Sciencemadness Discussion Board

Mercaptans from CS2, alcohol + alkali

garage chemist - 13-4-2005 at 11:53

I once read that someone prepared butyl mercaptan from 1-butanol (I have 50ml left from my old chemistry set) and carbon disulphide in a basic envoronment.
Would this work? What would the reaction proceed like- maybe the CS2 forms some weird thiocarbonate salt with the base? How would that thiocarbonate look like (structure), and how would it react with the butanol?

I have no CS2, but if it turns out to be a really useful reagent, I'll try to make some.

sparkgap - 14-4-2005 at 05:08

garage chemist,

As far as I am aware of (and looking at references besides), there is no note of carbon disulfide in basic medium reacting with alcohols; however, it is known that alkyldithiocarbamates are produced when basic CS<sub>2</sub> is reacted with the appropriate amine (with ammonia, the formation equilibrates with decomposition unless an appropriate electrophile is introduced.)

But the absence from the literature (except from where you have read it; can you recall?) does not, of course, exclude that such a reaction may happen. I would also suppose that a dithiocarbonate intermediate (R-O-C(=S)-S<sup>-</sup>;) may be involved; as to rearrangement into the alkylsulfide (since the medium is basic, the mercaptan will be afforded upon quenching with acid), I am not certain.

sparky (^_^)

P.S. I hope you are acutely aware of carbon disulfide's properties before attempting to make it. :)

Esplosivo - 14-4-2005 at 05:54

Regarding carbon disulfide, I find it is not an abnormally toxic chemical. It can be compared to aromatics such as phenylamine and benzene with respect to its toxic effect, which when handled safely are quite harmless. I am more worried about the 'may cause reproductive disorders' part than anything else :P. But I guess it requires some damn excessive inhalation of the stuff for this to occur, or else contact with the liquid itself, both of which can be prevented with proper ventilation and equipment. What do you think?

Btw sparkgap, thank you for your help on the P thread.

guaguanco - 14-4-2005 at 10:29

CS2 is also as flammable a material as you'd EVER want to deal with.

neutrino - 14-4-2005 at 13:20

No kidding, hot water will make this stuff catch fire. I find I suddenly want to make some now...

garage chemist - 14-4-2005 at 14:26

White Phosphorus self- ignites at 50°C. I once had some molten phosphorus under warm water in a test tube and poured all the stuff into a beaker filled with water and, what do you think, the shit violently catches fire and some of the burning phosphorus stayed at the surface of the water to crackle and spit burning phosphorus everywhere. WP is the most flammable material I am aware of. Nothing comes close.

I remembered where I found the mercaptan synthesis from CS2: on the powerlabs message board.

[Edited on 14-4-2005 by garage chemist]

sparkgap - 14-4-2005 at 23:18

Well, for sure I wasn't hinting at inflammability when I was talking about "properties", since we handle combustible stuff quite often.

Esplosivo, you seem to think on the same wavelength as I. :D

sparky (^_^)

mick - 15-4-2005 at 12:19

CS2 and base might give you a dithiocarbonate and an alcohol could react

mick

CS2 smells of rotten cabbage. can be ignited at around140oC (ether can be ignite at around 180 oC). It is a cold blue flame and it has been linked to genetic damage in males and other stuff.

mick

[Edited on 15-4-2005 by mick]

neutrino - 15-4-2005 at 13:00

Its autoignition point is lower--somewhere around 90*C.

unionised - 16-4-2005 at 01:54

"As far as I am aware of (and looking at references besides), there is no note of carbon disulfide in basic medium reacting with alcohols"
Sparkgap, you might not be aware of it, but the xanthate rayon process relied on it.

[Edited on 16-4-2005 by unionised]

sparkgap - 17-4-2005 at 02:18

How could I have forgotten?!? :( The vivid orange of the xanthogenate (or xanthate, as it is sometimes called) was the most stunning part of a trip to a textile factory I had taken quite a while back... (except for those dyeing vats; nice colors :D)

Thanks for the reminder, unionised.

sparky (^_^)

P.S. Has anyone attempted CS<sub>2</sub> yet?

Esplosivo - 17-4-2005 at 04:00

If I remember correctly BromicAcid has successfully prepared a sample of the stuff. I tried to last summer but my heat source was not good enough, my container did not seal as tightly as it should have and ended up with a complete, burning, mess.

[Edited on 17-4-2005 by Esplosivo]