extration with supercritical butane

[zeocrash]

OK today i built a device for extracting substances using supercritical butane.
the device is basically a standard bottle trap with the top closed down.
the sample is then placed on a piece of filter paper which is attached to the down pipe with a rubber band.
butane is sprayed down from the top of the pipe and collects in the trap, which is detachable.
i'll post pictures soon when i get around to taking pictures. anyway the whole setup cost me under £10.
at the moment i have only extracted clove oil, but i'm hoping to use it to remove active ingredients from fillers, e.g. asprin for picric acid production.

i was wondring if anyone had any ideas about the thing.

[Tuatara]

Super critical CO2 is also supposed to be a brilliant solvent, but the big drawback is the high pressure. Big advantage is it is a whole lot less flammable than butane.

Can't wait to see the pics!

[Haggis]

Not that I know anything about it, but I heard that you can extract THC with your butane. It seems your setup would work well, as you said that you extracted clove oil.

[Mr Cool]

Butane is a hell of a lot easier to work with than carbon dioxide, but I bet you could make a setup for CO2 extraction if you wanted to. But for us there probably isn't any real advantage.
It might be a nice way to purify things, since it will probably filter quickly due to the pressure of the liquid butane pushing everything through the filter, and the butane will evapourate/boil off very quickly. It is a great, tried and tested way to extract many things from plant materials, eg THC and some of the less polar freebase alkaloids. Therefore it may be useful for extracting some poisons.
One thing that concerns me slightly is the smelly stuff that they add to gas so that you can detect leaks - does anyone know what this is, and how much of it there is? If it's only a few ppm then you'll be OK, but it might be worth finding out.

[a_bab]

I suppose it's the classical methyl mercaptan.

[Rhadon]

I have read that ethyl hydrogen sulfide is used for this purpose. I don't know how much they use, but I don't think that it's more than necessary to make the gas smell (which is less than you would need H2S).

[Charlie Workman]

I've done this extraction about a hundred times over the last two years. It's not a true SFE, but actually a simple liquid extraction. The key is keeping the butane liquid long enough to make it through your tube. I use a pvc tube capped on both ends. The upper cap has a single hole just big enough for the nozzle of the butane can, the lower cap has 6 small holes like a salt shaker. I've found the best results come from precooling the butane in the freezer for a couple of hours before you start. This and the slight compression provided by the tube keeps it liquid. I tried it once with tobacco, but it was an abysmal failure. At that time I hadn't discovered the simple expedient of chilling the gas. I'd like to come up with a simple SFE apparatus to use CO2, but this has so far eluded me. Due to the nature of this gas, it is quite a bit more complicated. I occasionally scan one of the doper boards to see if they've had any success, but they spin their wheels a lot. Hard to come up with scientific breakthroughs when you're loaded all the time. That and their "Oil Guru" is a prick who thinks he knows everything about the process and shoots down anyone who challenges his "wisdom". He's not even close, but it's not worth the argument. I have a half pound of powdered aconite root I've been thinking of trying out, but haven't had the time. Maybe soon. Hope this helps.

[zeocrash]

ok well here's the pictures
i still have to take some shots of the machine in action, i'm outa butane at the moment.
http://www.angelfire.com/zine2/zeocrash/

the device works best when the downpipe is packed full of material, as the time the solvent is in contact with the material (residence time) is greater.

[nbk2000]

Here's the pictures, same pixel size, only optimized to be 1/10th of the original size (in Kilobytes). Please make use of them. ;)

[Charlie Workman]

Interesting apparatus Zero. What did it start life as? I'm a bit confused as to how it works. The way I've been doing it is just letting the liquid butane flow through the source material, collecting the butane that runs from the bottom and evaporating it in a dish of warm water to collect the extract. I don't think you really need to have the butane in contact with the material for very long to extract its essence, if it can be extracted using butane. But hey, if it works, it works. Proof in the pudding, as they say.

[Arthis]

It's made from a washbasin, I guess ? sure it should not be expensive.

Still, there are a few points I'd like precisions on.
First, how do you attach the sample ? I would say that any metal grid, or PVC would do the job.
Second, how do you connect the butane to the system to spray the butane ?
Third, how it really works ? Butane acts as a solvent, so you collect the filtrate ? I'm not sure to understand: how do you recover the product once dissolved in butane ?

I know many questions, but it's because of much interest :)

[zeocrash]

ok the sample is placed inside the middle downpipe (see picture 3 on my site) a piece of filter paper is then attached to the end with elastic bands
the butane is sprayed in through the small hole shown in picture 2, from a can of lighter gas


Downpipe
||
./||\
| || =waste Butane vent
| || |
| || |
\___/
product and solvent colledt here

the principle behind it is that butane has a boiling point at about 0°C, this is not very far from room temperature.
liquid butane is an amazing solvent. the other beauty of it is that once it's done it's job it evapourates fairly quickly into the air to leave the product.

device started life as a bottle trap for a sink. (an up market version of a U bend).
there is a problem with residence time, but the yeild extracted increases with the amount of material to extract from, this is not only because that there is more product to extract , but because of the increased residence time and the increased surface area. the device would also be more efficient if the material was crushed first.
i did another test today, using teabags, and now have a yellow ring in the bottom of the device from the tannin extracted, i hope bleach removes it.
i will be posting plans to the device on the ftp.

[Arthis]

But you need a fairly high quantity of lighter gas to use your system. It may be expensive. Are there other butane cans we can use to have liquid butane ? Because the big cans you buy at the petrol station are sold with a system that prevent from having liquid going out. Maybe by just putting it upside-down ?

[zeocrash]

lighter gas is £1.35 a can, and for a decent extraction i use between 1 and 2 cans.
the can has to be turned upside down for the liquid to come out, i guess this also applies to the big bottles of gas, but they may have other devices to stop the liquid draining out.
i'm not really sure though, the only way to find out is to try it i guess

[Marvin]

I think butane could be very useful. Ive tried a non pressurised extraction of iodine with butane in the freezer, it seemed pretty easy to handle. I think being able to recycle the butane you use would be a very big advantage, I wonder if an aquarium pump, provided it has no rubber in it, would be enough to compress the exit gas into a bottle in the freezer, I think it would. Ive kept butane for long periods in the freezer using an ordinary non pressurised bottle. I suspect a bottle modified to leak slowly if the contents ever got warm would be safe enough for short term storage. Rubber causes a problem, it dioesnt seem to dissolve, but it does absorb a lot of butane, and when its warmed up/depressurised it baloons up like an expanded foam.

I think you might want to remove the word 'supercritical' from the page though zerocrash, as Charlie has pointed out, it isnt SC. The terms 'liquid collects here' and 'supercritical' are mutually exclusive under the circumstances. For those people bored enough to want to know more, I'll summerise. Liquids make good solvents, apart from being mobile, simply becuase they have a high density. The fact they are liquid actually has nothing to do with the solvent properties at all. If you take a gas above its critical temperature, it cannot be turned into a liquid, nomatter how much pressure is applied, and compress it to a similar density to what it would have as a liquid it often makes a good solvent.

Since the solvent is at way above the temperature it would be possible to do a liquid extraction with, things are usually much more soluable than they are in the liquid. The high temperature also speeds up a lot of chemical reactions so SC water will dissolve a lot of organic matter, and this can be destuctivly oxidised easily. With a liquid, denisity is set by the physics, and you only have temperature to control. with a SC you can control temperature and pressure independatly, and this alows for control over the properties of what it will dissolve.

Charlie, I think outside an industrial setting supercritical methods probably dont have much over conventional extractions, I know I wont be messing with 70atm CO2 anytime soon. Interesting point about progress in drug chemistry, those who succeed probably arnt in much of a state to take the science furthur most of the time. Virtually everyone Ive met that has used drugs for a few years didnt seem capable of rational thinking when they were sober. Having said that, we aparently owe the big breakthrough in genetics, the PCR reaction, to the fact the guy was using acid to visualise what was happening to the DNA molecule. We keep being told that a lot of these drugs 'dont kill brain cells' but acid does fry minds, I wonder whats going on chemically/biologically.

[zeocrash]

ok well i did another test run, and i didn't get a very large yield, anyone know why.

the pintures of it in action are here
http://www.angelfire.com/zine2/zeocrash/use.htm

NBK i don't suppose you can shrink the pictures down for me again, i still havent worked out how to do it

+++++++++++=

Check your e-mail. ;)

NBK
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thanks man

[Charlie Workman]

Zero, you might want to try refrigerating the butane as I've mentioned. Since you've already ground up the peppercorns, the only other thing I can think of is to try a longer tube to give a little more "soak time". Long thin tubes seem to work better. Too bad, cause your apparatus is kinda cool looking. Marvin, my wanting to make an SFE appartus is basically because I'm a born gadgeteer. I get 300ml cans of butane for a buck where I am, so it's not really the expense. Recycling is really only worth the trouble if you have very limited access to the gas. I do have access to large amounts of CO2, so it seems worth a shot. Probably not worth the trouble in the long run, but who knows? Maybe I'll learn something in the process. I don't know about acid really frying minds. I did quite a bit of all kinds of drugs in my younger days and I'm relatively intact. Of course, that depends on who you talk to. One day, I discovered I was no longer having fun, so I quit. No drama or life altering occurences, just not fun anymore. The only thing I regret from it was the time wasted. Some of the boards, like The Hive or Rhodium, can be very informative on new improvised chemistry techniques. Some things have dual usage, if you catch my drift.
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"To paraphrase Aristotle, life is a gas!"
-Gidget

[crazyUser]

a friend of mine attached a valve to the bottom and top of an plastic bottle w. 4 inches height / 1 inche width. This allowed him to get some highly contrentrated thc oil due to the longer soaking time. To get the extract out of the bottle he just pushes the valve on the bottom onto a large glas plate.. this takes some time, but it works great.

[zeocrash]

yeah i realise now that the residence time was too short for any reasonable extraction of oils. i have rebuilt my aparatus using some instructions i found on overgrow about building a hash oil extractor.
i plan to try to use it ot extract capcicin from chillis as well as oil from my plants

[FragmentedSanity]

Just a coulpe of things to add, from what ive read it seems important to ensure the quality of the butane you are using. The gas in those camp gas cylinders contains an adulterant which leaves a nasty residue in your extract. Now of course this is only a problem if you want to consume the extract in some way. If your just testing out the concept using the cheapest gas available would be fine. There has also been debate over the safety of using PVC, its use in such systems is widespread. There are those who insist on making their device out of stainless steel. Zeocrash given the yello stain, using stainless for construction might be something to think about.

[zeocrash]

i'm kinda skeptical about the whole idea of quality of butane, as far as i was aware the other chemical was just mercaptans, and in the quantities present in the gas it would harmful effects would be neglegable. i'm not sure about the effects of butane on PVC, the the yellow tannin stain i got in the extraction on tea was quickly removed with a bit of bleach, so i assume that the stain was superficial and had not penetrated into the plastic.

[FragmentedSanity]

Your probably right, But I have heard of people who used camp gas to attempt a smokeable extract of a certain plant - and became very dissapointed to find it unsmokeable - but like I said if your not planning on consuming the extract it may not make a lot of difference. If your concerned about a quality product tho i'd suggest using good clean gas.

[zeocrash]

i'm not actually sure which butanes constitute as clean, i use swan lighter butane, is that clean

[FrankRizzo]

Check out this site for clean butane: http://www.keen-newport.com/ourBenchmark.htm