guaguanco
Hazard to Others
Posts: 216
Registered: 26-11-2003
Member Is Offline
Mood: heterocyclic
|
|
Unusually toxic hydrocarbon...
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
National Hazard
Posts: 582
Registered: 5-12-2003
Member Is Offline
Mood: No Mood
|
|
I use hexane often. Not n-hexane though.
Is a very unpolar solvent, therefore very usefull.
Where did you get this information?
|
|
|
chemoleo
Biochemicus Energeticus
Posts: 3005
Registered: 23-7-2003
Location: England Germany
Member Is Offline
Mood: crystalline
|
|
makes me wonder about the toxicity of pentandione (see my favourite thread  ) -
but it doesnt have a toxic label on it, only mild irritant...
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
|
|
|
guaguanco
Hazard to Others
Posts: 216
Registered: 26-11-2003
Member Is Offline
Mood: heterocyclic
|
|
A toxicology textbook, although there is info on the web:
http://www.cdc.gov/niosh/pel88/110-54.html
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&a...
|
|
|
guaguanco
Hazard to Others
Posts: 216
Registered: 26-11-2003
Member Is Offline
Mood: heterocyclic
|
|
| Quote: | 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
Unregistered
Posts: N/A
Registered: N/A
Member Is Offline
|
|
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.
|
|
|
Hermes_Trismegistus
National Hazard
Posts: 602
Registered: 27-11-2003
Location: Greece, Ancient
Member Is Offline
Mood: conformation:ga
|
|
Coleman Fuel n-hexane hexane white gas
Here's a link I wanted here, I had searched the forum because I couldn't remember what white gas contains.
http://www.oehha.ca.gov/public_info/pdf/Coleman%20Fuel%20Fac...
I guess this is Colemans official acknowledgement of its involvement in the crank business
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
|
|
|
PHILOU Zrealone
International Hazard
Posts: 2893
Registered: 20-5-2002
Location: Brussel
Member Is Offline
Mood: Bis-diazo-dinitro-hydroquinonic
|
|
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.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
|
|
|
unionised
International Hazard
Posts: 5128
Registered: 1-11-2003
Location: UK
Member Is Offline
Mood: No Mood
|
|
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
International Hazard
Posts: 2893
Registered: 20-5-2002
Location: Brussel
Member Is Offline
Mood: Bis-diazo-dinitro-hydroquinonic
|
|
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
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
|
|
|
unionised
International Hazard
Posts: 5128
Registered: 1-11-2003
Location: UK
Member Is Offline
Mood: No Mood
|
|
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
International Hazard
Posts: 2893
Registered: 20-5-2002
Location: Brussel
Member Is Offline
Mood: Bis-diazo-dinitro-hydroquinonic
|
|
Bof, you stil have to distillate your benzen first....
CH2=CH2 + HCl --> CH3-CH2Cl
CH2=CH2 + Cl2 --> Cl-CH2-CH2-Cl
2CH3-CH2-Cl + Cl-CH2-CH2-Cl -cat-> butane, hexane, (CH3-CH2-)2(-CH2-CH2-)x + CH3-CH2-(CH2-CH2)n-Cl
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.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
|
|
|
prole
Hazard to Self
Posts: 94
Registered: 4-8-2005
Member Is Offline
Mood: No Mood
|
|
What is Coleman's Fuel composed of?
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
lab constructor
Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline
Mood: Chemistry: the subtle science.
|
|
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."
The single most important condition for a successful synthesis is good mixing - Nicodem
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
