The reaction of iodine with lithium tri-tert-butoxyaluminohydride. A reaction with variable stoichiometry unsuitable for analytical standardization

Solutions of lithium tri-tert-butoxyaluminohydride (LTBA) have been standardized by reduction of cyclohexanone, followed by gas–liquid chromatography (glc) and/or spectral analysis of the extent of reaction. These results are compared with the standard titrimetric analysis of LTBA by iodine, to determine whether the standardizing equation is[Formula: see text]Or[Formula: see text]It is clear that in fact both of these reactions occur, with [5] predominating at low hydride to iodine ratios, and [3] becoming increasingly significant when the hydride and iodine concentrations become comparable. The usual titrimetric method of standardizing LTBA is therefore essentially unusable.