HYDROLYSIS-POLYCONDENSATION IN BINARY PHOSPHORUS ALKOXIDES TEOS SYSTEM STUDIED BY GC-MS

It is well known that various phosphorus precursors exhibit different reactivities towards hydrolysis-polycondensation in acidic media. The hydrolysis-condensation in binary P-alkoxides-TEOS system was studied by GC-MS, in relation to the mentioned reactivity. As P-precursors, th e following reagents were used: PO(OMe)(3), PO(OEt)(3), PO(OBu)(3), P( OEt)(3) and HOP(OMe)(2). PO(OMe)(3), PO(OEt)(3) and PO(OBu)(3) do not hydrolyze, but change the TEOS hydrolysis-polycondensation ratio. P(OE t)(3) partially hydrolyzes and transforms into a very stable HOP(OEt)( 2) form, while HOP(OMe)(2) reacts very fast with nonparental solvent a nd undergoes transesterification. Si-O-P bonds have not been observed in early stages of hydrolysis-polycondensation. However, the gelling t endency is strongly influenced by the P-precursor.