Nickel-based systems

The nickel-based systems include the flowing systems nickel—iron (Ni/Fe), nickel—cadmium (NiCd), nickel—metal hydrides (NiMH), nickel—hydrogen (Ni/ H2), and nickel—zinc (Ni/Zn). All nickel systems are based on the use of a nickel oxide active material (undergoing one valence change from charge to discharge or vice versa). The electrodes can be pocket type, sintered type, fibrous type, foam type, pasted type, or plastic roll-bonded type. All systems use an alkaline electrolyte, KOH. 

The cross-coupling of 3-iodopyridine and 4-dimethylamino-phenylacetylene was reported to work efficiently in the presence of a nickel based catalyst system too (7.42.),60 The described conditions (e.g. catalyst loading, solvent, temperature, additive) are more or less the same as in the conventional palladium catalyzed variant, although the nickel based system gave only poor results with bromoazines. 

Mann and Hartwig have also investigated the use of sodium ferf-butyldime-thylsilanoate (NaOTBS) in the C-0 bond forming reaction with aryl bromides [150]. The efficacy of DPPF- and tolBINAP-based catalysts, as well as nickel-based systems, were compared, Eq. (188). 

Another interesting nickel-based system is the nickel-hydrogen cell, a hybrid system similar to the zinc-air primary cell described in Section 2.3.1, under Zn-based systems . The cell and its reaction are ... 

Both NiL+ and NiL(C02) species are formed under CO2 atmosphere by irradiation at 313 nm in acetonitrile solutions containing TEA and NiL +. In order to understand the interesting behavior of these nickel-based systems we have studied the nature of the ground-state complexes, electrochemical CO2 reduction, and the differences in CO2 binding between cobalt and nickel macrocycles. 

A series of a-halopropionates (1-21 and 1-22, X = Cl, Br), model compounds of the dormant polymer terminal of acrylates, are suitable for not only acrylates but also styrenes and acrylamides. Ethyl 2-chlo-ropropionate (1-21, X = Cl) was employed for the controlled radical polymerizations of MA and styrene catalyzed by CuCl/L-1 to afford relatively narrow MWDs (MwIMn 1.5).84 A better controlled polymerization of MA is achieved with the bromides 1-21 and 1-22 (X = Br) in conjunction with CuBr/L-1 to give narrower MWDs (MJMn 1.2).84 A similar result was obtained with the combination of 1-23 and CuBr/L-1 for the polymerization of styrene.166 A nickel-based system with Ni-2 and 1-21 (X = Br) gave another controlled polymerization of nBA.134 The iodide compound 1-21 (X = I) is specifically effective in conjunction with an iodide complex such as Re-1 to induce controlled polymerization of styrene.141... 

Redox non-innocent ligands have also been employed in other kinds of processes. For example, a nickel-based system has been used in the purification of ethene gas streams [41]. The two forms (reduced and oxidized) of the dithiolene complex have different affinities for olefin, leading to separation of ethene from gas mixtures (Scheme 14). Intermediate 47 is obtained after electrochemical oxidation of the anionic nickel complex 46. The oxidized complex 47 reacts selectively with ethylene to form the adduct 48, thus the non-olefinic contamination of the multi-component stream... 

There is a dramatic solvent effect with the nickel-based system (Runs 14-15). A tetrahydrofuran (THF) solution of the nickel-based catalyst appears to be less active than the... 

The reaction rate remains constant up to high conversion rates (zero order in relation to benzene). Two side reactions must be avoided because they lower the cyclohexane purity. These are conversion to methylcydopentane and hydrocracking. The isomerization equilibrium of cyclohexane to methyicyclopentane corresponds to a conversion of 68 per cent at 200°C, reaching 83 per cent at 300°C. This makes it necessary to select a catalyst that does not favor this reaction. With nickel-based systems, the reaction appears only above 250°C. Moreover, the hydrogen must not contain impurities liable to poison the active phases introduced. 

Many nickel-based systems catalyze the dimerization of olefins. In 1966, Wilke [5] demonstrated that the well-defined cationic ri -allylnickel complex (1) catalyzes the regioselective dimerization of propene in organic chlorinated solvent. The AICI4... 

In principle, all dichloro aromatics can be coupled with the same Nickel based system which has been used for the synthesis of the poly(2-benzoyl-... 

Largely for reasons of cost, low maintenance requirements and proven technology, lead-acid batteries continue to dominate the traction battery market. The closest competitors, in specialist applications, are various nickel-based systems. For stationary batteries, used as a standby power source, the market is more closely divided between lead-acid and nickel-cadmium batteries. At the same time, new applieations have opened up in recent years for lead-acid batteries in electric-powered support vehicles (in recreational and industrial uses) and a potentially large new market in electric cars beckons (see Chapter 18, for a discussion of this and other new... 

The lithium reserve in the nickel-based system as described earlier, allows the time to reach a given nominal capacity loss due to lithium corrosion to be extended. For example, from Figure 12, calculated time to reach 80% of nominal capacity after continuous storage at 40°C would increase from 1200 days (20% loss in LiCo02 cells) to 3500 days (35% with Ni-based system), with this ceU design. 

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