After synthesizing NaAlO2 (or NaAl(OH)4) and having some fun with it, I have thought about the possibility to make NH4AlO2 (or NH4Al(OH)4). Of course,
NH3 is not as basic than NaOH, so, despite the amphoteric properties of aluminium, it might be a problem.
I have therefore thought about a way to create it without the Al2O3+H2O+base style, maybe with a displacement or under certain conditions or
catalysts.
Some sort of equilibrium like this one:
2NH4AlO2 <==> Al2O3 + H2O + 2NH3
...could be balanced to the left with an appropriate catalyst or pressure. So what do you think?
[Edited on 11-5-2013 by Eddygp]Adas - 12-5-2013 at 00:59
I doubt that would work. Why do you want this compound?Eddygp - 12-5-2013 at 07:37
Curiosity, basically. I know that it is purely theoretical and would need very strange conditions in order to react...12AX7 - 12-5-2013 at 10:56
Soak aluminum in ammonia and see what happens...
They say aluminum can be corroded by ammonia and sodium carbonate, which are both mild bases. Of course, this could be as much an electrolytic
reaction as acid-base.
Geez, I can't seem to find a table of pKa's right now. Whatever the aluminate pKa's are is pertinent here.
TimScienceSquirrel - 13-5-2013 at 03:23
Someone might be kind enough to get you this paper;
Looks like it's what I was looking for. Thank you!!!
[SPOILER] I don't think anyone will get it for me, though. [/SPOILER]
[Edited on 13-5-2013 by Eddygp]DraconicAcid - 13-5-2013 at 12:50
Using K values from Petrucci's General Chemistry, the overall K for
NH3 + Al(OH)3(s) + H2O = NH4Al(OH)4(aq)
would be 1.1e33 x 1.3e-33 x 1.8e-5 = 2.57e-5.
You could probably succeed in making tetramethylammonium aluminate, though. Eddygp - 15-5-2013 at 07:55
Is there any easy procedure to do so?DraconicAcid - 15-5-2013 at 08:16
If you can get tetramethylammonium hydroxide, then yes- just add it to an aqueous suspension of aluminum hydroxide. I don't know if it can be
isolated in the solid state, though. The tetramethylammonium ion will not deprotonate like the the ammonium ion will, and it may be that its size
(much bigger than sodium or potassium ions) fits better with the aluminate anion.ScienceSquirrel - 15-5-2013 at 08:27
Tetramethylammonium aluminate will exist.
Tetramethylammonium hydroxide is a very strong base and it will react readily to form the aluminate.
