Lithia

PetaHte, also a monoclinic lithium aluminum siHcate, LiAlSi O Q, has a theoretical Li O content of 4.88%. Commercial ores usually contain 3.5—4.5% Li O without concentration and ate a preferred source of lithia for use in ceramics and specialty gla2es. PetaHte is monoclinic and has a density of 2.4—2.5 g/cm. Heating to high temperature results in an irreversible phase change to a P-spodumene—Si02 soHd solution that could provide an extractable source... 

The resistance of PTFE to creep can be improved by blending in up to 25% of glass or asbestos fibre using PTFE dispersions as mentioned in the previous section. By the same technique alumina, silica and lithia may be incorporated to... 

The performance of a - Mn02 electrodes can be significantly improved if a -Mn02 is reacted with LiOH at 300-400 °C [17-20] these lithia-stabilized... 

Li,, V,0H can be regarded as a lithia-stabilized V205 compound, with notation 0.4 Li20 V2Os., where = 3 = 0.067. 

A comparison of boehmite with other raw materials is included in Table 6. In this table the soda and lithia contents of compositions based on a range of raw materials and the resultant properties are detailed. The level of / "-alumina was always higher with the hydrate-type raw material the hydrothermally prepared raw materials gave the highest content of / " -alumina. 

Similarly, (A )-( )-3-(2-methoxymethyl-l-pyrrolidinyl)-l-phenylpropene118 121, after lithia-tion and addition of acetone, acidic hydrolysis and oxidation of the intermediate lactol, gives (5)-dihydro-5,5-dimethyl-4-phenyl-2(3/f)-furanone with 98% ee and 54% overall yield. Thus, these sequences constitute asymmetric homoaldol addition. 

The synthesis of halogenated TTF is most often based on the lithia-tion/electrophilic halogenation of either the TTF core itself [50] or the five-membered l,3-dithiole-2-thione [36,51]. This procedure has been recently expanded to the analogous l,3-diselenole-2-thione [52,53], allowing for the formation of a wide variety of iodo- and bromotetraselenafulvalenes or dithiadiselenafulvalenes shown in Schemes 6 and 7. 

As the final example in this section, a Li-mediated carboaddition/carbocycliza-tion process will be described. Thus, Cohen and coworkers observed a 5-e%o-trig-cy-clization by reaction of the lithium compound 2-349 and a-methyl styrene 2-350 to give 2-352 via 2-351 (Scheme 2.82). Quenching of 2-352 with methanol then led to the final product 2-353 [189]. In this process, 2-349 is obtained by a reductive lithia-tion of the corresponding phenyl thioether 2-348 with the radical anion lithium 1-(dimethylamino)naphthalenide (LDMAN) (2-354). Instead of the homoallylic substance 2-348, bishomoallylthioesters can also be used to provide substituted six-membered ring compounds. 

The interconnection of two phosphanide substituents by sterically demanding RR Si groups allows the preparation of cage compounds [38], The two-fold lithia-tion of bis(phosphanyl)(alkyl)arylsilane and the dimerization of this bis(phos-phanido)silane leads to the formation of 19 with a strongly distorted Li4P4 hetero-cubane structure according to Eq. (5). 

In the early era of lithium ion cell research, Aurbach et al. noticed that the presence of CO2 in the electrolyte had pronounced effects on the lithia-tion behavior of graphitic anodes. A number of electrolytes, which were thought to be incompatible with graphite because they are based on solvents such as methyl formate or THE, delivered much improved performance under 3—6 atm of C02. ° They proposed that CO2 participated in the formation of the SEI by a two-electron process, yielding Li2C03, which assisted in the buildup of the protective surface film. However, in PC-based electrolytes. CO2 presence proved to be ineffective, while, in electrolytes based on carbonate mixtures such as EC/DMC, the... 

Di-2-thienyl and di-2-furyl ditelluride are prepared from thiophene and furan by lithia-tion with n-buthyllithium, tellurium insertion and oxidative work-up. 

One would expect the presence of trapped electrons in the oxidized samples to give rise to n-type conductivity, conduction possibly taking place by jump migration of the odd electron in the lattice of Cr + ions in a somewhat similar manner to the mechanism discussed by Heikes 174) for the migration of Ni + holes in lithia-doped NiO. The observed p-type conductivity of chromia in an oxygen atmosphere is presumably due to electron holes in a solid which is predominantly CraOs for the low concentrations of chromia-on-alumina where the 7-phase resonance intensity is maximum, the chromium is predominantly in the d-6 valence state 167). 

Korneev and Kaufmann successfully lithiated 2-bromo-l,l-diphenylethylene (46) by bromide-lithium exchange to form 2-lithio-l,l-diphenylethylene (47). A second lithia-tion could be effected in four hours at room temperature by deprotonation of the aromatic ring with w-butyllithium in the presence of TMEDA (Scheme 17). Like in the synthesis of compound 23, the first lithiation activates the ortho-hydrogen atom of the Z-phenyl substituent to give 1,4-dilithium compound 48. In total, three equivalents of the alkyl-lithium base are required the third equivalent is consumed in the trapping reaction of w-bromobutane with generation of octane. 

However, by far the most useful route to 3-pyridyl carbanions is via directed metalation [91AHC(52)187], which can be achieved by the lithia-tion of either 2- or 4-heterosubstituted pyridines (Tables IX and X). 

The 2-position of dibenzofuran represents an average of 88% of the total reactivity of dibenzofuran for protodetritiation, protodetrimethylsilylation, and benzoylation, which accords well with the results recorded for other electrophilic substitution reactions of dibenzofuran. Mercuration and lithia-... 

Mr, Bowen fused the pulverized mineral with caustic potash, dissolved the melt in hydrochloric acid, evaporated the solution to dryness, and digested the residue with warm alcohol That it was really the muriate of lithia, said Bowen, was evident from its tingeing the flame of alcohol of a deep crimson colour and from its affording, when added to a concentrated solution of carbonate of soda, an abundant precipitate of carbonate of lithia. The precise locality of the Spodumen from Deerfield, I am not able to point out.. . (57). 

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