CHEMICAL PROCESSES INVOLVED IN THE SOL-GEL PREPARATION OF AN ALUMINUMOXOHYDROXIDE GEL FROM ALUMINUM NITRATE IN ORGANIC MEDIUM

Hydrolysis of aluminium nitrate in propan-1-ol leads to an aluminium o xohydroxide optically clear spinnable material as well as a slightly e lastic, monolithic gel. The propanol has several roles in the hydrolys is. It dissolves the Al nitrate, induces the decomposition of the nitr ate ions through nitric acid and promotes the hydrolysis and condensat ion of Al-III. Furthermore it reacts with nitric acid and/or its decom position products resulting in formation of various oxidised derivativ es of propan-1-ol. The products of the gel preparation, i.e. the organ ic compounds formed during heating of the aluminium nitrate-propan-1-o l mixture were investigated by gas chromatography as well as tandem MS techniques and UV-VIS spectroscopy. The coordination sphere of Al-III and the role of the organic compounds in building up the gel network has been studied by Al-27 MAS NMR and IR spectroscopy.