Hydrogen activating titanium

Kitano, M., Tsujimaru, K., and Anpo, M. (2008) Hydrogen production using highly active titanium oxide-based photocatalysts. Topics in Catalysis, 49 (1-2), 4-17. 

Chloro-l fluoroethane (10) is prepared by treating chloroethene with anhydrous hydrogen fluoride ° in the vapor phase at 20-70 C in the presence of a catalyst consisting of active charcoal impregnated with 10-45 % by weight fluorosulfonic acid or with hydrogen fluoride/ titanium(IV) chloride. ... 

Seawater or brine is electrolyzed in diaphragmless cells. Activated titanium anodes and titanium cathodes are used. The yield based on current consumed is relatively poor, 40 to 60%, due to the hydrogen produced reducing part of the hypochlorite formed. The electrolysis cells are technically uncomplicated and small. The hypochlorite solutions obtained contain several grams of hypochlorite per L. 

For CO oxidation over gold supported on metal oxides, the catalytic activity is almost insensitive as to the type of metal oxide support but strongly depends on the strength of interaction with the supports. For the reaction of propylene with oxygenand hydrogen,only titanium-based oxide supports lead to the selective production of propylene oxide. 

Scheme 3-2. jS-Hydrogen activation of Ti(NMe2)4 to form titanium azo amido complexes. 

In non-carbonated concrete without chlorides, steel is passive and a typical anodic polarization curve is shown in Figure 7.3. The potential is measured versus the saturated calomel reference electrode (SCE), whose potential is +244 mV versus the standard hydrogen electrode (SHE). Other reference electrodes used to measure the potential of steel in concrete are Ag/AgCl, CU/CUSO4, Mn02, and activated titanium types. From this point on in the text, unless explicitly stated otherwise, potentials are given versus the SCE electrode. 

When titanium is cathodicaUy polarized or coupled to a more active metal in an acid like HCl, a surface film of titanium hydride may form. However, because of restricted diffusion of hydrogen in titanium at room temperature, penetration of hydrogen into the metal accompanied by metal embrittlement occurs only above about 80°C (175°F) [18]. 

The post-synthetic methodology has also been used to incorporate catalytic centres. The incorporation of chiral l,l -bi-2-naphthols (BINOLs) into CMPs has been used to perform catalytic reactions using the alcohol groups to bind to catalytically active centres such as phosphoric acids for asymmetric transfer hydrogenations or titanium for diethyl-zinc additions. Other metal-containing functionalities have also been incorporated into CMP networks. The coordination of metals to pyridine or phenylpyridine via Sonogashira reactions has also been reported for catal5Aic transformations such as reductive amination or aza-Henry reactions, a-atylations and oxyaminations. ... 

The basic compound of Brintzinger s ansa-titanocene complexes is ethylenebis-(tetrahydroindenyl)titanium dichloride, (EBTHI)TiCl2. Further analogues ((EBTHI)TiH, (EBTHI)Ti(Me)2, and (EBTHI)Ti(CO)2) have been wddely used for asymmetric hydrogenation, hydrosilylation, and Pauson-Khand reaction (121). Novel optically active titanium complexes containing a linked amido-cyclopentadienyl ligand have been developed and used for asymmetric hydrogenation (122). 

For example, the titanium trichloride can be prepared by reducing titanium tetrachloride with hydrogen, metallic titanium or with aluminum. It can be activated additionally by using physical or chemical methods. The greatest activity, without additional treatments, shows 5 trichloride of titanium. The characteristics of titanium trichloride as a catalyst for propylene polymerization are presented in Table 8.8. 

Catalysts. Iodine and its compounds ate very active catalysts for many reactions (133). The principal use is in the production of synthetic mbber via Ziegler-Natta catalysts systems. Also, iodine and certain iodides, eg, titanium tetraiodide [7720-83-4], are employed for producing stereospecific polymers, such as polybutadiene mbber (134) about 75% of the iodine consumed in catalysts is assumed to be used for polybutadiene and polyisoprene polymeri2a tion (66) (see RUBBER CHEMICALS). Hydrogen iodide is used as a catalyst in the manufacture of acetic acid from methanol (66). A 99% yield as acetic acid has been reported. In the heat stabiH2ation of nylon suitable for tire cordage, iodine is used in a system involving copper acetate or borate, and potassium iodide (66) (see Tire cords). 

Titanium Silicates. A number of titanium siUcate minerals are known (160) examples are Hsted in Table 19. In most cases, it is convenient to classify these on the basis of the connectivity of the SiO building blocks, eg, isolated tetrahedra, chains, and rings, that are typical of siUcates in general. In some cases, the SiO units may be replaced, even if only to a limited extent by TiO. For example, up to 6% of the SiO in the garnet schorlomite can be replaced by TiO. In general, replacement of SiO by TiO bull ding blocks increases the refractive indices of these minerals. Ti has also replaced Si in the framework of various zeofltes. In addition, the catalytic activity of both titanium-substituted ZSM-5 (TS-1) and ZSM-11 (TS-2) has received attention (161), eg, the selective oxidation of phenol, with hydrogen peroxide, to hydroquinone and catechol over TS-1 has been operated at the 10,000 t/yr scale in Italy (162). 

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