Catalyst titanium

Organic Titanium Compounds as A.crylicT.sterA.lcoholjsis Catalysts Titanium Intermediates, Ltd., London, 1967. 

This reaction can be carried out with numerous variations to give a broad range of catalysts. It is a heterogeneous high-surface TiCIs material of which the active sites contain titanium in an unknown valence state. It is quite likely that alkyltitanium groups at the surface are responsible for the co-ordination polymerisation. In more recent catalysts titanium supported on magnesium salts are used [4,5],... 

TBT = tetrabutyl titanate and C94 catalyst = titanium and silica-based catalyst. 

Both the ally lie alcohol and tert-hutyX hydroperoxide are achiral, but the product epoxide is formed in high optical purity. This is possible because the catalyst, titanium tetraiso-propoxide, forms a chiral (possibly dimeric [36]) complex with resolved diethyl tartrate [(+)-DET] which binds the two achiral reagents together in the reactive complex. The two enantiotopic faces of the allylic double bond become diastereotopic in the chiral complex and react at different rates with the tert-butyl hydroperoxide. Many other examples may be found in recent reviews [31, 37-39]. 

A unique titanium(IV)-silica catalyst prepared by impregnating silica with TiCLt or organotitanium compounds exhibits excellent properties with selectivities comparable to the best homogeneous molybdenum catalysts.285 The new zeolite-like catalyst titanium silicalite (TS-1) featuring isomorphous substitution of Si(IV) with Ti(IV) is a very efficient heterogeneous catalyst for selective oxidations with H2C>2.184,185 It exhibits remarkable activities and selectivities in epoxidation of simple olefins.188,304-306 Propylene, for instance, was epoxidized304 with 97% selectivity at 90% conversion at 40°C. Shape-selective epoxidation of 1- and 2-hexenes was observed with this system that failed to catalyze the transformation of cyclohexene.306 Surface peroxotitanate 13 is suggested to be the active spe-... 

Catalysts and LLDPE Polymerization Processes LLDPE resins are produced in industry with three classes of catalysts titanium-based catalysts (Ziegler), metallocene-based catalysts (Kaminsky and Dow), and chromium oxide-based catalysts (Phillips). 

P 4] For preliminary investigations a small-scale micro structured reactor was used to perform gas-phase epoxidation of propylene to propylene oxide with evaporated H202. As catalyst titanium silicate (TS-1) was used. 

Alkenes without functional groups are difficult to hydrogenate enantioselec-tively with noble-metal catalysts. Titanium complexes with a C2 symmetric chiral ligand framework, as in the ansa-titanocene (22-XVI), reduce aryl-substituted C=C bonds in very high isolated and optical yields 19... 

Long-range electron transfer is postulated to occur from ferrocene to tris(bipyridine)iron(lll) constructed within the pores of a NaY zeoUte. The iron bipyridine complex is too large to move throughout the faujasite pores to the surface, thus requiring the long-range transfer. The asyimnetric catalyst, titanium tartrate, has been prepared inside NaY and used as an immobilized catalyst for the epoxidation of cinnamyl alcohol. ... 

In the presence of a chiral zirconium " " or aluminum " catalyst, Bu3SnCN react with imines to give a-cyanoamines enantioselectively. The reaction of an imine and TMSCN gives the cyano amine with good enantioselectivity using a chiral scandium catalyst.Titanium catalysts have been used in the presence of a chiral Schiff base. Treatment of an imine with a chiral 1,4,6- triazabicy-clo[3.3.0]oct-4-ene and then HCN give the a-cyano amine with good enantioselectivity. 

More universal is the method of Cp determination using selective tracers such as carbon monoxide and carbon dioxide which interact only with active metal = polymer bondsUsing tagged CO and CO2 as quenching agents systematic data have been accumulated so far on the influence of the composition of catalysts (titanium chlorides with various organometallic compounds) and polymerization conditions on Cp and kp values for the polymerization of ethylene and propylene IS)... 

Warzelhan and Burger proposed to remove the cocatalyst before the introduction of C02 to avoid the possible influence of the cocatalyst on polymer radioactivity. However, two conditions have to be fulfilled to obtain correct data on Cp i) the life-time of an active metal-polymer bond has to be sufficiently long ii) the polymer must not contain Al—C bonds able to interact with a quenching agent. The possibility to use CO and CO2 for the quantitative determination of Cp was illustrated in the case of one-component catalysts (titanium dichloride supported organometallic catalysts when Cp values were independently determined by the use of other inhibitors including radioactive alcohol. 

Other Metal Sulphides as Hydrodesulphurization Catalysts. - Titanium. TiS2, precipitated by adding Li2S to TiCU in tetrahydrofuran, was effective, after heating in H2/H2S, in hds of benzothiophen (673 K, 32 atm). ... 

Molybdenum catalysts, Ruthenium porphyrins, Ruthenium(lll) complexes, Iron catalysts, Titanium catalysts. Sharpless epoxidation, Tungsten catalysts, Methyltrioxorhenium, Cobalt, Nickel, Platinum, Aerobic epoxidation, Lanthanum, Ytterbium, Calcium, BINOL-complexes. 2008 Elsevier B.v. 

Silica-Titania Catalyst Titanium isopropoxide (11.36 parts) was slowly added to a solution of I INO, (1 part) in water (136.4 parts). TEOS was mixed with ethanol, water, and HCl in a volumetric ratio 2000 525 625 1. Precursor sols were mixed, dialyzed, evaporated, and sintered to 300°C. 

Preparation of new solid super-acid catalyst, titanium sulfate supported on zirconia and its acid catalytic properties... 

The Ziegler process uses a finely divided catalyst (titanium halide and an aluminum alkyl) in a solvent and operates at temperatures ranging from 50 to 120 °C and pressures ranging from 150 to 300 psig. The product is treated to deactivate the catalyst and remove residues. 

Ivanova, Borovskaya, and Rudakov investigated the liquid phase isomerization of yS-pinene in the presence of the solid-acid catalysts titanium dioxide, and alumi-... 

Step 1 A titanium halide and an ethylaluminum compound combine to place an ethyl group on titanium, giving the active catalyst. Titanium has one or more vacant coordination sites, shown here as an empty orbital. 

The high oxophilicity of early transition metal catalysts (titanium, zirconium, or chromium) causes them to be poisoned by most functionalized olefins, particularly the commercially available polar comonomers. However, there are examples of copolymerizations with special substrates or with very high levels of a Lewis acid incorporated into the polymerization system to protect the polar functionality through complexation. " Alternative routes to polar copolymers involving metathesis of cyclic olefins and functionalization of the resulting unsaturated polymer or metathesis of polar cycloolefins followed by hydrogenation to remove the resulting unsaturation have been published.The cost of these multistep... 

Entry Catalyst Titanium source Ti content Substrates Yield (%) Ref. 

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