Sciencemadness Discussion Board

help with a soxlet extractor

BILLBUILDS - 13-2-2017 at 19:08


oh so i was using my brand new soxhlet extractor and it was just about to empt or the first time so i put off going to the toilet in anticipation. unfortunately this never happened as the ground pepper had clogged the tube not allowing fluid to flow though. how do i unlock this and how do i stop it happening again?

i was thinking of pouring some drain cleaner (H2SO4or NaOH) in for a half hour to dissolve it and then use some cotton wool over the tube before putting in material to be extracted


JJay - 13-2-2017 at 19:45

This probably belongs on one of the short questions threads... I don't have a Soxhlet yet, but I think I would try using water pressure.

A Halogenated Substance - 13-2-2017 at 19:55

Try bending a paper clip to try scrape/loosen the pepper that's stuck and rinse with water between attempts.

j_sum1 - 13-2-2017 at 21:31

A piece of wire bent to shape might be the easiest. Poke, scratch and dislodge rather than ram. Alternate with a squirty wash bottle.
Be patient.

When that stops working, allow it to dry for a few days. The material may contract and might dislodge more easily. Something like pepper should form a crumbly cake rather than cement together.

If everything else fails I would mix up some piranha solution and add it one drop at a time with a glass pipette. Clamp the soxhlet securely in a convenient position and wait a few minutes between drops for the piranha to work. Rinse and repeat.

(Disclaimer. I have never actually had this particular problem. But that is how I would approach it.)

jokull - 13-2-2017 at 23:17

Warm NaOH will do the work if the clogging is fatty material. Pipe cleaners are cheap and safe to use for such thin glass tubing.

JJay - 13-2-2017 at 23:35

A pair of pointy bent tweezers or forceps might be helpful too.

Edit: removed rogue image

[Edited on 2-14-2017 by zts16]

PHILOU Zrealone - 14-2-2017 at 01:56

A little liquid Inside and surrounding ultrasound bath or generator.

Sulaiman - 14-2-2017 at 02:06

As far as possible I would try to avoid scratching the glass,
have you tried warm water, shaking and patience ?

I have no soxhlet experience but I have read of filters being used,
a quick search of eBay.uk gave nothing,
try a wad of glass wool or similar at the bottom of the soxhlet next time ?

Lefaucheux10 - 14-2-2017 at 06:51

that's is in frech sorry but may be helpfull



http://alchimie-pratique.kruptos.com/MESZIMAGES/net14.gif



http://alchimie.kruptos.com/archives-2/archives-2011/la-corv...

aga - 14-2-2017 at 09:42

Soxhlet setup is easy, so long as a few simple rules are followed (IMHO).

The substance must be in a filter of some kind, even if that is just a plug of cotton wool at the bottom of the extraction chamber. I use a filter paper moulded into shape on the end of a broomstick.

Before adding the material to be extracted, pour in enough cold solvent to go about 1/2 inch up the syphon tube - this prevents really annoying air-locks.

Fill the material to about 1/2 inch <i>below</i> the top of the syphon tube. If you overfill, it will not work so well and tends to go everywhere.

Plug the top of the extraction chamber with cotton wool. This stops the material floating up.

The OP image looks like no filter was used at all, so the material went up the syphon tube along with the solvent, and got stuck.

feacetech - 19-2-2017 at 14:07

yea I always used Whatman cellulose thimbles, if the material has a tendency to float plug the thimble with glass wool or washed cotton wool.

just a plug of glass or cleaned cotton wool at the bottom and top would work if you cant be bothered with thimbles.

always watch the first 1-3 cycles of a soxhlet to make sure you haven't made a mistake or else you may end up with a fire or broken glassware.



NitratedKittens - 26-2-2017 at 03:46

Piranha solution will destroy the clog via oxidation

Sulaiman - 26-2-2017 at 04:40

I would personally NOT use Piranha solution in this case as I would surely spill some.
I use Piranha solution with no fear even for things like cleaning enammeled frying pans :o
but a near-closed vessel with plenty of organic matter is just an accident waiting to happen.

P.S. used Piranha solution makes an excellent weed killer.

[Edited on 26-2-2017 by Sulaiman]

JJay - 26-2-2017 at 06:39

I would avoid using piranha solution for that if at all possible, but if it comes down to a decision as to whether to use piranha solution or to buy a new Soxhlet, it's time to break out the face mask and asbestos-plated armor and mix up a batch of flesh-eating corrosives :D

macckone - 26-2-2017 at 13:21

Soak and dry cycle will loosen things up.

Warm water, soap with a little tubing to act as
a spray nozzle attached to a reusable ketchup bottle.

Alternate with q-tips attached to a straw or
a pipe cleaner with a plastic core. The metal ones
can scratch or chip glass. The coffee stirring straws
are excellent for this kind of thing.

A little vinegar works well to break up coffee grounds.
Not sure if it will work on pepper.
Bleach also breaks up organics and is usually readily
available.

ficolas - 26-2-2017 at 14:31

Quote: Originally posted by Sulaiman  

P.S. used Piranha solution makes an excellent weed killer.

Uuhh
And 100% environmentally friendly!

Sulaiman - 27-2-2017 at 01:06

Absolutely, it is my garden, I do not want to pollute it.


Given the small quantity of pirhana solution produced, and selective application to weeds,
What is it that you think may damage the soil long- or medium-term ?

I am not being petulent, I really want to know as it is my garden.

............................................................................................

BILLBUILDS ... any progress ?


[Edited on 27-2-2017 by Sulaiman]

JJay - 27-2-2017 at 01:37

Quote: Originally posted by Sulaiman  
Absolutely, it is my garden, I do not want to pollute it.


Given the small quantity of pirhana solution produced, and selective application to weeds,
What is it that you think may damage the soil long- or medium-term ?

I am not being petulent, I really want to know as it is my garden.

............................................................................................

BILLBUILDS ... any progress ?


[Edited on 27-2-2017 by Sulaiman]


Assuming that there are no heavy metals in the sulfuric acid or whatever you're cleaning, the worst long-term effect would be increased soil acidity, which might actually be a good thing, depending on your soil conditions and what plants you are planning to grow.