Influence of monolayer of titanium and zirconium coupling agents on dispersive and acid–base properties of modified silica gel

The silica gel (Fluka, silica gel 60, 0.2–0.5 mm (35–70 mesh)) was modified with four titanium {(2-propanolato) tris(dodecylbenzenesulfonato-O) titaniumIV; [2-[2-(methoxy-O-ethoxy-O)]ethanolato-O] tris(2-methyl-2-propenoato-O) titaniumIV; [2-[2-(methoxy-O-ethoxy-O)]ethanolato-O] tris(2-propenoato-O) titaniumIV; (2-propanolato) tris(2-ethyldiamino)ethylato-O) titaniumIV} and four zirconium {(neoalkoxy) tris(dodecylbenzenesulfonato-O) zirconiumIV; (neoalkoxy) tris(2-methyl-2-propenoato-O) zirconiumIV; (neoalkoxy) tris(2-propenoato-O) zirconium IV; (neoalkoxy) tris(2-ethyldiamino)ethylato-O) zirconiumIV} coupling agents. As a result we obtained a monomolecular layer of the titanium or zirconium coupling agent on the silica gel surface. Physicochemical properties of this layer and its influence on the modified silica gel properties were characterised by inverse gas chromatography (IGC) and expressed by both solubility and surface parameters. The influence of the modifier structure on surface parameters were presented and discussed. Relationships between solubility and surface parameters were also shown.