Structure and physical properties of aluminium alkoxides. Part II: Changes in physical properties of liquid aluminium isopropoxide during storage

Abstract

The density, refractive index, dielectric constant and viscosity of liquid aluminium isopropoxide have been studied.From observations for the liquid at 25", immediately after heating at 130" and cooling rapidly, an Onsager dipole moment of 1.7-2.5 D is calculated.During storage the physical properties change slowly. This confirms the occurrence of a molecular rearrangement reaction, which was inferred previously from molecular weight and NMR data. A further indication was obtained by the discovery of a second solid form of aluminium isopropoxide, which melts at 29.5", whereas we have found also a form with melting point of about 137", considerably higher than that for normal aluminium isopropoxide, 118".The rates of changes in density and viscosity have been measured at different temperatures, from which the activation energy for the rearrangement reaction is estimated to be about 12 kcal/mole.

Aluminum tri-isopropoxide as an alternative precursor for atomic layer deposition of aluminum oxide thin films

“…These include precursor polymerization upon heating and cooling, changes in the precursor reactivity, and precursor decomposition. 29,[32][33][34][35][36] Through the course of our experiments in vacuum and atmospheric pressure ALD systems, on flat substrates, and on nanoparticles, we did not encounter any issues with changes in the precursor reactivity. In the vacuum ALD system, no precursor decomposition was observed in the bubbler.…”