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Butane distillation

I have instructions for extracting pure esential oil from plant material using butane. The problem I have with it is that at the end, the butane is vented. I just don't feel right about venting unburned hydrocarbons into the atmosphere. I've been looking at glass lab equipment (distillation tubes, connectors, etc). I have no background in chemistry, but it seems to me it shouldn't be too difficult to put something together using standard glass lab equipment to capture, distill and reuse the butane.

Butane boils at 31 degrees farinhite and is heavier than air. At the end of the process, the oil is scraped from the bottom of a drying dish.

Does anyone have any suggestions on how to put something like this together?

Thanks

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GlobalVillageIdiot (author) 7 years ago
I'm considering that as a fall back plan. I won't be building a prototype for a few more months yet. It'll be outside and metal would defiantly work better.

I mention glass, first because butane can dissolve particles from metal, altho that's a better choice than PVC (which is what is commonly used anyway). 

Second, this seems like the kind of thing chemists do all the time. There may be some standard (and easy) way of doing this that I don't know about. In searching, I've found complete, efficient distilling set-ups using laboratory glass ready for sale. I'd like to minimize reinventing the wheel.
Here's a video on extracting "essential oils" from plant material: http://www.youtube.com/watch?v=fWrWfd-0UjI#

I have two friends who are both college professors and PhD's. They have degrees in chemistry and biology. They say this method is insanely dangerous. The bottom line is you want a solvent to get the oil from the plant.
Go to your local chemical supply house and purchase some reagent grade acetone and extract a little safer. http://packitdeep.com/hashish2.html

There's a lot of possibly good information here as well, IF you can force yourself to wade through it.
Personally I think these folks are brain damaged to start with. YMMV
C21H30O27 years ago
for safety reasons this should only be done outside and should be made of metal and the process should only be done once you have a step by step planned out.

either 304 or 316 grade stainless steel npt threaded pipe fittings that can withstand #150 psi should be fine for making the metal parts of the extractor, along with Teflon seated stainless steel full port lockable ball valves.

( this can all be had here as well as other places, here it seems cheaper then other places i have looked )
http://www.murrayequipment.com/dyncat.asp?Categ=Pipe%20Fittings

make sure to thoroughly cleanse the metals of any residue / factory lubricants that WILL still be in the pours of the metals prior to using for extracting oils for internal use. you dont want contamination in your consumables.

make sure to use butane that is 100% mercaptan free, if in doubt test the butane by spraying some on a mirror outside and make sure no residue is left after evaporation and no smell of "sulfur farts" is present from release of the gas

pure teflon tape ( white plumbers tape ) to seal the fittings together, its non reactive to butane and will make for air tight fittings that you can separate / unscrew when needed.

you will need at least 3 separate vessels and each vessel will require at least 2 ball valves and unions

extraction vessel (where plant material and solvent are combined)
evaporation vessel (where solvent and essential oils are separated)
reclamation vessel (where you will condense your butane vapor back into liquid and store for re-use) this vessel its best if you can get it welded shut

make sure to know the quantity in ml of solvent you will be storing and leave yourself a 10 - 20% overhead of room for vapor expansion ( we don't want anyone blowing themselves up)

these can be made up of threaded pipe nipples between .5" to 12 inches long and between 1" - 4" inside diameter. $$ goes up as you get the wider pipe fittings

you will need couplings, reducer bushings, T's, full port Teflon seated stainless steel ball valves, etc depending on how you design your extractor

I suggest at least 2 valve fittings on each portion of the extraction device

I am thinking  small 1 or 2 quart aluminum paint pressure pot would work perfectly for the evaporation vessel if you did not  opt to build one of stainless steel pipe fittings, it would also be helpful to have a Teflon beaker liner inside of your evaporation chamber to make collection of your essential oils easier.

if your concerned about aluminum oxide getting into your extract simply clean and dry your evaporation vessel well before use or use a stainless steel paint pressure pot for your evaporation chamber or build your own.

connections from evaporation chamber could possibly be 1/4 teflon tubing that can handle over 150 psi stainless steel 1/4" king nipples could be used to connect evaporation chamber and reclamation vessel.

plan out your process well in advanced and be in a clear headed state of mind before performing an extraction.

you want to keep temperatures under 100F during the evaporation / reclamation of the butane gas vapor phase I suggest a spark-less titainium aquarium heater for your warm water bath used to increase temperture for your evaporation vessel.

your butane reclamation vessel should be maintained around 0F to -5F which can be achieved with a mini fridge / freezer and recirculated brine solution (salt and water) . I believe some salts might be better then others with achieving lower temps of melting ice

you could use long nipples for the extraction chamber 1" wide 12" long with both the inlet and outlet reduced to 1/4" with valves on each end. this chamber will be eacy to open and put your plant matter in
dont use murry equipment for stainless steel pipe they will charge you a sales tax even if you are purchasing out of state...
I have been thinking about this problem for a few days.   It seem that there are a few issues with safety.

I  think you need at least 5 stages 
Butane tank supply connected by valve - valve - union -valve

Plant Material Exposure Chamber- butane drips through plant to extract essential oils.- threaded cap required to load and unload exposure chamber
valve-union-valve

Essential Oil Capture Tank-- Heated to encourage butane evaporation
(LARGE HOT WATER BATH FOR CHAMBER)   Threaded cap to access essential oil.
valve-union-valve


Butane Condensation-- 
LARGE COOLER FULL OF DRY ICE / BRINE TO CHILL BUTANE BACK TO LIQUID STATE- 

valve- union- valve

Butane Secondary Storage connected by valve -  In Cooler with additional dry ice to keep liquid butane in liquid state.


I would use 1/4 copper with compression fittings.

Some butane would be lost in each pass, but not as much a simply venting to the outside.

ethanol rise to gather essential oils as needed.

slow butane release to purge system before  connecting to storage tank, fast- release to rinse essential oils.


PS I saw a citation that butane, is photo-reactive and will be broken down by sunlight.

It is still flammable, explosive and dangerous.   In our area somebody tried this process in their hotel room.  They suffered 2nd and third degree burns over most of their body.


BUTANE ???? Couldn't you find something less explosive ? I would not, under any conceivable circumstances, suggest butane distillation on a domestic scale, and in glassware. Too volatile, too explosive. This is suicidal.
>>Too volatile, too explosive. This is suicidal.

Well, not suicidal. It used quite a bit because of it's low boiling temperature (31F). The way it is done is just to vent the butane, which I'm a little hesitant about.
In GLASS ? 

If you really did it, and you used metal, and you worked under suitable pressure, your vented butane could be flared off.