Soxhlet extractors

[Loulikesoud]

I think Mr. P can just try it.

Besides, most of the time people are using soxhlets with ethyl acetate, acetone, ethanol, heptane, toluene, etc.

If one wanted to use something like DCM or ether so as to maintain more of the volatiles it could be done if the condenser is set to a very cold temperature. At work, we have a recirculating bath that can go pretty low, not sure how low, but pretty sure -20 C or colder.

 

[Mr.P]

I was wondering about using refrigeration of the condenser as a way to operate the soxhlet at a lower temperature in the hypothetical example people are discussing here (which I assume is the goal of having a vacuum).

In fact a retired scientist friend I made recently was showing me a small custom made vacuum distillation device that he had made... operates by chilling the condenser down to a very low temperature, not by heating the solvent. I didn't see it in action but he says it did work.

 

[Matty]

@Oudh Analytics sorry if I've been offensive that is not my intention. Education by collection of thoughts and ideas are all I intended.

For a recirculating vacuum extraction how about a Gregar extractor using a cold finger condenser? Vacuum can thereby be applied above the condenser AND no siphon to worry about.

 

[Matty]

I was wondering about using refrigeration of the condenser as a way to operate the soxhlet at a lower temperature in the hypothetical example people are discussing here (which I assume is the goal of having a vacuum).

In fact a retired scientist friend I made recently was showing me a small custom made vacuum distillation device that he had made... operates by chilling the condenser down to a very low temperature, not by heating the solvent. I didn't see it in action but he says it did work.

You mean, by having cool condensed liquid falling back down upon the extraction material?

Cool idea about the vacuum distilling, cooling down the apparatus to create vacuum. Reminds me of those glass "love testers" but backwards.

 

[Oudh Analytics]

I was wondering about using refrigeration of the condenser as a way to operate the soxhlet at a lower temperature in the hypothetical example people are discussing here (which I assume is the goal of having a vacuum).

In fact a retired scientist friend I made recently was showing me a small custom made vacuum distillation device that he had made... operates by chilling the condenser down to a very low temperature, not by heating the solvent. I didn't see it in action but he says it did work.

This is interesting. In theory, I guess the Soxhlet operation cycle will be maintained. But the problem will be from another corner. A thumb of rule is that if the reaction temperature increases by twofold, the reaction rate will be tenfold. So, if you decrease solvent temperature twofold, the extraction rate will be reduced by tenfold. Then, to make it up, the total operation time must be ten times increased by theory. But in the end, the resultant product characteristics may be worth trying to see how it goes.

 

[Mr.P]

This is interesting. In theory, I guess the Soxhlet operation cycle will be maintained. But the problem will be from another corner. A thumb of rule is that if the reaction temperature increases by twofold, the reaction rate will be tenfold. So, if you decrease solvent temperature twofold, the extraction rate will be reduced by tenfold. Then, to make it up, the total operation time must be ten times increased by theory. But in the end, the resultant product characteristics may be worth trying to see how it goes.

I'm not even personally planning to do anything other than regular old ambient extractions.... I was just trying to contribute what I could to the conversation!

 

[Mr.P]

You mean, by having cool condensed liquid falling back down upon the extraction material?

Cool idea about the vacuum distilling, cooling down the apparatus to create vacuum. Reminds me of those glass "love testers" but backwards.View attachment 45319

It was more or less one of those! Scaled up, with a place in the middle where you could stuff a bunch of plant matter or whatever it is that you're attempting to extract.

 

[Oudh Analytics]

@Oudh Analytics sorry if I've been offensive that is not my intention. Education by collection of thoughts and ideas are all I intended.

For a recirculating vacuum extraction how about a Gregar extractor using a cold finger condenser? Vacuum can thereby be applied above the condenser AND no siphon to worry about.

View attachment 45318

No, I was not offended at all. You actually kept me engaged and made the conversation flow in the right direction. Today is Eid Day, and it could not have been a better day for making new friends. I'm happy to meet you here. My only concern was whether I was making someone confused unnecessarily. Cheers!

 

[Matty]

With the right solvent you could run the extraction from the heat of your hand 😄

 

[mesOUD]

@Mr.P
You will enjoy this process
Unlike the home-made process of making the concretes (where the alcohol evaporates and disappears), in your rotavap you will have all your alcohol on hand, the better news is that while you get your absolutes, you will also have a fragrant alcohol, you can make your perfumes just by mixing these alcohols

 

[Matty]

@Mr.P
You will enjoy this process
Unlike the home-made process of making the concretes (where the alcohol evaporates and disappears), in your rotavap you will have all your alcohol on hand, the better news is that while you get your absolutes, you will also have a fragrant alcohol, you can make your perfumes just by mixing these alcohols

Does the distilled alcohol retain a lot of fragrance after récupération?

 

[Mr.P]

@Mr.P
You will enjoy this process
Unlike the home-made process of making the concretes (where the alcohol evaporates and disappears), in your rotavap you will have all your alcohol on hand, the better news is that while you get your absolutes, you will also have a fragrant alcohol, you can make your perfumes just by mixing these alcohols

The fact that I won't be losing $25 of alcohol every time I do an extraction is definitely part of the appeal! Also being able to purge under vacuum to get a clean extract without too much heat or time

 

[mesOUD]

Does the distilled alcohol retain a lot of fragrance after récupération?

Quite potent
Especially animalics
İ use that alcohols

 

[Mr.P]

We have a tree covered with magnolia blossoms on our family property, a beautiful aroma and I will certainly see what I can extract from this next season, by which time I should have my extractor/rotovap well up and running. This one I'm not sure the identity of - I wish my mother were still alive because she would know as she selected the tree. Very beautiful clean creamy lily and ylang like aroma - not like southern magnolia or the large pink petaled kind.

 

[Mr.P]

So much Narcissus as well. It's going in the extractor. This is just a little clump of it but there are places along the driveway where there are huge banks.

Other plants in abundance in this area include black locust, wild (invasive species!) rose, valerian, pine, poplar bud, tobacco, and angelica to name a few. I don't think there's really much to be made other than poison from fresh tobacco but I will look into how bananas it would be to cure my own leaf and make a tobacco absolute.

 

[Al Shareef Oudh]

For the soxhlet process the time it takes for the solvent to build and drain is a fairly important aspect of the process. Based on the solvent and heat source after the first run it can easily be determined how long one full cycle takes to fill and drain the matter. This can then determine how many cycles will be needed to full extract the contents of the matter.

From a perfume ingredient perspective, and for saving yourself from headaches down the line, you should dry the biomatter first. Putting moist/fresh matter in the soxhlet extractor is going to be the biggest bite on your rear end down the line.

Reducing the cooling temperature of the condenser will mean that the solvent filling the biochamber will be cooler, however it doesn't reduce the temperature of the overall content in the boiling/heating flask.

The simplest way to reduce the overall temperature is opting for a solvent that has a low boiling.

Or change the extraction system.

@Loulikesoud if you don't mind answer, and apologies if you have already shared this before, what do you do for work?

 

[Matty]

@Mr.P I used to be a tobacco hobbyist. For the most aromatic leaves they need to be well grown and matured on the plant, cured properly and then aged or fermented. It's not an impossibility on a small scale, many people do it as a hobby. It might be easier to just buy the leaf, there are a few vendors in the US.

I've been out of the game since 2016 due to a serious cardiovascular event but still have pounds upon pounds of leaf stored in sealed plastic totes, after some time the aroma of the leaf has been absorbed into the plastic to the point of tinting it brown, which gives me the idea that for a workaround the toxicity, maybe some sort of contact-less enfleurage process could be used to capture the leafs aroma, maybe....

 

[Loulikesoud]

@Al Shareef Oudh

I am a chemist.

 

[Mr.P]

For the soxhlet process the time it takes for the solvent to build and drain is a fairly important aspect of the process. Based on the solvent and heat source after the first run it can easily be determined how long one full cycle takes to fill and drain the matter. This can then determine how many cycles will be needed to full extract the contents of the matter.

From a perfume ingredient perspective, and for saving yourself from headaches down the line, you should dry the biomatter first. Putting moist/fresh matter in the soxhlet extractor is going to be the biggest bite on your rear end down the line.

Reducing the cooling temperature of the condenser will mean that the solvent filling the biochamber will be cooler, however it doesn't reduce the temperature of the overall content in the boiling/heating flask.

The simplest way to reduce the overall temperature is opting for a solvent that has a low boiling.

Or change the extraction system.

@Loulikesoud if you don't mind answer, and apologies if you have already shared this before, what do you do for work?

Thanks for the suggestions! I have played around with the soxhlet extractors before but just with alcohol and no rotovap to recover solvent. The idea of noting the time of one cycle to avoid having to watch it excessively is appreciated.

Starting with dried material makes sense just from a density perspective because water takes up so much volume so thank you for suggesting that as well.

Honestly I was imagining fresh material would be steeped differently somehow because it's hard to imagine fitting enough into a soxhlet (at least of the size that I had used before).