[Urbanium]

I have quite an unusual question: I have to follow one procedure which involves continuous extraction. Since I never performed this before, I was thinking about "practicing" a bit and doing one extraction of something not related to my procedure first, just to get a clue how do the things work. Could sb suggest some mixture of chemicals or something relatively inexpensive I could mix in lab and then purify it in this way for practice? When it comes to solvents, we habe a plenty of hexane/acetone so I was planning to use something which involves these.

[baum0372]

If you want to use a soxhlet extractor you can always try using something like orange or lemon peels or even ground up cloves or cinnamon.  I'm sure you could use ether, acetone, or even ethanol and get a good extraction going.

From my understanding, you wan to grind up your compound and put your compound in a little cellulose thimble then slide it in to the top of the extractor.  Without the thimble your compound will just get sucked up into the side arm and that's a mess to clean and you risk breaking the side arm since it's so fragile.  Other than that just let the solvent reflux to a pretty healthy level underneath.

Best of luck.  Let us know what you decide to do!

[kamiyu]

Indeed, Soxhlet extraction is pretty simple and I really do not think anyone should waste time doing a pre-run/rehersal to get himeself familar with the technique.

If you really want to know what it is, why not go to youtube and look for video???

I persoanally have done a reasonable number of Soxhlet extractions which are routine method for polymer purification. Something to note (but not least):

1. The sample holder is a very strong and hard cellulose called "thimble", that I suggest using it.

2. Normally a cotton wool will be placed on the top of the sample in the thimble to fix the position of the samplle within the thimble, worrying that the sample may float out of the thimble.

3. Think about what impurity you have and come up with a solvent that selevtively dissolve the impurity, yet not dissolving the sample.

[Urbanium]

Thank you all for advices.

I know about the thimble and cotton wool, and I assembled the system with all the parts, I only do have one doubt:

3. Think about what impurity you have and come up with a solvent that selevtively dissolve the impurity, yet not dissolving the sample.

Isn't the point that while doing the extraction the component of interest passes through the thimble into the heated flask below? Is Soxhlet usually used when what is "of interest" and wants to be purified remains in the thimble or goes down to the flask? Or it can be used in both cases?

[kamiyu]

Both cases are possible. Some do it by leaving the impurities in the thimble while others leave them in the heated solvent reservoir.

[Furanone]

As Kamiyu points out, for defatting sample you can use the material recovered in the thimble, while if looking for the extracted material from the matrix, you would dry the solvent out of the bottom flask and have the recovered fat/essential oils/phospholipids. Weighing both fractions should balance and any weight not accounted for may have been to extremely volatile lost out top of condenser.

One point I will add is the general rule of thumb is that the Soxhlet extractor should fill and flush about 40 times for extraction to be complete and the solvent drips from condenser should be about 1-2 per second, and depending on the solvent this could take shorter or longer. For simple nonpolar fats, pet ether should take about 2-3 hours while with polar lipids I used Chloroform:Methanol 3:1 but this took far longer, and I found I even had to put aluminum foil around collection flask to keep in the heat for it to evaporate more efficiently up to condenser.