Structural investigation of the hydrolysis-condensation process of modified titanium isopropoxide

Abstract

The structures of modified Ti(OPr(i))4 with chelating ligands (L) such as ethylacetoacetate (Etac), acetylacetone (Acac) and methylacetoacetate (Mtac) were identified by using IR, 1H NMR and 13C NMR spectroscopies, and the octahedral structure was confirmed after modification. The pre-edge peaks of XANES spectra of modified metal alkoxides also denoted the mixture of five-fold and six-fold structures. The EXAFS fitting results showed the local structure around Ti atom after alkoxide modification. The hydrolysis- condensation rates of modified Ti alkoxide with organic additives were investigated by 1H NMR spectroscopy. The Ti(OPr(i))4 modified by Acac was less reactive toward hydrolysis-condensation reaction than those modified by the other alkoxides, which can be attributed to the stable ligand structure between Ti(OPr(i))4 and Acac. The small particle size of modified Ti(OPr(i))4 sol was obtained when Acac was employed.