math - 5-10-2008 at 04:44
hello,
I'd like to know if lipids (triglycerides in particular, vegetable oils) react in any way if mixed with elementar sulphur, as flowers of sulphur.
thank you
not_important - 5-10-2008 at 05:22
Under what conditions? Heating most hydrocarbons with sulphur results in the dehydrogenation of the hydrocarbon and production of H2S.
At lower temperatures sulfur will react with carbon-carbon double bonds, and crosslink molecules. This happens with rubber vulcanisation.
At STP, not much happens very quickly.
Klute - 5-10-2008 at 05:58
have a look at this patent:
WO/2003/041514
were the y treat triglycerides ith sulfur compounds (sodium sulfide,e lemental sulfur, etc). Not really sure what they obtain, but somethign is
definitvely going on. I would think some kinds of thiols, thioacids etc are formed, but how they hell could they call these "flavor-enhancing"? 
This patent is actually quite frightening: they are basicly saying take your triglycerides, throw in any sulfur or nitrogen containing waste your
factory is generating, cook the hell out of it, and sell as dog food....
[Edited on 5-10-2008 by Klute]
math - 5-10-2008 at 06:31
I was thinking about STP conditions...however also cooking temperatures would be interesting to know
I couldn't find any solubility data for sulfur in fats, so I supposed it reacts with them.
@klute: yeah that's frightening!
found that, but I couldn't find what's produced in detail ?
patent sulfurization of lard oil http://www.google.com/patents?id=G6hRAAAAEBAJ
[Edited on 5-10-2008 by math]
12AX7 - 5-10-2008 at 06:51
Sulfurized oils are excellent high-pressure (machining) lubricants. Awful stinky lubricants...
Tim
not_important - 5-10-2008 at 08:15
As with vulcanization, sulfur adds to the double bonds in the fatty acid chains, and cross links them. When the unsaturated acids primarily are
mon-unsaturated, you mostly only link 2 fatty acid chains together, with some having more linked chains from poly unsaturates, so the oil does not
turn into tar-like goop but remains fairly fluid. You get a bit of the sulfur equivalent of an epoxide, some pairs (or more) of fatty acids linked by
disulfid linked R-S-S-R, and some polysulfide links where there is one or more additional sulfur atoms in the of the sulfide link R-S-[S]n-S-R. The
longer sulfide chains can be thought of as 'dissolved sulfur', and also to a minor degree will do some simple solution of elemental sulfur.
The polysulfides in particular can lose sulfur to metals, forming surface laters of the sulfides of the metals. The metallic sulfides generally have
lower coefficients of friction than the bare metal surfaces. Also the sulfur bridges are fairly easily oxidised, they scavenge free oxygen dissolved
in or mixed into the oil.
kazaa81 - 10-10-2008 at 11:58
I don't think leaving elemental sulfur into vegetable oils at room temp. will yield anything else than...maybe an etherogeneous mixture?