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Author: Subject: Glassware stuck together by sulfur from sulfur monochloride
garphield
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[*] posted on 10-9-2021 at 11:44
Glassware stuck together by sulfur from sulfur monochloride


This happened like a month ago and I will be at uni until December but I may as well ask now since I can just reference this later.

Me and another guy on discord came up with a possible synthesis of phosphoryl chloride from a phosphate salt and S2Cl2 a while ago. Towards the end of summer, I tried going ahead with it but ran into several problems because S2Cl2 would get into joints and form solid sulfur, sticking it together.

The first incident was with a stoppered 250ml Erlenmeyer flask containing some sulfur chlorides which I left for about a week. After being unable to unstick the joint, I heated it with a blowtorch which always worked in the past but since I used petroleum jelly to grease it, the molten sulfur reacted with the petroleum jelly to form char which has made it permanently stuck together, I tried everything I could think of that wouldn't break the flask and nothing worked but it was only $10 worth of glassware and it looks nice as a display sample so it wasn't that bad.

When I made another batch of sulfur chlorides, I decided to store it in a stoppered flask without any grease in the joint so I could use a blowtorch when it got stuck, and to take apart the apparatus used for distilling the sulfur chlorides immediately after use so they wouldn't have enough time to react with water in the air and form solid sulfur. However, I did this on the day I got the second dose of the coronavirus vaccine and I ended up coming down with a fever and couldn't get out of bed that afternoon or the next day. I did use grease for the joints in the apparatus itself since I thought I would be able to take it apart before any sulfur formed, but because of that illness I couldn't do it in time.

Two days later, when I was actually able to do stuff again, almost all of the joints had been stuck together since it had been outside the whole time. I was able to get the flask containing the product unattached but everything else is still stuck together. I had to start packing for college right after this so didn't have time to do much, although I did pour in some water to neutralize any remaining sulfur chlorides after it was obvious there was no way for me to quickly unstick them. The entire apparatus is still stuck together in my garage right now. I haven't heated any of the joints enough to cause any reaction between the grease and the joints. All of the glassware it is made of probably is worth 60-70 dollars so leaving them like that isn't an option.

I have two main ideas on how to get it apart after I get back home. One would be to submerge the entire thing in bleach. I have used bleach to remove sulfur on the inside of flasks and it works very well for that, but I am not sure if it would be able to get into the joints very well. It would also require several gallons of bleach since I can't take the apparatus apart. Another would be to distil toluene in it, with the toluene getting into the joints and dissolving the sulfur. Sulfur chlorides are a better solvent of sulfur than chlorine so they might be able to work too, but toluene would be preferable for obvious reasons. Does anyone have any tips for how to execute these ideas and/or other ones that might work better? Thanks.
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Sulaiman
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[*] posted on 10-9-2021 at 19:36


If available, I'd put a few drops of CS2 on the joint as its the best sulphur solvent I've come across.

WD40 often helps with seized joints.
Apply, wait an hour or more and try.
If not, add some more, wait, try again.

PS I was just reading Vogel's 5th edition and read that an ultrasonic bath is excellent for un-freezing joints.
(Declon 90 surfactant recommended)

[Edited on 11-9-2021 by Sulaiman]




CAUTION : Hobby Chemist, not Professional or even Amateur
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[*] posted on 11-9-2021 at 02:35


Hot toluene should work, and is more available and less dangerous than carbon disulphide.

It never happened to me. I had once a distillation apparatus clogged with elemental sulphur deposit, but the joints did not stick, and hot toluene cleaned it really well. I use Rodaviss joints, which is supposed to free you from that sort of bind.


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unionised
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[*] posted on 11-9-2021 at 02:54


Can you just melt the sulphur?
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garphield
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[*] posted on 11-9-2021 at 11:54


Quote: Originally posted by unionised  
Can you just melt the sulphur?


I tried heating up the joints in the distillation apparatus shortly but it didn't work. I don't want to heat them too strongly as that is what made the stopper in the flask from the beginning of the post stuck permanently.
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Praxichys
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[*] posted on 14-9-2021 at 06:49


Worst case you can use a small point chisel and a hammer to break the stopper, recover the product, and save the flask. The remains of the male joint can usually be broken out with needle-nose pliers and a little coaxing from a blowtorch once the flask is washed and empty. Soaking in warm xylenes may also help with the sulfur. Hopefully you have the hollow type of stopper.

I know this is probably too late to help but I use vacuum grease from Dow Chemical which remains highly inert against things like sulfur chlorides even at elevated temperatures. I used it in my sulfur monochloride video and had no problem unsticking the joints at the teardown. My SOCl2 was stored for a couple years and some gentle persuasion from a heat gun freed it right up. The tube is $32 on Amazon but it's enough to last decades.
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