Zirconium propoxide

Zirconium Alkoxides. Like the corresponding titanium compounds, the 2irconium alkoxides are manufactured from soHd 2irconium tetrachloride and the respective alcohol in the presence of ammonia. Higher alkoxides are manufactured by alcoholysis. Zirconium -propoxide and -butoxide are commercially available in barrels at about 14/kg. 

FIGURE 12.11 Improvements of the mechanical properties of three-dimensional reinforced CMCs by hybrid infiltration routes (a) R.T. flexural stress-strain plots for a three-dimensional carbon fiber reinforced composite before and after cycles of infiltration (comparison between eight cycles with zirconium propoxide and fonr cycles pins a last infiltration with aluminum-silicon ester (b) plot of the mechanical strength as a fnnction of the final open porosity for composites and matrix of equivalent porosity, before and after infiltration (Reprinted from Colomban, R and Wey, M., Sol-gel control of the matrix net-shape sintering in 3D reinforced ceramic matrix composites, J. Eur. Ceram. Soc., 17, 1475, 1997. With permission from Elsevier) (c) R.T. tensile behavior (d) comparison of the R.T. mechanical strength after thermal treatments at various temperatures. (Reprinted from Colomban, R, Tailoring of the nano/microstructure of heterogeneous ceramics by sol-gel routes, Ceram. Trans., 95, 243, 1998. With permission from The American Ceramic Society.)... 

Another key reaction associated with the use of this solvent is the alcohol exchange reaction, which results in reduced hydrolysis sensitivity of the starting reagents, such as zirconium -propoxide and titanium i-propoxide, frequently used in the production of PZT films. This reaction is represented as Alcohol exchange... 

A 50 wt.% micellar solution of Cu(EO)6 was prepared by dissolving the surfactant at room temperature in an aqueous solution during 3 hours. The obtained medium was further stirred for three hours at room temperature before adding drop by drop the inorganic source zirconium propoxide [Zr(OC3H7)4]. The surfactant / zirconia molar ratio was varied from 0.5 to 10. The obtained gel was sealed in Teflon autoclaves. Hydrothermal treatment was performed during 2 days at 60°C, in a first time. The surfactant was removed by ethanol extraction. 

From Fig. 5, we can see that samples prepared without template have a lower specific surface area than those obtained with a surfactant / zirconium molar ratio lower than 5. A beneficial effect of the template on the specific surface area is thus observed. All these results led us to propose the mechanism represented in Fig. 6. When- zirconium propoxide is added to the micellar solution, its rapid polymerization will disturb the micellar array. Furthermore, the large amount of propanol produced during the hydrolysis of Zr(OPr)4 will provoke a change of organisation of the surfactant molecules in solution. This variation in organisation of the surfactant molecules associated with the high... 

Zirconia nanotubes were also obtained using a similar method with a zirconium propoxide precursor [75]. After oxidizing the carbon, zirconia tubes with a diameter of 40 nm, 6 nm wall thickness, and several micrometers long were obtained. The Zr02 was composed of mixed crystal phases (monoclinic and tetragonal). Increased temperature treatment led to collapse of the nanotubes. The addition of yttria in a slightly modified procedure gave a more stable nanotube structure with similar wall thicknesses. The yttria-stabilized zirconia had a cubic structure. 

Similar results have been found with zirconium alkoxides. Solvated dimeric species are formed when zirconium propoxide is dissolved in its parent alco-... 

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] ... 

A very recent work by Patra et al, [ 184] describes a sol-emulsion-gel method for the synthesis of nanoparticles (27-50 nm) of monoclinic and tetragonal zirconia with low dopant concentration of erbium and cubic zirconia with high dopant concentration. The emulsions were prepared with cyclohexane as the oil phase and Span 80 (5 vol%) as the surfactant. The aqueous phases contained dissolved zirconium propoxide and erbium acetate, and the sol thus produced was used in the ratio sol.cyclohexane =1 4 for the synthesis. 

Kobayashi et al. investigated asymmetric intra-molecular [3+2] cycloaddition reactions (reaction 7.21) of acyl-hydrazones, 105, using a chiral zirconium propoxide or tert-butoxide-BlNOL, 106, catalytic systems with acceptable yield and enantioselectivity [71]. 

Dielectric constants have been reported for several polymers including PI [40-42], epoxy resins [43], PU [43], XLPE-PE [44], LDPE-zinc oxide nanocomposites [45], PANI nanofibres [46], doped polyimines derived from selenophene [40], Pl-zirconium propoxide nanocomposites [47] and PANI-cerium oxide composites [48]. 

The behavior of 316L stainless steel in corrosive conditions was improved upon deposition of nanohybrid coatings based on PMMA-Zr02- The coatings were deposited via dip-coating of sols prepared by mixing zirconium propoxide and... 

Zirconia, which is stable as well as titania, especially, in alkali solution, is also one of the promising materials for separation membranes. Several manufacturers have commercialized zirconia UF membranes, but not NF membranes. Zirconium propoxide [30] or butoxide [31], which are mainly used as precursors of zirconia sols, are highly sensitive to water to form suspensions (the reaction rate with water is much faster than titanium alkoxide), the preparation of nanosized sols is difficult. Therefore, very few reports have appeared on the successful preparation of zirconia nanofiltration membranes. Vacassy et al. [30] added acetylacetone to zirconia propoxide to prevent hydrolysis, and reported a successful preparation of porous zirconia membranes showing a water permeability of 3.4 X 10 ms Pa and a rejection of 55% towards saccharose (MW = 342). 

Zirconium propoxide titanium isopropoxide Partial and controlled hydrolysis using CHaCOOH-propanol, and a ratio h = [CH3COOH]/ [metal] 1 < h < 8 If h < 3, homogeneous gels were obtained If h > 3, white precipitate M(OR)x(CH3COO)y Munoz et al, 1990... 

Dielectric constant data have been reported on several unreinforced polymers, including polyimides [19-21], silicones [22], epoxy resins [23], polyurethanes [23], polyaniline nanofibers [16, 17], zirconium nanocomposites [24], cross-linked polyethylene [15], low-density polyethylene [22], doped polyimines [19], polyimide-3-zirconium propoxide nanocomposites [24], poly linu-naphthyl ether [30], and cross-linked polyethylene-polyethylene polyacrylate acid blends [15]. 

WO source ammonium tungstate solution Calcination at 700 to 1000°C for 2 h in air Zr02 source Zirconium -propoxide gelled with ammonium tungstate solution WO source ammonium tungstate solution Gel was supercritical dried in CO2 at 70° C, dried at 110 and 250° C, and calcined at 700 to 1000°C in air... 

Multicomponent hybrids containing zirconium propoxide, tetraethoxysilane and dimethyl-diethoxysilane, intended for dental restorative or adhesive materials, were successfully obtained by the dual-cure [272]. Zirconium-containing species proved to be highly effective in catalyzing the epoxy polymerization/crosslinking reactions, as compared to those containing Ti, and enhanced mechanical properties, as well as thermal stability of nanocomposites. 

For the preparation of PZT ceramic by the sol-gel method, many precursors are available, but the typical process employs titanium isopropoxide, zirconium propoxide, and lead acetate [91]. In some syntheses, zirconium -butoxide was also used as a Zr source [90]. 

Konishi et al [52] used zirconium -propoxide as the precursor in a sol-gel transition accompanied by phase separation. The hydrolysis was carried out in... 

---