Using acetone to winterize BHO and ultrasonic distillation?

Has anyone tried using acetone for the winterizing solvent? We've been experimenting with it using our lab grade acetone, and the waxes seem to drop out quicker (3-4 hrs in the deep freeze), and evaporating the acetone off is also pretty quick (a couple hours for a zip of oil using vac assist, sonication, and heat) compared to using 99% ISO or hard to find 95% Etoh. If we can distill off the acetone and recover it for re-use, it makes using lab grade acetone pretty economical. Acetone has a lower bp and higher vapor pressure than either ISO or EtOH, and we check for residual acetone by pulling a high vac under gentle heat and checking the exhaust of our vac pump with a snap-on combustible gas detector.

We've also found that sonication of the winterized extract solution helps with purging the solvent, especially when applying a vacuum. All we're using is a 60W ultrasonic cleaner off ebay right now that is normally used in the lab to prepare a sample for chromatography. We will be upgrading our process sonicator to a model that has both heat and sonication controls so we have better control over the temp, as the sonicator we have now lacks heat control, even though it does get the water hot enough to boil acetone after running for about 30 minutes.

My only concern is that we're leaving cannabinoids behind along with the nonpolar waxes. I guess I need to fire up the GC and run some samples out of our used filters.

any thoughts, reservations, comments?

Impressive! Not sure if all cannabinoids are polar. Either way, whatever compounds your method leaves behind, iso and ethanol likely would too. Good luck and STAY SAFE.

Thanks Bong!

The polarity index of acetone is 5.1 Pure ethanol is 4.3. Not sure what the polarity of 95% EtOH is, but I would imagine that the 5% water content would make it more polar. Maybe somewhere around 5?

Another advantage to using acetone is that it forms a superb azeotrope by mixing in 79% (by weight) of pentane. That drops the bp to 32C from 56C. I was thinking a few mils of pentane towards the end of evaporation of the acetone will purge the remaining solvent pretty quickly, and at very low temps.

Lab grade pentane is relatively cheap compared to lab grade hexane, so a one liter bottle of it could literally treat hundreds of grams of acetone winterized bho.

Here's a handy dandy link to an azeotrope database: http://www.chemeng.ed.ac.uk/people/jack/azeotrope/access.html

Northern Lab said:

Has anyone tried using acetone for the winterizing solvent? We've been experimenting with it using our lab grade acetone, and the waxes seem to drop out quicker (3-4 hrs in the deep freeze), and evaporating the acetone off is also pretty quick (a couple hours for a zip of oil using vac assist, sonication, and heat) compared to using 99% ISO or hard to find 95% Etoh. If we can distill off the acetone and recover it for re-use, it makes using lab grade acetone pretty economical. Acetone has a lower bp and higher vapor pressure than either ISO or EtOH, and we check for residual acetone by pulling a high vac under gentle heat and checking the exhaust of our vac pump with a snap-on combustible gas detector.

We've also found that sonication of the winterized extract solution helps with purging the solvent, especially when applying a vacuum. All we're using is a 60W ultrasonic cleaner off ebay right now that is normally used in the lab to prepare a sample for chromatography. We will be upgrading our process sonicator to a model that has both heat and sonication controls so we have better control over the temp, as the sonicator we have now lacks heat control, even though it does get the water hot enough to boil acetone after running for about 30 minutes.

My only concern is that we're leaving cannabinoids behind along with the nonpolar waxes. I guess I need to fire up the GC and run some samples out of our used filters.

any thoughts, reservations, comments?

Click to expand...

Sorry haven't tried winterizing with acetone, but you sure make it sound interesting. I'll run it by our chemistry geek Joe, for his thoughts.

We saved up winterizing filters and washed them all at the same time, for use in our topicals. Not much there, but enough that we still save filters.

Good link below, thanks!

Northern Lab said:

We've also found that sonication of the winterized extract solution helps with purging the solvent, especially when applying a vacuum.

Click to expand...

Are you going to use ultrasound exposure to the thin layer and, if so, how it is implemented?

jump117 said:

Are you going to use ultrasound exposure to the thin layer and, if so, how it is implemented?

Click to expand...

We haven't tried true thin layer purging per se. So far we've just been experimenting with different sizes and shapes of ball canning jars and volumes of extract. We wanted to have a cheap, common, readily available supply of containers we can use to both process and package gear we have extracted for folks. What we've come up with to test our procedure is a simple 1/4" flare fitting bulkheaded into a ball jar lid that is then attached to either a distilling coil or a vac pump while heat is applied. Kind of shade tree, but it is good enough for testing. If it works out, we'll have to have a purpose built lid made out of acceptable material.

What we've been doing, since our solvent recovery still isn't built yet, is just doing the bulk of the evap to atmosphere under heat or heat combined with sonication. For the final purge, we sonicate, heat, and vac at the same time until there is no longer any boiling going on, then the oil is done. The final step is where I'd like to try adding a couple mls of pentane to force the rest of the acetone off by forming an azeotrope.

We've performed this procedure (sans pentane) using a half pint ball jar on both ISO winterized and acetone winterized extract with varying volumes (5-35g finished extract at a time) The acetone winterized extract seems to be much stiffer than the ISO winterized extract after purging, indicating that the acetone winterized extract may be less decarboxylated than the ISO stuff. We think that is largely because the higher temp that is required to boil off ISO effectively also contributes to some partial decarboxylation of the extract.

This is how our proposed finishing procedure will go:

1. With vessel attached to acetone recovery still, heat sonicator just above the bp of acetone (~60C) and sonicate extract and solvent until volume is reduced 80-90%.

2. Remove from heat and perform one deep vac purge. (ball jars seem to be able to handle our 75 micron vac pump no problem, even under heat). Look for evidence of boiling.

3. While extract is warm and still fluid (estimated at >40C), add a few mls of pentane to force off remaining acetone and sonicate to atmosphere. This should induce rapid boiling if the extract is still fluid.

4. Back to the vac pump, sonicator, and heat. Inducee another deep vac to check for further boiling, if there is none, you're done, if there is, repeat process.

Nice read N L
Do you sonicate the liquid solvent/oil extract, or a ball jar filled with it?
How do you apply vac on the sonicator?

Gray Wolf said:

Sorry haven't tried winterizing with acetone, but you sure make it sound interesting. I'll run it by our chemistry geek Joe, for his thoughts.

We saved up winterizing filters and washed them all at the same time, for use in our topicals. Not much there, but enough that we still save filters.

Good link below, thanks!

Click to expand...

Thank you GW. I'd be interested to hear what he says.

RulaTone said:

Nice read N L
Do you sonicate the liquid solvent/oil extract, or a ball jar filled with it?
How do you apply vac on the sonicator?

Click to expand...

Ball jar filled with it. then we apply a vac to the jar itself while immersed in the water filled sonicator.

First off, I want to say kudos to your ingenuity, documented both in this thread as well in the construction of your MI style terpenator.

I understand about the need for something cheap and readily available to store and package your product, but if you are really gonna go down the rabbit hole with the whole vac scene--don't skimp on the chamber. I'm not trying to preach, but pulling a deep vacuum on anything other than rated vacuum chamber/oven is risky at best. Or--shade tree as you put it.

Safety first.

Northern Lab said:

We haven't tried true thin layer purging per se. So far we've just been experimenting with different sizes and shapes of ball canning jars and volumes of extract. We wanted to have a cheap, common, readily available supply of containers we can use to both process and package gear we have extracted for folks. What we've come up with to test our procedure is a simple 1/4" flare fitting bulkheaded into a ball jar lid that is then attached to either a distilling coil or a vac pump while heat is applied. Kind of shade tree, but it is good enough for testing. If it works out, we'll have to have a purpose built lid made out of acceptable material..

Click to expand...

Trichgnomes said:

First off, I want to say kudos to your ingenuity, documented both in this thread as well in the construction of your MI style terpenator.

I understand about the need for something cheap and readily available to store and package your product, but if you are really gonna go down the rabbit hole with the whole vac scene--don't skimp on the chamber. I'm not trying to preach, but pulling a deep vacuum on anything other than rated vacuum chamber/oven is risky at best. Or--shade tree as you put it.

Safety first.

Click to expand...

Thanks!

Not to pick too much of a nit, but ball jars are kinda rated for vacuum already, not full -29.925", but some... Foodsaver vac sealers for ball jars have been known to pull a 25-27" vac on the jar, so we're not too far off. That being said, you're absolutely right, we need a safer solution for that. We've already caught a crack in one abused jar and promptly discarded it. We know it's not the safest, but we had to prove the concept before building out a prototype. Risk vs reward and all that.

We've kicked around the possibility of a final vac purge chamber big enough to hold the sonicator so we can heat, sonicate, and vac at the same time like we do now with the not terribly safe shade tree ball jar rig. Something like a bell jar vac chamber with a sealed bulkhead fitting through the bottom plate for the sonicator's power cord would do nicely.

Northern Lab said:

Thank you GW. I'd be interested to hear what he says.




Ball jar filled with it. then we apply a vac to the jar itself while immersed in the water filled sonicator.

Click to expand...

i think sonication will affect only the immersed outer surface of the ball jar. Not sure though...

forgive me if this is silly, but wouldnt it just be easier to make your extract with clean hexane?

RulaTone said:

i think sonication will affect only the immersed outer surface of the ball jar. Not sure though...

Click to expand...

my 60w sonicator seems to penetrate all the way to the center. lower wattage models may or may not.

magiccannabus said:

forgive me if this is silly, but wouldnt it just be easier to make your extract with clean hexane?

Click to expand...

I believe hexane still pulls out the nonpolar waxes, so winterizing with a more polar solvent would still be necessary.

True, they are to an extent, and it seems that you are being cautious about it. Regardless, the glass is not that strong, and with temperature fluctuations, there is definitely some potential for breakage. I know a few people that have imploded a food saver polypro chamber, which are 'rated for vac.' However, evacuating air to keep food fresh is not as serious as pulling out gaseous solvents, nor does it require as deep of vac.

Northern Lab said:

Thanks!

Not to pick too much of a nit, but ball jars are kinda rated for vacuum already, not full -29.925", but some... Foodsaver vac sealers for ball jars have been known to pull a 25-27" vac on the jar, so we're not too far off. That being said, you're absolutely right, we need a safer solution for that. We've already caught a crack in one abused jar and promptly discarded it. We know it's not the safest, but we had to prove the concept before building out a prototype. Risk vs reward and all that.

We've kicked around the possibility of a final vac purge chamber big enough to hold the sonicator so we can heat, sonicate, and vac at the same time like we do now with the not terribly safe shade tree ball jar rig. Something like a bell jar vac chamber with a sealed bulkhead fitting through the bottom plate for the sonicator's power cord would do nicely.

Click to expand...

Vacuum oven for the win. Still playing around with what temp to use, but it makes purging way more fun! Still have yet to purge any anything other than a concrete with the new setup, but it is some space age shit for sure.

An update on this technique:

We've been experimenting with times and temps used to de-wax our BHO using Acetone.

We successfully extracted, winterized, and purged a batch of AA in less than 8 hours. This batch was made from very good bud heavy trim and tested at 80%+ total cannabinoids. Acetone is an excellent winterizing solvent and it starts to drive the waxes off above room temperature. Cooled in the freezer for an hour in a SS bowl, the acetone+BHO solution quickly turns from clear to very cloudy as the waxes coagulate and drop out of solution.

We filter with simple paper filters into one pint mason jars. Then the jar is placed in an oil bath and we screw a lid onto it with a fitting connected to a simple stainless steel still coil that allows us to control the fumes, capture, and re-use the acetone. Once the volume is reduced by 75% or so and still pretty thin, we weigh what's there and estimate how much of it is acetone and how much is AA. Generally we add about half the weight of the remaining solution in n-pentane. Pentane forms an azeotrope with acetone and they both begin to boil quite rapidly at 32C. Any extra pentane boils at 36C, so it's very easy to purge off the remaining solvent with gentle heat and less than gentle vacuum.

We've got the total process time - from loading the columns to purging the pentane - down to about 4-5 hours.

As a side note, I can say that one pint mason jars seem to be working out very well for us as processing vessels. They stand up to our 75 micron vac pump no sweat. We only use them once, however, and we never re-use jars after they've been used to process oil and exposed to heat and vac. I feel they are safe enough to use as long as we're careful, and we obviously are or we'd have blown ourselves up by now. LOL.

No thoughts from our chemistry geek other than he wants to try it out and I do too.

I didn't implode any of the smaller Bell or Kerr jars doing vacuum experiments either, but haven't tried anything larger than a pint.

We do it now using a glass vacuum desicator and covet a vacuum oven.

Gray Wolf said:

No thoughts from our chemistry geek other than he wants to try it out I do too.

I didn't implode any of the smaller Bell or Kerr jars doing vacuum experiments either, but haven't tried anything larger than a pint.

We do now using a glass vacuum desicator and covet a vacuum oven.

Click to expand...

That's pretty close to the setup we use except we use an oil bath - an electric frying pan 3/4 full of vegetable oil alternating with an occasional trip to the sonicator. Not terribly sophisticated, but it gets the job done. We ran another 40 grams of AA last night in exactly 5 hrs with lots of breaks and screwing around in the shop. Acetone winterization took 30 minutes in the deep freeze. After the initial filtration, we wash the wax caught in the filter until it turns almost white. I've recovered as much as 10 grams out of a wax laden filter by washing it with acetone. Seems like once the waxes are driven out of solution, acetone doesn't like to re-dissolve them, even at or slightly above room temperature.

Sonicating the hot extract seems to assist boiling because it breaks the surface tension of the fluid quite well. We'll be messing around with a heat controlled ultrasonic cleaner in the very near future and I'll keep everyone updated with our progress.

What we're really lacking is a proper dab rig to perform proper testing. Gas chromatography is a wonderful tool, but it's so damned objective lol.

Northern Lab said:

We'll be messing around with a heat controlled ultrasonic cleaner in the very near future and I'll keep everyone updated with our progress.

Click to expand...

Hei NL
some time ago i was workin on sonic baths, i dont know if this can help you but i saw many "Branson" brand baths, they also come in very little and economic models.
I think something like this would work:
http://www.hach.com/branson-ultrasonic-bath-115-vac-60-hz/product?id=7640228836

Hee, hee, hee, we started with the subjective part first and are just getting around to the objective GC parts.

Are you building a heated sonicator, or have you found one that is already available?

Probably the next step, would be a vacuum furnace with sonicator..............

Maybe something made out of a 6" Sanitary spool, wrapped with heating elements and insulated? I just happen to have a surplus 60W ultrasonic transducer and driver from my dry sieving experiments..................

RulaTone said:

Hei NL
some time ago i was workin on sonic baths, i dont know if this can help you but i saw many "Branson" brand baths, they also come in very little and economic models.
I think something like this would work:
http://www.hach.com/branson-ultrasonic-bath-115-vac-60-hz/product?id=7640228836

Click to expand...

Thanks for the link Rula!

Gray Wolf said:

Hee, hee, hee, we started with the subjective part first and are just getting around to the objective GC parts.

Are you building a heated sonicator, or have you found one that is already available?

Probably the next step, would be a vacuum furnace with sonicator..............

Maybe something made out of a 6" Sanitary spool, wrapped with heating elements and insulated? I just happen to have a surplus 60W ultrasonic transducer and driver from my dry sieving experiments..................

Click to expand...

As much fun as it would probably be to build one, I was thinking about this one to start with.
http://www.ebay.com/itm/DSA50SE-GL2...835?pt=LH_DefaultDomain_0&hash=item46073a0dbb

Two frequency settings, 3L capacity, variable power, 60 min timer, and a nice 200w heating element capable of 175F will probably do at least an adequate job. I'd like a higher wattage transducer just because more seems like better, but I think the 50W should work.

Or maybe this one, no variable frequency, but it is wider and shallower so we can get two one pint jars in it side by side.

http://www.ebay.com/itm/2-L-LITER-E...696?pt=LH_DefaultDomain_0&hash=item1c19e8ae70