Date: 2001 - 2002
I am looking for one or few solvents which dissolve
AlCl3 without reacting with it, in order to produce solvated Al3+ ions for an
Because Al3+ reacts readily with water, I do not know of any common solvent
that will dissolve AlCl3. In the commercial process, I believe that the Al
salt is molten. I am sure you can find out on the Web just how it is done.
I know of solvents that will dissolve AlCl3, but I don't know that the
solute will dissociate into its ions. Basically, AlCl3 is a Lewis acid, so
ethers, which are weakly Lewis basic, can dissolve it. Anhydrous ethyl
ether or tetrahydrofuran would be good choices. Nitromethane also works.
If you want Al3+ ions in aqueous solution, your best bet is to use sulfate
or, better yet, nitrate as the counterion. Those aluminum salts are
actually soluble in water. Potassium alum, which is a sulfate salt of
aluminum and potassium, is also water-soluble. Of course, if you want to do
any redox chemistry on the Al3+ ion, you'll be in trouble, because water is
more easily reduced than Al3+.
Another possibility is to use an "ionic liquid" solvent. There has been
some work on systems of aluminum chloride in quaternary ammonium chlorides.
Unfortunately for your objective, the aluminum chloride does not dissociate
in these environments, but instead forms complex ions such as AlCl4- and
Al2Cl7-. If you are interested in these systems, you can start by looking
for papers by Robert Osteryoung, Research Professor of Chemistry at North
Carolina State University (http://www2.ncsu.edu/ncsu/chemistry/rao.html).
Richard E. Barrans Jr., Ph.D.
PG Research Foundation, Darien, Illinois
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