Per - 21-12-2007 at 06:07
I had the chance to buy cheaply Caesium in an ampoule.
The problem is that I haven´t Argon to protect the metal by opening the ampoule from air, so my idea is to open it under Toluene where it could be
molten and poured out of the ampoule.
In Brauer is noted that Caesium reacts gradually under Kaerosene so I have my doubts that it can be stable under Toluene.
Does anybody knows if Cs is stable under sodium dried Toluene?
YT2095 - 21-12-2007 at 06:17
can`t you go to a Welding suppliers and buy a bottle of Ar gas?
garage chemist - 21-12-2007 at 06:33
Since potassium reacts with toluene, I would expect cesium to be absolutely noncompatible with it.
Get some paraffin oil or petrolether! Aromatics are too reactive for K, Rb and Cs.
JohnWW - 21-12-2007 at 13:37
What could K (or Cs) possibly form on reaction with C6H5CH3, assuming it is pure, or at least without non-oxidizing impurities? The aromatic ring is
too stable for it to pick up two electrons from K on adjacent carbons to form a non-aromatic dianion. By contrast, toluene much more easily forms a
cation, as in electrophilic substition reactions, with the positive charge able to be delocalized.
BTW 1,3,5,7-cyclooctatetraene, C8H8, which is not aromatic, reacts with K metal to form a salt in which it becomes a planar aromatic dianion, K2C8H8,
containing 10 pi electrons.
[Edited on 22-12-07 by JohnWW]
Per - 22-12-2007 at 10:59
Thanks for the informations.
Until now I´ve just common petroleum used for petroleum lanterns, for Na it´s enough, but reacted smooth to form a pale coating on the Na pieces.
But I don´t think that the normal petroleum is comparable with petrol ether.
It should be contained in "Fleckenwasser", maybe I will prove this with Na firstly.
Dr. Beaker - 22-12-2007 at 14:57
1. If you take tol right from the botle it will be wet and have O2 (tol quit "likes" water for a hydrocarbon).
If you got access to Na it is advisable to distile your tol from Na (i.e reflux it with molten Na for several hrs then distile)
2. heavy alkali metals have afinity to pi bonding with aromatic rings, thus any oxide\hydroxide that will form will disolve - thus revealing more
metal for oxidation.
3. toluene will form the anion radicals with alkali metals (dark brown colored).
better of use parafin oil.
[Edited on 23-12-2007 by Dr. Beaker]
JohnWW - 22-12-2007 at 23:55
I thought that it was transition metals with incomplete "d" shells, of much greater electronegativity than alkali metals, that had affinity for
pi-bonding to aromatic rings, especially as cations. Benzene and cyclopentadienide complexes of them are well-known. By comparison, alkali metals and
their cations are much less inclined to form complexes
Dr. Beaker - 23-12-2007 at 14:32
1. I didn't say that pi complexes of alkali metal with aryl are as common as, say, TMEDA complexes, but since the heavier metals are "softer" they
have a greater afinity to the soft eta 6 toluene ligand then, say, lithium.
2. see for an example:
Junk, P. C.; Cole, M. L. Chem. Com. 2007, 1579.
page 1587