Lithium iodide iodination

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. 

The cathodic reaction is the reduction of iodine to form lithium iodide at the carbon collector sites as lithium ions diffuse to the reaction site. The anode reaction is lithium ion formation and diffusion through the thin lithium iodide electrolyte layer. If the anode is cormgated and coated with PVP prior to adding the cathode fluid, the impedance of the cell is lower and remains at a low level until late in the discharge. The cell eventually fails because of high resistance, even though the drain rate is low. 

Potassium iodide Potassium iodate Lithium iodide Sodium iodide Scrdium iodate Iodine Lead iodide... 

Reduction to Halocarbons. The best conditions for the reductive chlorination of ketones use the reagent combination Me2ClSiH/In(OH)3 (Eq. 241).331 Examples include conversions of aryl ketones to benzyl chlorides, ethynyl ketones to propargyl chlorides, and alkyl ketones to alkyl chlorides (Eq. 242).331 Addition of lithium iodide to the reaction mixture yields the corresponding iodide product. The combination of TMDO/I2 reductively iodinates aryl ketones and aldehydes in good yields (Eq. 243).357... 

Lithium iodide is the electrolyte in a number of specialist batteries, especially in implanted cardiac pacemakers. In this battery the anode is made of lithium metal. A conducting polymer of iodine and poly-2-vinyl pyridine (P2VP) is employed as cathode because iodine itself is not a good enough electronic conductor (Fig. 2.3a). The cell is fabricated by placing the Li anode in contact with the polyvinyl pyridine-iodine polymer. The lithium, being a reactive metal, immediately combines with the iodine in the polymer to form a thin layer of lithium iodide, Lil, which acts as the electrolyte ... 

These diffuse through the lithium iodide via cation vacancies that form as part of the intrinsic Schottky defects in the crystals, to reach the iodine in the cathode (Fig. 2.3b). The electrons lost by the lithium metal on ionizing traverse the external circuit and arrive at the interface between the cathode and the electrolyte. Here they react with the iodine and the incoming Li+ ions to form more lithium iodide. 

Lithium iodide pacemaker batteries use lithum iodide as the electrolyte, separating the lithium anode and the iodine anode. The function of the electrolyte is to transport ions but not electrons. Lithium iodide achieves this by the transport of Li+ ions from the anode to the cathode. This transport is made possible by the presence of Li vacancies that are generated by the intrinsic Schottky defect population present in the solid. Lithium ions jump from vacancy to vacancy during battery operation. 

Lithium hydroxide, 15 134, 140-141 Lithium hypochlorite, 4 52 15 141 pool sanitizer, 26 175 Lithium iodide, 3 417 15 140 Lithium-iodine cells, 3 463-464 characteristics, 3 462t speciality for military and medical use, 3 430t... 

Li2S204 being the SEI component at the Li anode and the solid discharge product at the carbon cathode. The Li—SOCI2 and Li—SO2 systems have excellent operational characteristics in a temperature range from —40 to 60 °C (SOCI2) or 80 °C (SO2). Typical applications are military, security, transponder, and car electronics. Primary lithium cells have also various medical uses. The lithium—silver—vanadium oxide system finds application in heart defibrillators. The lithium—iodine system with a lithium iodide solid electrolyte is the preferred pacemaker cell. 

Naphthalene-catalyzed (5%) lithiation of the diiodinated ketal 205 afforded directly the cyclobutane derivative 206, a i5-iodinated organoUthium compound probably being involved (Scheme 71). In this case, a 5-elimination of lithium iodide is preferred to a y- or 5-elimination of lithium aUcoxide. 

Estimate a value for the radius of the iodide ion. The distance between the lithium and iodine nuclei in lithium iodide is 300 pm. 

Lithium-iodine cells are produced simply by making direct contact between anode and cathode. On touching, a thin layer of lithium iodide is formed by direct reaction. As soon as the layer becomes complete, the reaction rate decreases sharply, since diffusiou of iodine through lithium iodide is very slow. Thus the cell may be written as... 

As a result of the influence of the very great polarizability of the iodine ion it can happen that the order of the boiling points of the alkali iodides is just such that lithium iodide shows the lowest boiling point. Thus it can also be made plausible that... 

Lithium iodide tetrachloride,7 LiICl4,4H20, forms yellow, deliquescent needles, melting at 70° to 80° C., and is prepared by the action of chlorine and iodine on a saturated solution of lithium chloride in hydrochloric acid. 

Stannyl anions with a highly coordinated tin center are also known. A hydridostannyl anion in the shape of a trigonal bipyramid in which two iodine atoms occupy the apical positions was obtained by oxidative addition of lithium iodide to the corresponding tin hydride (equation 58) . It was characterized by Sn NMR. Since apical iodines are more nucleophilic than the hydrogen, in its reactivity with a-ethylenic carbonyl compounds, attack by iodine precedes reduction by hydrogen, achieving regioselective 1,4 reductions. 

The layered oxide ion conductors Srj Bi9 0(27-.t)/2 and BaBigOis show similar intercalation reactions with iodine. The iodine atoms intercalate into the van der Waals gap between adjacent Bi sheets to form stage 1 compounds. The spacing between adjacent Bi layers increases by 3 A corresponding to the intercalation of a monolayer of iodine atoms. Micro-Raman spectroscopy shows that the intercalated iodine species is predominantly I3. Ag-1 intercalated Sri,5Bi7,50i2.75, was synthesized by reaction with iodine and then in a second step with silver metal. Intercalation of lithium iodide into the ferroelectric layered compound Bi4Ti30i2 j has also been reported. ... 

Reduction of the dication 138 by excess lithium iodide gives a complex which seems to exist as an equilibrium mixture of a neutral charge-transfer complex 139 and ion-radical salt 140. The ratio of iodine, = 2.8, is estimated by elemental analysis. ... 

The location of the cation in these canal compounds is not clear, but the cation definitely influences the nature of the crystal which is formed. With sodium and lithium iodides, a form II type of complex crystallizes as hexagonal plates. In the sodium iodide-iodine complex, the inclusion compound is not stoichiometric but rather the iodine atoms are packed into the canals in linear rows, with a spacing not related to the spacing of the dextrin molecules. 

The catalysts used are bromine, iodine, haloamides I and/or polymerization inhibitors, in general in amounts of from 0.0001 to 0.1 preferably from 0.001 to 0.05, mole of catalyst per mole of methyi ketone. Instead of the above catalysts, it is also possible to usr compounds which form such catalysts under the reaction conditions, e.g to use bromides and iodides in place of bromine or iodine. Water-soluble halides are preferred and are advantageously used in the form of thei alkaline earth metal salts or, especially, their alkali metal salts, e.g calcium bromide, calcium iodide, magnesium bromide, magnesiais iodide, lithium bromide, lithium iodide and especially sodium bromide or iodide or potassium bromide or iodide... 

From equation (10) it is evident that if the theory is correct the values of the potential, E, for a given cell should vary directly with the square of the number of revolutions per second, w2, or in other words E/n2 should be a constant. That this is substantially true is shown in Table II which gives the data for a cell containing molal lithium iodide and 0.01 molal iodine. 

HgjCU Noncombustible solid. Violent reaction with sodium. Slow decomposition in light, forming mercury and mercuric chloride. Incompatible with acetylene, alkali chlorides, ammonia, bromides, azides, carbonates, chlorine dioxide, cocaine hydrochloride, cyanides, copper and copper salts, hydrogen peroxide, hydroxides, iodides, iodine, iodoform, lead salts, lithium, potassium iodide, mbidium, silver salts, sodium carbide, sulfates, sulfides, sulfites. On small fires, use any kind of extinguishers. 

The previously unknown phosphoryl iodide has been prepared in 42% yield by treating alkyl phosphoro-iodites ROPI2 with iodine. Although the phosphoro-iodites decompose slowly at —20 C, they can be prepared by reactions between the corresponding dichlorides and lithium iodide at low temperatures. Lower yields of POI3, which is obtained as dark violet crystals melting at 50—53 C, can be obtained from POCI3 and lithium iodide. ... 

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