Titanium modified with acetylacetone

Titania and Zirconia Membranes Prepared by the Polymeric Route Titanium and zirconium propoxides can be used as precursors for the preparation of nanoporous titania and zirconia membranes. To avoid the precipitation of inhomogeneous hydroxide particles during the hydrolysis step, the alkoxide reactivity can be modified with acetylacetone (acacH). This chelating agent reacts readily with transition metal alkoxides, as follows [34] ... 

Scheme 27.2 Molecular structure of a titanium alkoxide modified with acetylacetone.

Que et al. have reported the fabrication of optical channel wavegides and gratings made from composites of titania and organically modified silane (Que et al., 2002). The composite is prepared using 3-glycidoxypropyltrimethoxysilane and titanium tetrapropoxide stabilized with acetylacetone as precursors. Dense and porosity-free waveguide film is obtained... 

Table 7). In an early application, VF was polymerized with a catalyst composed of diethylalnminnm bromide-titanium tetrachloride-carbon tetrachloride (82). A Ziegler-Natta system based on vanadyl acetylacetonate and AIR(OR)Cl compounds gives good yields (82) at polymerization temperatures up to 50°C. A modified catalyst prepared from vanadium oxytrichloride, triisobutylaluminum, and tetrahydrofnran was foimd to be the most effective Ziegler-Natta system... 

Silica/chromia catalysts have also been modified by the incorporation of other oxides such as alumina" or zirconia," by impregnating a silica support with zirconium acetylacetonate or aluminum sec-butoxide or co-gelling the silica gel with appropriate soluble salts. Zirconia-modified catalysts are similar to those with added titanium in their effect but have not been widely reported. Aluminum-modified catalysts have increased activity and provide lower-molecular-weight polymers, but the procedure for their preparation is complicated. Neither type of catalyst is widely described in the literature but they are reported as containing different active sites." ... 

---