Sciencemadness Discussion Board

Sulfur chlorides preparation

madscientist - 22-9-2002 at 20:02

Today I attempted to prepare sulfur chlorides, more specifically, S2Cl2. Polverone several months ago tipped me off to his discovery that strongly heating sulfur and cupric chloride together yielded a terrific stench and beads of reddish liquid condensing on the sides of the heating vessel. So this is what I tried:

17.4g CuCl2 + 12.5g S8

Both reactants were finely powdered and thoroughly mixed. When the temperature reached somewhere around 65C (I wasn't paying close attention...), an exothermic reaction began, and the mix gradually took on a brown color so deep that it was almost black, and appeared wet. I gradually turned off the heat on the hotplate, and the temperature continued to rise rapidly. It finally levelled off at 110C; held for a minute; and then, after a while longer, fell down to room temperature. The was a gradually solidifying wet-appearing black solid. After a while longer, it solidified, ceased to appear wet, and took on a slightly lighter color. Here's a picture of it at that point. Sorry I took the picture so close, I admit that it's terribly blurry. But it's better than nothing.


madscientist - 22-9-2002 at 20:05

I forgot to mention the reaction that I think occurred.

CuCl2 + 3/8S8 ----> CuS + S2Cl2

madscientist - 23-9-2002 at 13:37

It has completely solidified - it didn't seem to take too long for that to happen. The solid is a very dark brown. It's quite hard, too. Right now this is my hypothesis as to what happened:
CuS + S2Cl2 ----> Cu(SSCl)(SCl)

No chlorine gas was liberated, by the way.

madscientist - 23-9-2002 at 13:56

Whatever it may be, it does not react violently with water. I added a piece of it to 200mL of water (expecting a violent reaction), and got essentially nothing. It slowly dissolved, becoming increasingly yellow (sulfur?), and yielding a somewhat opaque aqua-blue solution. There was no noticeable temperature change.

Ramiel - 24-9-2002 at 01:32

Would you say that the solution was aquamarine or just blue?

It's probably just a copper solution. However if it was more aquamarine it could be some weird/complicated ligand-chlorine-complex. Well, that's my detailed hypothesis.

Ramiel - 25-9-2002 at 05:00

for instance [Cu(Cl)4]2- is green, and Cu+(aq) is blue, all this dissolving of copper and chlorine might leave sulfur. So that might be your colours.

Nick F - 26-9-2002 at 13:34

S2Cl2 doesn't react *very* vigorously with water. Not compared to PCl5, for example, because of the low amount of contact between the water and the comparatively big blob of S2Cl2.
Why not use the common method with chlorine and molten sulphur? It takes a bit longer to get it set up, but it'll give you a nicer product.
Bubble Cl2 (choose your favourite method for producing this, and dry it with H2SO4) through molten sulphur, while distilling off the S2Cl2 formed, and venting waste gases into NaOH (aq).
The result will be a lovely and clear golden/orange liquid.

I wonder if

Boob Raider - 15-10-2002 at 20:11

anhydrous Stannic Chloride (SnCl4) with S8 will do the job.
Also will passing SO2 through CCl4 produce Thionyl Chloride (SOCl2) and Phosgene.

Polverone - 16-10-2002 at 00:19

I wouldn't discount the CuCl2 method just yet. I know that CuCl2 decomposes to give chlorine at elevated temperatures. I am sure I got something that wasn't just molten sulfur when I did this experiment on a test-tube scale. SnCl4 isn't something that you can just pick up at the hardware store. You have to generate it using chlorine gas, in which case you might as well lead the Cl2 straight into your sulfur.

I don't think that you'll get SOCl2 and COCl2 from SO2 and CCl4, but I can't verify this as I have no CCl4. An interesting tidbit that I learned on the Hive the other day: standard Energizer lithium batteries contain thionyl chloride as well as lithium metal. They're not a very economical source of chemicals, but if you want a little SOCl2 and lithium to play with...

Another thing I've considered trying is heating a small amount of sulfur with some of the non-hypochlorite pool chlorination chemicals, which are generally based around tri- and di-chloroisocyanuric acid and their salts. Hypochlorites give up too much oxygen to be good for preparing sulfur chlorides, but I wonder about these chlorinated isocyanuric acids. I know that salts of cyanic acid (of which trichloroisocyanuric acid can be considered a chlorinated modified trimer) hold on to their oxygen pretty strongly. "Bubble chlorine through molten sulfur" is probably always going to be the best answer for large-scale production, but I really don't want to have to handle pure Cl2 and dry it. Distilling a couple of powders together seems much nicer to me.