Dosage iodométrique de solutions d'hydrure d'aluminum et de lithium Hugh FelkinBull. Soc. Chim. France 347-348 (1951)
(
https://www.thevespiary.org/rhodium/Rhodium/pdf/lah.analysis.pdf)
Describes the iodometric titration of lithium aluminum hydride to provide solutions of the same with an experimentally determined concentration (moles LAH per liter).
This is very useful, as you can then reflux LAH (even old, half-decomposed material) in THF or ether overnight to effect complete dissolution (complete dissolution is slow in the absence of any reducible substance), then you quickly decant (or filter the solution through a fritted glass funnel) into a dry storage bottle, and then titrate an aliquot as per the above article.
With this stock solution in hand you have several advantages:
1) You do not need to weigh LAH several times (spreading dust all over the place) if you are running a series of experiments.
2) You know exactly how much LAH you add (the powder can be anything between 95% pr below, depending on storage).
3) The solution is more reactive than the powder as all of the LAH is already in solution.
4) You are able to perform "reverse addition reductions", where the LAH is added to the substrate. This opens up several novel possibilities, such as the one described in
Post 443723
(GC_MS: "Reverse Addition of LAH to Nitroölefins - A", Novel Discourse)
