Production of Methanethiol (Methyl Mercaptan)?

[irisscientist]

Hi all,

 

I need to produce some of this rather unpleasant smelling gas for a bioassay. Can anybody please suggest an easy (pseudo-home) chemical reaction with ideally, easily obtainable/not-too-expensive compounds that will form this gas upon reaction? Although Sigma do sell the gas (neat), as I only need a limited/small quantity for my tests, I do not want to order cylinders of the stuff, which incidentally are not only currently out-of-stock are also also very expensive.

 

My limited Chemistry back ground has revealed the following:

 

"Sodium merthiolate sold on the market is spontaneously converted to methanethiol in acidic medium". In addition, Wikipedia suggests that "Methanethiol is prepared commercially by the reaction of methanol with hydrogen sulphide gas over an acidic solid catalyst, such asalumina".

 

Sodium merthiolate however is extremely expensive (even from Sigma) and obviously it would not be possible to replicate the Wiki procedure even in a basic biological lab environment.

 

Another option suggested was the use of Sodium thiomethoxide to produce methanethiol after hydrolysis of the salt.

 

Not being a Chemist however, I do not know if this (salt hydrolysis), or any other reaction would actually produce the gas required in sufficient quantities?

 

Is anybody please able to offer any suggestions relating to the production of this gas? Many thanks in advance for any information relating to this matter.

 

 

Mark

[Enthalpy]

Not only does it smell badly, it's also a poison. If your chemistry knowledge doesn't suffice to produce it, I recommend not to do it at all. Same for hydrogen sulphide.

[irisscientist]

Thankfully I only need a small quantity. IS this a Chemistry forum, or a judgemental forum? Do you wish me to submit COSHH records and produce a full RISK assessment for the planned experiment?

Edited July 11, 2013 by irisscientist

[John Cuthber]

Do you really think it's "judgemental" for us not to want someone hurt?

 

What do you really need the stuff for?

There may be a less stupid alternative.

[irisscientist]

No, nobody wants anybody hurt. Unfortunately however there is NO alternative, otherwise I would have used that instead. It is intended to be used to ascertain it's attraction capabilities to a specific species of butterfly. 5 years of research has resulted in the implication that this particular species of butterfly utilise Methanethiol (part of the Methionine degradation pathway) to find the methyl branched hydrocarbon precursors that are required to produce the male pheromone compound. I could quote the 100+ references that I have for my research, but nobody really wants to read these. Bottom line is that these butterflies utilise Methanethiol to locate a source of Methionine, which is one of the known insect precursors (along with Valine, Isoleucine and Propionate) for the biosynthesis of methyl branched hydrocarbon chains (the pheromone compound). Due to the butterflies highly specific antennal recognition, ONLY Methanethiol will do. We ideally wanted a quick, easy (as well as cheap) way to produce this gas to order, as and when it was required for use with some extremely sensitive EAD (electro-antennographic detection) analysis.

 

This is therefore the why and what-for. Can anybody therefore please help in the how? If you'd rather not simply post the answer on here, please could you drop me a PM, or alternatively send me an email. Your answers really would be very much appreciated. These butterflies are only around for 3 weeks every year, and considering that they all started to hatch a few days ago, the clock is now already ticking. If we are unable to perform these experiments in the next couple of weeks we'll have to wait another calendar year before we'll be able to perform these experiments again.

Edited July 11, 2013 by irisscientist

[John Cuthber]

Have you considered this sort of thing?

http://www.mathesongas.com/pdfs/products/Methyl-Mercaptan-Gas-Mixtures.pdf

I know it's expensive, but it makes life a lot easier if you can just open the tap and get the stuff.

 

Anyway, the real problem here is that when you say "an easy (pseudo-home) chemical reaction " it doesn't inspire confidence.

 

The reaction of dilute acid with the sodium salt will certainly produce plenty of the stuff (I'm assuming that a butterfly doesn't make much of it so even a small quantity would be plenty).

The galssware required is pretty trivial (at least compared to how good a fume extraction system you are going to want.

 

Finally, if you are going to play with thiols please let the emergency services know in advance so that they know how to react when they get lots of calls saying there's a gas leak.

(Been there- done that)

[StringJunky]

A probably useless thought but I'll throw it out anyway...at risk of ridicule: would using propane which has Mercaptan in be of any use or would it render the experiment useless?

Edited July 11, 2013 by StringJunky