: coffee filters, the reason I dislike them for filtering extracts is the pore sizes are so variable. Pore sizes range from ~5-100 microns, often with an average around 20 microns. FWIW, from my past experiences filtering plant lipids (like fats and waxes), using at least a 10 micron filter gives the best results.


3. I am going to make a DIY -80'C (-112'F) freezer with dry ice and coolers with insulation (maybe using some EtOH with the dry ice; not sure yet). I am planning on testing usage of the -80'C freezer for a 24 hour chill of the EtOH wash to strongly coagulate waxes. I got the idea to use -80'C freezer from DNA work using EtOH. Do you think -80'C is unnecessary overkill? I was thinking it may just be, so I thought instead I may use a normal freezer at 0'F like you have done, for 24 hours.

I believe there should be very little water in the concrete after using a Tamisium extractor with 99.9% pure n-butane. And thus there should be very little (if any) water in the final absolute if I use 100% pure EtOH wash; please correct me if I am wrong. That said, I am not sure what effect (if any) water from ethanol azeotrope would have, re -80'C freezer and EtOH wash, if I used 190 proof Everclear. What do you think? Do you think using 100% pure EtOH is overkill? I need to make 100% EtOH for other projects anyway, so I figured I might as well use it to re-dissolve the concrete after n-butane extraction of plant matter.


4. What ratio do you use for ethanol to concrete when re-dissolving the concrete with ethanol? Is it 'played by ear', or do you use a strict protocol?


5. You wrote:
In a nutshell, many of those non cannabinoid ingredients came along for the ride because there was water present and they are water soluble. It is easier to use a process that minimizes their extraction in the first place, but what if that is a moot point, because you already have an extraction with excessive non-active ingredients and wish to remove them?

Next best to a process that doesn't pick up many water soluble ingredients, is one to take them out, so let's talk about a couple processes that we use at skunk pharm:
What about the many water soluble flavonoids? I am of that opinion because many have medicinal proprieties and IMO some may positively affect (potentiate) the high from THC (similarly to the seemingly potentiating effects from some terpenoids). Do you know if re-dissolving the concrete with EtOH, chilling for 24 hours and filtering precipitates removes flavonoids? I have a feeling that some flavonoids stay put, but I am not sure, it's more of a guess than an educated guess. Consdering some (many?) flavonoids are pigments I assume you do not want them in your final concentrate, correct?


6. With the methods I have been putting together (at a total cost of ~$1,500 for the high-tech version with vac pump, etc.; and a total of ~$500 for low-tech version using water aspirator, manometer, etc.), I think/hope the absolute should be 100% free from hydrocarbons and alcohol as butane and ethanol, respectively. However, I wish to get the absolute tested with mass spec or something similar, do you, or anyone else reading, know of lab(s) offering such tests for cannabis concentrates?


7. How to you know when your absolute has been fully purged of EtOH (when all EtOH has evaporated off)? You wrote about evaporating off hexane, and testing by smell, but what about the EtOH?

I am planning on dropping the partial vacuum in the vacuum chamber to at least 80 Torr. But depending upon the ultimate vacuum and flow curve of the pump I will buy, I would like to increase the partial vacuum to ~60 Torr. I am still comparing pumps but I am leaning toward the VaccuBrand ME1 or ME1C because they are < $1,000, and have an ultimate vacuum of 75 Torr, which is considerably less than I would like in a perfect world, but should be sufficient if I bump up room temp a bit. And the ME1 is corrosion resistant which should suffice for EtOH vapors (I think), so I shouldn't need to go for the ME1C; also they can be fitted with a factory analog manometer and control value to regulate the partial vacuum. If only the ME1 models had a greater absolute vacuum! I have not yet found the flow curve for those models, that will be the deciding factor I think.

If the work rate at a partial vacuum near the ultimate vacuum of 75 Torr (e.g., a partial vacuum of 80 Torr) of the VaccuBrand ME1 models is too low I may simply turn up the ambient air temp in my lab a bit and run 85 Torr (or use a slightly heated water bath if all else fails). Granted, at 80 Torr 100% EtOH has a BP of just under 81'F, so the heat would need to be running anyway (I keep house at around 68'F most of the time). That said, I would rather buy a more powerful vacuum pump for $2k or $3k with sufficiently low absolute vacuum and flow curve. Ideally the absolute vacuum would be at or below 40 Torr so I can keep my room temp at 68-71'F and just use 55-60 Torr in the vacuum chamber to evaporate the EtOH (and any possibly remaining n-butane).

I just realized I am rambling a bit, forgive me. My ramblings do have a purpose though: I am hoping you can suggest a brand/model of vacuum pump, an oil-free (dry) diaphragm pump that I can use with EtOH vapors. Pump(s) that have high work rates around 60-75 Torr, and low absolute vacuum, at least down to 60 or 70 Torr...all for under ~$1,500.



Anyway, great post as always; I will need to re-read again. I yield the remainder of my time and look forward to learning from you :tiphat:
 
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spurr

Active member
Veteran
Public opinion appears to be split on the salubriousness of including chlorophyll and other plant water solubles in our extracted oils, so this is written not to stir controversy, but specifically for those of ya'll whom do not wish ingredients other than cannabis in your extracts.

...

In a nutshell, many of those non cannabinoid ingredients came along for the ride because there was water present and they are water soluble...

After re-reading your post, it seems you do not want anything but cannabinoids (in various states) in the concrete, is that an accurate statement? You seem to oft refer to water soluble constituents of a butane concrete as undesirable to you. However, I wonder (as a corollary to my previous post, re flavonoids) do you also wish to avoid inclusion of flavonoids (which include some pigments) into the final concentrate/absolute (being that many, or all, are water soluble)? And do you wish to exclude terpenoids too? Granted most (all?) terpenoids are not water soluble as far as I know, being a subclass of prenyllipid terpenes.

Because you use the concentrates for oral and topical application, I wonder if some flavonoids and terpenoids would not have the same level of medical efficacy vs being inhaled/smoked. And if at least some terpenoids that offer seemingly potentiating effects for the high from THC when smoked, would not offer similar benefits if ingested or used topically. Would those be reasons, if the answers are negative, for why you would not want at least flavonoids included, and maybe not terpenoids too?

I am not trying to debate the salubriousness (nice word usage BTW ;) ) of some flavonoids and terpenoids (which is pretty well proven at this point). I am merely wondering if you wish to exclude them or include them, from your concentrate. It seems excluding terpenoids would be pretty darn hard, or at least non-trivial...but you know more about this topic than I.

P.S. I just noticed the picture of your syringe and filter, so that answers one of my questions, re your syringe size is 20 ml. I really like that glass syringe BTW, did you buy it off of ebay? I am still interested in the brand of syringe filter.

P.P.S. Thanks again for the very useful and good info you shared, esp. re saturated salt water and physics behind it's usage. I may try a few of the steps you detailed, in the future, with butane concrete just to gain more experience with various methods of making concentrates/absolutes. I have a separatory funnel already so it'd be a shame not to use it for cannabis related work.

:tiphat:
 
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spurr

Active member
Veteran
Great post. I just started toying with hash just this morning. Currently messing with hashetone simply because acetone evaporates quickly and cleanly. The result is nasty tasting and dark green. I'll get the separatory funnel out later this week and begin working on a cleaner product.

FWIW, you can make anhydrous acetone (and anhydrous methanol for that matter) with the same molecular sieve I wrote about for making anhydrous (100% pure) EtOH from ethanol azeotrope.

The only issue with anhydrous chemicals such as acetone or EtOH, as I am sure you are aware, is they will absorb moisture from the air; so proper storage and usage helps keep them water free.

Whether it's better to use anhydrous solvents or hydrous solvents for cannabis extractions and concrete cleaning I am unsure. My best guess is it's better using anhydrous than using hydrous versions of those solvents. But I could be wrong...

Reference (for acetone info):
Molecular Sieve Information
Dale Callaham
University of Massachusetts Amherst, The Central Microscopy Facility (n.d.)
http://www.bio.umass.edu/microscopy/mol_sieves.htm
 
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jump117

Well-known member
Veteran
EtOH azeotrope
The water present in ethanol has nothing to dissolve from BHO/BHC to spoil the absolute,
I see no use in dehydration azeotrope to higher grade to achieve the absolute from concrete.

Water soluble flavonoids do not dissolve in the butane,
BHO/BHC is free from water-soluble components including water soluble flavonoids
but they clearly play a role in the primary non-polar extraction.

Water cured plant material has no aromas, they all washed away by water.
But butane extract from water-cured turns out dirtier than from not treated stuff, contrary to expectations.
I suspect that the lipophilic oily dirt inside the plant cell is covered with a layer
of water-soluble substances that protect it from the non-polar solvent.

After a non-polar extraction the bouquet of water-soluble aromas probably better to extract of leftovers
as a separate special action, but not simultaneously with extraction resin.

Vacuum
Certainly very attractive seems purging of ethanol at room temperature under vacuum.
THCA-Amber is the crystallized solid at room temperature and it has melted by heating to the melting point
in order to necessary mobility of residual solvent.
 

Gray Wolf

A Posse ad Esse. From Possibility to realization.
Mentor
ICMag Donor
Veteran
Hey Graywolf,

Long time no see, I know you from TCC, this is gojo :wave:. This thread comes at a perfect time for me and a buddy, thanks.

Have you tried using 3A molecular sieve to make 100% pure EtOH from ethanol azeotrope, such as 190 proof Everclear? That is what I am planning in the near future for a method that I and a buddy have been PMing about (incl. using oil-free diaphragm vacuum pump, manometer, Nalgene vacuum chamber, etc.). One can make a column style molecular sieve for < $100 incl. cost of the 3A zeolite (~$60 for 10 lbs of 3 angstroms pore diameter 3A that is 2.5-4.5 mm bead size). Or just using the tub method, not a column, should also work. However, using the tub method seems less ideal due to issues like possibility of fines from the zeolite beads getting into the EtOH when removing the zeolite beads.


I have a few questions for you, if you don't mind, please and thank you:


1. From everything I have read, using 2.4-4.5 mm 3A beads seems to be common practice to break the ethanol azeotrope and remove the water for 100% EtOH. However, it seems to me using 1.5-2.5 mm might work better (or at least more efficiently); thoughts?


2. I was thinking about using a sub-micron syringe filter from Whatman for filtration like you are doing (not sure if you're using Whatman brand, though). Do you find it's an efficient method?

I ask because when I make poppy extracts for CFO (cooked flake opium) I use filter bags made from nylon monofilament to filter the water/opiate extract to remove coagulated waxes and particulate. I use filter bag sizes from 25 micron to 10 micron to 5 micron and I have also used down to 1 micron. I use them in 'steps', from one to the next, to the next.

Due to the success I found using that method, I was thinking about using a 10 micron or a 5 micron or even a 1 micron filter bag for the cannabis concrete re-dissolved into EtOH; to filter out the coagulated lipids (like waxes). The only concern I have is the size of the bags, they are 7" wide at mouth x 32" long. I looked into Whatman filter paper and glass filters, but they are small and not easy to work with; not to mention non-pressurized filtration time is slow for sub-micron filters. So when I read you have used sub-micron syringe filters I got a bit excited; I already have a bunch of 0.2 micron Whatman syringe filters for other projects. What size syringe do you use and what brand/model filter?

Re: coffee filters, the reason I dislike them for filtering extracts is the pore sizes are so variable. Pore sizes range from ~5-100 microns, often with an average around 20 microns. FWIW, from my past experiences filtering plant lipids (like fats and waxes), using at least a 10 micron filter gives the best results.


3. I am going to make a DIY -80'C (-112'F) freezer with dry ice and coolers with insulation (maybe using some EtOH with the dry ice; not sure yet). I am planning on testing usage of the -80'C freezer for a 24 hour chill of the EtOH wash to strongly coagulate waxes. I got the idea to use -80'C freezer from DNA work using EtOH. Do you think -80'C is unnecessary overkill? I was thinking it may just be, so I thought instead I may use a normal freezer at 0'F like you have done, for 24 hours.

I believe there should be very little water in the concrete after using a Tamisium extractor with 99.9% pure n-butane. And thus there should be very little (if any) water in the final absolute if I use 100% pure EtOH wash; please correct me if I am wrong. That said, I am not sure what effect (if any) water from ethanol azeotrope would have, re -80'C freezer and EtOH wash, if I used 190 proof Everclear. What do you think? Do you think using 100% pure EtOH is overkill? I need to make 100% EtOH for other projects anyway, so I figured I might as well use it to re-dissolve the concrete after n-butane extraction of plant matter.


4. What ratio do you use for ethanol to concrete when re-dissolving the concrete with ethanol? Is it 'played by ear', or do you use a strict protocol?


5. You wrote:
What about the many water soluble flavonoids? I am of that opinion because many have medicinal proprieties and IMO some may positively affect (potentiate) the high from THC (similarly to the seemingly potentiating effects from some terpenoids). Do you know if re-dissolving the concrete with EtOH, chilling for 24 hours and filtering precipitates removes flavonoids? I have a feeling that some flavonoids stay put, but I am not sure, it's more of a guess than an educated guess. Consdering some (many?) flavonoids are pigments I assume you do not want them in your final concentrate, correct?


6. With the methods I have been putting together (at a total cost of ~$1,500 for the high-tech version with vac pump, etc.; and a total of ~$500 for low-tech version using water aspirator, manometer, etc.), I think/hope the absolute should be 100% free from hydrocarbons and alcohol as butane and ethanol, respectively. However, I wish to get the absolute tested with mass spec or something similar, do you, or anyone else reading, know of lab(s) offering such tests for cannabis concentrates?


7. How to you know when your absolute has been fully purged of EtOH (when all EtOH has evaporated off)? You wrote about evaporating off hexane, and testing by smell, but what about the EtOH?

I am planning on dropping the partial vacuum in the vacuum chamber to at least 80 Torr. But depending upon the ultimate vacuum and flow curve of the pump I will buy, I would like to increase the partial vacuum to ~60 Torr. I am still comparing pumps but I am leaning toward the VaccuBrand ME1 or ME1C because they are < $1,000, and have an ultimate vacuum of 75 Torr, which is considerably less than I would like in a perfect world, but should be sufficient if I bump up room temp a bit. And the ME1 is corrosion resistant which should suffice for EtOH vapors (I think), so I shouldn't need to go for the ME1C; also they can be fitted with a factory analog manometer and control value to regulate the partial vacuum. If only the ME1 models had a greater absolute vacuum! I have not yet found the flow curve for those models, that will be the deciding factor I think.

If the work rate at a partial vacuum near the ultimate vacuum of 75 Torr (e.g., a partial vacuum of 80 Torr) of the VaccuBrand ME1 models is too low I may simply turn up the ambient air temp in my lab a bit and run 85 Torr (or use a slightly heated water bath if all else fails). Granted, at 80 Torr 100% EtOH has a BP of just under 81'F, so the heat would need to be running anyway (I keep house at around 68'F most of the time). That said, I would rather buy a more powerful vacuum pump for $2k or $3k with sufficiently low absolute vacuum and flow curve. Ideally the absolute vacuum would be at or below 40 Torr so I can keep my room temp at 68-71'F and just use 55-60 Torr in the vacuum chamber to evaporate the EtOH (and any possibly remaining n-butane).

I just realized I am rambling a bit, forgive me. My ramblings do have a purpose though: I am hoping you can suggest a brand/model of vacuum pump, an oil-free (dry) diaphragm pump that I can use with EtOH vapors. Pump(s) that have high work rates around 60-75 Torr, and low absolute vacuum, at least down to 60 or 70 Torr...all for under ~$1,500.



Anyway, great post as always; I will need to re-read again. I yield the remainder of my time and look forward to learning from you :tiphat:

Hi GJ! Thanks for joining in!
Good idea on the mol sieve columns bro!

We have a couple 10" Altech Associates mol sieve gas columns, but haven't used mol sieve to pick up the last 5% water from the 190 proof azeotrope yet.

Sounds like we are playing in the same sandbox though, as I have been playing with vacuum purging as well.

In answer to your questions:

1. Good question on mol sieve size, my thoughts are that the smaller size would have more surface area per unit volume and be more efficient. It would probably be faster to regenerate as well.

2. Looks like my 20 ml glass and our 60 ml plastic syringes are Becton Dickerson and they work efficiently, if not fast with a filter in the batch sizes that we run.

We use what ever syringe filters we can get the best price on, and it looks like the last batch was Gelman, which we picked up from American Scientific. We have used Whatman, which we picked up on E-Bay, and they seemed to work just as well.

I have a filter membrane holder, plus we also pick up fully assembled throw away syringe filters. Depending on how dirty the mix is and the pore size, it takes several to complete a run, but they work reasonably fast and efficiently.

On larger batches, we also use vacuum pre-filtration, before resorting to the syringe filters and use incremental filtration steps if it is really turbid.

Joe picked the vacuum filtration unit up from American Scientific, but I notice that it doesn't have a brand name on it. It screws on a 1.75 liter Clear Springs 190 proof bottle and we use a MASH unit vacuum pump to provide the vacuum. Cost was probably less than $20.

For small batches, two or three syringe filter membranes are however quick and easy.

Good point on the coffee filters. As you know, there are average pore size filters and absolute pore size filters. Coffee filters belong to the former and some pores will pass multiples of the ostensible filtration range and others will plug at a small fraction of it.

Pre-filtration with average pore size filters however does take the load off of the precision filters and extends their lives.

As far as pore size, we clean up with whatever is the cheapest, but use 0.45 and 0.2 for final cleanup. No particular magic or insight in selecting those sizes, other than they are readily available and work well. As near as I can tell, anything below ~1.0 micron removes everything from bacteria up in size and delivers a pristine product.

I like 0.2, because in a previous life time, I was even able to clean up a radioactive industrial waste stream to below background at that filtration level.

3. Excellent question and one which I will run by Joe, our young energetic biochemistry student pharmer, because I'm not sure what happens at -80C to an alcohol water mixture. As far as I know, nothing different, but there certainly would be no question about free water at that temperature if you also used anhydrous EtOh.

It may be overkill, given that I get good results at 0F and 95.6% ethanol. I would probably try at it those parameters before spending much money improving upon the process, to see what the incremental gain is going to be for the added investment.

4. I actually just pour in "enough ethanol", because too much isn't an issue. I use more for filtration, so as to lose less to the filter gods.

5. Good point on the turpenoids and flavoids! I tried to side step that issue, because they do in fact have known medicinal qualities, and are mostly not water soluble.

I was trying to zero in on the water solubles, because I don't consider the turpenoids and flavoids inert ingredients. My disclaimer is because some folks strongly don't consider the chlorophyll, waxes, and plant alkaloids inert ingredients and I didn't want to start a new battle front on the subject.

In truth, we neither try to remove or preserve flavoids and turpenoids when cleaning up a messy extraction, though we do try to preserve them in an initial extraction.

They are also neither preserved or eliminated by the above process, only reduced. That is primarily why I prefer to do a clean extraction to start with, so that we don't have to use draconian measures that diminish the desirable aromatics lending flavor and character to the cannabis oil.

Even though they may have high boiling or vaporization temperatures, the turpenoids and flavoids are for the most part aromatic compounds (Benzene ring) that give off molecules at ambient temperatures and pressures, which is why they are aromatic. The more we thrash and slap the oil about and the hotter it is, the more of them exit.

At the pharm, we also don't go for a specific color, so we don't care about pigments and the solvent solubles don't filter out anyway. I have noted that the oil seems to vary a lot in color, depending on what we have done to it. The anthocyanins in cannabis move the colors from yellow to red and even on to blue.

6. Sadly no, there are no local labs, so we have been stuck with anecdotal evidence. We have however researched an HPLC and if there is enough local market to support the return on investment, we may add one. There are labs in California performing that service, if you are in that state.

7. Most of our meds go into orals or topicals, so we decarboxylate the mixture. When cooking off the mixture in a 250F hot oil bath, it is easy to watch the bubble formation and keep track of when the solvents are purged and the remaining bubbles are primarily C02.

Bubble watching is also the same way that I am keeping track using vacuum and low heat thus far, with taste and smell as a backup.

That can actually be a hoot! A patient told me that he missed the old days honey oil that tasted "sweeter" than my oil. I promptly added some alcohol tincture to the oil in the well, and when he sampled it, he exclaimed, "yes!" Clearly it was the residual alcohol that he was missing.

Good information on the vacuum pumps and I will check them out, but have no better solution than possibly an aspirator. As I mentioned, we use an old medical MASH vacuum pump with inlet and outlet collection bottles for filtration, but are also playing with a CPS AC vacuum pump (100 micron/.10 torr), and a faucet aspirator (-28.5 Hg/10.5 torr).

Our primary focus using vacuum has been alcohol reclaim, though I have an aging agenda on the schedule to further pursue cold boiling for the sake of the end product for vaporization. I am sorry to say that my vacuum solvent recovery success thus far is less than my simple pot still, because I need more condensing surface.

The issue with a vacuum pump of course is crank case contamination, which is why you are probably looking at a diaphragm pump.

I have never measured it, but a faucet vacuum aspirator will ostensibly pull down to -28.5 Hg at around 6/7 liters per minute water flow rate, or about .005 atmospheres. 80 torr is around .105 atmospheres, so you might give a faucet aspirator a look see for a possible cheap initial capital cost solution.

Thanks for sharing brother GJ and I hope you will keep us up to date with your progress!
 

Gray Wolf

A Posse ad Esse. From Possibility to realization.
Mentor
ICMag Donor
Veteran
P.S. I just noticed the picture of your syringe and filter, so that answers one of my questions, re your syringe size is 20 ml. I really like that glass syringe BTW, did you buy it off of ebay? I am still interested in the brand of syringe filter.:tiphat:

I picked up my BD 20 ml glass syringe on E-Bay, and Joe picked up some glass 60 ml syringes there, but alas I broke the one in the lab and didn't notice the brand.

We also use 60 ml BD plastic ones, which we picked up on E-Bay.
 

spurr

Active member
Veteran
Hello Jump, :tiphat:

I have read many of your posts and threads in this forum and I would first like to thank you for your contributions. Please correct me if what I post below is wrong.

EtOH azeotrope
The water present in ethanol has nothing to dissolve from BHO/BHC to spoil the absolute, I see no use in dehydration azeotrope to higher grade to achieve the absolute from concrete.

I was thinking along the lines of a more pure absolute from using anhydrous EtOH vs EtOH azeotrope. However, when one evaporates the ~95% EtOH the water from azeotrope will also evaporate, so using anhydrous EtOH might be overkill, I agree. It seems though, there might be benefit to using anhydrous EtOH instead of EtOH azeotrope; what the benefit(s) could be, if they exist, I am unsure. Of course that is only my speculation backed by zero evidence ;)

Water soluble flavonoids do not dissolve in the butane,
BHO/BHC is free from water-soluble components including water soluble flavonoids but they clearly play a role in the primary non-polar extraction.

Flavonoid aglycones (no attached sugar) are non-polar (and thus fairly water insoluble), and flavonoid glycosides (sugar attached) are polar (water soluble). Thus cannabis flavonoid aglycones should be present in BHO/BHC because n-butane is non-polar and the non-polar flavonoids are soluble in n-butane; as are most terpenoids/terpenes because they are fairly non-polar too. EtOH is both polar and non-polar, so a EtOH wash of butane concrete works well solublize flavonoid aglycones. Examples of flavone molecules that can be aglycones are quercetin, luteolin, hesperitin, apigenin; as well as some anthocyanidins and isoflavones (aka isoflavonoids). Using EtOH as the primary solvent yeilds a less pure concrete due to inclusion of polar substances such as flavonoid glycosides, chlorophyll, etc.

Here are some relevant quotes from a cannabis related study, book and thesis paper. All showing various flavonoid aglycones found in cannabis. IIRC in cannabis flavonoids are not present in trichomes:

1. Ross, et al., 2005:
"About 20 flavonoids have been reported to be present in the cannabis plant as aglycones or as conjugated O-glycosides or C-glycosides (Paris et al., 1973, 1975; Gellert et al., 1974; Turner et al., 1980; Ross and ElSohly, 1995)."

2. ElSohly (ed.), 2006:
"Twenty-three commonly occurring flavonoids have been identified in Cannabis, existing mainly as C-/O- and O-glycosides of the flavon and flavonol-type aglycones apigenin, luteolin, quercetin, and kaempferol (see Table 6; ref. 36). Orientin, vitexin, luteolin-7-O-glucoside, and apigenin-7-O-glucoside were the major flavonoid glycosides present in low-THC Cannabis cultivars (37). The cannflavins A and B are unique to Cannabis (38,39)."

3. Soto, 1971:
"Retention times for [flavonoid] aglycones [in cannabis extract] were as follows: apigenin 23.02 min, kaempferol 21.95 min, luteolin 18.37 min, quercetin 16.37 min, isovitexin 5.32 min, vitexin 4.71 min and orientin 3.64 min..."


References:
Flavonoid Glycosides and Cannabinoids from the Pollen of Cannabis sativa L.
Ross SA, ElSohly MA, Sultana GN, Mehmedic Z, Hossain CF, Chandra S
Phytochem Anal. 2005 Jan-Feb;16(1):45-8
(full text study) http://www.home.olemiss.edu/~suman/Suman%202005%20-FlavonoidGlycosides.pdf

Marijuana and the Cannabinoids

Edited by Mahmoud A. ElSohly, PhD
Humana Press; 1 edition (October 15, 2006)
(full text book) http://www.scribd.com/doc/22257816/Marijuana-and-the-Cannabinoids


Polyketide synthases in Cannabis sativa L.
Isvett Josefina Flores Sanchez
Thesis paper
Geboren te Pachuca de Soto, Hidalgo, Mexico (1971)
(full text thesis paper) https://openaccess.leidenuniv.nl/bitstream/1887/13206/2/ThesisFloresSanchez.pdf#page=127


Water cured plant material has no aromas, they all washed away by water. But butane extract from water-cured turns out dirtier than from not treated stuff, contrary to expectations. I suspect that the lipophilic oily dirt inside the plant cell is covered with a layer of water-soluble substances that protect it from the non-polar solvent.

After a non-polar extraction the bouquet of water-soluble aromas probably better to extract of leftovers as a separate special action, but not simultaneously with extraction resin.

What do you mean by "water cured"? Do you mean water-fermented, as in buds placed in water for a few days? I ask because terpenoids/terpenes (ex., monoterpenes and sesquiterpenes) are a major source of aroma and flavor for most fruits and flowers, such as tomato and cannabis, respectively; e.g., the monoterpene S-linalool (Lewinsohn, et al., 200). One reason I love, as do others, a good extract is the smell retained from the flowers, thanks to mono-and-sesquiterpenes.

As of 1980, 58 monoterpenes and 38 sesquiterpenes had been identified in cananbis samples (Turner, Elsohly and Boeren, 1980). Two of the more well known terpenoids/terpenes found in cannabis are limonene and myrcene. According to Nigam, et al., (1965), "The essential oil [terpenoids/terpenes] obtained by hydrodistillation of freshly harvested Indian Cannabis sativa L. has found to contain the following constituents that have not previously been reported: or-pinene, camphene, p-pinene, a-terpinene, p-phellandrene, yterpinene, linalool, trans-linalool oxide, sabinene hydrate, or-bergamotene, terpinene-4-01, p-farnesene, or-terpineol, or-selinene, curcumene, and caryophyllene oxide."

Terpenoids/terpenes are fairly non-polar, so they are fairly water insoluble. Thus it seems a water cured bud will still retain them to my understanding. Whether water curing affects terpenoids/terpenes in some manner that makes them less aromatic I am unsure (ex., maybe increases volatilization?). However, the terpenoids/terpenes should still be present after water curing...

On thing that is not clear to me is when something is a terpenoid and when something is a terpene. Many authors seem to use those two terms for the same substance, such as beta-caryophyllene; even though a terpenoid is really a subclass of terpene. Any terpenoid I guess could be considered a terpene but not all tepenes are terpenoids to my understanding...

References:
Enhanced levels of the aroma and flavor compound S-linalool by metabolic engineering of the terpenoid pathway in tomato fruits
Lewinsohn E., Schalechet F., Wilkinson J., Matsui K., Tadmor Y., Nam K.H., Amar O., Lastochkin E., Larkov O., Ravid U., Hiatt W., Gepstein S., Pichersky E.
Plant Physiol. 2001 Nov;127(3):1256-65
(full text study) http://www.plantphysiol.org/cgi/content/full/127/3/1256

Constituents of Cannabis sativa L. XVII. A review of the natural constituents

Turner C. E., M. A. Elsohly and E. G. Boeren
Journal of Natural Products 43 (2): 169-234 (1980)

Essential oils and their constituents XX1X.l. The essential oil of marihuana: Composition of genuine Indian Cannabis sativa L.

I.C. Nigam, K.L. Handa, I.C. Nigam, and L. LEV
Canadian Journal of Chemistry, Volume 43 (1965)
(full text study) http://article.pubs.nrc-cnrc.gc.ca/ppv/RPViewDoc?issn=1480-3291&volume=43&issue=12&startPage=3372
Vacuum
Certainly very attractive seems purging of ethanol at room temperature under vacuum. THCA-Amber is the crystallized solid at room temperature and it has melted by heating to the melting point in order to necessary mobility of residual solvent.

I am not sure I understand what you are writing. Are you suggesting that to fully remove residual solvent (ex., after evaporating EtOH) the absolute needs to be heated to the melting point of THCA-A?

The melting point (MP) of THCA-A is 65-68°C (Lehmann and Brenneisen, 1992), so I wonder if when creating a partial vacuum to evaporate the EtOH the THCA-A would reach its MP. I failed in my attempts to find a nomograph for melting points under partial vacuum. I want to find such a nomograph (if such a beast exists) so I can calculate the MP of THCA-A under partial vacuum of ~60-70 Torr.

Do you know the melting point of CBD-A by chance? Here are the listed melting points I have, please let me know if they are not the same as what you have:


  • Melting point of THCA-A is 65-68°C according to Lehmann and Brenneisen (1992).
  • Melting point of CBD is 66–67°C according the UNODC manual ST/NAR/40 (2009).
  • Melting point of CBN is 76–77°C the UNODC manual ST/NAR/40 (2009).


References:
A new chromatographic method for the isolation of (−)-Δ9-(trans)-tetrahydrocannabinolic acid A
T. Lehmann,2. R. Brenneisen
Phytochemical Analysis, Volume 3, Issue 2, pages 88–90, March 1992


Recommended methods for the identification and analysis of cannabis and cannabis products
United Nations Office on Drugs and Crime manual ST/NAR/40 (2009)
(full text manual) http://www.unodc.org/documents/scientific/ST-NAR-40-Ebook.pdf



 

spurr

Active member
Veteran
Hey Jump,

I forget to ask you something about a point you made regarding THCA-A:

Vacuum
Certainly very attractive seems purging of ethanol at room temperature under vacuum.

THCA-Amber is the crystallized solid at room temperature and it has melted by heating to the melting point in order to necessary mobility of residual solvent.

Kind of on this topic is something I have been considering: the pliability (or lack there of) of the absolute immediately after evaporation of EtOH (using partial vacuum to reduce EtOH BP below or very near room temp). I am wondering if I did not carry out decarboxylation of THCA-A into THC during the EtOH wash of the concrete, whether the absolute would be pliable immediately after removing it from the vacuum chamber. What do you think, would such an absolute be pliable immediately after removing it from the vacuum chamber? Or do you think such an absolute would be solid and/or non-pliable, immediately after removing from vacuum chamber?
 

spurr

Active member
Veteran
Hi GJ! Thanks for joining in!

No worries, glad to be here :)

Good idea on the mol sieve columns bro!

We have a couple 10" Altech Associates mol sieve gas columns, but haven't used mol sieve to pick up the last 5% water from the 190 proof azeotrope yet.

Thanks, although I am unsure if using anhydrous EtOH is better than hydrous EtOH (as azeotrope). However, I do like the idea of using 100% EtOH...


Sounds like we are playing in the same sandbox though, as I have been playing with vacuum purging as well.

Yea, I am surprised more people don't use vacuum purging because it's so cheap to use drain-to-waste with water aspirator and analog manometer. Even if using a recirculating system with water aspirator it's still pretty damn cheap. The most expensive part is buying the vacuum chamber, if one is not a DIY'er; which is the case with me.



1. Good question on mol sieve size, my thoughts are that the smaller size would have more surface area per unit volume and be more efficient. It would probably be faster to regenerate as well.

That is exactly what I was thinking too.

Good point on the coffee filters. As you know, there are average pore size filters and absolute pore size filters. Coffee filters belong to the former and some pores will pass multiples of the ostensible filtration range and others will plug at a small fraction of it.

Pre-filtration with average pore size filters however does take the load off of the precision filters and extends their lives.

Yup, agreed. I am thinking about using Whatman 22 micron funnel filter paper as a pre-filter instead of using coffee filters. The Whatman filter funnels come in 250 ml and 25 ml sizes. Here is the page for that funnel filter (47 mm model; Grade 41, 22 micron): http://www.whatman.com/DisposableFilterFunnels.aspx

As far as pore size, we clean up with whatever is the cheapest, but use 0.45 and 0.2 for final cleanup. No particular magic or insight in selecting those sizes, other than they are readily available and work well. As near as I can tell, anything below ~1.0 micron removes everything from bacteria up in size and delivers a pristine product.

Just a quick note: 0.2 micron filters need to be used to remove small bacteria, spores, etc.


3. Excellent question and one which I will run by Joe, our young energetic biochemistry student pharmer, because I'm not sure what happens at -80C to an alcohol water mixture. As far as I know, nothing different, but there certainly would be no question about free water at that temperature if you also used anhydrous EtOh.

It may be overkill, given that I get good results at 0F and 95.6% ethanol. I would probably try at it those parameters before spending much money improving upon the process, to see what the incremental gain is going to be for the added investment.

Sounds good, will do. And I look forward to hearing back from Joe.


5. Good point on the turpenoids and flavoids! I tried to side step that issue, because they do in fact have known medicinal qualities, and are mostly not water soluble.

I was trying to zero in on the water solubles, because I don't consider the turpenoids and flavoids inert ingredients. My disclaimer is because some folks strongly don't consider the chlorophyll, waxes, and plant alkaloids inert ingredients and I didn't want to start a new battle front on the subject.

In truth, we neither try to remove or preserve flavoids and turpenoids when cleaning up a messy extraction, though we do try to preserve them in an initial extraction.

They are also neither preserved or eliminated by the above process, only reduced. That is primarily why I prefer to do a clean extraction to start with, so that we don't have to use draconian measures that diminish the desirable aromatics lending flavor and character to the cannabis oil.

Cool, thanks for explaining your thought process. What do you consider to be the cleanest non-polar alkane solvent for initial extraction? (> 99% n-butane seems to be a great choice for most people, I think; but I could be off base)

Below is data I thought you may like to read regarding initial extractions with EtOH, hexane and Co2:
Taken from the patent application:
Method for producing an extract from cannabis plant matter, containing a tetrahydrocannabinol and a cannabidiol and cannabis extracts
United States Patent Application 2004/0049059
http://www.freepatentsonline.com/y2004/0049059.html

picture.php



Even though they may have high boiling or vaporization temperatures, the turpenoids and flavoids are for the most part aromatic compounds (Benzene ring) that give off molecules at ambient temperatures and pressures, which is why they are aromatic. The more we thrash and slap the oil about and the hotter it is, the more of them exit.

That brings up another point I wanted to ask you about: storage of the final concentrate. I know pure delta-9-THC degrades into CBN (and delta-8-THC?) due to various environmental factors, such as ambient temperature, basicity of concentrate, etc. But does the same hold true for THC in a final concentrate, e.x., as an absolute? I plan on storing my concentrates (probably as absolutes) in a vacuum desiccator at 5'C because I read data showing 5'C slows degradation of THC. I also want to use the vacuum desiccator because humidity is no friend of THC.

My question to you is whether cool/cold storage of the final concentrate would slow/reduce loss (volatilization?) of the aromatic compounds? Also, you wrote that "ambient...pressures" affects loss of aromatic compounds; does that mean a partial vacuum would increase or decrease loss of those compounds?


7. Most of our meds go into orals or topicals, so we decarboxylate the mixture. When cooking off the mixture in a 250F hot oil bath, it is easy to watch the bubble formation and keep track of when the solvents are purged and the remaining bubbles are primarily C02.

This too brings up another point: ideal decarboxylation. I think maybe I should start a new thread as to not take this one (any further ;) ) off-topic. I am looking into using an alkaline solvent to re-dissolve the concrete, not heat, to decarboxylate THCA-A (ex., ethanolic KOH instead of just EtOH). However, I am unsure if taking such a route is wise (my gut says it's not wise but I am not an organic chemist, nor even a chemist...).

I read a good study the other day I think you would like very much to read, if you have not yet done so. Re: ideal temp/time for highest decarboxylation of THCA-A into THC (i.e., 70%) without oxidation of THC into CBN. Spoiler: 150'C (302'F) for 15 min; if I read the study correctly. The study is about decarboxylation of THCA-A before using HPLC to get the same (or very similar) quantitative results of delta-9-THC as from GC assay (which decarbs the THCA-A from the heat used during GC assay). The study also goes into why HPLC and GC results are often different even if using the same standard, re "total thc" (THCA-A + delta-9-THC) vs delta-9-THC:
Isolation of D9-THCA-A from hemp and analytical aspects concerning the determination of D9-THC in cannabis products
Franz E. Dussy, Cornelia Hamberg, Marco Luginbuhl,Thomas Schwerzmann and Thomas A. Briellmann
Forensic Science International, Vol. 149 (2005) pp. 3–10
Bubble watching is also the same way that I am keeping track using vacuum and low heat thus far, with taste and smell as a backup.

That is how I too was planing on gauging when to stop evaporation; by bubbles. Granted all of this is just words to me at this point, I have never used the methods we are discussing so I could be off base...we'll see what happens when the rubber meets the road (as they say).

That can actually be a hoot! A patient told me that he missed the old days honey oil that tasted "sweeter" than my oil. I promptly added some alcohol tincture to the oil in the well, and when he sampled it, he exclaimed, "yes!" Clearly it was the residual alcohol that he was missing.

LOL, the lush (j/k)! :laughing:

Good information on the vacuum pumps and I will check them out, but have no better solution than possibly an aspirator. As I mentioned, we use an old medical MASH vacuum pump with inlet and outlet collection bottles for filtration, but are also playing with a CPS AC vacuum pump (100 micron/.10 torr), and a faucet aspirator (-28.5 Hg/10.5 torr).

Yea I was thinking about setting up an outlet condenser (aka exhaust condenser) for the diaphragm pump to re-collect the EtOH (so the re-condensed EtOH doesn't spray all over the table).

The main reason I want to use a vacuum pump (with manometer) is it's more user friendly, i.e., needs less babysitting, than a water aspirator setup. The other bonus is what you wrote: EtOH reclamation. The main reason I want to use an aspirator (with manometer) is low cost and strong vacuum (an equally strong vacuum using a pump would cost into the $2k range).

Below is the "water-jet" aspirator I am going to buy, and the analog manometer is on the same page. I am going to setup the manometer inline between the aspirator and vacuum chamber so I can read real-time vacuum pressures. That way I can open/close the hose valve and/or increase/decrease water temp (as you know cold water pulls a stronger vacuum); that will allow me to adjust the vacuum enabling me to keep it at ~55 or ~60 or ~65 Torr, etc.

I am also going to test a recirculating system with the water aspirator using a 5 or 10 gallon rez and a water pump with hose valve. That way I won't be wasting so much water as happens with faucet drain-to-waste and I can properly dispose of the water (that will contain the re-condensed EtOH). I plan on using ice packs or maybe my water chiller to keep the rez cold to control vacuum pressure. I also plan on using the hose valve to control water flow to assist in controlling vacuum pressure.

The whole cost of water-jet, manometer, and vacuum chamber setups for drain-to-waste is ~$400 (the vacuum chamber is by far the priciest piece of equipment on that list).

Sources and resources for yourself (though I doubt you need them, you are way ahead of me) and anyone else reading:

Water-jet polypropylene aspirator and inline manometer (total ~$75): link


Nalgene vacuum chamber and vacuum plate (~$250-300): link


Vacuum desiccator (for storage of final concentrate if so desired; will not hold vacuum indefinitely): link


Hand-pump for vacuum desiccator to pull weak vacuum: link


Online (java based) EtOH azeotrope and anhydrous EtOH boiling point calculator (more user friendly and more accurate than using a nomograph): link


Conversion chart between % vacuum, Torr (mm Hg), micron, inches Hg, etc: link

Info for those that wish to make a DIY vacuum pump (I am all thumbs when it comes to DIY stuff):

"The Budget Vacuum Pump"
Jim Wilson
http://www.paragoncode.com/shop/vacuum_pump/


"DIY Homemade Vacuum Bagging Pump"
http://www.diy-boats.com/2010/diy-homemade-vacuum-bagging-pump/


"The Cheap Little Sucker"
James Redmond
http://www.berkut13.com/sucker.htm
Our primary focus using vacuum has been alcohol reclaim, though I have an aging agenda on the schedule to further pursue cold boiling for the sake of the end product for vaporization. I am sorry to say that my vacuum solvent recovery success thus far is less than my simple pot still, because I need more condensing surface.

Re EtOH re-condensing and reclamation with a vacuum pump: have you looked into buying/making an exhaust condenser? They only have to be used at just below room temp, cool tap water (ex., ~60'F or ~65'F) is normally used, AFAIK. Here is a good page with info you may find useful:

  • "Pump Selection Tips: What is solvent recovery?" link
Re "cold boiling", I would love to read more about it and your intentions in regard to cannabis extracts. Maybe shoot me a PM if you don't want to get into that here?

The issue with a vacuum pump of course is crank case contamination, which is why you are probably looking at a diaphragm pump.

Yup, no oil in the vapor path; that and oil-free diaphragm pumps require less maintenance.

They are also normally better for corrosive vapors. The least expensive VaccuBrand model I am looking at (ME1) has PTFE diaphragm and valve(s), but an aluminum head. I think that should suffice for EtOH vapors, but if not, the ME1-C has PTFE head as well as PTFE diaphragm and valve(s). And one can buy an inline manometer and valve control for the ME1 and ME1-C to control vacuum pressure. Here is a source for those pumps, but like I wrote before, the ultimate vacuum is not as strong as I would like and I haven't seen the flow curve yet: link


I have never measured it, but a faucet vacuum aspirator will ostensibly pull down to -28.5 Hg at around 6/7 liters per minute water flow rate, or about .005 atmospheres. 80 torr is around .105 atmospheres, so you might give a faucet aspirator a look see for a possible cheap initial capital cost solution.

Yea, that is exactly what I was thinking and planning. And the colder the water the stronger the vacuum*. There are pluses and minuses to both methods: a vacuum pump and a water aspirator.
* Cite
[A water aspirator] pump operates on Bernoulli's principle. An ideally-designed water jet pump would provide a vacuum limited only by the vapor pressure of water, given sufficient water flow. Theoretically, better vacuum is achieved with cold water; at 15°C the vapor pressure of water is about 12.8 mm Hg [12.8 Torr], and at 10°C the pressure is about 9.2 mm Hg [9.2 Torr].
Thanks for sharing brother GJ and I hope you will keep us up to date with your progress!

No problem, I learned good info from you in this thread, and others. I think what I share pales in comparison to what you share :tiphat:
 

G.O. Joe

Well-known member
Veteran
On thing that is not clear to me is when something is a terpenoid and when something is a terpene.

https://www.icmag.com/ic/showpost.php?p=3164156

Copy and paste this to Google:
terpene terpenoid oxygen site:.edu
I have given up correcting people, everyone INSISTS on the oid word, even though there is very little, even though the entire chemical profile of Cannabis has huge variation between strains.

BTW the 80C mp of THC very probably refers to an artificial +/- mixture by synthesis. Many, many capable chemists have been unable to obtain solid real (-)THC.
 

Govinda

Member
I am not bringing this up to inspire controversy, but just as something to consider before refining one's concrete extracts into absolutes. This is not about the purity of the herb, simply an efficiency concern.

Many experienced in DMT extraction prefer less refined extracts for personal use, even by identical weight dosages (purification and crystallization is necessary for commercial handling however). Many conjecture that the excess plant waxes might serve as "buffer" when conduction vaporizing to ensure as little psychoactive material as possible is scorched and destroyed.

For those using hot titanium, quartz, or glass to vaporize this is something to consider.

All of this being said, I salute all efforts to experiment with cannabis in any way conceivable so long as nobody is harmed, best of luck in striving for the highest % by weight possible!
 

spurr

Active member
Veteran
https://www.icmag.com/ic/showpost.php?p=3164156

Copy and paste this to Google:
terpene terpenoid oxygen site:.edu
I have given up correcting people, everyone INSISTS on the oid word, even though there is very little, even though the entire chemical profile of Cannabis has huge variation between strains.

Thanks for that, answered my question well. It seems I should use terpene not terpenoid; good to know. The ambiguous part is many well known academics that study cannabis and its constituents use the term terpenoid for molecules that other authors term terpenes.

Also, thanks for the link to the "Organic chemistry" thread. I read the PDF in that thread and learned something I didn't know, re the slight water solubility of some terpenes that are commonly found in cannabis.

BTW the 80C mp of THC very probably refers to an artificial +/- mixture by synthesis. Many, many capable chemists have been unable to obtain solid real (-)THC.

Hmmm, good point. Now I think about it D9-THC extract is a vicious oil at room temp (and below), not a solid. I will edit that bit of info; can't believe I didn't realize that before I posted.

Thanks Joe, you have taught me a good bit of info and corrected me too, I like learning when I am wrong.
:tiphat:
 

jump117

Well-known member
Veteran
What do you think, would such an absolute be pliable immediately after removing it from the vacuum chamber?
Or do you think such an absolute would be solid and/or non-pliable, immediately after removing from vacuum chamber?
Hello spurr,
I have repeatedly watched the amber fossilized instantly after taking from a hot (~70C) evaporating dish.
I did not even have time to remove it blade from the blade so that second blade rests on a stone.
Amber jumps from the bending of blade.

I can only assume that under the vacuum purging the increasing viscosity at some point be able
to balance the pulling force of the vacuum and keep the residual ethanol in THCA-absolute.
MP of THCA-A under partial vacuum
I suppose it’s higher than BP of EtOH under same partial vacuum.
MPs and BPs of various aromas-givers also will shift and vacuum will pull them together with EtOH.
Optimal temperature and vacuum depend on viscosity of extracted resin,
on its thca/thc ratio and presence of any softeners.

You're right about the dehydrated ethanol. In a vacuum azeotropic point shifts in favor of EtOH -
0.895 mol under 760 mm Hg ,
0.996 mol under 100 mm Hg .
Evaporated in a vacuum of 96% ethanol will leave a puddle of water.
 

Trichgnomes

Member
Hello spurr,
I have repeatedly watched the amber fossilized instantly after taking from a hot (~70C) evaporating dish.
I did not even have time to remove it blade from the blade so that second blade rests on a stone.
Amber jumps from the bending of blade.

I can only assume that under the vacuum purging the increasing viscosity at some point be able
to balance the pulling force of the vacuum and keep the residual ethanol in THCA-absolute.

This is purported by many who have participated in and/or observed this phenomenon (including myself). I believe that it will react similarly under vacuum as it does when heat is applied via hot water bath, oven, etc.

I imagine it will be soft and pliable under vacuum, but once returned to atmospheric pressure it will harden, or fossilize as Jump has described.
 
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