Sciencemadness Discussion Board

Fun/cool reactions/experiments to do with CS2?

bolbol - 9-5-2016 at 18:18

I got my hands on ~800 mls of CS2.
I needed around 200 mls for realgar(As4S4) mineral recrystallization so I'll have plenty left over.

The things I've noticed so far are that it retracts light and it burns with a very nice blue flame.

I know about the barking dog reaction but I'm not sure if it's something I'd wanna do.

Anything you guys can think of? I heard it dissolves some semi metallic elements. I tried arsenic and it didn't seem to dissolve any. Would it dissolve red phosphorus? It would be interesting to see what color flame that solution would burn at.

NitreRat - 9-5-2016 at 18:50

You could make some Carbon tetrachloride and use it to write your name into the ozone layer

DraconicAcid - 9-5-2016 at 20:06

You can react with with ionic sulphides to make orange trithiocarbonates. Or calcium hydroxide to give calcium trithiocarbonate via

3 Ca(OH)2 + 3 CS2 --> CaCO3(s) + 2 CaCS3(aq) + 3 H2O.

bolbol - 9-5-2016 at 21:00

Quote: Originally posted by DraconicAcid  
You can react with with ionic sulphides to make orange trithiocarbonates. Or calcium hydroxide to give calcium trithiocarbonate via

3 Ca(OH)2 + 3 CS2 --> CaCO3(s) + 2 CaCS3(aq) + 3 H2O.


By ionic sulphides you mean sulfide salts that dissolve in water? How much water/CS2 ratio is required?

DraconicAcid - 9-5-2016 at 22:42

Yes, soluble ionic sulphides. I don't know about the ratio of water to CS2. You want enough water to dissolve the ionic sulphide, then add CS2 slowly until it's done reacting.

solitanze - 10-5-2016 at 02:22

You could prepare xanthate salts from CS2 and KOH (or NaOH) in ethanol: EtOH + CS2 + KOH → EtOCS2K + H2O
From there you could prepare various xanthate esters, via alkyl halide.

Alkaline CS2 dissolves cellulose, which is interesting.

bolbol - 10-5-2016 at 08:51

Quote: Originally posted by solitanze  
You could prepare xanthate salts from CS2 and KOH (or NaOH) in ethanol: EtOH + CS2 + KOH → EtOCS2K + H2O
From there you could prepare various xanthate esters, via alkyl halide.

Alkaline CS2 dissolves cellulose, which is interesting.


Would methanol work too? I happen to have some

DraconicAcid - 10-5-2016 at 10:47

I'm not sure if you can react an alcohol directly with CS2 to get the xanthate; Cotton & Wilkinson say they can be formed by reacting the alkoxide with CS2. Primary and secondary amines will react with CS2 in the presence of base to give dithiocarbamates, though. Tertiary phosphines will similarly react with CS2 to give a zwitterionic beast which makes a cool ligand.

bolbol - 11-5-2016 at 23:51

I tried it with methanol. I made a room temp sat solution of NaOH in methanol and added CS2 to it until it stopped reacting. Decanted the top piss yellow colored layer and added HCl to it. And here's what I got


I added cotton to a small sample of the solution before adding the HCl and It didn't seem to dissolve any

[Edited on 12-5-2016 by bolbol]

DSC_0353.JPG - 2.7MB

Metacelsus - 12-5-2016 at 06:24

Quote: Originally posted by DraconicAcid  
I'm not sure if you can react an alcohol directly with CS2 to get the xanthate


Yes, you can. I've done it with KOH and isopropanol. The product precipitates as a yellow solid. Yields might be better using the pre-formed alkoxide, but the direct reaction is definitely feasible.

Also: Imgur is notorious for losing images after a few years. If you don't want that to happen, just attach the image directly to your post on Sciencemadness.

[Edited on 5-12-2016 by Metacelsus]

bolbol - 12-5-2016 at 08:32

I was about to filter off this stuff in the morning and I noticed this nice red colored layer...

I noticed a few blobs yesterday night but I'm pretty sure it formed overnight.
Any ideas about what it is?



DSC_0354.JPG - 2.6MB


[Edited on 12-5-2016 by bolbol]

DSC_0355.JPG - 2.6MB

woelen - 12-5-2016 at 09:49

CS2 does not dissolve red P. Actually, there is no solvent which dissolves red P without converting it to something else (e.g. oxidizing it to phosphate or phosphite). White P dissolves very well in CS2. When such a solution is poured over paper and the CS2 is allowed to evaporate, then after a minute or so the white P bursts in flame. At that time, the CS2 already is gone and does not contribute to the reaction. It is the white P which gives the spectacular reaction.
Be VERY careful with this solution of white P in CS2. If you get this on the skin you have a serious problem. The CS2 quickly evaporates and what remains on your skin is a thin layer of white phosphorus, which is extremely poisonous and may lead to fire on your skin, leading to exceptionally dangerous wounds (combination of burn and white P poisoning). If you ever get any solution of white P on your skin, then IMMEDIATELY rinse with a lot of clean CS2 in a well ventilated place or immerse in a cold solution of CuSO4, otherwise you're screwed.

CS2 does dissolve iodine and sulphur very well. You can make concentrated solutions of these elements and these solutions are very reactive. One interesting thing is to add some powdered tin to CS2 and then add iodine. The tin is converted to beautiful red SnI4.
Just for fun, put a single small drop of a solution of sulphur in CS2 on your thumb. The CS2 evaporates in seconds. After that, you really can smell the sulphur. This demonstrates that sulphur has quite a strong and peculiar, but for many people familiar smell.

A nice experiment is to add some sulphur to a solution of NaOH and then heat the solution, until all sulphur has dissolved. This solution contains sulfide ion and thiosulfate ion. Add a few drops of CS2 to this solution to get the thiocarbonate ion CS3(2-) in solution.

The barking dog reaction can be done safely. A safer version on a smaller scale is presented here, together with the original large scale version:

http://woelen.homescience.net/science/chem/exps/barkingdog/i...

CS2 itself also is quite toxic, but it is not instant death in a bottle. To my opinion the risk of poisoning is exaggerated. As with many other solvents, try to avoid inhaling much of the vapor but if a whiff of it is inhaled accidently there is no need to worry if this occurs occasionally. If you get some CS2 on your skin just let it evaporate quickly. I have had this happen quite a few times without any nefarious after-effect. Only if you work with CS2 professinally and you get exposed every day, then there is a serious long-term risk.

One thing which really must be taken into account is the low temperature of ignition of CS2. Water at 100 C can ignite CS2 (it is borderline on ignition temperature). A hotplate at 150 C or so certainly does ignite vapor of CS2. So be careful with hot objects around if you use CS2.

Another experiment which is supposed to be cool is mixing CS2 and CCl4 and pouring some of this mix on your skin and igniting the vapor of this mix. The mix burns with a blue flame, but this flame apparently is so cold that you can have it on your hand without gettting burnt. I never tried this personally. CCl4 is far more toxic than CS2 and it is a well-known carcinogen. I would not pour this deliberately on my skin.

[Edited on 12-5-16 by woelen]

Metacelsus - 12-5-2016 at 13:41

Quote: Originally posted by bolbol  
I was about to filter off this stuff in the morning and I noticed this nice red colored layer...

I noticed a few blobs yesterday night but I'm pretty sure it formed overnight.
Any ideas about what it is?


I also noticed that red layer sometimes when I was doing the reaction with isopropanol. However, it didn't always appear. All my attempts to isolate the compound causing the red color failed (I tried extraction with organic solvent, and also crystallization). My guess is that it was some sort of polysulfide, potentially formed from impurities in the carbon disulfide.

bolbol - 12-5-2016 at 15:33

I separated it and added water on the top because it smelled harsh. After a while the redness went away and it turned dark yellow.