Lithium carbon dioxide

As with the hydroxides, we find that whilst the carbonates of most metals are insoluble, those of alkali metals are soluble, so that they provide a good source of the carbonate ion COf in solution the alkali metal carbonates, except that of lithium, are stable to heat. Group II carbonates are generally insoluble in water and less stable to heat, losing carbon dioxide reversibly at high temperatures. 

For initial experience in the uae of Uthium, the preparation of either p-toluic acid or of a-napbtboic acid mcay be undertaken. For the former, p-bromotoluene is converted into the lithium derivative and the latter carbonated with soUd carbon dioxide ... 

It is advisable to filter the a-picolyl-lithium solution rapidly through a thin layer of glass wool (to remove any unreacted lithium) on to the solid carbon dioxide. 

A solution of 0.20 mol of butyl lithium in about 140 ml of hexane was cooled to -6Q°C and 140 ml of dry THF were added. The mixture was cooled to about -80 C (liquid nitrogen bath) and 0.23 mol of the allenic hydrocarbon (see Chapter VI, Exp. 1, 2, 44) was added in 5 min (methylal1ene was added as a 1 1 solution in THF). The solutions were kept for 1 h at -55°C. Into another 1-1 flask (see also Fig. 1, but without a dropping funnel), cooled at -90°C by immersion in liquid nitrogen, was poured a solution of dry carbon dioxide (from a cylinder) in 130 ml of dry THF. This solution was obtained by introducing about 40 g of carbon dioxide (note 1) into the THF at -90°C. The gas inlet was removed from the second flask and the solution of the lithiated allene (still cooled below -60 C) was poured... 

One ion-exchange process, which was used for several years by Quebec Lithium Corp., is based on the reaction of P-spodumene with an aqueous sodium carbonate solution in an autoclave at 190—250°C (21). A slurry of lithium carbonate and ore residue results, and is cooled and treated with carbon dioxide to solubilize the lithium carbonate as the bicarbonate. The ore residue is separated by filtration. The filtrate is heated to drive off carbon dioxide resulting in the precipitation of the normal carbonate. 

Anhydrous lithium hydroxide [1310-65-2], LiOH, is obtained by heating the monohydrate above 100°C. The salt melts at 462°C. Anhydrous lithium hydroxide is an extremely efficient absorbent for carbon dioxide (qv). The porous stmcture of the salt allows complete conversion to the carbonate with no efficiency loss in the absorption process. Thus LiOH has an important role in the removal of carbon dioxide from enclosed breathing areas such as on submarines or space vehicles. About 750 g of lithium hydroxide is required to absorb the carbon dioxide produced by an individual in a day. 

Lithium Oxide. Lithium oxide [12057-24-8], Li20, can be prepared by heating very pure lithium hydroxide to about 800°C under vacuum or by thermal decomposition of the peroxide (67). Lithium oxide is very reactive with carbon dioxide or water. It has been considered as a potential high temperature neutron target for tritium production (68). 

Lithium Peroxide. Lithium peroxide [12031 -80-0] Li202, is obtained by reaction of hydrogen peroxide and lithium hydroxide in ethanol (72) or water (73). Lithium peroxide, which is very stable as long as it is not exposed to heat or air, reacts rapidly with atmospheric carbon dioxide releasing oxygen. The peroxide decomposes to the oxide at temperatures above 300°C at atmospheric pressure, and below 300°C under vacuum. 

Peroxides. In the presence of lithium peroxide, both water and carbon dioxide react, resulting in evolution of oxygen. The following steps have been postulated (17) ... 

Because of the delay in decomposition of the peroxide, oxygen evolution follows carbon dioxide sorption. A catalyst is required to obtain total decomposition of the peroxides 2 wt % nickel sulfate often is used. The temperature of the bed is the controlling variable 204°C is required to produce the best decomposition rates (18). The reaction mechanism for sodium peroxide is the same as for lithium peroxide, ie, both carbon dioxide and moisture are required to generate oxygen. Sodium peroxide has been used extensively in breathing apparatus. 

Potassium Superoxide. Potassium, mbidium, and cesium form superoxides, MO2, upon oxidation by oxygen or air. Sodium yields the peroxide, Na202 lithium yields the oxide, Li20, when oxidized under comparable conditions. Potassium superoxide [12030-88-5] KO2 liberates oxygen in contact with moisture and carbon dioxide (qv). This important property enables KO2 to serve as an oxygen source in self-contained breathing equipment. 

Gas-phase oxidation of propylene using oxygen in the presence of a molten nitrate salt such as sodium nitrate, potassium nitrate, or lithium nitrate and a co-catalyst such as sodium hydroxide results in propylene oxide selectivities greater than 50%. The principal by-products are acetaldehyde, carbon monoxide, carbon dioxide, and acrolein (206—207). This same catalyst system oxidizes propane to propylene oxide and a host of other by-products (208). 

Ion Selective Electrodes Technique. Ion selective (ISE) methods, based on a direct potentiometric technique (7) (see Electroanalytical techniques), are routinely used in clinical chemistry to measure pH, sodium, potassium, carbon dioxide, calcium, lithium, and chloride levels in biological fluids. 

Simultaneous elimination of chloride ion and carbon dioxide occurs dunng heating of methyl chlorodifluoroacetate with lithium chloride in hexamethyl-phosphoric tnamide (HMPA) The difluorocarbene generated in this way is trapped by electron-rich alkenes to form 1,1-difluorocyclopropanes [26] (equation 24)... 

Carbon dioxide may be eliminated even from the ester of a fluonnated acid by using lithium chlonde-hexamethylphosphonc tnamide complex at reflux temperature The intermediate carbene is formed in 78-90% yield [96, 97] (equation 64)... 

The in situ generation of the carbon dioxide adduct of an indole provides sufficient protection and activation of an indole for metalation at C-2 with r-butyl-lithium. The lithium reagent can be quenched with an electrophile, and quenching of the reaction with water releases the carbon dioxide. ... 

Leclanche or dry cell Alkaline Cell Silver-Zinc Reuben Cell Zinc-Air Fuel Cell Lithium Iodine Lithium-Sulfur Dioxide Lithium-Thionyl Chloride Lithium-Manganese Dioxide Lithium-Carbon Monofluoride... 

The poor efficiencies of coal-fired power plants in 1896 (2.6 percent on average compared with over forty percent one hundred years later) prompted W. W. Jacques to invent the high temperature (500°C to 600°C [900°F to 1100°F]) fuel cell, and then build a lOO-cell battery to produce electricity from coal combustion. The battery operated intermittently for six months, but with diminishing performance, the carbon dioxide generated and present in the air reacted with and consumed its molten potassium hydroxide electrolyte. In 1910, E. Bauer substituted molten salts (e.g., carbonates, silicates, and borates) and used molten silver as the oxygen electrode. Numerous molten salt batteiy systems have since evolved to handle peak loads in electric power plants, and for electric vehicle propulsion. Of particular note is the sodium and nickel chloride couple in a molten chloroalumi-nate salt electrolyte for electric vehicle propulsion. One special feature is the use of a semi-permeable aluminum oxide ceramic separator to prevent lithium ions from diffusing to the sodium electrode, but still allow the opposing flow of sodium ions. 

Introduction of an iodine to C-2 of indole can be accomplished using lithium derivatives. Since direct iodination tends to give mixtures it is essential to activate the 2-position at the expense of the inherently more reactive 3-position. This has been done by lithiating 1-f-butoxycarbonylin-doles (25) and then converting them into iodo derivatives before deprotection (85JHC505) (Scheme 19). Alternatively carbon dioxide can be used... 

Mn02 is used for the same purpose as the cathode active material in lithium-manganese dioxide (Li - Mn02) batteries it has been used for a long time in zinc-carbon and alkaline-manganese dioxide batteries, which are aqueous-electrolyte systems. 

Carbon dioxide has been proposed as an additive to improve the performance of lithium batteries [60]. Aurbach et al. [61] studied the film formed on lithium in electrolytes saturated with C02, and using in situ FTIR found that Li2C03 is a major surface species. This means that the formation of a stable Li2C03 film on the lithium surface may improve cyclability [62], Osaka and co-workers [63] also studied the dependence of the lithium efficiency on the plating substrate in LiC104-PC. The addition of C02 resulted in an increase in the efficiency when the substrate was Ni or Ti, but no effect was observed with Ag or Cu substrates. 

Unfortunately, both lithium and the lithiated carbons used as the anode in lithium ion batteries (Li C, l>x>0) are thermodynamically unstable relative to solvent molecules containing polar bonds such as C-O, C-N, or C-S, and to many anions of lithium salts, solvent or salt impurities (such as water, carbon dioxide, or nitrogen), and intentionally added traces of reactive substances (additives). 

Passivating films may change their chemical composition after their formation due to reactions with water or carbon dioxide lithium alkylcarbonates react with traces of water to yield lithium carbonate (see Table 8). 

Carbon dioxide as additive improves the behavior of (Li02C0CH2)2 films formed above intercalation potentials in EC/DEC-based electrolytes due to increased formation of Li 2 CO 3 [200], It is interesting to note that SO2 reduction occurs at quite high potentials, before the reduction of other electrolyte components films contain inorganic and organic lithium salts [201]. 

Tin/lithium exchange on the a-alkoxy stannanes and subsequent addition of carbon dioxide led to optically active (7-protected a-hydroxy acids 18 with retention of configuration and without any loss of stereochemical information11. 

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