Metallosilicates prepared by non-hydrolytic condensation reactions
| Autoři | |
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| Rok publikování | 2013 |
| Druh | Konferenční abstrakty |
| Fakulta / Pracoviště MU | |
| Citace | |
| Popis | Non-hydrolytic sol-gel reactions are efficient alternatives to classical aqueous techniques for synthesis of multimetallic oxides and inorganic-organic hybrid materials. We developed non-hydrolytic sol-gel routes to several groups of metallosilicate hybrid inorganic-organic materials based on polycondensation reactions. Titanosilicate xerogels were prepared by reactions between Ti(NEt2)4 or Ti(OR)4, R = OiPr, OtBu and Si(OAc)4. These non-hydrolytic polycondensation reactions led to the formation of Si-O-Ti bonds and to release of acetic acid ester and diethylacetamide as byproducts, respectively. Then the catalytic activity of xerogels in epoxidation of cyclohexene was studied. Alumosilicates were prepared by reactions between Al(NMe2)3 or Al(OiPr)3 and acetoxysilanes R4-nSi(OAc)n, n = 1-4 and R = Me, Ph, H, OtBu. In this case these non-hydrolytic condensation reactions proceeded with the formation of Si-O-Al networks and dimethylacetamide or acetic acid ester and as byproducts as well. As a further step, bridged bis(triacetoxysilyl)alkanes (AcO)3Si(CH2)xSi(OAc)3 , x = 1, 2, 3, 6 were used for the synthesis. Using alkylacetoxysilanes as silicon precursors we can modify some physico-chemical properties (hydrophobicity, porosity) of the resulting xerogels. We have examined also the surface modification of xerogels at the residual organic groups and established their acidic properties. The resulting xerogels and volatile byproducts were characterized by liquid and solid-state NMR, IR, GC-MS, surface area analysis, TGA, and XRD. |
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