Aluminium thermochemical data

Interest in the metal borides is due mostly to the presence of boron in certain steels and its interaction with other alloying elements. An example of other industrial use of borides is the use of titanium borides for the grain refining of aluminium. Thermochemical data for metal borides are, however, virtually non-existent. The reason, again, is the difficulty of finding suitable experimental methods for enthalpy and Gibbs energy determinations. 

TABLE 2 Thermochemical Data of Selected Chemical Compounds Aluminium (Al), crystal-liquid, mol. vyt. = 26.98154... 

The mechanism of trimerisation of butadiene by a mixed cobalt(ii) chloride-aluminium triethyl catalyst has been inferred from the natures of the three products characterised. The determination of the enthalpy of dimerisation of aluminium triethyl provides a useful piece of thermochemical data for quantitative discussion of the role and energetics of aluminium triethyl in this type of reaction. Polymerisation of isoprene in the presence of Fe(acac)3-aluminium triethyl-pyridine derivatives mixtures has a negative apparent activation enthalpy, which can be attributed to the instability of the catalytic complex at elevated temperatures. Bis-cyclo-octatetraeneiron(o) is an effective oligomerisation catalyst. The composition of products accessible only by hydrogen migration indicates an oxidative addition-reductive elimination mechanism rather than insertion. 

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