Sciencemadness Discussion Board

Easiest homebrew of methyl mercaptan

Globey - 17-8-2010 at 11:30

Supposing it would be to react phosphorus pentasulfide with methanol @ room temp, and viola. But how would one go about making the pentasulfide with redP and flowers of. Just mix the appropriate molar amounts in a crucible and heat? But what if the desired product catches on fire. Does anyone know of a practical way using the taboo red p and sulfur? Or are there even easier more OTC routes to the end product desired, methyl mercaptan.

Many thanks for your suggestions.

gardenvariety - 17-8-2010 at 11:37

'Homebrew' and 'mercaptan' don't belong in the same sentence. Seriously, your neighbors will riot.

Otherwise, methyl halide + thiourea then hydrolysis, if my memory serves.

Globey - 17-8-2010 at 12:44

Quote: Originally posted by gardenvariety  
'Homebrew' and 'mercaptan' don't belong in the same sentence. Seriously, your neighbors will riot.

Otherwise, methyl halide + thiourea then hydrolysis, if my memory serves.



Sooo, sodium chloride, thiourea, and heat? Where does the metal halide enter the equation. I suppose the MH could be an isotope of Uranyl iodide. Thanks. I'd be doing this on a micro-scale. The fart would be the whole point. MM doesn't just smell like any old fart. Oh no, it smells more like Tony Soprano who jealously chalked down a Philly egg cheese steak without chewing, and so the anaerobic in his large intestines are forced to break the pepperoni down in suboptimal ways. It is far uglier than almost any fart I have had the opportunity to smell. Back in the day, we used it to derivatise Lewisite, when I worked for the Chemical Demilitarisation lab, in Edgewood Arsenal. We worked just across from the building where all the hallucinogens and narcotics (and other experimentals) were made, and given EA numbers. A real piece of history.

[Edited on 17-8-2010 by Globey]

ScienceSquirrel - 17-8-2010 at 13:30

You don't half breed them clever and thick in America!
Put a man on the moon but the average Joe struggles to differentiate between metal and methyl ;(
Thiourea and methyl iodide are quite nasty, boiling them up is a bad idea unless you know what you are doing.

Globey - 17-8-2010 at 14:21

Oh yes, I misread. And Metal v/s Methyl are so different, what with the different letters. Rest my case in regards to the overblown egos and the purposeless anti-socialites. So I2's the leaving here? Too bad not everything leaves so easily;)U< I'm not sure you'd have to boil anything. Activation energy is probably below room temp. here I'm guessing, and the Rxn. would be endothermic once cull is reached. That is just a guess. But too bad I just can't tell the difference between Methyl and Metal-what a PISSER! Are diamonds made of Metal, and are cars made of the main component of natural gas?

Anyway, the tone of your insult reminds me of a sort of truck-stop restaurant banter, politically right leaning. Yo>u< know the type.

Gosh, hopefully I didn't make an oversight in my typing/reading. Just one and POOF,
let's call him the village idiot. Overreaction, just like the Taliban. Not as harsh of course, but the same Overreaction to a non-infarction event. Now, that's the truth.

[Edited on 17-8-2010 by Globey]

[Edited on 17-8-2010 by Globey]

ScienceSquirrel - 17-8-2010 at 14:47

A possible home synthesis of methyl mercaptan:

1) React methanol with sulphuric acid and potassium iodide. Easy stuff but it is nasty so watch yourself.

2) Purify thiourea from silver polish or buy from a photography or similar supplier

3) React the methyl iodide with the thiourea to form a Bunte salt

4) Heat the Bunte salt with alkali to make the methyl mercaptan

Easy peasy, lemon squeezy!

ScienceSquirrel - 17-8-2010 at 15:12

I am trying to be quite pleasant.
This is chemistry that can kill if you do not know what you are doing.
My first chemistry experiment should not be; potassium cyanide, phosgene, picric acid, etc.
Learn the highway code before you play in the road!

Globey - 17-8-2010 at 15:32

Actually picric acid was one of my 1st, about 30 years ago. The NOX's just went outside. Used the Field Expedient manual bought from The Larder (Loompanics was a small company at this time.) Picric acid even in it's dry state is not very easy to detonate. Now, I can truly appreciate your pleasantries, but what exactly was your point here? You basically call me an idiot of the masses in your earlier post, and then change your message to something like "your just a newbie, and shouldn't be playing with our big boy stuff", under the guise of the popular "harm reduction". I guess you know me real well.

I think alkali hydrosulphide (please get over my old British spelling without forming an insult out of it, thanks) is an elegant route to substitution. Just distill with your substituted potassium sulphate, to obtain your main, substituted thiol.

Even easier was my original idea, P2S5 plus whatever chain alcohol you desire. A side product being the useful P2O5 (you know, acetonitrile is STILL expensive, what gives!)

[Edited on 17-8-2010 by Globey]

ScienceSquirrel - 17-8-2010 at 16:50

Quote: Originally posted by Globey  
Even easier was my original idea, P2S5 plus whatever chain alcohol you desire. A side product being the useful P2O5 (you know, acetonitrile is STILL expensive, what gives!)

[Edited on 17-8-2010 by Globey]



An alcohol plus phosphorous pentasulphide will make a thiol but the other product is a vile black mess and not phosphorous pentoxide.
It is very acidic, it pongs, it can be dissolved in a lot of water and poured down the drain but that is it.
It is not a useful reagent at all!

Globey - 17-8-2010 at 18:53

Quote: Originally posted by ScienceSquirrel  
Quote: Originally posted by Globey  
Even easier was my original idea, P2S5 plus whatever chain alcohol you desire. A side product being the useful P2O5 (you know, acetonitrile is STILL expensive, what gives!)

[Edited on 17-8-2010 by Globey]



An alcohol plus phosphorous pentasulphide will make a thiol but the other product is a vile black mess and not phosphorous pentoxide.
It is very acidic, it pongs, it can be dissolved in a lot of water and poured down the drain but that is it.
It is not a useful reagent at all!


Sounds like you have environmental control issues. These aren't notably labile, complex organics with tons of carbon. Try using a vacuum, a small amount of catalyst, lower heat perhaps (made possible by your good suction), and of course, keep the damn thing anhydrous. Balance the equation, it works out beautifully. Also, the mercaptan will be removed as a liquid once formed. So your receiving vessel needs to be very cold. Acetone dry ice should do it. That way you get your liquid mercaptan and avoid all the reactions which can lead to a tarry goop.

Mr. Wizard - 17-8-2010 at 19:32

Quote: Originally posted by Globey  
Supposing it would be to react phosphorus pentasulfide with methanol @ room temp, and viola. But how would one go about making the pentasulfide with redP and flowers of. Just mix the appropriate molar amounts in a crucible and heat? But what if the desired product catches on fire. Does anyone know of a practical way using the taboo red p and sulfur? Or are there even easier more OTC routes to the end product desired, methyl mercaptan.

Many thanks for your suggestions.


Perhaps the tips of strike anywhere safety matches, which contain Phosphorus Sesquisulfide (P4S3) could have the other active ingredients leached out and a little more sulfur added, with heat, to make the pentasulfide (P4S10) you are looking for? I never have done it, but it's supposed to work. I'd use a small test tube filled with an inert gas, sulfur vapor,or a sealed tube with a vacuum.

[Edited on 18-8-2010 by Mr. Wizard]

ThatchemistKid - 17-8-2010 at 19:43

Well, the easiest way for making mercaptans that I have come up with gives you about 50% or 60% yield, but works nicely for the some higher mercaptans
they can just be distilled out of the reaction mix.

first, prepare some sodium polysulfide by action of a concentrated solution of hot sodium hydroxide on sulfur usually a 2:1 or 3:1 sulfur to sodium hydroxide mole wise.

then take this horrid smelling solution and add the appropriate amount of alcohol (whatever alcohol that gets you to your desired product). (generally i give a 2:1 molar excess of sodium polysulfide to alcohol).

this is all placed in a flask on a heading mantle then the appropriate amount (or just until the H2S stops forming) of sulfuric acid is added and the product maybe distilled or condensed over (whatever the case may be).

I know that this works well for alcohols such as ethanol and 2-propanol but I have not tried it with methanol.

*note* although your body does have natural oxidases that help in the detoxification of hydrogen sulfide, it is still more toxic then Hydrogen Cyanide and stinks of rancid ass, so please use appropriate safety precautions.

*note* along with the hydrogen sulphide elemental sulfur is formed in the reaction.

ThatchemistKid - 17-8-2010 at 19:54

Also to catch the hydrogen sulphide as it is being formed you may bubble it through a hypochlorite solution, this was suggested to me by one of my professors and it seems to work well from when I have tried it.

DJF90 - 18-8-2010 at 02:52

Quote:
3) React the methyl iodide with the thiourea to form a Bunte salt

This isn't actually a bunte salt (metal alkylthiosulfate), but S-alkylisothiouronium halide.
Quote:
I think alkali hydrosulphide (please get over my old British spelling without forming an insult out of it, thanks) is an elegant route to substitution. Just distill with your substituted potassium sulphate, to obtain your main, substituted thiol.

Hardly elegant, Globey. Hydrosulfide is typically prepared as needed, by gassing an anhydrous solution of K or Na ethoxide (in ethanol) with H2S. And just to clarify, in your last sentence you mean distill a mixture of hydrosulfide and potassium alkyl sulfate? The thiourea method is much more simple.
Quote:
Balance the equation, it works out beautifully.

This shows just how inexperienced you are as a chemist. A balanced equation means very little in practical organic chemistry. Its quite likely that if P2O5 is formed, it'll react with your starting material (an alcohol) producing the carbonous, acidic material ScienceSquirrel speaks of.

Mildronate - 18-8-2010 at 02:58

you can easy get merkaptan from empy propane tank.

Awesome post from ThechemistKid

Globey - 18-8-2010 at 05:15

Quote: Originally posted by ThatchemistKid  
Well, the easiest way for making mercaptans that I have come up with gives you about 50% or 60% yield, but works nicely for the some higher mercaptans
they can just be distilled out of the reaction mix.

first, prepare some sodium polysulfide by action of a concentrated solution of hot sodium hydroxide on sulfur usually a 2:1 or 3:1 sulfur to sodium hydroxide mole wise.

then take this horrid smelling solution and add the appropriate amount of alcohol (whatever alcohol that gets you to your desired product). (generally i give a 2:1 molar excess of sodium polysulfide to alcohol).

this is all placed in a flask on a heading mantle then the appropriate amount (or just until the H2S stops forming) of sulfuric acid is added and the product maybe distilled or condensed over (whatever the case may be).

I know that this works well for alcohols such as ethanol and 2-propanol but I have not tried it with methanol.

*note* although your body does have natural oxidases that help in the detoxification of hydrogen sulfide, it is still more toxic then Hydrogen Cyanide and stinks of rancid ass, so please use appropriate safety precautions.

*note* along with the hydrogen sulphide elemental sulfur is formed in the reaction.


This is what I'm talking about. Thank you for the awesome and informative post.;)

Globey - 18-8-2010 at 05:16

Quote: Originally posted by DJF90  
Quote:
3) React the methyl iodide with the thiourea to form a Bunte salt

This isn't actually a bunte salt (metal alkylthiosulfate), but S-alkylisothiouronium halide.
Quote:
I think alkali hydrosulphide (please get over my old British spelling without forming an insult out of it, thanks) is an elegant route to substitution. Just distill with your substituted potassium sulphate, to obtain your main, substituted thiol.

Hardly elegant, Globey. Hydrosulfide is typically prepared as needed, by gassing an anhydrous solution of K or Na ethoxide (in ethanol) with H2S. And just to clarify, in your last sentence you mean distill a mixture of hydrosulfide and potassium alkyl sulfate? The thiourea method is much more simple.
Quote:
Balance the equation, it works out beautifully.

This shows just how inexperienced you are as a chemist. A balanced equation means very little in practical organic chemistry. Its quite likely that if P2O5 is formed, it'll react with your starting material (an alcohol) producing the carbonous, acidic material ScienceSquirrel speaks of.



Oooh, OUCH! Oooh, stop it already!

ScienceSquirrel - 18-8-2010 at 08:25

I have done quite a few reactions with phosphorous tribromide, phosphorous trichloride, phosphorous oxychloride, phosphorous pentachloride, etc.
They all produce condensed phosphorous acids that are usually pretty syrup like and the mixture will usually go black due to the powerful dehydrating and condensing nature of the reactants.
I would expect the trisulphide not to react completely and hydrogen sulphide will be liberated during the work up.
Most practical organic chemistry has a huge gloppification factor.
The reaction of methyl iodide with thiourea is a good way to go, it yields a crystalline solid which is easily stored that hydrolyses to the methyl mercaptan when you want it.
No pongy bottle in the bottom of your freezer!

Methansaeuretier - 19-8-2010 at 05:51

Quote: Originally posted by ScienceSquirrel  
Quote: Originally posted by Globey  
Even easier was my original idea, P2S5 plus whatever chain alcohol you desire. A side product being the useful P2O5 (you know, acetonitrile is STILL expensive, what gives!)

[Edited on 17-8-2010 by Globey]



An alcohol plus phosphorous pentasulphide will make a thiol but the other product is a vile black mess and not phosphorous pentoxide.
It is very acidic, it pongs, it can be dissolved in a lot of water and poured down the drain but that is it.
It is not a useful reagent at all!


The mainproduct would be trimethylphosphate and not P4O10 I think. It's a nice methylating agent. :cool:

Globey - 19-8-2010 at 07:20

Quote: Originally posted by Methansaeuretier  
Quote: Originally posted by ScienceSquirrel  
Quote: Originally posted by Globey  
Even easier was my original idea, P2S5 plus whatever chain alcohol you desire. A side product being the useful P2O5 (you know, acetonitrile is STILL expensive, what gives!)

[Edited on 17-8-2010 by Globey]



An alcohol plus phosphorous pentasulphide will make a thiol but the other product is a vile black mess and not phosphorous pentoxide.
It is very acidic, it pongs, it can be dissolved in a lot of water and poured down the drain but that is it.
It is not a useful reagent at all!


The mainproduct would be trimethylphosphate and not P4O10 I think. It's a nice methylating agent. :cool:


I love useful by products/side products. Especially when they can methylate mildly without alkylating parts of your own body! Excellent point you make. Too many peeps throwing chlorine down the sewer or letting off NO>NO2. Look, in the long run, were really insignificant as far as polluters go. We account for maybe 0.00000000000000000001 of all pollution? Maybe add a few zeroes in there. But what is more important is setting the example, and doing the right thing, no matter what statistically small effect one less emission will have. The cumulative effect of everyone adopting this, it become a fashion, and even ultimately influence larger corporations.

ALWAYS have a use for your side product, unless it's just sucky ass. Then down the drain, toilet, wherever!

ScienceSquirrel - 20-8-2010 at 03:02

Quote: Originally posted by Methansaeuretier  


The main product would be trimethylphosphate and not P4O10 I think. It's a nice methylating agent. :cool:


The main product would be a filthy phosphorous mess with some alkylation, some remaining suphur, some oxides, some acid groups etc.


Inorganic chemistry

A + B -> C + D

:)

Organic chemistry

A + B -> C + yuck

:(

[Edited on 20-8-2010 by ScienceSquirrel]