Reactions with Lithium Vapor

Lithium vapor is much more reactive than even the finest lithium dust. This was shown already in 1955 by H6rold who obtained lithium carbide from graphite in quantitative yield. 

Tetralithiomethane 5 (CLi4) and hexalithioethane 72 (C Li ), the first examples of perlithiated alkanes, were prepared by reacting lithium vapor with the appropriate halocarbon between 800 and 1000 °C 1 ° . 

The main side products were CjLi and CjLi. Starting with partially halogenated hydrocarbons in addition part and sometimes even all of the hydrogens are replaced 

The purest CjLig 12 obtained by using diethylmercury instead of C Clg as the starting material, while (C2H5)4Sn and (C2H5)4Pb delivered mainly ethyllithium (CjHjLi) 

The reaction of carbon vapor with atomic lithium, on the other hand, yielded C3Li4 26 as the main product 

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EXPLOSION and FIRE CONCERNS nonflammable NFPA rating (not rated) explosive reaction with crown ethers or potassium hydroxide violent reaction with lithium, sodium-potassium alloy, acetone, or bases incompatible with metals, caustic alkali, and strong oxidants decomposition emits highly toxic gases and vapors (such as hydrogen bromide and bromine) use dry chemical, carbon dioxide, water spray, fog or foam for firefighting purposes. 

Anionic polymerization of vinyl monomers can be effected with a variety of organometaUic compounds alkyllithium compounds are the most useful class (1,33—35). A variety of simple alkyllithium compounds are available commercially. Most simple alkyllithium compounds are soluble in hydrocarbon solvents such as hexane and cyclohexane and they can be prepared by reaction of the corresponding alkyl chlorides with lithium metal. Methyllithium [917-54-4] and phenyllithium [591-51-5] are available in diethyl ether and cyclohexane—ether solutions, respectively, because they are not soluble in hydrocarbon solvents vinyllithium [917-57-7] and allyllithium [3052-45-7] are also insoluble in hydrocarbon solutions and can only be prepared in ether solutions (38,39). Hydrocarbon-soluble alkyllithium initiators are used directiy to initiate polymerization of styrene and diene monomers quantitatively one unique aspect of hthium-based initiators in hydrocarbon solution is that elastomeric polydienes with high 1,4-microstmcture are obtained (1,24,33—37). Certain alkyllithium compounds can be purified by recrystallization (ethyllithium), sublimation (ethyllithium, /-butyUithium [594-19-4] isopropyllithium [2417-93-8] or distillation (j -butyUithium) (40,41). Unfortunately, / -butyUithium is noncrystaUine and too high boiling to be purified by distiUation (38). Since methyllithium and phenyllithium are crystalline soUds which are insoluble in hydrocarbon solution, they can be precipitated into these solutions and then redissolved in appropriate polar solvents (42,43). OrganometaUic compounds of other alkaU metals are insoluble in hydrocarbon solution and possess negligible vapor pressures as expected for salt-like compounds. 

Lithium Iodide. Lithium iodide [10377-51 -2/, Lil, is the most difficult lithium halide to prepare and has few appHcations. Aqueous solutions of the salt can be prepared by carehil neutralization of hydroiodic acid with lithium carbonate or lithium hydroxide. Concentration of the aqueous solution leads successively to the trihydrate [7790-22-9] dihydrate [17023-25-5] and monohydrate [17023-24 ] which melt congmendy at 75, 79, and 130°C, respectively. The anhydrous salt can be obtained by carehil removal of water under vacuum, but because of the strong tendency to oxidize and eliminate iodine which occurs on heating the salt ia air, it is often prepared from reactions of lithium metal or lithium hydride with iodine ia organic solvents. The salt is extremely soluble ia water (62.6 wt % at 25°C) (59) and the solutions have extremely low vapor pressures (60). Lithium iodide is used as an electrolyte ia selected lithium battery appHcations, where it is formed in situ from reaction of lithium metal with iodine. It can also be a component of low melting molten salts and as a catalyst ia aldol condensations. 

When lithium vapor was reacted with SiCU in a Knudsen cell, and the reaction product was treated with excess methyl chloride, Me4Si was obtained in 5-10% yield. This result was interpreted in terms of the formation of SiLi4117. Interestingly, tetrahedral SiLi4 is a saddle point of 3rd order at the 3-21G level of theory118. The minimum structure of... 

Vanadium oxytrichloride is a lemon-yellow liquid. Its boiling point is 124.5°C. at 736 mm. and 127.16°C. at 760 mm. It remains liquid at —77°. The vapor pressure at —77° is 4.1 mm. at 0°, 21 mm. and at 85°C., 270 mm. Its density in grams per milliliter is 1.854 at 0° and 1.811 at 32°C. At ordinary temperatures, it neither dissolves nor reacts with carbon, hydrogen, nitrogen, oxygen, silicon, tellurium, or metals except the alkali metals and antimony. The reactions with the alkali metals are explosive at characteristic temperatures, varying from 30°C. for cesium to 180°C. for sodium (lithium not determined). Small... 

The cleavage of a P-Ph bond (method (1)) has been widely used to create a variety of phospholide salts. Notably, this methodology has been employed in the synthesis of group 13 phospholyl complexes, which have come to the fore in recent years as potential single source substrates for the preparation of the corresponding metal phosphides by chemical vapor deposition (CVD). This is exemplified by the reaction of lithium 2,5-di(tert-butyl)phospholide with GaBr to afford a Ga(l) polymer 297 (Scheme 101) <1999AGE1646>. Additionally, this synthesis nicely illustrates the use of bulky substituents in the position a to phosphorus to favor -coordination. 

SAFETY PROFILE A highly corrosive irritant to the eyes, skin, and mucous membranes. Mildly toxic by inhalation, Explosive reaction with alcohols + hydrogen cyanide, potassium permanganate, sodium (with aqueous HCl), tetraselenium tetranitride. Ignition on contact with aluminum-titanium alloys (with HCl vapor), fluorine, hexa-lithium disilicide, metal acetylides or carbides (e.g., cesium acetylide, rubidium ace-tylide). Violent reaction with 1,1-difluoro-ethylene. Vigorous reaction with aluminum, chlorine + dinitroanilines (evolves gas). Potentially dangerous reaction with sulfuric acid releases HCl gas. Adsorption of the acid onto silicon dioxide is exothermic. See also HYDROGEN CHLORIDE (AEROSOL) and HYDROCHLORIC ACID. 

SAFETY PROFILE A powerful irritant to skin, eyes, and mucous membranes. Flammable when exposed to heat or flame. Ammonia is liberated and Uthium hydroxide is formed when this compound is exposed to moisture. Reacts violently with water or steam to produce toxic and flammable vapors. Vigorous reaction with oxidizing materials. Exothermic reaction with acid or acid fumes. When heated to decomposition it emits very toxic fumes of LiO, NH3, and NOx. Used in synthesis of drugs, vitamins, steroids, and other organics. See also LITHIUM COMPOUNDS, AMIDES, AMMONIA, and LITHIUM HYDROXIDE. 

SAFETY PROFILE A very dangerous fire hazard in the form of dust when exposed to heat or flame or by chemical reaction with moisture or acids. In contact with water, silane and hydrogen are evolved. Slighdy explosive in the form of dust when exposed to flame. Will react with water or steam to produce flammable vapors on contact with oxidizing materials, can react vigorously on contact with acid or acid fumes, can emit toxic and flammable fumes. To fight fire, use CO2, dry chemical. See also LITHIUM, SILICON, and POWDERED METALS. 

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