wg48
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CS2 from C + S in a thermite
Has making CS2 from C and S in a thermite mix with say iron and aluminium been considered or tried?
The idea is to use the reaction of the aluminium and iron with the sulphur to raise the temperature of the mixture so that excess sulphur reacts with
the carbon to produce CS2. The iron being required to moderate the temperature.
I apologise in advance if there is an existing thread on this subject but I failed to find it with a search.
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DraconicAcid
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I suspect that this would only give you iron sulphide.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Eddygp
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Heating C and S in a furnace under inert atmosphere would surely give you a better yield: S can easily, and preferentially, react with oxygen, same
for carbon. Iron sulphides and the sort will also be a bit of a hassle even if you are using excess S.
How would you plan to separate the CS2 from the mess?
there may be bugs in gfind
[ˌɛdidʒiˈpiː] IPA pronunciation for my Username |
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careysub
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http://www.sciencemadness.org/talk/viewthread.php?tid=10564
"We all knew from the beginning what the problem was: the reaction between charcoal and sulfur requires a temperature far above the boiling point of
sulfur, so that heating a charcoal- sulfur mixture in a retort always only results in the sulfur boiling off, without any noticeable reaction."
On the other hand, aluminum-sulfur thermite is definitely a thing, and iron and sulfur famously react exothermically to make iron sulfide (popular lab
demo).
And of course if any CS2 were formed, it would be a combustible gas that would burn off instantly unless this thermite reaction occurred in an
oxygen-free sealed system.
GarageChemist found that a vapor-phase reaction was necessary and succeeded using a tube furnace.
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careysub
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I wonder if a steel pipe "bomb" could be used to make CS2. The maximum operating temperature of steel pressure vessels and minimum temperature for CS2
formation don't overlap very much though.
Carbon steel loses something like 80% of its strength at 750 C, which is apparently the lower end of the range given for CS2 formation.
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wg48
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Reply to some of the responses above:
Yes iron sulphide and aluminium sulphide would be formed but if the sulphur is in excess it may react with the carbon.
The idea is similar to the method of making phosphorus using aluminium to reduce a phosphate as described in https://www.sciencemadness.org/whisper/viewthread.php?tid=65...
If CS2 is formed and it manages to escape the thermite it will be a gas which can be condensed just as in making phosphorus in the above referenced
thread. Apart from the initial air in the reaction retort (small molar fraction of the reaction mass) the CS2 can not burn.
If only I had a tube furnace, it is on my to make list.
I assume the increased pressure in a sealed retort would favour the reaction of sulphur vapor with the carbon but I will pass on high pressure 1000C
reaction retorts.
Yes I agree the sulphur my simply distils away before reacting with the carbon or remain trapped in the molten reaction products as is suspected in
the phospurous production thread.
Thanks for the replies. I guess I will have to try it I purchased some flowers of sulphur I spotted in the gardening shop I visited to day and there
are lots steel and aluminium turning on the lathe bed and I have charcoal. I will try small scale to get aluminium to iron ratio correct.
Correction edit: At 1000C and below sulphur vapour molecules consist of two or more atoms. Which means CS2 is favored by low pressure not high. Though
I suspect its not a significant effect compared to keeping the sulphur in contact with the carbon.
[Edited on 18-5-2016 by wg48]
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unionised
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Briefly- perhaps.
Sulphur vapour is corrosive to metals- including steel
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wg48
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I am hoping the surface sulphide will protect the metal for at least one reaction. It could also be coated with pyrolitic carbon or simple use a
glass test tube within the steel retort.
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careysub
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I was thinking that the iron sulfide scale formation might be a self-limiting reaction, consuming a certain quantity of sulfur that could be supplied
in excess.
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violet sin
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Sulfide scales tend to crack and spall more readily than oxides, which can remain continuous and provide some degree of corrosion protection. In some
cases, depending on the form in which sulfur is present in the atmosphere, continuous sulfide scales cannot form, so attack will proceed linearly;
that is, the scale will afford no protection-
http://www.mearscorrosion.com/sulfidation/
The site had mentioned flue gas so i assume there is some oxygen in there amongst other things. Deff not perfectly in line with a sealed pipe
reaction chamber, though i thought it might emphasize some concernes/hopes role in the process.
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AJKOER
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Here is a more rationale temperature route extracted from the literature and presented at Atomistry.com. To quote:
"When calcium carbide and sulphur are heated together at 270° C. carbon disulphide in about 20 per cent, yield and considerable quantities of carbon
are produced. At higher temperatures the amount of carbon disulphide diminishes, only traces being detected at 500° C."
Link: http://sulphur.atomistry.com/carbon_disulphide.html
Accept the low yield, and just work with larger quantities!
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careysub
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Quote: Originally posted by AJKOER  | Here is a more rationale temperature route extracted from the literature and presented at Atomistry.com. To quote:
"When calcium carbide and sulphur are heated together at 270° C. carbon disulphide in about 20 per cent, yield and considerable quantities of carbon
are produced. At higher temperatures the amount of carbon disulphide diminishes, only traces being detected at 500° C."
Link: http://sulphur.atomistry.com/carbon_disulphide.html
Accept the low yield, and just work with larger quantities! |
That sounds like the disposable metal can stills explored in the benzene synthesis threads would be about right for this.
I see 10 lb lots of CaC2 available for $105, and single pounds for $17. German "vole" carbide on eBay is available for $10/lb shipped to U.S. in 2 lb
lots, it would be cheaper in Europe. 10 lb would yield about a kilogram of CS2.
[Edited on 19-5-2016 by careysub]
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