Lithium chromite

Lithium Chromite, Li O.CrjOa, is produced by fusing lithium chromate with kaolin. - Brown octahedra. 

Modification of the burning rates, pressure exponents, and temp coefficients of burning rate of the fluorocarbon composites has been accomplished with copper, lead, tin, sodium, ammonium and potassium fluoborates sodium, potassium, lithium, lead, copper and calcium fluorides potassium and ammonium dichromate lead and zinc stearate cesium carbonate potassium and ammonium sulfate copper chromite oxides of magnesium, copper and manganese boron zinc dust and carbon black (Ref 75)... 

Horton (H9, H10) has obtained additional acoustic-admittance data for a series of composite propellants. At a given frequency, decreasing the mean oxidizer particle size increases the acoustic admittance and thereby the tendency for instability. Horton also investigated the effects on the acoustic admittance of the incorporation of traces of copper chromite, a known catalyst, for the decomposition of ammonium perchlorate, lithium fluoride (a burning-rate depressant), and changes in binder these data are difficult to analyze because of experimental errors. 

Reduction of unsaturated ketones to saturated alcohols is achieved by catalytic hydrogenation using a nickel catalyst [49], a copper chromite catalyst [50, 887] or by treatment with a nickel-aluminum alloy in sodium hydroxide [555]. If the double bond is conjugated, complete reduction can also be obtained with some hydrides. 2-Cyclopentenone was reduced to cyclopentanol in 83.5% yield with lithium aluminum hydride in tetrahydrofuran [764], with lithium tris tert-butoxy)aluminium hydride (88.8% yield) [764], and with sodium borohydride in ethanol at 78° (yield 100%) [764], Most frequently, however, only the carbonyl is reduced, especially with application of the inverse technique (p. 21). 

Usually alcohols accompany aldehydes in reductions with lithium aluminum hydride [1104] or sodium bis 2-methoxyethoxy)aluminum hydride [544], or in hydrogenolytic cleavage of trifluoroacetylated amines [7772]. Thus terr-butyl ester of. -(. -trifluoroacetylprolyl)leucine was cleaved on treatment with sodium borohydride in ethanol to rerr-butyl ester of A7-prolylleucine (92% yield) and trifluoroethanol [7772]. During catalytic hydrogenations over copper chromite, alcohols sometimes accompany amines that are the main products [7775]. 

Phthalimide was hydrogenated catalytically at 60-80° over palladium on barium sulfate in acetic acid containing an equimolar quantity of sulfuric or perchloric acid to phthalimidine [7729]. The same compound was produced in 76-80% yield by hydrogenation over nickel at 200° and 200-250 atm [43 and in 75% yield over copper chromite at 250° and 190 atm [7730]. Reduction with lithium aluminum hydride, on the other hand, reduced both carbonyls and gave isoindoline (yield 5%) [7730], also obtained by electroreduction on a lead cathode in sulfuric acid (yield 72%) [7730]. 

Esters may alternatively be reduced to primary alcohols either using hydrogen under pressure in the presence of a copper chromite catalyst,56 or with lithium aluminium hydride (Expt 5.38), but not with sodium borohydride which is insufficiently reactive. However it has been found recently that sodium borohydride in mixed solvents (methanol/tetrahydrofuran) reduces /1-ketoesters to 1,3-diols, and this method offers a convenient route to this type of compound.57... 

Like the parent compounds, the methyl ethers of aldobiouronic acids are resistant to acid hydrolysis, and it is difficult to carry out hydrolysis without some decomposition of the product. This difficulty has recently been overcome by reduction of the uronic acid residue with lithium aluminum hydride66-67 the resulting disaccharide then undergoes hydrolysis without difficulty. The first reduction of the uronic acid residue of a methylated aldobiouronic acid methyl ester was accomplished by Levene, Meyer and Kuna,69 who reduced the methylated aldobiouronic acid from gum arabic with hydrogen in the presence of copper chromite catalyst under the conditions previously used701 for reducing the acety-... 

Hydrogenation Copper chromite (Lazier catalyst). Copper chromium oxide (Adkins catalyst). Lindlar catalyst (see also Lithium ethoxyacetylide, Malealdehyde, Nickel boride). Nickel catalysts. Palladium catalysts. Palladium hydroxide on carbon. Perchloric acid (promoter). Platinum catalysts. Raney catalysts, Rhenium catalysts. Rhodium catalysts. Stannous chloride. Tributylborane. Trifluoroicetic acid, Tris (triphenylphosphine)chlororhodium. 

The parent base, morphan, has been synthesized as follows. Condensation of m-nitrobenzaldehyde with benzoyl chloride and sodium cyanide yielded [cxl], which was converted to [cxli] and hydrogenated over Raney nickel at 200° C. to give [cxt.tt] the latter was then reduced to morphan [cxliji] with hydrogen and copper chromite [45], Morphan may be more simply prepared by the hydrogenation of ethyl m-nitro-phenylacetate over platinum oxide, followed by reduction of the [oxui] so formed by lithium aluminium hydride [40],... 

Reducing agents Aluminum hydride. Bis-3-methyl-2-butylborane. n-Butyllithium-Pyridine. Calcium borohydride. Chloroiridic acid. Chromous acetate. Chromous chloride. Chromous sulfate. Copper chromite. Diborane. Diborane-Boron trifluoride. Diborane-Sodium borohydride. Diethyl phosphonate. Diimide. Diisobutylaluminum hydride. Dimethyl sulfide. Hexamethylphosphorous triamide. Iridium tetrachloride. Lead. Lithium alkyla-mines. Lithium aluminum hydride. Lithium aluminum hydride-Aluminum chloride. Lithium-Ammonia. Lithium diisobutylmethylaluminum hydride. Lithium-Diphenyl. Lithium ethylenediamine. Lithium-Hexamethylphosphoric triamide. Lithium hydride. Lithium triethoxyaluminum hydride. Lithium tri-/-butoxyaluminum hydride. Nickel-aluminum alloy. Pyridine-n-Butyllithium. Sodium amalgam. Sodium-Ammonia. Sodium borohydride. Sodium borohydride-BFs, see DDQ. Sodium dihydrobis-(2-methoxyethoxy) aluminate. Sodium hydrosulflte. Sodium telluride. Stannous chloride. Tin-HBr. Tri-n-butyltin hydride. Trimethyl phosphite, see Dinitrogen tetroxide. 

Z. Weyberg reported crystals of lithinm chromite, LiCrOg, to be formed along with lithium aluminate when mixtures of an excess of lithium chromate with china clay are calcined. The brown powder consists of microscopic, isotropic, octahedral crystals. As previously indicated, there are differences of opinion as to the nature of the green liquid obtained when freshly precipitated hydrated chromic oxide is treated with alkali-lye. The process is one of either peptization or dissolution or else it includes both. R. Kremann, M. Kreps, and J. K. Wood and V. K. Black consider that the soln. of hydrated chromic oxide in alkali is chromite while W. Herz and H. W. Fischer, A. Hantzsch, C. F. Nagel, W. V. Bhagwat and N. R. Dhar, and H. B. Weiser consider it to be peptized, hydrated chromic oxide. C. Fricke and... 

Esters of long-chain acids can be reduced to the corresponding alcohols. In the laboratory this is most conveniently effected with lithium aluminium hydride. On an industrial scale reduction is effected by copper chromite at high temperature and pressure though this reaction may be accompanied by some hydrogenation of double bonds. 

Regarding ceramic-containment materials," sihca, SiO, and alumina, Al O, are strongly attacked and hence readily dissolve in liquid lithium. By contrast, alkaline-earth oxides such as beryllia (BeO), magnesia (MgO), and calcia (CaO) and rare-earth oxides such as ceria (CeOJ, yttria (YfiJ, chromite spinel (FeCr OJ, and yttrium aluminum garnet (Y AljOj ) seem to be noncorroded below 500 C, while aluminum, titanium, and zirconium nitrides or... 

LaCrOs, LaFeOg, and LaMnOs perovskite catalysts were compared and the highest activity for soot combustion of the chromite catalyst was related to its highest concentration of suprafacial, weakly chemisorbed oxygen, which actively contributes to soot combustion by spillover in the temperature range of 300-500 °C [29]. The introduction of lithium into the chromium position of LaCrOs soot combustion perovskite catalysts has also shown to improve the activity due to enhancement of the amount of weakly chemisorbed oxygen 0 species [30]. 

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