[magician4]

Hi y'all,

working on the oxidation of CH₃-O-C₂H₄-S-C₂H₄-OH to CH₃-O-C₂H₄-SO₂-C₂H₄-OH , I found different examples for -S-  -SO₂- in literature: mainly those using H₂O₂ in aqueous acetate buffer directly, and those using Na₂WO₄ as an additional catalyst.
Aside from this, there seemed to be only minor differences with respect to yield, temperature, concentration..

Though I'm aware that Na₂WO₄ is a catalyst in oxidation ( esp. for formation of olefins by catalytic dehydrogenation), I fail to see how it should have a special function in this transformation.

Anybody has experience in this, or has an idea whether I'd be better off with or without it, in my special case?


tnx for all your ideas

regards

Ingo

[Archer]

Hi Ingo,

I can't offer too much help here as I have little experience of the complete oxidation of sulphides to sulphones.

However during a synthesis of tetrahydro-2H-thiopyran 1-oxide, I used H₂O₂ and as I recall there was little or no dioxide present. This may be due to the fact that this was a cyclic compound and complete oxidation was not favoured but Perhaps the catalyst, Na₂WO₄, aids in the complete oxidation of the sulphur rather than partial oxidation.

Needless to say my lab book is woefully inadequate (it is very old now) with details for this experiment detailing just the scheme, yield and the reference I was working from.

http://pubs.acs.org/doi/abs/10.1021/jo01031a025

I am sorry I can't offer any more help than this, I avoid sulphur where I can these days.

Kind regards

Archer

[clarkstill]

m-CPBA is also a pretty good bet for this transformation, if the catalytic reaction you described is proving tricky...

[magician4]

@ Archer

most probably, the outcome in your case was the "low - temperature - without - catalyst" type


(picture taken from: link)


@ clarkstill , Archer

I take it that in my case the acetic acid ( from the acetate buffer) would provide CH₃CO-OOH, which should be approx. comparable to m-CPBA, esp. at ~ 80°C

what I mostly am worried about is the -O- function, and how it might be sensible to hydroperoxide-formation with H₂O₂/AcOH/Ac^-   , and how Na₂WO₄ might fit into the picture here

... and I didn't want to learn about this the hard way

that's why I wanted to avoid anything that might not be absolutely necessary in the setup

anyway, thanks to both of you for sharing your thoughts with me

regards

Ingo