It turns out that chronic exposure to n-hexane is much worse that exposure to other small alphatic hydrocarbons. Hexane is converted by the body to
2,5-hexanedione, which condenses with amines in the body to Pyrroles of various kinds.Tacho - 16-1-2004 at 10:24
I use hexane often. Not n-hexane though.
Is a very unpolar solvent, therefore very usefull.
Where did you get this information?chemoleo - 16-1-2004 at 10:49
makes me wonder about the toxicity of pentandione (see my favourite thread ) -
but it doesnt have a toxic label on it, only mild irritant...guaguanco - 16-1-2004 at 11:14
A toxicology textbook, although there is info on the web:
Originally posted by chemoleo
makes me wonder about the toxicity of pentandione (see my favourite thread ) -
but it doesnt have a toxic label on it, only mild irritant...
pentanedione can't form the crosslinked pyrroles that hexanedione does, so it doesn't have that particular toxicity. It is quite reactive
and readily forms heterocyclic rings with difunctional chemicals (like guanidine, hydraxine, hydroxlamine), so it wouldn't surprise me if it had
it's own set of problems.If_6_was_9 - 24-1-2004 at 12:37
I found an art store that sells Bestine Heptane formula. I asked about hexane containing Bestine, but no one in the store knew anything about it.
Coleman Fuel n-hexane hexane white gas
Hermes_Trismegistus - 9-5-2004 at 19:22
Here's a link I wanted here, I had searched the forum because I couldn't remember what white gas contains.
I guess this is Colemans official acknowledgement of its involvement in the crank business PHILOU Zrealone - 7-6-2004 at 16:36
n-pentane also is bad.
In organic labs they now prefer to use cycloheaxne wich has equivalent solvant properties but with a much lower toxicity. unionised - 8-6-2004 at 00:58
It's a bit tricky to measure human toxicity but if you take OSHA's or ACGIH's guidance then pentane is about 10 to 20 times less toxic
than hexane. With a permitted exposure level of 750 ppm in air it is comparable with acetone (750 ppm); ethyl acetate (400ppm); or ethanol (1000 ppm).
In reality pentane is one of the least toxic solvents.
Cyclohexane is a bit more toxic than pentane and is used for a number of reasons, not least is that it is easy to get in a high purity.PHILOU Zrealone - 8-6-2004 at 09:39
Yes less toxic but much more volatile...hence the trouble.
I don't think it is much more difficult to purifiate n-pentan than cyclohexan but definately there was a purity issue since n-hexane contained a
lot of phtalates...and cyclohexane while displaying similar properties was a lot cheaper for higher purity...the process to make it are more selective
and less energy cost/steps --> go for cyclohexan unionised - 10-6-2004 at 14:28
Purification of cyclohexane is easy enough, just freeze it- most of the impurities will be left behind in the lastof the liquid.
The real advantage of cyclohexane over hexane in terms of purification is that you can start from relatively pure benzene and hydrogenate it. Getting
pure hexane means distilling it from crude oil and it is difficult to fractionate it from the isomers that have similar boiling points.PHILOU Zrealone - 22-6-2004 at 09:38
Bof, you stil have to distillate your benzen first....
CH3-CH=O + CH3-CH=O + CH3-CH=O -base or acid-> CH3-CH=CH-CH=CH-CH=O
+ others
CH3-CH=CH-CH=CH-CH=O + H2 -cat-> n-hexanol -H2SO4-> 1 hexene -H2-> hexane...
yes by cyclising the aldehyde you get also benzen.
What is Coleman's Fuel composed of?
prole - 23-3-2006 at 10:09
I am distilling some Coleman's to have on hand, and see that it's got several different fractions in it (bp 26C-100C). Does anyone know what these
fractions are? I've searched MSDS, TFSE, and google, and only find 'petroleum distillates'. Hermes Trismegistus' link is dead (I couln't give two
shits about crank).
When I found this thread in a search, I didn't notice it was in the biochemistry forum. Admins - move my post to Reagents 'n Apparatus Acquistion if
necessary.
-prole
[Edited on 3/23/2006 by prole]
[Edited on 3/23/2006 by prole]Magpie - 23-3-2006 at 11:25
Coleman has an MSDS for lantern fuel on their web site.
Here's a quote from an earlier post of mine in the OTC phosphoric acid thread:
"I just finished the extraction with Coleman lantern fuel. BTW as a correction this solvent is not strictly hexane but is a mixture of C5-C9
hydrocarbons according to the Coleman MSDS. I think this is more properly called "petroleum naptha."
) -
but it doesnt have a toxic label on it, only mild irritant...