Sciencemadness Discussion Board

Large volume soxhlet extraction

chemrox - 28-8-2015 at 13:30

This is a continuation of https://www.sciencemadness.org/whisper/viewthread.php?tid=63...
There was NO HEAT EXCHANGE ISSUE. As it turned out the solvent as incorrectly documented. The published bp of 85*C was wrong. In working with hydrocarbon mixture solvents like naptha one should always check the bp in the lab before desining the experiment. In this case the bp could have been and subsequently was easily determined by capillary method. It turned out to be 136*C. A fresh gallon from the hardware store had a bp of 130*C. An MSD for the same stuff indicated >240*F which translated to somewhere over 117*C. These numbers were too high for a large bowl on my hot plate/stirrer. I used dibutyl pthalate as the bath and acetone as the solvent. Acetone boils @55-60*C. The acetone started boiling with the bath at 65-68*C and was refluxing well at 70*C. I have the hot plate at 70% power and a power cutoff set at 70*C. I feel comfortable leaving this running over the weekend but I'd like to see one cycle to make sure the setup siphons properly. I have two large capacity soxhlets. This is the one with the extraction tube off the side so there's lots of cooling during extraction. That requires more cycles than my other one which extracts at the vp of the solvent. Only problem is I need an adapter for the top joint which is something like 135/120. Clamping is kind of amusing too.

[Edited on 28-8-2015 by chemrox]

extraction process1.jpg - 129kB

aga - 28-8-2015 at 14:26

why create a new thread if this is a continuation ?

Not trusting the labels 100% is always a good idea.

chemrox - 28-8-2015 at 15:01

I changed the title so I started a new thread about a successful process.

Bert - 28-8-2015 at 15:19

If you want to merge and re-title, just ask a moderator.

ELRIC - 29-8-2015 at 14:31

Is it just me, or does the link not work for anyone else

aga - 29-8-2015 at 14:59

Which link ?

All seem OK from here.

Bert - 29-8-2015 at 17:16

Curious as to what the material being extracted is?

chemrox - 11-9-2015 at 16:01

@Bert- interesting you asked. A natural material legal in my state. A relative with a nearly hopeless case of cancer is to be the beneficiary when it's done. The solvent is technical acetone. I had to lean the apparatus 3º away from the main body (cylinder) to get it to siphon. I since wrapped it with Al and heating cord to maintain heat in the cylinder. Still into 300 hrs and have some color in the extract.

[Edited on 12-9-2015 by chemrox]

Big_soxhlet2.jpg - 134kB

PHILOU Zrealone - 12-9-2015 at 03:12

Aceton will likely dissolve all moderate molecular weight organic material (unpolymerised organic material).

As such it will dissolve chlorophyle, polyphenols and a lot of colourizers of plants but at reduced speed owing to the large quantity and particle size.

Maybe that your target molecule is already extracted for long.

I suppose you did made a pretest on a tinier scale and with thin layer chromatography follow up?

It may be good to test various solvents with different polarities:
-Water
-Methanol or Ethanol
-Aceton
-dichloromethane
-cyclohexane/hydrocarbon

Solubility/extraction of your desired target molecule might be easier in one than in another and some perturbating stuffs might be taken out of the path depending on the order of extraction sequence of solvents...

careysub - 12-9-2015 at 06:25

For terpenoid extractions isopropyl alcohol is known to be superior to acetone, due to more selective extraction. Commercially hexane (or other petroleum solvents) are used with excellent results.

[Edited on 12-9-2015 by careysub]

Little_Ghost_again - 12-9-2015 at 06:32

Lighter refill gas can and use critical extraction, its quicker and better and the oil is much better purity. I think I have a link to a good resource for this sort of thing, if I find it I will U2U you.
Its not my thing but I did look at it at one time. Basicaly you set up a plastic tube with a wire gauze at the bottom, the top has a small hole just big enough for the tip of the gas can to fit. You packed out the plastic column leave the gauze end over a bowl and empty the entire gas can in (they are cheap), like filling a lighter the gas comes out as a liquid.
As it passes through the material it extracts all the oils, leave it for 20 mins after the gas has run out. What your left with should just be the required oil, cheap simple and pretty pure with no faffing,. I wish your relative well

Sulaiman - 13-9-2015 at 02:26

suppose that someone had started a similar extraction
by putting c150g of dried plant material in methanol
producing a solution with a lot of chlorophyll present.
What would be an easy way to separate the active ingredient ?

hyfalcon - 13-9-2015 at 03:03

Extraction with an oil of your choice. Olive?

[Edited on 13-9-2015 by hyfalcon]

Bert - 13-9-2015 at 04:40

Quote: Originally posted by Sulaiman  
suppose that someone had started a similar extraction
by putting c150g of dried plant material in methanol
producing a solution with a lot of chlorophyll present.
What would be an easy way to separate the active ingredient ?


Ah. A plant extract "legal in your state". I can't quite make out what that might be, but I was never a Bright Young Thing.

You modern kids are soft... When we were young, we had to walk uphill the whole way to school both ways, in a blizzard, with blue meanies constantly snapping at us, godawful slow dial up modems and NO INTERNET FOR ANYONE OUTSIDE OF DARPA!

image.jpg - 190kB

Some have filtered such an alcoholic extract repeatedly through activated charcoall, using a Büchner funnel, side arm flask and a water powered aspirator The chlorophyll is a large, "sticky" molecule, it will remain in the charcoal while the target substance (and a bunch of sugars and similar crap) remain in the solvent...

image.jpg - 18kB

When the alcoholic extract shows no green coloration, the alcohol may be removed by vacuum distilation, the remaining extract taken up in a minimum possible volume of diethyl ether and repeated liquid-liquid extractions done with lukewarm water, continuing until the water layer shows no color. The ether may be distilled off and reclaimed for further use- or some have just let it evaporate away into the atmosphere.

(And I NEVER knew anyone who blew up/burned down a house doing such things. No sir, I was too busy studying and attending the church of my communities choice, in between going to ROTC and the young Republicans on campus committee meetings to have met any such people!)


[Edited on 13-9-2015 by Bert]

Little_Ghost_again - 13-9-2015 at 06:56

I couldnt find a video using the plant material you describe, all I found was one using cannabis! But it should work exactly the same as the plant stuff your working with.

https://www.youtube.com/watch?v=uw9x9MvXCf0

Chromatography would separate it I guess. But if you do it again try the method in the video, dad gave it a go once and he seemed pretty happy (for about 2 months actually).