Caesium chloride, reaction

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... 

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 ... 

Of particular interest is Caesium Chlor-ruthenite, Cs,.RuC]6.H20, which Howe4 obtained by the action of hydrochloric acid on ruthenium tetroxide and subsequent addition of caesium chloride to the solution. The salt is precipitated as a dark brown powder, fairly soluble in water and hydrochloric acid, exhibiting the chemical reactions of a trivalent ruthenium salt. Howe also describes an isomeride of this salt, which lie termed, in accordance with Werner s nomenclature, Caesium Aquo-chlor-ruthenate [vide infra). 

Analogous anionic complexes with other monodentate ligands replacing fluorine are not formed so readily. Thus matrix isolation studies9 failed to result in the formation from methyltrifluorosilane and caesium chloride of the complex Cs+[MeSiF3Cl] under conditions where a similar reaction of the fluorosilane with caesium fluoride allowed... 

In all these studies by Jonah et al., no estimate of the variation of encounter radius or diffusion coefficient was made, though they were presumed to be small changes with electrolyte concentration. In studies on aqueous solutions of LiCl (0—14mldm ) or CsCl (0—6 mol dm ) at 293 K containing electron scavengers nitrobenzene, IrCl or Fe(CN) , Hankiewicz and Schulte-Frohlinde [120] produced hydrated electrons by pulse radiolysis and observed the decays. For reactions between eaq and nitrobenzene, the rate coefficient was independent of the caesium chloride concentration (just as the viscosity is independent of CsCl concentration), while with lithium chloride, the rate coefficient decreased exponentially with LiCl concentration (the viscosity is 0.001 exp (0.059 [LiCl] Pa s). They estimated that the reaction radius, R, was constant to within 5% over all the change of electrolyte concentration... 

The first syntheses were developed in the 1980s by Kozo Shiokawa at Nihon Bayer Agrochem. The iminoimidazolidine was formed by reaction of the diamine with cyanogen bromide however, this product could be nitrated on the nitrogen in only poor yields (a). [ 145] Shigeru Kojima prepared imidacloprid by reaction of the diamine with dimethyl nitrocarboimidodithioate in dichloro-methane (b). [146] The best synthesis is probably the reaction of 2-chloro-5-(chloromethyl)pyridine and 2-nitroiminoimidazolidine with potassium carbonate in acetonitrile. [ 147] The reaction may be catalysed by 3-5 mole percent of caesium chloride (c). [148]... 

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). 

Precipitate with aq. ammonia. Evaporate the soln. down to about 100 c.c., and filter the ot liquid so as to remove calcium sulphate. The cone. soln. is sat. with ammonium alum and allowed to stand for some time. The mixed crystals of potassium, rubidium, and oeesium alums and of lithium salt are dissolved in 100 c.c. of distilled water and recrystal-lized. The recrystallization is repeated until the crystals show no spectroscopic reaction for potassium or lithium. The yield naturally depends on the variety of lepidolite employed. 100. grms of an average sample gives about 10 grms. of crude crystals and about 3 grms. of the purified caesium and rubidium alums. For the purification of caesium and rubidium salts, see the chlorides. The mother-liquors are treated with an excess of barium carbonate, boiled, and filtered. The filtrate is acidified with hydrochloric acid, and evaporated to dryness. The residue is extracted with absolute alcohol in which lithium chloride is soluble, and the other alkali chlorides are sparingly soluble. 

By appending crown ether moieties to the amidopyrrole skeleton it had been shown that it is possible to both enhance the binding of anions to the cleft by the introduction of caesium cations but only with a limited degree of success (Figure 16).13 Compounds 16 and 17 were synthesized by reaction of the 4 -aminobenzo-15-crown-5 with the 2-methyl-5-mono-acid chloride-3,4-diphenylpyrrole and the analogous 2,5-bis-acid chloride in 28 and 33% respective yields. 

It should be noted that while enyne metathesis is considered incompatible with molybdenum catalyst 1, ruthenium catalysts other than the Grubbs type also promote the reaction. Semeril et al. [103] reported efficient enyne RCM with a catalyst conveniently generated in situ from [RuCl2(p-cymene)]2,1,3-bis(mesityl)imidazolium chloride and caesium carbonate. Interestingly the authors found that the in situ derived system gave better results than the isolated catalyst. One of the most impressive examples of the use of enyne RCM is the total synthesis of (-)-longithorone by Layton et al. [104]. Inspired by a pro-... 

For an example of a related cyclisation reaction using caesium carbonate as a base in DMF, see Protocol 3. The starting ditoluenesulfonamide (m.p. 119-20°C) is readily prepared by reaction of the corresponding diamine with p-toluenesulfonyl chloride (aq NaOH/Et2OI. 

Reaction of a mixture containing hexafluoroacetone and caesium fluoride with allyl bromide or chloride occurs readily [131, 132] (Figure 8.31) but the mixture does not react with trimethylchlorosilane [131]. 

The two extrathermodynamic assumptions used in Table 9 to derive solvent activity coefficients of anions, lead to different values of y cicHsi-)+ The assumption (i) that caesium cation is similarly solvated in methanol and in DMF, suggests that the large rate difference between reaction (27) in methanol and in DMF is as much due to differences in transition state solvation as to differences in solvation of chloride ion. This is the situation shown qualitatively in Fig. 1. On the other hand, the somewhat smaller rate difference between reaction (27) in formamide and in DMF is due entirely to differences in solvation of chloride ion, if the caesium assumption is applied to formamide and to DMF. 

Under conditions mentionned in Table 21, tetramethylammonium chloride is more effective than caesium fluoride to improve the Halex reaction on DCNB at 130°C (refs. 65 - 67). However, a synergistic effect is observed when combining these two catalysts (Table 22). 

---