ISSN:
1573-4846
Keywords:
SiO2-P2O5 sol-gel system
;
P-precursor reactivity
;
GC-MS investigations
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract 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, the 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(OEt)3 partially hydrolyzes and transforms into a very stable HOP(OEt)2 form, while HOP(OMe)2 reacts very fast with nonparental solvent and undergoes transesterification. Si–O–P bonds have not been observed in early stages of hydrolysis-polycondensation. However, the gelling tendency is strongly influenced by the P-precursor.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1026438820378
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