Cesium with ethanol, reaction

The reactions of all the alkali metals with water, of cesium and rubidium with methanol, of cesium with ethanol, and of cesium with HC1 and with NH4Br have been examined. Figure 1 shows a typical oscilloscope trace, and Figure 2 shows a plot of log absorbance vs. time for this trace. The reaction is pseudo-first-order in metal (since solute concentration is ten or more times greater than metal concentration), and the overall rate constants and their order in solute are obtained by varying solute concentration. 

Rate studies of the reaction between cesium and water in ethylenediamine, using the stopped-flow technique, have been extended to all alkali metals. The earlier rate constant (k — 20 NT1 sec.-1) and, in some cases, a slower second-order process (k — 7 Af"1 sec.-1) have been observed. This is consistent with optical absorption data and agrees with recent results obtained in aqueous pulsed-radiolysis systems. Preliminary studies of the reaction rate of the solvated electron in ethylenediamine with other electron acceptors have been made. The rate constant for the reaction with ethylene-diammonium ions is about 105 NCl sec.-1 Reactions with methanol and with ethanol show rates similar to those with water. In addition, however, the presence of a strongly absorbing intermediate is indicated, which warrants more detailed examination. 

Ethanol. Two runs with cesium and ethanol were carried out. Once again the overall reaction times were comparable with those using water. Traces giving two rate constants of 17.0 =t 3.8 and 5.4 M l sec.-1 were observed in some cases. The lower rate constant was obtained from a log k vs. log [EtOH] plot which had a slope of unity. Several traces exhibited nonreproducibility similar to that observed with methanol. 

Reaction with sodium or potassium hydroxide forms trans-osmate ion, trans-[0s04(0H)2]2 , which is reduced by ethanol to form dark purple [0s i(0)2(0H)4]2 . On the other hand, reaction of osmium tetroxide with rubidium or cesium hydroxide in stoichiometric ratios usually form the ions, [0s04(0H)] and [0s0( j,-0H)0s04] in addition to trans-[0s04(0H)2]27... 

Dimethyl- and l,3-dimethyl-5-halo-substituted uracil derivatives react with cesium fluor-oxysulfate under mild reaction conditions. The reaction carried out in an acetonitrile/water mixture or in an alcohol (methanol, ethanol, propan-2-ol or /a7-butyl alcohol) results in the regioselective formation of 5-fluoro-6-hydroxy- or 6-alkoxy-5-lluoro-l, 3-dimethyl-5,6-dihydro-uracil derivatives 27, respectively, while the stereochemistry of the reaction is strongly syn predominant.29... 

The complications which result from the hydrolysis of alkali metal cyanides in aqueous media may be avoided by the use of non-aqueous solvents. The one most often employed is liquid ammonia, in which derivatives of some of the lanthanides and of titanium(III) may be obtained from the metal halides and cyanide.13 By addition of potassium as reductant, complexes of cobalt(O), nickel(O), titanium(II) and titanium(III) may be prepared and a complex of zirconium(0) has been obtained in a remarkable disproportion of zirconium(III) into zirconium(IV) and zirconium(0).14 Other solvents which have been shown to be suitable for halide-cyanide exchange reactions include ethanol, methanol, tetrahydrofuran, dimethyl sulfoxide and dimethylformamide. With their aid, species of different stoichiometry from those isolated from aqueous media can sometimes be made [Hg(CN)3], for example, is obtained as its cesium salt form CsF, KCN and Hg(CN)2 in ethanol.15... 

The cyclic sulfide 1,4,8,11-tetrathiacyclotetradecane has been prepared 1n 7.5% yield by reaction of the bis-Na+ salt of 3,7-dithianonane-1,9-dithiol in boiling ethanol with 1,3-dibromopropane. A marked improvement in yield by the use of cesium salts in N,N-dimethylformamide has been documented for other macrocycllc sulfides,3 as well as macrocycllc lactones, 5 and amines.6 Moreover, the nucleophilic properties of cesium salts have been used to advantage in substitution reactions. ... 

Oxo-2-(trifluoromethyl)-4//-benzopyran-6-yl]methyl esters were proposed by Kemp and Hanson as a benzyl-like protecting group.After reaction of Boc amino acid cesium salts with the corresponding 6-(bromomethyl)-2-(trifluoromethyl)-4//-benzopyran-4-one esters are obtained in good yields. These esters can be used in Boc chemistry, since the N -Boc group can be cleaved in the presence of [4-oxo-2-(trifluoromethyl)-4//-benzopyran-6-yl]methyl esters. They are stable to secondary amines, but are cleaved by unhindered primary amines such as propylamine or dilute ethanolic hydrazine. 

The reaction of Re(CO)5Br with PhCOSH gives the dimeric complex 30, where the thiocarboxyl sulfur atom is coordinated to the two rhenium atoms [99], whereas heating with cesium thiobenzoate in ethanol leads to the anion complexes 31 in which the S-thiobenzoato ligands are triply bridged to the two rhenium atoms [213]. In addition, reaction with Cs2(SOC-COS) affords (OC)5Re(SOC-COS)Re(CO)5 [326], the structure of which resembles that of the corresponding manganese complex 28. 

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