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Titanium preparation/formation

Preparation/Formation of Cp2Ti(CO)2 via other Titanium Complexes... [Pg.331]

Analogous to the DSA manufacture, a pure htanium dioxide coating can be prepared, which shows a high activity and stabihty (also against titanium hydride formation), for electroorganic cathodic reductions (e.g. [40], see Chapter 7). [Pg.45]

Furstner and coworkers have continued to explore the titanium-mediated formation of indoles from o-V-diacylanilines. The use of a sodium-aluminum oxide mixture prepared from alumina and molten sodium was developed. This material has the advantage over potassium-graphite of being non-pyrophoric. <95S63> Additional specific applications of the reaction were also reported, for example the synthesis of the phytoalexin camalexin, 21b. <95T773>... [Pg.107]

Reductive coupling of carbonyl compounds to yield olefins is achieved with titanium (0), which is freshly prepared by reduction of titanium(III) salts with LiAIH4 or with potassium. The removal of two carbonyl oxygen atoms is driven by T1O2 formation- Yields are often excellent even with sensitive or highly hindered olefins. (J.E. McMurry, 1974, 1976A,B). [Pg.41]

Another important class of titanates that can be produced by hydrothermal synthesis processes are those in the lead zirconate—lead titanate (PZT) family. These piezoelectric materials are widely used in manufacture of ultrasonic transducers, sensors, and minia ture actuators. The electrical properties of these materials are derived from the formation of a homogeneous soHd solution of the oxide end members. The process consists of preparing a coprecipitated titanium—zirconium hydroxide gel. The gel reacts with lead oxide in water to form crystalline PZT particles having an average size of about 1 ]lni (Eig. 3b). A process has been developed at BatteUe (Columbus, Ohio) to the pilot-scale level (5-kg/h). [Pg.500]

Transesterification of methyl methacrylate with the appropriate alcohol is often the preferred method of preparing higher alkyl and functional methacrylates. The reaction is driven to completion by the use of excess methyl methacrylate and by removal of the methyl methacrylate—methanol a2eotrope. A variety of catalysts have been used, including acids and bases and transition-metal compounds such as dialkjitin oxides (57), titanium(IV) alkoxides (58), and zirconium acetoacetate (59). The use of the transition-metal catalysts allows reaction under nearly neutral conditions and is therefore more tolerant of sensitive functionality in the ester alcohol moiety. In addition, transition-metal catalysts often exhibit higher selectivities than acidic catalysts, particularly with respect to by-product ether formation. [Pg.248]

Some phosphides, such as titanium phosphide [12037-65-9] TiP, can be prepared bypassing phosphine over the metal or its haUde. Reaction of phosphine with heavy metal salt solutions often yields phosphines that may contain unsubstituted hydrogens. Phosphides may also be prepared by reducing phosphoms-containing salts with hydrogen, carbon, etc, at high temperatures, the main example of which is the by-product formation of ferrophosphoms in the electric furnace process for elemental phosphoms. Phosphoms-rich phosphides such as vanadium diphosphide [12037-77-3] may be converted to lower phosphides, eg, vanadium phosphide [12066-53-4] by thermal treatment. [Pg.377]

The key step to this first reported case of the highly diastereoselective addition of a fluorinated enolate in an aldol process is the selective formation of the enolate a,a-Difluonnated enolates prepared by a metallation process employing either a zinc-copper couple [S] or reduced titanium species [9] undergo aldol condensation smoothly (equation 9) (Table 5)... [Pg.617]

R)-Benzoins and (/ )-2-hydroxypropiophcnonc derivatives are formed on a preparative scale by benzaldehyde lyase (BAL)-catalyzed C-C bond formation from aromatic aldehydes and acetaldehyde in aqueous buffer/DMSO solution with remarkable ease in high chemical yield and high optical purity (Eq. 8.112).303 Less-stable mixed benzoins were also generated via reductive coupling of benzoyl cyanide and carbonyl compounds by aqueous titanium(III) ions.304... [Pg.278]

Recently, Bercaw and co-workers have described the preparation of the first ethylene complex of titanium (64). The sodium amalgam reduction of a toluene solution of (Tj-C5Me5)2TiCl2 under an ethylene atmosphere afforded (T C5Me5)2Ti(T -C2H4) in 80% yield. Treatment of this complex with CO at low temperature resulted in the displacement of C2H4 and quantitative formation of (rj-C5Me5)2Ti(CO)2 (27). [Pg.338]

The electrochemistry of Ti2+ in 66.7 m/o AlCl3-NaCl has been investigated wherein the electroactive Ti2+ was prepared by the oxidation of Ti metal with liquid A1C13 [176, 185] and by the electrochemical dissolution of titanium metal [120, 177], The authors of both studies concluded that Ti2+ may be oxidized stepwise to Ti3+ and Ti4+ and that both processes are reversible at platinum and tungsten electrodes. However, anomalous voltammetric behavior at high Ti2+ concentrations (greater than 50 mmol L ) suggests the formation of polymeric Ti2+ species in the melt. The reduction of Ti2+ to the metal was not observed at potentials more positive than that required for aluminum deposition. [Pg.330]

Asymmetric syntheses of (3- amino acids result from the addition of chiral enolates (399) to nitrone (400) via A-acyloxyiminium ion formation (642, 643). Regioselective convergence is obtained in the reactions of chiral boron- and titanium- enolates (399a,b), (401), and (402). This methodology was used in preparing four stereoisomers of a-methyl- 3-phenylalanine (403) in enantiomeric pure form (Scheme 2.179) (644). [Pg.276]

Apart from the reactions described above for the formation of thin films of metals and compounds by the use of a solid source of the material, a very important industrial application of vapour phase transport involves the preparation of gas mixtures at room temperature which are then submitted to thermal decomposition in a high temperature furnace to produce a thin film at this temperature. Many of the molecular species and reactions which were considered earlier are used in this procedure, and so the conclusions which were drawn regarding choice and optimal performance apply again. For example, instead of using a solid source to prepare refractory compounds, as in the case of silicon carbide discussed above, a similar reaction has been used to prepare titanium boride coatings on silicon carbide and hafnium diboride coatings on carbon by means of a gaseous input to the deposition furnace (Choy and Derby, 1993) (Shinavski and Diefendorf, 1993). [Pg.106]


See other pages where Titanium preparation/formation is mentioned: [Pg.289]    [Pg.263]    [Pg.410]    [Pg.451]    [Pg.58]    [Pg.152]    [Pg.53]    [Pg.106]    [Pg.39]    [Pg.45]    [Pg.191]    [Pg.562]    [Pg.60]    [Pg.134]    [Pg.244]    [Pg.216]    [Pg.59]    [Pg.29]    [Pg.285]    [Pg.110]    [Pg.46]    [Pg.452]    [Pg.399]    [Pg.152]    [Pg.44]    [Pg.430]    [Pg.164]    [Pg.345]    [Pg.539]    [Pg.251]    [Pg.611]    [Pg.38]    [Pg.128]   


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Titanium formation

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