Aluminium trialkoxides

This process (shown in Figure 4.17) develops alkyl chains of the required molecular weight by adding ethylene onto triethylaluminium. The resulting growth product is oxidised to aluminium trialkoxide in the presence of air which is then hydrolysed to liberate the alcohol. 

The fragmentation pattern for tantalum penta-alkoxides Ta(OR)5 (R = Me, Ft, Pr, CH2CH20Me), in their mass spectra is similar to that for alkoxides of zirconium and hafnium, niobium, molybdenum, and tungsten. For example, at first the loss of OR groups occurs, followed by elimination of the molecules of unsaturated hydrocarbons (usually, with the same number of carbon atoms as R). However, the decomposition of Ta(OMe)s differs from that of other homologues by the loss of HCHO molecules and H atoms. Elimination of ethers, R2O, which is accompanied by the formation of the metal oxoalkoxide ions of the above mentioned alkoxides is typical. In the absence of X-ray crystallographic data, considerable effort had been directed earlier to throw light on the molecular complexities of aluminium trialkoxides in different (solid, liquid, or vapour) states. 

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