Fantasma4500
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SO2 and Cl2 by decomposition, both at once?
was looking at this compound, finding decomposition somehow interesting
https://pubchem.ncbi.nlm.nih.gov/compound/Chloroacetamide#se...
and then it hit me, many compounds give off NOx under decomp, and some Cl2, but is there none that produces SO2 under heating, and if so is there no
compound that gives off both Cl2 and SO2 under decomposition? having looked at SO2Cl2 preparation i find it problematic to require 2 gas generators
running at the same time, and one of them requiring also air
any ideas of compounds that could give off SO2 rather easily, preferably without addition of other chemicals and water?
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woelen
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You could try sodium metabisulfite. This is Na2S2O5 and I can imagine that heating of this gives SO2 and leaves Na2SO3 behind. The compound Na2S2O5
has a pungent smell of SO2 when you open the container, hence my expectation that it can give off SO2 fairly easily.
In literature, however, this is not described as a method for easily making SO2. The preferred method of making SO2 is dripping half concentrated
sulphuric acid (40 ... 60 % by weight) on solid Na2S2O5 and gently heating to drive off the SO2. Drying in a CaCl2 or P4O10 tube makes it useful for
anhydrous experiments.
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mayko
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It sounds like you're generating SO2 by burning sulfur. Have you tried metabisulfite + acid?
edit - scooped by woelen. I'm at work or I'd run a test-tube experiment, but I'm suddenly curious what would happen if HCl were added to a mixture of
bisulfite and TCCA: one-pot production of Cl2 and SO2?
[Edited on 30-3-2016 by mayko]
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Fantasma4500
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yeah i was thinking exactly of one pot synth, possibly some hardcore reflux could be used?
it just doesnt look like easy to acquire glassware you use for the common setup for SO2Cl2 synthesis
anhydrous HCl could maybe be added, formed through conc HCl and anh CaCl2, as SO2Cl2 apparently hydrolyzes with water, but can also form "fuming
mixtures with water" (https://en.wikipedia.org/wiki/Sulfuryl_chloride), so HCl gas would only be for assisting yields a slight bit
if this could work it would also remove H2S created when burning sulfur with air -- simply by discarding the combustion of sulfur with air
i have TCCA and NaHSO3 laying around somewhere, so i could go ahead and try this out with HCl
TCCA could maybe be swapped with MnO2, supposing it would react with more or less anhydrous HCl gas, but could be problematic to use with a SO2
generator as it may form the SO2 faster, if 2 reactions could run at a slow pace, run peacefully in a somewhat closed chamber it could be possible to
extract the SO2Cl2 from that reaction chamber using very energy on running the preparation, but this could also be trashed by the SO2Cl2 reacting with
water
i have another idea, maybe the chlorine could be directed into a substance that somewhat easily gives off SO2, to maybe drag the SO2 out of the
substance?
[Edited on 30-3-2016 by Antiswat]
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clearly_not_atara
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What happens when your brilliant scheme produces a little SO3 byproduct? Is there a fume hood in this garage? A respirator? Performing untested
oxidations of SO2 should be done very carefully.
I'm suspicious that heating metabisulfite in air will accomplish this; TCCA seems more likely to give chlorosulfonic acid which will then hydrolyze.
You could use SO2 and NaCl with a Cl+ source in GAA, and you might be able to produce SO2 in GAA by passing the latter over metabisulfite
quickly, so that decomposition occurs without complete solution.
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woelen
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In purely anhydrous conditions, Cl2 and SO2 can coexist for quite a long time. With a suitable catalyst, however, they can be brought to react to
SO2Cl2.
In the presence of water, Cl2 and SO2 react immediately and completely in a fraction of a second. They form H2SO4 and HCl and in this reaction a LOT
of heat is produced. I expect that if you mix TCCA and Na2S2O5 and add some HCl, then a very violent and exothermic reaction occurs. Do this outside
with small quantities!
I once did an experiment with Br2 and SO2. I filled a 250 ml bottle with dry SO2 and added a single small drop of Br2. The Br2 evaporated and the
bottle was filled with brown vapor and SO2. No reaction occurred. Then I added a few drops of water and capped the bottle again. When this was done,
the color of Br2 very quickly disappeared and on opening of the bottle, air was sucked in and a lot of fume of humid HBr could be observed. With
chlorine the effect will be similar, but even more pronounced.
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annaandherdad
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woelen, in this reaction you describe, Cl2 + SO2 + 2H2O -> 2HCl + H2SO4, do you know if it's possible to use up all or most of the water to make
concentrated H2SO4?
Any other SF Bay chemists?
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mayko
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Quote: Originally posted by woelen  | In the presence of water, Cl2 and SO2 react immediately and completely in a fraction of a second. They form H2SO4 and HCl and in this reaction a LOT
of heat is produced. I expect that if you mix TCCA and Na2S2O5 and add some HCl, then a very violent and exothermic reaction occurs. Do this outside
with small quantities!
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I mixed a spatula of TCCA and Na2S2O5, put a bit in two test tubes. To the first I added a few drops of water, which was enough to evolve gas and
heat. KI/starch paper was darkened by the offgassing, while pH paper was bleached with no indication of acidity.
A few drops conc. HCl were added to the second tube. The reaction was again vigorous and exothermic; the offgassing darkend KI/starch and *slightly*
pinkened the pH paper, though no more than I'd expect given the heat produced and the volatility of the HCl.
I couldn't detect any SO2 by smell, but then again I was trying to avoid sniffing the tubes entirely. I thus set up three new tubes; one with a
knifetip of bisulfite, one with TCCA, and one with the mixture. I also made a bit of permanganate solution and dipped a few strips of paper in it.
When HCl was added to the bisulfite, the resulting SO2 bleached the permanganate but did not impact a KI/starch strip. When HCl was added to the TCCA,
the resulting chlorine turned the permanganate strip a reddish brown but didn't bleach it, and obviously darkened the KI/starch. When HCl was added to
the mixture, the gasses that resulted bleached the permanganate, and darkened the KI/starch.
I tentatively conclude that both gasses are being produced with relatively little reaction between, but agree that this is a mixture to be treated
with caution!
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woelen
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The fact that you get both Cl2 and SO2 is because of imperfect mixing. Probably your pieces of TCCA are coarse and the mix is not very intimate. You
will have local spots with excess SO2 and local spots with excess Cl2 and once the gases bubble out of the water and escape, they can coexist. Any
water vapor in the gas mix quickly is used up and dry Cl2 and SO2 pass over.
An inteesting thing would be to try the experiment again, with stoichiometric amounts of bisulfite and TCCA (use two mol of TCCA for three mol of
Na2S2O5) mixed very well. Grind the chemicals SEPARATELY and then mix the dry chemicals and to this mix add HCl.
Be careful with this experiment, use small quantities, the reaction may be very violent.
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Fantasma4500
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it appears sodium chlorosulfonate could be one way to go
Preparation of alkali metal chlorosulfonates
http://www.google.com/patents/US2415358
Preparation of sulfuryl chloride
http://www.google.com/patents/US2431880
but, either you would need a source of the salt, or you would have to handle SO3 and react it with table salt, SO3 isnt something many prefer to
handle
i also read catalysts are activated carbon and camphor, maybe a slight mixing could be used, maybe molecular sieves (if im not totally
misunderstanding the way activated carbon works as catalyst, that is)
however sodium chlorosulfonate is used at 400*C, which isnt as handy as if you could run it below 100*C (from start, lets ignore the whole exothermic
part as long as this is just carried out "on the paper")
im thinking -- how fast does SO2 and Cl2 get absorbed into activated charcoal? maybe some way of pulling the formed gasses out of the reaction chamber
and blast through activated carbon, to then pull the remaining gasses out and repeat it, over and over, preferably shooting the gasses through a very
long tube containing catalyst
to attend the question about SO3 being formed, it doesnt appear to being formed when sodium chlorosulfonate is decomposed, but if it was really a
problem, the gas(ses?) could be lead through water, scrubbing off SO3 which would supposedly react faster with water than SO2, and potentially Cl2
(could just be left out if water gas scrubber were to be used, as in forming gasses seperately)
in this experiment, i would actually suggest forming excess of SO2 would be preferred, simply because SO2 is less nasty than Cl2, and i also have an
assumption that TCCA would be the pricier reagent in this reaction, so we would want to use as much of the Cl2 as possible
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mayko
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I might take another look at the reaction of the mixture soon (but not too soon; it's interesting but very unpleasant)... for now some wildly
speculative armchair chemical engineering 
* v1
What if you used a reaction flask of hydrochloric acid (stirred for good mixing and aggressively cooled to reduce water vapor) and flushed with dry
inert gas (to quickly separate the reaction products from liquid water) followed by an efficient drying system? You could then add the mixed powders
with a powder addition funnel, and liquify the dried gasses (dry ice? bp Cl2: -34C; bp SO2: -10C; sub CO2: -78C. ) This could be used to remove
gaseous HCl from the mixture (bp -85C) as well as trapping residual water vapor as ice. Then, the liquified gas container could be warmed in a
controlled manner to release the gasses into the second reaction chamber.
This has a number of issues e.g., safety, and whether the liquified SO2 and Cl2 will covolatilize at an acceptable rate; so:
* v2
Instead of mixing the solid reactants, they are layered in the powder addition funnel, perhaps with an inert separating layer (eg, NaCl + food
coloring). After the drying step, there is a 3-position valve (Cl2 route, SO2 route, closed to prevent backflow later), with the two open routes
leading to independent gas collectors in the cold bath. Since the powders will be added separately, there will be less rush to remove them from the
wet reaction flask and dry them. Once the powder funnel is down to the boundary between the two reactants, switch the valve over. Once the gasses are
generated, you can warm their containers independently to control the gas flow.
These schemes both involve concentrating the reactants and then using them, rather than using them on the fly; before trying something like this, I'd
think carefully about what to do if cooling failed or if I couldn't proceed for some reason after accumulating them.
al-khemie is not a terrorist organization
"Chemicals, chemicals... I need chemicals!" - George Hayduke
"Wubbalubba dub-dub!" - Rick Sanchez
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Fantasma4500
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for cooling anh CaCl2 and ice is suppoedly gonna reach around.. -50*C? i may have confused this with Ba(OH)2 and NH4Cl, regardless the barium cooling
mix is the one which goes lowest, which may even be -70*C, it produces ammonia, which brings me to wonder whether that could be a very simple way to
produce liquid ammonia..?? problem may be seperating the liquid from the solids -- offtopic.
i am really curious to hear if there could be a cooling plate produced that could reach significantly low temperatures (i know they have made -70*C
freezers for sushi storage, which effective kills bacteria, or so they say) im thinking not a closed room but maybe approx same appearance as a RBF
heating mandle, where it is maybe formed as a cup that makes sure air flux wont kill a whole lot of the cooling effect
an cooling plate could be very useful for chemistry applications, especially handling toxic volatile stuff which will severely be halted in difficulty
by handling in liquid state -- and increasing its usefulness.
supposing CO2 wouldnt make sidereactions with SO2, Cl2 and/or SO2Cl2 why not just toss the gasses directly onto solid CO2? they should condense with
no probs and react (this is where it may be problematic however) i suggest 2 hoses leading the gasses onto the CO2 in a container with a hole so you
could keep adding CO2 as the reaction is gonna produce some heat effectively tearing away the solid CO2
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