KINETICS AND MECHANISM OF COMPLEX FORMATION BETWEEN ETHYLENE AND RUTHENIUM(II) CHLORIDE IN AQUEOUS SOLUTION

1966 ◽  
Vol 44 (4) ◽  
pp. 495-500 ◽  
Author(s):  
Jack Halpern ◽  
Brian R. James

The formation of a 1:1 π-complex between ethylene and ruthenium(II) in aqueous hydrochloric acid solution is described. The kinetics of the reaction were examined over a range of temperatures and of concentrations of ruthenium(II), ethylene, hydrogen ion, and chloride ion. The results suggest that complex formation proceeds through a stepwise (SN1) mechanism in which the initial step involves the dissociation of a chlororuthenate(II) complex.

Author(s):  
Owen Rhys Howell ◽  
Albert Jackson ◽  
Eric Keightley Rideal

The change in the absorption spectrum of cobalt chloride in aqueous solution with increasing concentration of hydrochloric acid at constant temperature (20° C) has already been investigated.* It was shown that with increasing concentration of acid up to 5N HCl, no blue constituent was formed. The cobalt atom, therefore, retains its six grouping over this range. The effect of increasing acid concentration is to replace two molecules of water by two atoms of chlorine: [Co(H 2 O) 6 ] → [Co(H 2 O) 4 Cl 2 ].


1965 ◽  
Vol 18 (10) ◽  
pp. 1507 ◽  
Author(s):  
RD Brown ◽  
AS Buchanan ◽  
AA Humffray

The kinetics of protodemercuration, or displacement of the HgCl group by hydrogen, have been measured for phenylmercuric chloride, and also for its meta and para methyl-, chloro-, and methoxy-substituted derivatives. The reactions of the compounds with aqueous alcoholic hydrochloric acid were first order in RHgC1, first order in hydrogen ion, and zero order in chloride ion. At 70" the relative rates, which were largely determined by entropy factors, were: phenyl, 1; p-tolyl, 7; m-tolyl, 2.4; p-chlorophenyl, 0.67; m-chlorophenyl, 0.26; p-methoxy, 150; m-methoxy, 0.71. A plot of log k against σ+ gives a ρ value of -2.44, and correlation coefficient of 0.986.


1975 ◽  
Vol 28 (9) ◽  
pp. 1901 ◽  
Author(s):  
SF Lincoln ◽  
AC Sandercock ◽  
DR Stranks

The parameters describing chloride exchange on indium(III), determined by 35Cl N.M.R., are: k(298 K)= (8.8�0+4) x 106 s-1, ΔH? = 45.7�2.3 kJ mol-1 and ΔS? = 42�8 J mol-1 K-1; and k(298 K)= (2.0�0.1)x106 s-1, ΔH? = 37.7�1.9 kJ mol-1, and ΔS? = 3�6 J mol-1 K-1 in 10.95M and 7.00M aqueous hydrochloric acid respectively, calculated from the observed exchange rate kex4[InCl4(H2O)2-].��� For thallium(III) lower limits of kex(219 K) = 1.6 x 106 s-1 and 1.3 x 106 s-1 were obtained in 10.95M and 7.00M aqueous hydrochloric acid, respectively, where [TlCl6]3- is assumed to be the exchanging species.


1979 ◽  
Vol 32 (9) ◽  
pp. 1905 ◽  
Author(s):  
AF Godfrey ◽  
JK Beattie

The oxidation of butan-1-ol by ferricyanide ion in alkaline aqueous solution is catalysed by solutions of ruthenium trichloride hydrate. The kinetics of the reaction has been reinvestigated and the data are consistent with the rate law -d[FeIII]/dt = [Ru](2k1k2 [BuOH] [FeIII])/(2k1 [BuOH]+k2 [FeIII]) This rate law is interpreted by a mechanism involving oxidation of butanol by the catalyst (k1) followed by reoxidation of the catalyst by ferricyanide (k2). The non-linear dependence of the rate on the butanol concentration is ascribed to the rate-determining, butanol-independent reoxidation of the catalyst, rather than to the saturation of complex formation between butanol and the catalyst as previously claimed. Absolute values of the rate constants could not be determined, because some of the ruthenium precipitates from basic solution. With K3RuCl6 as the source of a homogeneous catalyst solution, estimates were obtained at 30�0�C of k1 = 191. mol-1 s-1 and k2 = 1�4 × 103 l. mol-1 s-1.


1965 ◽  
Vol 18 (10) ◽  
pp. 1513 ◽  
Author(s):  
RD Brown ◽  
AS Buchanan ◽  
AA Humffray

The kinetics of protodemercuration, or displacement of the HgCl group by hydrogen, have been measured for 2- and 3-furyl, 2-thienyl, and 2-selenophenylmercuric chlorides. The reactions of these compounds with aqueous alcoholic hydrochloric acid were first order in hydrogen ion, first order in RHgC1, and zero order in chloride ion, when the latter was present at concentrations less than 0.1M. At 70�, the relative rates were: 3-furyl, 1; 2-furyl, 27; 2-thienyl, 11; 2-seleno- phenyl, 25. At higher chloride concentrations, the rate increases; this is discussed in terms of formation of complex anions of the type RHgCl32- and in terms of H+Cl- ion pair attack. The dominant influence of entropy effects in the case of furan compounds emphasizes the danger of trying to account for observed relative rates in terms of π-electron effects alone.


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