supercritical extraction of freebase pseudoephedrine?

ahgreich · Wed Apr 13, 2005 5:57 am

is anyone aware of this process?
If one reviews the subject of supercritical extraction of hash-oil from the plant material, it seems worth trying the same process with pseudoephedrine with a modified tetra trap.
modification - after saturation of the pill mass with the PCE, use it as the source material in the supercritical extraction tube and see what comes out.

IndoleAmine · Dreamreader Deluxe

Sounds interesting.

Since butane/propane are alkanes, you will remove waxes, fats, binders - but no water-soluble salts like pseudoephedrine.HCl. Maybe "gaak" too?

Just don't do a dry a/b or something like that BEFORE attempting a butane extraction, or you will extract the pseudo along with all impurities and "gaak".

(SWIA is absolutely not familiar with pill stuff, btw - so sorry for my vagueness.. Wink

)

Maybe this extraction method can be used to remove gaak, maybe to recover pseudo from it. Has to be checked.

Please only make sure that you don't stuff up the pipe too much; maybe mix the pill mass with some broken glass pieces, marbles or similar, to make for an even butane/propane flow, without developing too much pressure on its way down...

(BTW contrary to what I thought too, this is not really considered a "supercritical fluid" extraction, but works still much better than solvent extractions in many cases)

Good luck!

i_a

ahgreich · Wed Apr 13, 2005 9:22 am

the idea would be to dry-base the pill mass with sodium carbonate, saturate with PCE thoroughly, THEN put it in the tube. The tetra should hold the fillers but not the freebased pseudoephedrine, allowing the butane to only extract the pseudoephedrine.

IndoleAmine · Dreamreader Deluxe

I must admit that I don't know what you mean with tetra and PCE (is it the same?), but they sound like solvents to me.

If these solvent(s) are miscible with hexane for example, then you can't use butane/propane - it would simply rinse out the tetra/PCE..

hAzzBEEn · Thu May 19, 2005 12:28 am

meme · Thu May 19, 2005 12:43 am

Extracting using liquid butane is not a supercritical extraction, this is a persistant misnomer.

"Everybody knows the three physical states: solid, liquid and gas. But - no kidding! - a fourth one exists. By controlling temperature and pressure every substance can be set into a supercritical state (click here for a Phase Diagram).

Supercritical fluid, as its called, is heavy like liquid but with penetration power of gas. These qualities make supercritical fluids effective and selective solvents."
-http://www.aromtech.com/tp/definition.htm

The term should be "liquid butane extraction."

MargaretThatcher · Thu May 19, 2005 6:13 am

Thank you for pointing this out. This is really a boiling solvent extraction - still a good one though, but not supercritical. Supercriticality normally requires high pressures and lots of engineering.

loki · guinea pig

Actually, the definition of supercritical is a bit vague. Technically speaking, carbon dioxide in a cylinder is in its supercritical state, way above its boiling point but in liquid form. Same goes for butane and propane and methane gas in cylinders. Or have i got the definition wrong? gas at high pressure such that it becomes a liquid.

let's change examples then - water, for example. If you were to have a cylinder of water at over 100 degrees, then it would go supercritical... right? So what is different about a cylinder at a good 90 degrees above the liquid-gas phase change temperature of butane or propane?

also, i would like to point out that simply adding crushed sodium carbonate to dry pill mass won't basify it in the slightest, unless the mixture is slightly dampened to mobilise the ions. Alcohols won't help a bit unless they are wet. and one is trying to avoid water.

Here's the problem: ionically bound substances such as pseudoephedrine sulphate or pseudoephedrine hydrochloride, they are bound directly without an intervening water molecule as occurs in solution. In water they become free ions in a solution, and they bond weakly via the intervening water molecule between them, the amine forms a hydroxide out of the water and the acid gains its hydrogen. When these substances dissolve in an alcohol, they are not separated, they dissolve holus bolus - for this reason salts such as sodium chloride and the like do not dissolve in dry alcohols. once they are dry and fully dessicated, they are bonded 100% without any water. Only water will make them separate. If I am wrong about this i would be more than happy to be corrected.

if you ask me, the simplest way to ensure extraction of just what you are wanting and nothing else, is steam distillation. If such things as PVP (povidone) are in there, usually they are polymerised to such a degree that they won't azeotrope with the water, and a chlorinated hydrocarbon wash should remove it anyway, in the case I am wrong about PVP and steam distillation. Other than that, there is little else in a pill formulation that would come across in a steam distillation. I think one needs actual hot steam rather than just boiling a base solution too, although it is my understanding that that method of steam distillation works perfectly with the product that is frequently produced from pseudoephedrine.

MargaretThatcher · Fri May 20, 2005 4:46 pm

Think about it: liquid butane in a cylinder is no more supercritical than liquid water under atmospheric pressure. Supercriticality is well defined. Basically, a gas above its critical temperature cannot be liquified. A supercritical fluid has the density of a liquid but the fluidity of a gas - there is no meniscus for example.

joe_aldehyde · huxleys associate

the whole process is no more than a percolation by definition, whether you use a liquid or supercritical gas. [/b]

MargaretThatcher · Fri May 27, 2005 5:36 am

That is not so. Think about what supercritical means.

loki · guinea pig

i was just talking about supercritical extraction to a friend and something occurred to me.

what if you have an extraction vessel with a venting valve and can be opened by screwing the top off. vent valve at the bottom, filling lid at the top (as it would sit while being vented). Fill the vessel with the plant material one wants to extract to about 1/3 and fill the rest with dry ice. Seal up the container's filling opening. Put the cylinder into a heated quantity of water and continue to heat it until all of the solid CO2 is melted within the chamber. Vent the cylinder into a collection vessel et voila

the logic is that when the dry ice melts from the heat, it goes to the liquid state, but because it is contained, it does not boil out except for the space above the liquid. Because the amount of solid CO2 is greater than the amount of material below it, when it melts into the liquid state, it entirely covers the material and thus is able to dissolve solids and liquids which are soluble in carbon dioxide. Shaking might be helpful once it reaches liquid state to ensure that it fully penetrates all of the solids/liquids being extracted from.

braindamage · Thu Jul 14, 2005 2:47 pm

the main thing w supercritical fluids is that their properties can be modifyed by changing P and T.So while one subtance may be poorly soluble in CO2,in supercritical conditions it may be very soluble.Also you can practically engineer the proces-you can play w CO2 density,viscosity,etc.Now here is the main problem you,i mean the average clandenstine chemist will never have the equipment to acomplish the needed pressures(>78bar),not if you want to keep all of your limbs.
using the vessel you decribed you will get a complicated 3 phase system which may not do too much good.And the pressure build up may be dangerous.

no guys ive pondered w this a long time,there is no easy solution,but there is one interesting side note-in one paper(a part of it can be found on rhods site) some guys(its nice when you call PhDs guys) analysed pseudo pill extr w CO2.Now the story is not that all imporant but if i remember well they used some complexing agents to increase the solubility of pse.hcl in CO2.Now if we could use that to increase sol in butane,now there is a prospect....any thoughts?

loki · guinea pig

i don't quite understand what you mean by 3 phase system, all supercritical extractions involve 3 phases, the headspace where the supercritical gas is as the gas, the liquid phase which will mostly be carbon dioxide, and the solid phase, which is mostly the material being extracted. I think it kinda goes without saying that the device would have to be engineered to retain carbon dioxide at the pressure and temperature being used in the extraction, and that the quantity of dry ice put in it determined to produce the quantity of supercritical liquid desired once all the dry ice melts.

as for increasing pseudo.hcl's solubility in butane... butane: nonpolar; pseudoephedrine.HCl: polar. one would sacrifice the selectivity of the extraction by adding solublising agents, which presumably would have to be alcohols (talk about complex three phase systems lol)

the problem with butane is nothing more than the fact that it is extremely (and i use the term most emphatically) polar. it works for THC extraction because THC is extremely polar too.

given a properly engineered extraction cylinder up to the task of retaining liquid carbon dioxide at the temperature of say about 40 degrees (the warming process would probably be best done by a thermostatically controlled water bath set to hold a constant temperature, stirring would help ensure that the heat is evenly and rapidly transferred into the vessel), is there any good reason why dry ice would not be a much more cost effective and accesible way to do this sort of thing?

making the pseudoephedrine into freebase form is easily done anyway, about a teaspoon of NaOH in a litre of methanol for the extraction fluid, boil, filter, evaporate. when you look at the scale of the gummy material that extraction would produce from a kilo of pillstock (maybe 50g) it's not really a massively difficult prospect building a vessel which can house that and another 100-150g of solid CO2, and being sure that it won't go leaking, or worse still, exploding. Main thing is to put a pressure release valve on it calibrated to open at the pressure about 50% below what the device is engineered to handle.

braindamage · Thu Jul 14, 2005 4:01 pm

when i said 3 phase system i should have been more clear-i thought that solubility of the substance in co2(unless it is alread very,very,VERY soluble) will suffer greatly.you have complex 3phase equilibrium,and the change of pressure which in this case is the main governing parameter.yes it will work to a certain extent,but im afraid that the yields would be shitty and the procedure not very feasable.in theory of course.

supercritical co2 is a great solvent,ordinary co2 so-so.butane/propane,or to be more exact c3/c4 mixtures may have a greater potential.
when i was talking about complexing agent i think they were some organometalic salts,i had the paper but i cant find it now,i was wrong its not the one on the rhods site.if you were to use those salts w butane one the MeOH/EtOH pre pulled pill mass,maybe you could have a novel rather efficient procedure.but it all still remains a theoretic "playing around and acting sooo smart",lol...for now at least

PS the supercritical extrs include usually 2 phase systems-supercrit CO2(its neither gas nor liquid) and the liquid/solid substance that needs extr.Rarely people use MeOH or other lower alc to increase solubility,but the agents added are in such small conc that the system can be regarded as a 2 phase one...most of the time,anyway