Caesium reaction

The catalytic activity of doped nickel oxide on the solid state decomposition of CsN3 decreased [714] in the sequence NiO(l% Li) > NiO > NiO(l% Cr) > uncatalyzed reaction. While these results are in qualitative accordance with the assumption that the additive provided electron traps, further observations, showing that ZnO (an rc-type semi-conductor) inhibited the reaction and that CdO (also an rc-type semi-conductor) catalyzed the reaction, were not consistent with this explanation. It was noted, however, that both NiO and CdO could be reduced by the product caesium metal, whereas ZnO is not, and that the reaction with NiO yielded caesium oxide, which is identified as the active catalyst. Detailed kinetic data for these rate processes are not available but the pattern of behaviour described clearly demonstrates that the interface reactions were more complicated than had been anticipated. 

Kinetic studies of base-catalysed hydrogen exchange have been carried out by Roberts, by Shatenshtein, and by Streitweiser and their coworkers. In earlier work, potassium amide was used as base in liquid ammonia as solvent, whereas later workers used lithium and caesium cyclohexylamides in cyclohexylamine. The reaction can be represented by equilibria (239) and (240)... 

Kinetic studies with caesium cyclohexylamide have also been performed593. For reaction of tritiated benzene, the kinetic order was one in both hydrocarbon and caesium cyclohexylamide ion-pair (Table 180) and rate coefficients were... 

Rubidium is more reactive than potassium. Therefore there is greater risk of dangerous reactions of the seime nature. Since it belongs to the category of alkali metals which are less used, like caesium, this explains why there is only a small number of accidents. 

Reaction of caesium or potassium ozonides with water or aqueous acids is violent, producing oxygen and flashes of light. 

Sodium hydride ignites in oxygen at 230°C, and finely divided uranium hydride ignites on contact. Lithium hydride, sodium hydride and potassium hydride react slowly in dry air, while rubidium and caesium hydrides ignite. Reaction is accelerated in moist air, and even finely divided lithium hydride ignites then [1], Finely divided magnesium hydride, prepared by pyrolysis, ignites immediately in air [2], See also COMPLEX HYDRIDES... 

The electrides. Following many experimental difficulties, Dye and coworkers were able to demonstrate that reaction of 18-crown-6 with caesium in a 1 2 ratio (under specified conditions) leads to isolation of shiny, black crystals of a product of composition Cs+(18-crown-6)2 (El-laboudy, Dye Smith, 1983 Dye Ellaboudy, 1984). The solid-state 133Cs nmr spectrum, the esr spectrum, and the magnetic susceptibility of this product all indicated that it was of type Cs+(l8-crown-6).e" that is, a crystalline electride in which the anion is a single electron. In overall terms, this exotic class of compound may be considered to lie on the border between metals and non-metals. 

Due to the high interest in metalation reactions with lithium amide or alkyllithiums, an indicator scale of lithium ion pairs in THF has been developed119. Aggregation studies have indicated that organolithium species exist predominantly, if not exclusively, as monomers in the 10-3-10-4 M concentration range. Particular attention has been devoted to the lithium and caesium ion-pair acidities of diphenylamine in THF120 that, at 25 °C, have been found to be 19.05 and 24.20, respectively. 

Reactions of amines with alkenes have been reviewed298,299. Alkali metal amides are active homogeneous catalysts for the amination of olefins. Thus diethylamine and ethylene yield triethylamine when heated at 70-90 °C at 6-10 atm in the presence of lithium diethylamide and /V./V./V. /V -tetrarncthylcthylcncdiaminc. Solutions of caesium amide promote the addition of ammonia to ethylene at 100 °C and 110 atm to give mixtures of mono-, di- and triethylamines300. The iridium(I)-catalysed addition of aniline to norbomene affords the anilinonorbomane 274301. Treatment of norbomene with aniline... 

The collected papers of a symposium at Dallas, April 1956, cover all aspects of the handling, use and hazards of lithium, sodium, potassium, their alloys, oxides and hydrides, in 19 chapters [1], Interaction of all 5 alkali metals with water under various circumstances has been discussed comparatively [2], In a monograph covering properties, preparation, handling and applications of the enhanced reactivity of metals dispersed finely in hydrocarbon diluents, the hazardous nature of potassium dispersions, and especially of rubidium and caesium dispersions is stressed [3], Alkaline-earth metal dispersions are of relatively low hazard. Safety practices for small-scale storage, handling, heating and reactions of lithium potassium and sodium with water are reviewed [4],... 

Crystallisation was one of the earliest methods used for separation of radioactive microcomponents from a mass of inert material. Uranium X, a thorium isotope, is readily concentrated in good yield in the mother liquors of crystallisation of uranyl nitrate (11), (33), (108). A similar method has been used to separate sulphur-35 [produced by the (n, p) reaction on chlorine-35] from pile irradiated sodium ot potassium chloride (54), (133). Advantage is taken of the low solubility of the target materials in concentrated ice-cold hydrochloric acid, when the sulphur-35 as sulphate remains in the mother-liquors. Subsequent purification of the sulphur-35 from small amounts of phosphorus-32 produced by the (n, a) reaction on the chlorine is, of course, required. Other examples are the precipitation of barium chloride containing barium-1 from concentrated hydrochloric acid solution, leaving the daughter product, carrier-free caesium-131, in solution (21) and a similar separation of calcium-45 from added barium carrier has been used (60). 

The structure of Helvite, Mn CBeSiOJjS, has been reported. The tetrahedral manganese ii) ions are bonded to one sulphur and three oxygen atoms. M2Mn3S4 (M = Rb or Cs) have been prepared by reactions in the molten state under nitrogen. An X-ray study on the caesium compound showed the manganese and caesium atoms to be arranged in layers separated by layers of sulphur atoms. ... 

In their review of the classification of donors and acceptors in inorganic reactions, Williams and Hale (7) pointed out that for reactions in water, class (a) character was exhibited most strongly by lithium and least by caesium, which was indeterminate between classes (a) and (b). Here class (a) character means that the fluoride is more stable in water than the iodide. In general Group IA metals prefer hard ligands, F, O, N their interaction with sulphur and carbon is considered in para. IV. 

The reaction between dry phosphine and hydrogen iodide, first described in 1817 by J. J.Houtonde la Billardiere produces phosphonium iodide. The simplest laboratory preparation of this compound is by the hydrolysis of an intimate mixture of diphosphorus tetraiodide and white phosphorus According to X-ray diffraction investigations, phosphonium iodide crystallises in a caesium chloride type lattice 3m,32s). 326) hydrogen atoms... 

A reaction of sulfoximine 268 with ort o-substituted halobenzaldehydes 269 takes place in the presence of a catalytic amount of Pd(ii), 2,2 -bis(diphenylphosphanyl)-l,l -binaphthyl (BINAP), and caesium carbonate at 110°C to afford fully conjugated 2-phenyl-2,l-benzothiazine 2-oxides 270 with a S(vi) oxidation state (Scheme 38) <1999AGE2419>. Bis-benzothiazine 75 has been prepared from dibromo-dialdehyde 271 in a similar manner and investigated as a ligand for Pd-catalyzed allylic alkylation reactions (see Section 8.07.12.3) <20010L3321>. 

Butler and co-workers studied the quatemisation of 3,5-diaryl-l,2,4-thiadiazoles 77 with trimethylsilylmethyl triflate at 40 °C and observed reaction at N-2 to give salt 78. Desilyation of 78 with caesium fluoride resulted in ring expansion to 2ff-l,3,5-thiadiazines 79 which on heating in ethanolic sodium ethoxide gave 2,4-... 

The tonic compound caesium chloride, Cs + CI-, dissolves readily in water to give a solution containing the individually hydrated Cs+ (aq) and Cl-(aq) ions. The thermodynamic parameters for the formation reaction of Cs hCl and for the reaction of its solution in water are ... 

The same reaction, the conversion of 2-iodophenol to 2-arylbenzofuranes was also accomplished in the presence of a copper-phenantroline catalyst and caesium carbonate. Different arylacetylenes and iodophenols were coupled to give the corresponding benzofurane derivatives in good to excellent yield (3.55.)71... 

The 7V-arylation of indoles has been achieved both in palladium and copper catalyzed coupling reactions. In an early example Hartwig succeeded in converting indole to 1-arylindoles in excellent yield, using a palladium -dppf catalyst and caesium carbonate as base (6.71.)."a Buchwald99b and... 

The coupling of secondary phosphines with aryl iodides was also extended to pyridines. 3-Iodopyridine and diphenylphosphine were coupled to give 3-diphenylphosphino-pyridine in 60% yield (7.80.), The catalyst in this reaction consisted of copper(I) iodide and N,N -dimethylethylenediamine and caesium carbonate was used again as base.102... 

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