Bedlasky
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Preparation of cyclo-hexasulfur
Hello  .
I found few days ago this document:
https://link.springer.com/article/10.1007/s00897010458a
In this document is reported preparation of cyclo-hexasulfur. I want to try it, but I have few questions. They wrote:
A precipitate (not the product) will form, which must be removed from the solution before the extraction of the product can be attempted. This
will require that a vacuum filtration be done such that the solutions are still kept cool, even after filtering. This requires some prior planning to
have the appropriate flasks chilled. The precipitate forms immediately on addition of thiosulfate solution, no matter how fast the addition.
The product is isolated by extracting the acidic solution with toluene (30 mL). One extraction is sufficient, but stir well (best to keep it in the
flask at this stage). The separatory/dropping funnel used for the slow addition can be re-used for the separation. Toluene [CAS registry #108-88-3] is
a toxic, flammable liquid.
This seems like they are extracted sulfur from filtrate, which is nonsense. Sulfur isn't soluble in water! I really don't understand this. They need
extracted sulfur, which is precipitate!
Is sulfur soluble in gasoline? I don't have toluene and I don't know what I would do with 700 ml of toluene if I buy it.
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woelen
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Can you upload the entire paper? It would be quite interesting to make hexasulfur, S6. I have toluene and I also have CS2, so I can dissolve the
sulfur in the solvent. Maybe I can help you if I can read the complete paper.
According to the short page on Wikipedia, S6 is vivid orange, so it must be easy to distinguish it from standard S8 which you can buy on eBay from
numerous sellers. If S6 is stable on storage, then it could be nice in an element collection as another allotrope of sulphur.
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Bedlasky
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Woelen: If you click on the URL address and roll down, you can read the paper. Or is it not showing you?
And yes - cyclo-S6 is orange - it would be very interesting sample of sulfur .
How you prepare it from cyclo-S8?
[Edited on 8-5-2019 by Bedlasky]
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woelen
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Indeed, I could read the paper. I only saw the payment page at the top and did not continue to the lower off-screen part.
As I understand it, the reaction consists of two parts. A fast part, in which mainly S8 is formed, which forms a precipitate and then a slow reaction,
in which S6 is formed, which can be extracted from the liquid with toluene while it is formed and requires good stirring or shaking so that there is a
lot of contact between toluene and the aqueous liquid. Nearly all sulphur quickly precipitates as S8 in the first step of the reaction, the yield of
S6 is very low, only 5% in best case.
The filtration step at -15 C, which must be carried out quickly and during which the liquid must remain cold, is not easy for me. I think I wil not
have the right equipment for doing such a fast filtration step at low temperature. Careful planning and preparation of the experiment will be
necessary. The paper also provides hints in that direction.
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fusso
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Quote: Originally posted by woelen  | | The filtration step at -15 C, which must be carried out quickly and during which the liquid must remain cold, is not easy for me. I think I wil not
have the right equipment for doing such a fast filtration step at low temperature. Careful planning and preparation of the experiment will be
necessary. The paper also provides hints in that direction. |
Toluene MP -95C, maybe dry ice toluene bath may
work? Or will CO2 dissolve into toluene and reduce S6 solubility alot?
[Edited on 190508 by fusso]
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Bedlasky
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| Quote: Originally posted by woelen | | The filtration step at -15 C, which must be carried out quickly and during which the liquid must remain cold, is not easy for me. I think I wil not
have the right equipment for doing such a fast filtration step at low temperature. Careful planning and preparation of the experiment will be
necessary. The paper also provides hints in that direction. |
What do you mean - is this enough fast filtration?
https://www.youtube.com/watch?v=rm-5UM3HqU4
It is cheap and simple.
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woelen
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This is a really funny idea. This may indeed be useful for this experiment with making hexasulfur.
There is one difference, we are not interested in the solid, but in the liquid. So we should not use a thick piece of wadding, but with some fiddling
it should be possible to do the filtration quickly while keeping the liquid ice cold.
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Bedlasky
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I don't give up if I want something  . And I remembered that I saw once
something about simple vacuum filtration, so I wrote "simple vacuum filtration" in to Google and found it.
And what with waste? I don't know what to do with sulfur solution in toluene, how to dispose of it.
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woelen
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With that kind of organic waste I have a simple solution. I take a paper tissue and pour the liquid over the tissue, outside. Then I burn it. There
may be some sooty smoke, but when you are outside, then this need no be a problem, not even when you live in a city, when you burn the waste in the
backyard.
Of course, this only can be done with a few tens of ml of waste, but this experiment does not produce more than that. In this way I take care of all
of my flammable liquid organic waste (toluene, acetone, THF, diethylacetate, etc.). Very volatile liquids like CHCl3, CH2Cl2 and diethyl ether I
simply let evaporate on a paper tissue and after that, the tissue goes into the waste bin.
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Bedlasky
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Thanks. I don't have much expirience with organic waste - ethanol isn't problem and acetone I let evaporate.
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woelen
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I have done more searching on internet about hexasulfur. There is not much info, but the following is an interesting read:
https://books.google.nl/books?id=igJPDAAAQBAJ&pg=PA801&a...
Page 805 tells that hexasulfur is not stable on storage, it also is light-sensitive. This explains why it is not available commercially as element
sample. It reverts to octasulfur, so your orange sanple of sulfur soon will become light yellow again.
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Bedlasky
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It's a pity that isn't stable  . But I'll try it.
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