# How hazardous are peroxide-able ethers if stored properly?

This question is directed towards laboratory scientists and technicians who actually deal with ethers that can develop peroxides upon concentration (e.g. diethyl ether, THF, dioxane). I am already very familiar with the literature, the normal precautions (dispose of after 1 year, test for peroxides, etc.), how to remove peroxides (shake with ferrous salt or metabisulfate).

My question is how hazardous are peroxides in reality if stored properly. If a peroxide-able ether upon concentration is stored in a cool dark cabinet, is rarely opened, has an inhibitor (BHT or ethanol), and argon is used above the headspace, it is likely that the ether can be used for longer than a year?

Again, I need the input of an actual practitioner. Simply quoting written material will not help me, as I have consulted LOTS of written material and I believe I understand the theoretical issues. I am looking for practical experience. I have heard informally that some ethers are available in European countries as OTC solvents, and so it leads me to think that the standard warnings may be too severe. Thanks!

• I believe, that when I was still a student in university, we kept and used DEE and THF for more than a year, especially when dried and kept in inert atmosphere. I think most safety concerns apply to quantity. There are probably other reasons why you should not use solvents after a year or so... – Martin - マーチン Aug 18 '14 at 17:48
• One of may previous labs used some diethyl ester and THF, and no accidents occurred. As long, as they are properly stored (no direct sunlight, tightly sealed bottle, a tiny bit of $\ce{KOH}$ on the bottom of the bottle) they are reasonably safe. Of course, I would be a bit ... concerned in case of work with diisopropyl ester, but not so much. – permeakra Aug 19 '14 at 0:18
• @permeakra: Thanks! Can you answer these two questions I have: 1) do I need to pre-dry (I would assume yes with something not so water reactive), and 2) how much to use (I would assume you don't need much)? You seem to agree with my answer to 2). And I have no diisopropyl ether and agree that it is a higher order of storage danger! – user467 Aug 19 '14 at 0:26
• 1) DEE and THF dissolve quite a bit of water, so boiling and then distillation of marketed solvent over excess of sodium or potassium hydroxide is common. In case of extra large quantities, another pre-drying stage may be economically justified, but in common labs it is usually dried with alkali hydroxide directly. The amount of hydroxide required for drying is very dependent on quality of the raw solvent, so no suggestion here. I would use roughly 1-2 table spoons per liter unless it is extremely wet. – permeakra Aug 19 '14 at 0:35
• 2) As far as I remember, it was a small amount. Again, 1 table spoon per liter should do. – permeakra Aug 19 '14 at 0:36