Author Topic: Short Term Ether Safety Issues  (Read 4027 times)

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grellobanans

  • Guest
Short Term Ether Safety Issues
« on: January 04, 2004, 01:31:00 AM »
Swim has never worked with ether before and has heard/read about all the dangers, peroxide formation, fire, etc. It seems pretty damn scary! A static charge could set it off!

But anyway, if one were to distill a small amount from starting fluid (making all fire safety precautions), say 250ml, and use it all immediately within the next 2 days, is there any risk of peroxide formation? So basically, are any stabilizers required? It seems as if most dangers come from ether that has been stored for quite some time. How long does it take for ether to form peroxides in contact with air?

Rhodium

  • Guest
peroxide
« Reply #1 on: January 04, 2004, 03:41:00 AM »
You won't have any significant amounts of peroxide formed over a couple of days in a closed bottle. But watch out - there might  already be peroxides in the starter fluid - do not distill to dryness, always distill ether on a water-bath!


chilly_willy

  • Guest
ether..
« Reply #2 on: January 04, 2004, 03:53:00 AM »
Ether is not as evil as most make it out to be.  At one time ether was used much like DCM for its solvent properties..(actually still is) but the people using it were also aware of the "what COULD happen" dangers.  It was used safely because these people were fully aware of these dangers and treated it with due respect.  Yes, it is highly flammable and it does form peroxides (dependant on exposure to air, impurities, and time. If using a screw cap on bottle..wash it and threads wet rag before closure!)  Its potential flammability is reduced to nil with careful forethought and use (its heavier than air..and yes your fridge compressor sparks every time it kicks on. Maybe even your hotplate too..use a fan!!!  Wrap every joint on your glass with teflon tape..then electrical tape..vent outside!!).  The peroxides are reduced with addition of some copper turnings or a piece of sodium wire (many other ways..use TFSE). BTW- dangerous LEVELS of peroxides will most likely not form after 2 days.  Treat it with care..and you should have no problems.  As it should be with any other chemical.  MSDS are not meant to "scare" the user..it simply informs them of the full potential of a particular chemical.


biffman

  • Guest
Don't be too paranoid
« Reply #3 on: January 04, 2004, 04:01:00 AM »
If you are sure you must use diethyl ether and your only source is from starting fluid from aerosol cans then I can suggest a few things;
   Don't worry too much about the peroxide scare stories that you hear.  That is usually only for old diethyl ether that has been stored under bad conditions for a long time.  If you are just trying to obtain fresh ether through instant car-start aerosol cans, don't worry about it.  Worry more about trying to collect enough of it because you will lose so much of it just by the fact that it is so soluble in water and evaporates almost immediately.
   Be very aware that ether fumes are heavier than air and will be ignited by any sort of pilot light or spark.
 
  If you manage to actually collect enough ether and are still worried about peroxides, all you have to do is shake it up with some ferrous sulphate which should remove any peroxides.

chilly_willy

  • Guest
distillation..
« Reply #4 on: January 04, 2004, 05:47:00 AM »
Use a vigreux column and a long, efficient- 400mm allihn or inner-coil condenser w/fully ice chilled receiver flask and your yields wont be so bad when distilling.  You will get some carry-over though so vent properly!!


mr_pyrex

  • Guest
Biff, I don't mean to be disrespectful or...
« Reply #5 on: January 05, 2004, 10:56:00 AM »
Biff, I don't mean to be disrespectful or anything but I would consider the statement 'it is so soluble in water' to be incorrect.  Unless this information from the Merck could be construde as 'so soluble'.....Ether is slightly sol in water and water is slightly sol in ether.  A satd water soln contains 8.43% (w/w) of ether @ 15'C and 6.05% (w/w) at 25'C.  Ether satd with water contains 1.2% H20 at 20'C.  Soly in water can be increased by HCL.  Azeotrope with water (1.3%).  Like I said no disrespect intended, but it isn't like it is misicble with water.  And as for removing most of the moisture it may contain after processing it, this can be accomplished by use of Calcium Chloride as stated in the text Purification of Laboratory Chemicals.  As for those who think it isn't as dangerous as 'some make it out to be'  ...completely dried ether shaken in a glass bottle can create enough staic electricity to ignite itself.  Just a thought.  That sounds a little more dangerous then say toluene ;-)  Pyrex out of textbooks


biffman

  • Guest
You're right of course Mr. Pyrex
« Reply #6 on: January 05, 2004, 09:30:00 PM »
I obvious had a little brain fart there when I hastily typed 'so soluble'.  I actually meant that ether holds a more water than other immiscible polar solvents that are used in extractions (eg DCM) and you tend to lose more of the ether over the course of extractions than other solvents, mostly due to high evaporation and slightly greater solubility in water than DCM. (or something like that).
  Thanks for pointing that out since I hate to have slip ups like that.

ClearLight

  • Guest
starting fluid ether
« Reply #7 on: January 08, 2004, 11:34:00 PM »
can't distill heptane and ether, it forms an azeotrope.  I have an excellent fractional column i used and no joy.  BP was wrong and the mix came over smelling like the starting product sans the lubricating oil... so heptane and ether is a no/go for ether..

  If you don't mind the heptane, np then..


livid

  • Guest
re: starting fluid
« Reply #8 on: January 09, 2004, 08:40:00 AM »
just because you can't get the heptane out, doesn't mean it can't bee done. that is misinformation. I bet Rhodium could do it.

grellobanans

  • Guest
azeotropes
« Reply #9 on: January 09, 2004, 08:04:00 PM »
azeotropes can't be separated with fractional distillation. what about extractive distillation?

grellobanans

  • Guest
can storage
« Reply #10 on: January 10, 2004, 06:46:00 AM »
Another question: is it safe to store starting fluid in the cans (not distill) for many months? The metal cans themselves should help prevent peroxide formation right? The cans you buy in the store have probably been sitting there for a while anyway. Swim is wondering this because it would seem quite suspicious to buy starting fluid in the summer, so it would be better to stock up in the winter time. Why would anyone buy starting fluid in the summer anyway? Oh yeah, lawnmowers...hmmm

pyroflatus

  • Guest
buying starting fluid in summer
« Reply #11 on: January 10, 2004, 08:38:00 AM »
>Why would anyone buy starting fluid in the summer anyway?

One would buy it in summer if one had a crank-start vintage automobile (pre 1950s) since it's often the only way to get these cantankerous beasts to start.