sanketh - 19-5-2006 at 22:06
guys im tryin to remove excess sodium borohydride from a sloution containin DMSO also.....and am plannin to remove it by reaction with nitric
acid.....so im wonderin if the DMSO will also react with the HNO3...plz help.....
Swany - 19-5-2006 at 22:32
" Stable. Incompatible with a very wide range of materials, including acid chlorides, strong acids, strong oxidizing agents, strong
reducing agents, phosphorus halides, moisture, copper wool + trichloroacetic acid. Reacts violently with a number of materials - consult a full data
sheet before use. Hygroscopic."
From http://ptcl.chem.ox.ac.uk/MSDS/ME/methyl_sulfoxide.html.
BromicAcid - 20-5-2006 at 06:33
The technical bulletin 105 has a table listing the decomposition of DMSO over time while being heated at 100C with phosphoric (85%), hydrochloric (12
M), and sulfruic acids (18 M). After 120 minutes with sulfuric only 2% of the DMSO had decomposed, after 120 min with the phosphoric 13% of the DMSO
had decomposed and after 120 min with the HCl 2% had decomposed. But the problem with the nitric lies in its oxidizing ability, strong oxidizing
agents give dimethyl sulfone (CH<sub>3</sub>SO<sub>2</sub>CH<sub>3</sub>
and with nitric there could be other potential side reactions. I don't think it would do much somewhat dilluted right
away but the conversion to the sulfone is rapid and lots of heat comes off it when NaOCl is added to DMSO so there could be a appreciably rapid
reaction with HNO<sub>3</sub>. Why not just use a different acid.
unionised - 20-5-2006 at 06:42
Why not use a less aggresive acid like water?
Is DMSO stable in the presence of borohydride anyway, or is it reduced to the sulphide?
BromicAcid - 20-5-2006 at 06:48
I've personally heard of borohydride reductions being done in DMSO although I don't know of the conditions. As for using water, it's pretty slow in
destroying borohydride.
unionised - 21-5-2006 at 03:53
Well, one thing's for certain. If the DMSO got reduced to the sulphide and/ or mercapatan, you would know about it. I know water's slow; it's also
cheap and non toxic.