Surface modification of phosphosilicate gels: Control of composition, porosity, acidity, and hydrophobicity

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Authors	STÝSKALÍK Aleš BARNES Craig Elliot PINKAS Jiří
Year of publication	2012
Type	Conference abstract
MU Faculty or unit	Central European Institute of Technology
Citation
Description	We developed a non-hydrolytic sol-gel synthesis of phosphosilicate gels and hybrid organic-inorganic materials from silicon acetates and trimethylsilyl phosphates and. The inorganic microporous SiOP frameworks with residual surface organic groups was built in a polycondensation reactions within the elimination of acetic acid ester. Herein we report chemical modification reactions of residual acetoxy and trimethylsilyloxy groups by variety of compounds (SiCl4, POCl3, RSiCl3, AlX3, ROH, Me3SiOSiMe3). Our aim was to show the versatility of the primarily synthesized phosphosilicate xerogels in tuning their properties. As an example, the phosphosilicate gels can be modified by alcohols to form Brônsted acidic POH groups on one hand and by aluminum compounds to form Lewis acidic four-coordinated Al atoms on the other hand. The obtained materials and by-products were characterized by liquid and solid-state NMR, IR, BET and elemental analyses.
Related projects:	Oxidy a fosforečnany kovů jako formy jaderného odpadu: studium sonochemického srážení, tepelných přeměn a rozpustnosti Nehydrolytické sol-gelové reakce pro přípravu křemičitanů a fosforečnanů s řízenou porozitou a funkčními skupinami na povrchu CEITEC - Central European Institute of Technology