Adas
National Hazard
Posts: 711
Registered: 21-9-2011
Location: Slovakia
Member Is Offline
Mood: Sensitive to shock and friction
|
|
Sulfur and oil reaction
Hello, it's me again. 
A while ago, I performed an experiment in which I heated sulfur under sunflower oil. The sulfur melted and colored the oil red-black. Then I cooled it
down and poured the oil (very viscous liquid) out, the solid sulfur remained at the bottom of the test tube.
I think that the sulfur made disulfide bonds on double bonds in the oil (like vulcanizing rubber), am I correct?
P.S.: You can imagine the TERRIBLE smell.  I may do some more experiments with
it.
Rest In Pieces!
|
|
|
AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
Posts: 1986
Registered: 2-3-2011
Member Is Offline
Mood: No Mood
|
|
It is also possible that traces of thiols may have been formed.
|
|
|
platedish29
Hazard to Self
Posts: 76
Registered: 2-9-2012
Member Is Offline
Mood: absorbing CO2
|
|
TRy adding caustic soda to it, you should reverse the process and get the oil clear again.
|
|
|
Adas
National Hazard
Posts: 711
Registered: 21-9-2011
Location: Slovakia
Member Is Offline
Mood: Sensitive to shock and friction
|
|
I don't think so, or they were thiols with high molecular weight, so they might have smelled different.
Rest In Pieces!
|
|
|
blogfast25
International Hazard
Posts: 10562
Registered: 3-2-2008
Location: Neverland
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by Adas  |
I think that the sulfur made disulfide bonds on double bonds in the oil (like vulcanizing rubber), am I correct?
P.S.: You can imagine the TERRIBLE smell. I may do some more experiments with
it. |
It's possible. Normal vulcanisation reactions do require also accelerators, otherwise the formation of -S- and -S-S- bonds is very slow.
|
|
|
Eddygp
National Hazard
Posts: 858
Registered: 31-3-2012
Location: University of York, UK
Member Is Offline
Mood: Organometallic
|
|
Probably a dealkylation, making dimethyl sulfide or diethyl sulfide gases.
there may be bugs in gfind
[ˌɛdidʒiˈpiː] IPA pronunciation for my Username |
|
|
Adas
National Hazard
Posts: 711
Registered: 21-9-2011
Location: Slovakia
Member Is Offline
Mood: Sensitive to shock and friction
|
|
I would have noticed that! I know roughly how DMS and DES smell, and they would have caused VERY intense smell. The smell I observed was not so
intense, probably a small amount of H2S, and maybe some SO2 and something else.
I tried heating that red oil with NaOH, but it didn't seem to get its original color back.
[Edited on 11-3-2013 by Adas]
Rest In Pieces!
|
|
|
AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
Posts: 1986
Registered: 2-3-2011
Member Is Offline
Mood: No Mood
|
|
I suspect there are -S-S-S-S-S- sulfur chains in the oil. I am not sure where the red color is coming from, but it molten sulfur also has a dark red
color, and there might be a connection.
I doubt that. The hydrogens would come off first before that.
There are hydrocarbon cracking reactions, but those usually only happen at much higher temperatures, which I doubt is the case here.
But even for the hydrogens in alkane groups to be oxidized, that still typically requires combustion temperatures. Unless perhaps the heat is enough
to break the weak sulfur-sulfur bonds, which could then act like radicals to attack the alkane. This is the case with chlorine in the presence of
light, for example.
I think most likely the unsaturated double bonds in the oil are being oxidized by the sulfur, like Adas originally guessed.
[Edited on 12-3-2013 by AndersHoveland]
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
Reducing sulfur by heating it with hydrocarbons (like paraffin oil, for example) gives hydrogen sulfide at high enough temperature. Check the
literature. This is one of the laboratory methods at producing hydrogen sulfide.
Triglicerides are likely to behave similarly.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
|
|
|
Nicodem
|
Thread Moved
11-3-2013 at 23:57 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
