Hydrolysis-condensation reactions of diethylphosphato-ethyltriethoxysilane involved in organic–inorganic talc-like hybrid synthesis: liquid and solid-state NMR investigations

Abstract

Hydrolysis and condensation reactions involved in the synthesis of organic–inorganic talc like hybrids (TLH) starting from diethylphosphatoethyltriethoxysilane (SiP), magnesium nitrate (Mg(NO₃)₂), ethanol and sodium hydroxide have been studied. The influence of magnesium nitrate, concentration of NaOH aqueous solution and pH value of the reaction media was investigated by high resolution ¹H, ²⁹Si and ³¹P liquid Nuclear Magnetic Resonance (NMR) and ²⁹Si and ³¹P solid state NMR. It was shown that Mg(NO₃)₂ has a catalytic effect on the hydrolysis-condensation reaction rates of SiP and that high concentrations of NaOH lead to a scission of siloxane bonds as well as a partial hydrolysis of ethoxy groups linked to phosphorous. The final TLH products have been characterized by solid state ²⁹Si NMR.