Sciencemadness Discussion Board - Chlorination of Sulphur

Chlorination of Sulphur

aga - 24-3-2015 at 10:06

deltaH's thread in Energetics mentioned 'Factice', which led me to attempt to make Brown Factice.

To make White factice, the papers say that Sulphur Chloride SCl₂ is used instead of elemental Sulphur, so here is my second effort at SCl₂ synthesis.

From http://en.wikipedia.org/wiki/Sulfur_dichloride it appears that the reaction is multi-step and complicated, however the process is simply a matter of passing enough Chlorine gas over powdered elemental Sulphur.

Here's what i came up with :-

In the vacuum flask on the left is 25g KMnO₄ with an addition funnel on top, containing 100ml of 20% HCl, acting as the Cl₂ generator.

2 KMnO₄ + 16 HCl => 2 KCl + 2 MnCl₂ + 5 Cl₂ + 8 H₂O

The gas is led to one side of the U-tube, at the bottom of which is 5g powdered Sulphur and tiny magnetic stir-bar.

To dispose of excess Chlorine gas the right hand outlet is led into a 'scrubber' filled with NaOH solution.

2 Cl₂ + 2 NaOH => NaCl + NaClO + H₂O.

The HCl flow was begun at ~1 drip per second, and remained there for the entire run.

At the start, the Sulphur looked like this :-

After 5 mins :-

At 8 mins 18 seconds it was all a liquid. Note the distinct surface layer :-

At 30 minutes the liquid was very much Red. Notice the volume increase :-

Amazingly the bubbling of the scrubber pot could be affected by agitating the liquid at this stage.

So much so that sufficient agitation caused a slow suck-back effect.

Wagging a magnet under the stir-bar was so effective that i got carried away, causing a lot of suck-back and destruction of the product.

In the future i must either grow up and take things seriously (unlikely) or make an anti-suck-back jar (much more likely).

Edit: typos, equations and balancing errors corrected (cheers blogfast25)

[Edited on 24-3-2015 by aga]

Magpie - 24-3-2015 at 10:27

Quote: Originally posted by aga

The gas is led to one side of the U-tube, at the bottom of which is 5g powdered Sulphur and tiny magnetic stir-bar.

Ingenious.

I have made S2Br2 several times. This is easy, but never SCl2. IIRC Len1 has a procedure for making it in Prepublication. You have probably seen it I imagine.

Chemosynthesis - 24-3-2015 at 10:29

I also really like that setup.

Molecular Manipulations - 24-3-2015 at 10:31

Nice job man!
Keep in mind that this stuff is rather unstable, and exists in equilibrium with both disulfur dichloride and sulfur tetrachloride (somehow both, which is weird).
At first when chlorination begins this reaction predominates:
2 S + Cl₂ → S₂Cl₂, once all or most of the sulfur is in the first oxidation state, it oxidizes again to form sulfur dichloride, which at low temperatures can be further oxidized to the tetrachloride, which is quite unstable and only a small fraction will form regardless of excess chlorine being added. Sulfur dichloride slowly releases chlorine forming disulfur dichloride again, so it's best to store it in a freezer.
I'm going to use your setup next time I try the reaction. In the past I've used a pressure equalized addition funnel a two neck flask and a Liebig condenser to distill it as it's produced. What happens is rather than boiling it decomposes to disulfur dichloride which boils at 137.1 °C, I used a big excess of chlorine, which reacts again as shown above to form the pure sulfur dichloride. I have one ampule of the stuff left, and every time I break one to use it, pressure is released and chlorine can be detected via my usual (smell, cough, run, throw up, repete).
I like your setup cause it doesn't require distillation (and I broke my damned Liebigs, both!). However the sulfur I have is only 90% pure, the rest being bentonite clay, so that won't work...
Anyway great job!

careysub - 24-3-2015 at 10:32

Keep it away from ethylene!

Molecular Manipulations - 24-3-2015 at 10:42

Sulfur dichloride reacts with ethyene? I know disulfur dichloride combines to produced bis(2-chloroethyl) sulfide (mustard gas) but does sulfur dichloride work as well?
The reaction for the former is: S₂Cl₂ + 2 C₂H₄ → (ClC₂H₄)₂S + S, so this could be applied to sulfur dichloride like this: SCl₂ + 2 C₂H₄ → (ClC₂H₄)₂S. But just because I can balance a reaction doesn't mean it works, do you have a reference?

deltaH - 24-3-2015 at 10:53

Wow aga, that is extremely beautiful! Well done :cool:

blogfast25 - 24-3-2015 at 11:09

Very nice experiment. I like direct union of elements reactions.

Shame about the suck back, though. A suck back vessel would have saved it

.

Also, you used KMnO4(permanganate +7), not KMnO3 (manganate +5).

And, NaOH + plus chlorine leads to NaClO, not NaClO3...

aga - 24-3-2015 at 11:29

Thanks for the comments !

It's a breeze to do, and i shall do it again (properly) in a day or two to get some SCl₂ for the White Factice experiment.

Quote: Originally posted by blogfast25

Also, you used KMnO4(permanganate +7), not KMnO3 (manganate +5).

And, NaOH + plus chlorine leads to NaClO, not NaClO3...

Doh ! KMnO3 was a typo.

NaClO₃ was my own lazy self not checking the reaction at all, and copying it wholesale off the 'web.

Thanks for noticing and for the corrections.

I should mention that the overall reaction is slightly exothermic, yet starting with 5g of S never made the glass too hot to touch.

[Edited on 24-3-2015 by aga]

[Edited on 24-3-2015 by aga]

Molecular Manipulations - 24-3-2015 at 11:34

I melt the sulfur first and then add chlorine, either works, but I think yields will be better if it starts out molten in your' setup, but with mine it shouldn't make any difference (because the apparatus is closed off).
Depending on the temperature of the hydroxide solution, chlorate can form, I believe hypochlorite decomposes at around 70°C.

careysub - 24-3-2015 at 11:42

Quote: Originally posted by Molecular Manipulations

Sulfur dichloride reacts with ethyene? I know disulfur dichloride combines to produced bis(2-chloroethyl) sulfide (mustard gas) but does sulfur dichloride work as well?
The reaction for the former is: S₂Cl₂ + 2 C₂H₄ → (ClC₂H₄)₂S + S, so this could be applied to sulfur dichloride like this: SCl₂ + 2 C₂H₄ → (ClC₂H₄)₂S. But just because I can balance a reaction doesn't mean it works, do you have a reference?

I believe the SCl2 will be contaminated with S2Cl2.

aga - 24-3-2015 at 12:05

Quote: Originally posted by careysub

I believe the SCl2 will be contaminated with S2Cl2.

It will, however an over-dose of Chlorine will make the product predominantly SCl₂ initially, decomposing over time to S₂Cl₂.

It seems that sealing the container ends up causing a slight positive pressure of chlorine gas, halting the decomposition effect.

Pyro - 24-3-2015 at 12:08

MM, don't you have a hell of a time cleaning the flask?
Do you distill the S2Cl2 off immediately?

aga - 24-3-2015 at 12:17

Quote: Originally posted by Pyro

MM, don't you have a hell of a time cleaning the flask?
Do you distill the S2Cl2 off immediately?

As you can see, the suck-back destroyed the product, and i've left it all in the fume hood overnight for the Cl₂ to disappear.

Everyone thinks we're about to re-open our pool 3 months early ...

The previous run ended up with clag-free SCl₂ after filtering, and there was no real meass to speak of.

I stored it in a handy plastic container overnight, which the SCl₂ ate through, and ran away to freedom (hence this second effort).

Edit:

Sorry, i thought you meant Mmmm instead of Molecular Manipulations.

[Edited on 24-3-2015 by aga]

Molecular Manipulations - 24-3-2015 at 12:17

Ever melted rubber in glassware? It's easier to buy a new flask then clean the shit.
Since I can't afford such things, I cleaned it out yes. I melted it and poured out what was left, let it cool and scraped out some more, added nitric acid, sulfuric acid with hydrogen peroxide and finally toluene to get most of it out. The sulfur I think wasn't the hard part, toluene would taken care of that from the start, it was then damn clay.
Yeah I had distillation going at the time of the reaction. Otherwise it would have just decomposed to disulfur dichloride.

Pyro - 24-3-2015 at 12:27

Sounds nasty! should try hot chromic acid as per Vogel's prescription

I'm trying this as soon as I get my lab relocated!

aga - 24-3-2015 at 12:49

Quote: Originally posted by Molecular Manipulations

Ever melted rubber in glassware? It's easier to buy a new flask then clean the shit.

I tried Making factice artificial rubber in two 250ml beakers, and it didn't work.

The beakers were horribly gooped up with brown tar.

Toulene hardly touched it, nor did acetone.

Pihraña Fluid was a thought, although my H₂O₂ is just 3%.

A few hours in a charcoal fire removed all of the brown goop, but also removed the graduations, which i liked.

aga - 24-3-2015 at 14:01

Quote: Originally posted by Magpie

IIRC Len1 has a procedure for making it in Prepublication. You have probably seen it I imagine.

I hadn't seen it as it happens.

Having now looked at it, all i have done is pass chlorine over sulphur powder and got lucky !

Len1's Work is rather more involved, precise and useful than my random experiment.

Magpie - 24-3-2015 at 14:46

Quote: Originally posted by aga

Len1's Work is rather more involved, precise and useful than my random experiment.

Yes, it is easy to get over awed by Len1's accomplishments. He is after all a professor at a university in Australia. When doing the experiments for his book I believe he had full access to all of his school's labs, library resources, colleagues, etc. This is not to take away from his hard work and brilliant mind.

aga - 24-3-2015 at 15:05

My 1 hour's tinkering, a few photos and a final failure due to over-excited idiocy really bear no comparison to Len1's paper.

Having said that, it seems to work, and is do-able for an amateur.

Oscilllator - 24-3-2015 at 15:08

Quote: Originally posted by Magpie

Do you know which university he is a professor at? I am currently sitting in a lecture hall at a university in Australia

Quote: Originally posted by Pyro

MM, don't you have a hell of a time cleaning the flask?
Do you distill the S2Cl2 off immediately?

Cleaning the flask was actually really easy (much to my surprise). All you need to do is get a hot dilute solution of NaOH and the sulfur comes right off leaving the flask sparkling clean. I have some cool pictures of the reaction of sulfur and chlorine, perhaps I'll post them when I get home.

Magpie - 24-3-2015 at 15:50

Quote: Originally posted by Oscilllator

Do you know which university he is a professor at? I am currently sitting in a lecture hall at a university in Australia

Flinders University, Adelaide

Oscilllator - 24-3-2015 at 16:05

Quote: Originally posted by Magpie

Flinders University, Adelaide

To bad, I'm at the university of new south wales

Success !

aga - 25-3-2015 at 13:24

Tried again with an anti-suck-back device and some brains engaged.

Result is 9.38g, 6ml of stuff, having started as 5.25g of flowers of Sulphur.

Woohoo !

Molecular Manipulations - 25-3-2015 at 13:32

Nice, 31% yield ain't bad for such a simple apparatus.

gdflp - 25-3-2015 at 13:42

Quote: Originally posted by Molecular Manipulations

Nice, 31% yield ain't bad for such a simple apparatus.

How are you calculating that, based off of theoretical formation of SCl₂? I'm getting a number around 56% yield, am I missing something?

Molecular Manipulations - 25-3-2015 at 13:47

Me Tired, you're probably right, I'll check my work later but I'm sure I made some error.

aga - 25-3-2015 at 14:35

Ah. I filtered it after the reaction finished, as there appear to be some small yellow grains in my 'pure sulphur'.

The weights are accurate though (so my 0.01 dig scales say).

When i stuffed the product in that 25ml RBF there immediately appeared a few yellow blobs.

I assumed there was some water in there, and the SCl2 reacted with that to make Purest Yellow Blob.

j_sum1 - 25-3-2015 at 14:44

This is a seriously cool procedure. I am tempted to try it myself.
The problem is that I have no need for sulfur dichloride whatsoever. I have no idea what I might do with it when done.

aga - 25-3-2015 at 14:52

gdflp is being generous : i work it out as 55.63% yield.

It looks great and will get dumped into some linseed oil to see if White Factice can be had.

Happy happy.

Molecular Manipulations - 25-3-2015 at 14:53

Chlorinate organics? That's its main use.

aga - 25-3-2015 at 15:10

Sulphonate so the papers says.

The idea seems to be to cross-link the oily stuff to make it gel, then harden.

I cannot pretend to have much of a clue as to the mechanics of that.

Edit:

The Objective is to make a synthetic rubber (factice) from some oil.
I tried sulphur & olive & sunflower oil, and it failed (sticky tar, no rubbery stuff).

For White factice the papers say to use SCl₂ hence this experiment.

My expectation is a White tar, rather than a Brown one.

Future experiments will tell.

[Edited on 25-3-2015 by aga]

Texium - 25-3-2015 at 16:26

Definitely something I'd like to try too. Favoriting this thread for now, and hopefully I'll be able to make time in the next couple weeks to try it out. But I might want to wait until I get some ampoules...
Looks like a great procedure though, aga. Even if it isn't the most precise and clean method for making sulfur dichloride, it's quite approachable and doable. I really look forward to trying it.

aga - 10-8-2015 at 08:28

Having had some luck with S₂Cl₂ in factice making, i stumbled on a one-line reference to CS₂ doing the same trick :

http://www.sbioinformatics.com/design_thesis/Carbon_Disulfid...

A bit of reading says that CS₂ is Nasty, but then, every chemical is called nasty.

Apparently heating carbon and sulphur at high temps yields some CS₂.

Does anyone have any experience with Carbon Disulphide and/or any thoughts on it ?

[Edited on 10-8-2015 by aga]

Loptr - 10-8-2015 at 08:43

I thought this might be a worthwhile mention.

If you heat an excess of TCCA ground finely with sulfur a red-orangish liquid starts to distill off. I ran a few test tube scale experiments have obtained about 120 mL of this liquid that seems to also contain some solids that settle to the bottom. The reaction seems to begin at the time the sulfur starts to melt. A lot of gas is given off, so this needs to be directed somewhere. I heat the flask with a propane torch to ensure the reaction goes to completion.

I have not worked this up to isolate the product and get a boiling point, so it could be anything, however, it seems to be a very quick way of producing a lot of liquid within a minute or so, so if the major product is S2Cl2, then its a quick way to get enough for an experiment. It's still sitting in a stoppered test tube waiting for me to get around to it.

An interesting thing happened after the experiment. I was using a latex tube to leading into a beaker to help wash the gases being generated. This latex tube turned grey and hardened upon exposure to the reaction vapors and resembles nothing of latex any longer. Is this perhaps vulcanized latex rubber? Rubber stoppers also swell very badly when exposed to the vapors.

I hope to get back around to this and conduct experiments in a more methodical manner, but I just lack the time right now.

The downside to this is that a mass begins to form in the flask as the reaction progresses. I am assuming this is cyanuric acid. It's a bit of a pain to clean, but isn't difficult.

[Edited on 10-8-2015 by Loptr]

[Edited on 10-8-2015 by Loptr]

[Edited on 10-8-2015 by Loptr]

aga - 10-8-2015 at 08:49

That sounds like a very quick shortcut to disulphur dichloride !

Drip a little into water and see if it instantly dumps elemental sulphur out.

Loptr - 10-8-2015 at 08:50

Quote: Originally posted by aga

That sounds like a very quick shortcut to disulphur dichloride !

Drip a little into water and see if it instantly dumps elemental sulphur out.

It does and gives off HCl.

aga - 10-8-2015 at 08:53

Excellent discovery Loptr.

Chlorination with Cl₂ gas takes a lot longer than a few minutes.

Nicodem - 10-8-2015 at 09:17

Quote: Originally posted by Loptr

If you heat an excess of TCCA ground finely with sulfur a red-orangish liquid starts to distill off.

See making SCl2 From TCCA-Na2S,possible or not?
and posts in the other disulfur dichloride thread.

Rynoaus - 28-3-2016 at 15:43

If anyone in aus us having trouble finding good sulphur they have elemental sulphur at bunnings in very section it states 99+% I'll get the name of it soon its fine granules easily crushed to a powder

Rynoaus - 28-3-2016 at 18:54

Fertilizer bloody spell check and fat fingers lol