Hi All,
I am using Diethyl Ether in a synthesis which has been failing. The ether is a few weeks past expiration and I was just wondering what that could mean chemically and whether that could be affecting the synthesis.
Thanks so much!
Eddie
For some synthesis Et2O is good enouph if it was pyrified several days ago by You personally because no "extra" marks on bottle do NOT garanteed really extra pyrity .... because Ether VERY easily can oxydise to form peroxides and very hydroscopic. If You want to purify commercial Ether You have at first check it to peroxide existing (Fe 2+-3+ probe). If peroxides exist wash the ether with alkaly to derstroy peroxides then with distilate water and pre-dry with MgSO4 and then after dacantation with P2O5. All vessels have to be extra goog CLOSED to prevent oxydation. Then after dacantation such ether You have to mix with a metal sodium (dispersed in a very small parts) and vigorously stirr with refluxing in system that protected from air moisture and O2. Add to this mixture 1-2 g of benzophenone (PhCOPh). When the intensive green then blue then dark-blue colour appear (ketyl formation) there is NO OH groups (water alcohol ets...) and NO peroxides in ether. Distill ether from this colour mixture and use it for any metalorganic synthesis immediately
In our laboratory refluxamos ether in the presence of sodium hydroxide for several days to eliminate peroxides, alcohols , distill and distill again using sodium wires drying
Peroxides are the most usual problem. Even for chemical anlalysis (e.g. persistent organics) I prefer to use ether freshly distilled over sodium wire. Set up a large apparatus in a convenient fumehood then a few minutes before you need the ether turn the heat on to start the still.
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