Lithium-tin system

Measurements were also made of the potential-composition behavior, as well as the chemical diffusion coefficient and its composition dependence, in each of the intermediate phases in the Li-Sn system at 415 °C [42]. 

It was found that chemical diffusion is reasonably fast in all of the intermediate phases in this system. The self-diffusion coefficients are all high and of the same order of magnitude. However, due to its large value of thermodynamic enhancement factor W, the chemical diffusion coefficient in the phase LiisSns is extremely high, approaching 7.6 x 10 cm s , which is about 2 orders of magnitude higher than that in typical liquids. These data are included in Table 14.3. 

A smaller number of binary lithium systems have also been investigated at lower temperatures. This has involved measurements using LiN03-KN03 molten salts at about 150 °C [44] as well as experiments with organic solvent-based electrolytes at ambient temperatures [45, 46]. Data on these are included in Table 14.4. 

Comparable information on the Li-Bi and li-Sb systems was also obtained, and their room-temperature potentials are also included in Table 14.4. The temperature dependence of the potentials of the different two-phase plateaus is shown in 

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The lithium-tin system has been investigated at room temperature and the influence of temperature upon the composition dependence of the potential is shown in Figure 14.7. It is seen that five constant-potential plateaus are found at 25 °C. Their potentials are listed in Table 14.4. It was also shown that the kinetics on the longest plateau, from x = 0.8 to 2 in Li Sn, are quite favorable, even at quite high currents (see Figure 14.8). 

The lithium-tin binary system is somewhat more complicated, as there are six intermediate phases, as shown in the phase diagram in Figure 14.5. A thorough study of the thermodynamic properties of this system was undertaken [27]. The composition dependence of the potential at 415 °C is shown in Figure 14.6. 

Hydroisoquinolines. In addition to the ring-closure reactions previously cited, a variety of reduction methods are available for the synthesis of these important ring systems. Lithium aluminum hydride or sodium in Hquid ammonia convert isoquinoline to 1,2-dihydroisoquinoline (175). Further reduction of this intermediate or reduction of isoquinoline with tin and hydrochloric acid, sodium and alcohol, or catalyticaHy using platinum produces... 

Reaction conditions that involve other enolate derivatives as nucleophiles have been developed, including boron enolates and enolates with titanium, tin, or zirconium as the metal. These systems are discussed in detail in the sections that follow, and in Section 2.1.2.5, we discuss reactions that involve covalent enolate equivalents, particularly silyl enol ethers. Scheme 2.1 illustrates some of the procedures that have been developed. A variety of carbon nucleophiles are represented in Scheme 2.1, including lithium and boron enolates, as well as titanium and tin derivatives, but in... 

In recent years lithium - ion power sources have occupied one of the first places among other modem energy storage systems. Their functioning is based on the possibility of reversible intercalation of lithium ions in active materials (AM). Substances of tin are investigated often as negative materials for lithium-ion batteries. 

A more popular method for the generation and cycUzation of unstabilized a-amino-organolithium compounds uses tin-lithium exchange, and has been explored extensively by Coldham and others. A variety of solvent systems can be employed, although the use... 

Ahlbrecht and coworkers showed that tin-lithium exchange can be used to lithiate enamines of 2-methoxymethylpyrrolidine, as shown in Scheme 46. A 50 50 mixture of diastereomers is transmetalated, and the resultant organohthium(s) alkylated to give, after enamine hydrolysis, a 98 2 ratio of ketone enantiomers. In this system, the low barrier to inversion allows equilibration to a single organolithium species, which alkylates by an S 2inv mechanism. 

The first commercial lithium-ion cell containing a carbon based hybrid material is the Sony Nexelion cell which was introduced in 2006.30 Nexelion cells contain a graphite/cobalt-doped amorphous tin hybrid electrode. Batteries of this cell type are used in video cameras which require high energy density but can accept the lower cycling stability of the Nexelion batteries compared to conventional lithium-ion battery systems. 

Michael addition of tin enolates to a,/3-unsaturated esters is accomplished in the presence of catalytic amount of Bu4NBr. Other typical system using lithium enolates or silyl enolates with catalysts (Lewis acid or Bu4NF) fails to give the Michael products. An ab initio calculation reveals that higher reactivity is caused by high coordination of the tin enolate and the keto enol tautomerization for Michael adducts contributes to thermodynamical stabilization (Equation (77)).231 232... 

Tin(iv) enolates are normally generated by transmetallation from lithium enolates with trialkyltin halides or transesterification between enol acetates with trialkyltin alkoxides.220 Other types of generation systems are described below. 

The work on stannacycloalkanes and -cycloalkenes up to 1972 has been reviewed (9), and again, though in less detail, in 1982 (10). Most of the early studies concern the formation of five- and six-membered rings, and claims for smaller systems in particular should be treated with caution. More recent efforts have been directed to the synthesis of both strained and expanded rings. The synthetic methodology, however, remains dominated by the use of difunctional carbanion sources (Grignard and lithium reagents) or the hydrostannation reactions of tin dihydrides. 

Ziegler-Natta Catalysts (Heterogeneous). These systems consist of a combination of a transition metal compound from groups IV to VIII and an organometallic compound of a group I—III metal.23 The transition metal compound is called the catalyst and the organometallic compound the cocatalyst. Typically the catalyst is a halide or oxyhalide of titanium, chromium, vanadium, zirconium, or molybdenum. The cocatalyst is often an alkyl, aryl, or halide of aluminum, lithium, zinc, tin, cadmium, magnesium, or beryllium.24 One of the most important catalyst systems is the titanium trihalides or tetra-halides combined with a trialkylaluminum compound. 

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