Gotta love the Soxhlet rig. It is simple, easy to run and it is exhaustive on the extraction.
I know that a bunch of you do industrial sized runs, and scaling these up is not normally done. Therefore, I assume that small batch runs are its prime forte.
I have a 55/50 size, and it is so small. Every sample is only 15-20 gms, so it does take a while to run a larger quantity.
The nicest thing is the ability to really load up the solvent with extracted oil. The Soxhlet extractor is a reflux setup, so clean fresh solvent is always hitting your sample. Once one sample is exhausted (I usually see this around the 4th or 5th dump), I can replace it with fresh material.
I use a glass thimble in my setup. It is heavy, and could easily break the chamber wall, if dropped. I have tried to minimize this possibility by packing cotton into the chamber. The thimble sits on top of the cotton.
Once you exhaust your sample, and desire to change out the thimble, you have to get it out of the extraction chamber. This has been a small stumbling block…it’s hot in there. I have been using tongs, but it is sketchy, so want to research other choices. How would you remove a hot thimble?
Oh, BTW, a word of warning. When placing a new sample, you might choose to add a small quantity of new solvent directly into the thimble. If your new sample is dry, it will absorb and hold some solvent. The solvent volume in the boiling flask will gradually decrease, if you are using only the reflux to wet your sample. Not a big problem, unless you let the solvent get too low.
Dry material can actually make life easier, by holding solvent that you would otherwise have to remove later. If you pay attention, you can gradually decrease the solvent level in the boiling flask, making post-processing faster.
Recovery of the solvent is possible, via simple distillation.
The extract that I just made is super-terpinated. I am having difficulty getting it to firm up.
Anybody put any thought to drawing a vacuum in a Soxhlet? I have thought about pulling a vacuum through the open end. Has anyone pulled a vacuum in a Soxhlet rig?
