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Zirconium to Nickel

Ni(0)-catalyzed coupling of a vinyl zirconocene with a chloromethylated heteroaromatic. [Pg.138]


Transmetallation from an early to a late transition metal is kinetically accessible and, most often, thermodynamically favorable. Treatment of 1,9-anthracendiyl zirconocene 36 with bis(triphenylphosphine)nickel(ii)bromide in the presence of diphenylacetylene gives 1,2-diphenylaceanthrylene in good yield (Equation 11), suggesting that the transmetallation of zirconium to nickel proceeds efficiently <2000JA9880>. [Pg.569]

It is used for the production (thermal reduction) of other metals, such as zinc, iron, titanium, zirconium, and nickel. For instance, because of its strong electropositive nature, magnesium can desulfurize molten iron when it combines with the sulfur impurities in the iron to produce high-grade metallic iron plus MgS. [Pg.71]

Nobium also is added to nickel- and cobalt-based superaUoys and is a component of zirconium, titanium and tungsten alloys. [Pg.628]

The action of carbon tetrachloride or a mixture of chlorine with a hydrocarbon or carbon monoxide on the oxide.—H. N. Warren 9 obtained aluminium chloride by heating the oxide to redness with a mixture of petroleum vapour and hydrogen chloride or chlorine, naphthalene chloride or carbon tetrachloride was also used. The bromide was prepared in a similar manner. E. Demarpay used the vapour of carbon tetrachloride, the chlorides of chromium, titanium, niobium, tantalum, zirconium, cobalt, nickel, tungsten, and molybdenum H. Quantin, a mixture of carbon monoxide and chlorine and W. Heap and E. Newbery, carbonyl chloride. [Pg.216]

In the case of so-called active soldering an active solder is used a metallic solder containing interface active additives which make certain that the molten solder wets the ceramics. An example of such a solder is a silver / copper alloy with a titanium or titanium / indium additive which can be used when soldering zirconium (IV) oxide to certain steels, aluminium oxide to nickel / cobalt or iron / nickel alloys and aluminium oxide to a iron / nickel / cobalt alloy. [Pg.287]

Catalysts prepared by the wash-coating method were first used to check the reproduction of the measured values. For this reason, six elementary metal salts (platinum, zirconium, molybdenum, nickel, silver, and rhodium) were dissolved and impregnated onto a titer-plate. The catalysts were pre-reduced inside the reactor with 5% hydrogen in 95% nitrogen at 250 °C. The results were recorded first before the pre-reduction and then after the pre-reduction. The repeated measurements indicated good reproducibility in both cases. The conversion of methane with the rhodium catalyst is better after the pre-reduction. Methane conversion after 18 h runtime was still stable. [Pg.105]

Conversion of monocyclic and polycyclic vinylcyclopropanes with low-valent transition-metal complexes, (e.g. iron, rhodium, zirconium, cobalt, nickel, palladium) mainly leads to ring opening and rearrangement products. A typical reaction pathway of vinylcyclopropanes with transition-metal complexes leads to f/Calkyl-j/ -allyl complexes, which as homodiene complexes exhibit interesting reaction patterns (e.g. carbonylation) leading to organic products. ... [Pg.2681]

Although stoichiometric amounts of transition metal complexes were employed, the cross-[2+2+2] cycloaddition of three different alkynes has been achieved using zirconium and nickel complexes. The reaction of 2-butyne, 4-octyne, and Cp ZrEt selectively afforded unsymmetrical zirconacyclopentadiene. Subsequently, it reacted with 3-hexyne in the presence of NiBr fPPhjlj to give the desired hexasubstituted benzene (Scheme 21.6) [9]. [Pg.590]

Transmetallation of the organic group from zirconium to another metal opens up possibilities. The palladium-catalysed coupling reactions can be found in Section 2.4. Addition of dimethyl cuprate results In transmetallation to copper. The resulting cuprate then displays typical cuprate reactivity, such as addition to enones. More economically, small amounts of copper can catalytically activate the zirconium complex towards this kind of chemistry, although the precise mechanism is unclear. Additions to enones can also be achieved directly using nickel catalysis (Scheme 5.64). Transmetallation to zinc has also been demonstrated. ... [Pg.177]

The AB2 type in Line 2 of Table 1.10 is based on vanadium, titanium, zirconium, and nickel. Especially for these intermetallic compounds the stoichiometry is not well defined. So some alloys ascribed to this group may be named A2B or AB as well. [Pg.115]

Many engineering metals, such as iron, nickel, chromium, and titanium, produce metal ions of a variable valency. Uniquely, zirconium is predominantly quadrivalent in its oxides and many other compounds. It forms very few compounds in which its valence is other than 4. The chemistry of zirconium is characterized by the difficulty of achieving an oxidation state less than 4. This character, along with high oxygen affinity, allows zirconium to form protective oxide films even in highly reducing media, such as hydrochloric acid and dilute sulfuric acid. Under these conditions, common metals and alloys may form subordinate oxides or other compounds of low or no protective capability. [Pg.577]

The manufacturing industry is emphasizing quality, efficiency, and environmental compatibility. Zirconium is well positioned to meet these needs. Interest in zirconium and its chemicals is on the rise. However, there is still a persistent perception that zirconium is exotic and costly. Actually, zirconium is plentiful. In the earth s crust, zirconium is more abimdant than many common elements, such as nickel, copper, chromium, zinc, lead, and cobalt. The prices of zirconium and its alloys have been relatively stable for many years. They are very competitive with other high-performance materials. Life cycles costs of zirconium equipment can be particularly attractive. There is much room for zirconium to grow in the coming years. [Pg.617]

The mechanism of action of the nickel addend proceeds probably through a reduced form of nickel (e.g. nickel(I)) which is involved in a electron transfer process with the enone. Further reaction with the organozirconium reagent affords the addition product through transfer of the organic radical from zirconium to the nickel center, followed by a reductive elimination step (see [45] for a similar mechanistic proposal). [Pg.110]


See other pages where Zirconium to Nickel is mentioned: [Pg.138]    [Pg.138]    [Pg.138]    [Pg.138]    [Pg.138]    [Pg.138]    [Pg.138]    [Pg.138]    [Pg.68]    [Pg.88]    [Pg.427]    [Pg.69]    [Pg.88]    [Pg.309]    [Pg.68]    [Pg.1594]    [Pg.201]    [Pg.73]    [Pg.58]    [Pg.1096]    [Pg.73]    [Pg.190]    [Pg.1560]    [Pg.351]    [Pg.396]    [Pg.90]    [Pg.202]    [Pg.323]    [Pg.53]    [Pg.361]    [Pg.145]    [Pg.339]    [Pg.460]    [Pg.243]    [Pg.69]    [Pg.121]    [Pg.124]    [Pg.130]   


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