Ferricyanide Oxidation of Butanol Homogeneously Catalysed by Chlororuthenium Complexes

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.

1959 ◽  
Vol 37 (9) ◽  
pp. 1446-1450 ◽  
Author(s):  
J. Halpern ◽  
J. F. Harrod ◽  
P. E. Potter

The kinetics of the reduction of ferric chloride by molecular hydrogen in aqueous solution, in the presence of chloropalladate(II), were examined. The latter acts as a homogeneous catalyst for the reaction. The rate-law was found to be,[Formula: see text]where[Formula: see text]The mechanism of the reaction is discussed.


1992 ◽  
Vol 70 (1) ◽  
pp. 135-143 ◽  
Author(s):  
B Zhao ◽  
M. H. Back

The kinetics of the photochemical reactions of the dianion of croconic acid (1,2-dihydroxycyclopentenetrione) have been studied in aqueous solution in the presence of electron acceptors. In neutral solutions the quantum yield for disappearance of croconate dianion was small (< 10−3) but was substantially increased in basic solution and in the presence of electron acceptors. At pH 12 in the presence of 4-nitrobenzylbromide and biacetyl a quantum yield of 1 was obtained. The kinetics of the rate of disappearance of croconate dianion as a function of pH and concentration of acceptor showed that the excited dianion is oxidized by acceptors and reacts with hydroxyl ion. A mechanism is proposed that, by assuming reasonable values for the rate constants involved, is shown to be consistent with the results. Keywords: photolysis, kinetics, croconate dianion, electron transfer.


2012 ◽  
Vol 1 (2) ◽  
pp. 39-45
Author(s):  
Lawrence Hugh Kolopajlo ◽  
Nekuma Korey Hollis ◽  
Ian Pendelton

We report a rate law, rate constants and a mechanism for the ligand substitution reaction between Ni(tetren)2+ and 2, 2'-bipyridine in aqueous solution at 25.0 0C. The rate law is: R = k [Ni(tetren2+)] [bipy]. The data supports a mechanism involving a hydrogen ion assisted pathway in which a ternary complex is not formed.


2009 ◽  
Vol 74 (10) ◽  
pp. 1531-1542 ◽  
Author(s):  
Vlado Cuculić ◽  
Ivanka Pižeta

The kinetics of iron(III) hydrolysis and precipitation in aqueous glycine solutions were studied by cathodic voltammetry with a mercury drop electrode. The kinetics was controlled by changing ionic strength (I), pH and glycine concentration. Voltammetric measurements clearly showed formation and dissociation of a soluble Fe(III)–glycine complex, formation of iron(III) hydroxide and its precipitation. The rate constants of iron(III) hydroxide precipitation were assessed. The precipitation is first-order with respect to dissolved inorganic iron(III). The calculated rate constants of iron(III) precipitation varied from 0.18 × 10–5 s–1 (at 0.2 M total glycine, pH 7.30, I = 0.6 mol dm–3) to 2.22 × 10–3 s–1 (at 0.1 M total glycine, pH 7.30, I = 0.2 mol dm–3). At 0.5 M total glycine and I = 0.6 mol dm–3, the iron(III) precipitation was not observed.


1968 ◽  
Vol 2 (9) ◽  
pp. 234-243 ◽  
Author(s):  
Inga Christenson

The products and kinetics of hydrolysis of the nerve gas antidote bis(4-hydroxyiminomethyl - 1 - pyridinemethyl) ether dichloride (Toxogonin ®) have been investigated. A survey of these studies is given: The hydrolytic reactions were studied in the pH range 1 M hydrochloric acid to 1 M sodium hydroxide at 25, 45, 75 and 85° C. Rate constants were determined in dilute aqueous solution, generally with an initial Toxogonin concentration of 0.01 mg per ml. In addition, a report is given concerning two-year storage of 25 percent (w/v) Toxogonin solutions at pH 2.5, 3.0 and 3.5. The solutions were stored in glass or polypropylene ampuls at 5, 15, 25 and 45°C. At 5 and 15C° decomposition was negligible, at 25 and 45 °C average decomposition was 1.5 percent and 3.3 percent, respectively.


1977 ◽  
Vol 22 ◽  
pp. 61-67 ◽  
Author(s):  
G. Calvaruso ◽  
F.P. Cavasino ◽  
E.Di Dio ◽  
R. Triolo

1992 ◽  
Vol 45 (12) ◽  
pp. 2049 ◽  
Author(s):  
A Ellis ◽  
A Fultz ◽  
R Hicks ◽  
T Morgan ◽  
L Parsons ◽  
...  

The synthesis of the trifluoromethanesulfonate salt of the pentaarnmine (dimethy1 sulfide)-cobalt(III) ion, [NH3)5Co-S(CH3)2]3+, is described along with the kinetics of its hydrolysis in basic and acidic solutions. The synthesis proceeds in 44% yield from the reaction of [(NH3)5Co-OSO2CF3] (CF3SO3)2 with CH3SCH3 in tetramethylene sulfone at 80�C. The salt has been characterized by elemental analysis, visible-U.V. spectroscopy, and 1H n.m.r. In basic solution the complex decomposes by Co-S cleavage to yield [(NH3)5CO-OH]2+ and non-coordinated CH3SCH3. The kinetics of this reaction were studied in phosphate buffers ranging from pH 8.50 to 11.67 ( �= 1.0 M); a linear dependence of the reaction rate on [OH-] was observed. At 25�C, kOH = 8.8 � 0.2 dm3 mol-1 s-1. Activation parameters, determined over a temperature range from 15 to 44�C, were ΔH‡ = 152 � 3 kJ mol-1 and Δ S‡ = 286 � 9 J K-1 mol-1. In 0.01 M HClO4 ( � = 1.0 M, 25�C), the cobaltsulfur bond is cleaved at a rate of 1.6×10-6 s-l. Activation parameters, determined over a temperature range from 25 to 60�C, were ΔH‡ = 106 � 5 kJ mol-1 and ΔS‡= -2 � 16 J K-1 mol-1.


Author(s):  
Yu.E. Romanenko ◽  
A.A. Merkin ◽  
O.V. Lefedova

The problem of kinetics of skeletal nickel samples saturation with hydrogen in an aqueous solution of 2-propanol of azeotropic composition was discussed. 2-propanol dehydrogenation and acetone hydrogenation rate constants were calculated. Kinetic model of processes under study was offered.


2004 ◽  
Vol 08 (11) ◽  
pp. 1269-1275 ◽  
Author(s):  
Ahsan Habib ◽  
Masaaki Tabata ◽  
Ying Guang Wu

The kinetics of the reaction of the tetrakis(1-methylpyridium-4-yl)porphyrin tetracation, [ H 2( TMPyP )]4+, with gold(III) ions were studied along with equilibria of gold(III) species in aqueous medium at 25°C, I = 0.10 M ( NaNO 3). The equilibrium constants for the formation of [ AuCl 4-n( OH ) n ]- ( n = 0,…,4), defined as β n = [ AuCl 4- n ( OH ) n ]- [ Cl -] n / [ AuCl 4-][ OH -] n were found to be that log β1 = 7.94 ± 0.03, log β2 = 15.14 ± 0.03, log β3 = 21.30 ± 0.05 and log β4 = 26.88 ± 0.05. The overall reaction was first order with respect to each of the total [ Au (III)] and [ H 2 TMPyP 4+]. On the basis of pH dependence on rate constants and the hydrolysis of gold(III), the rate expression can be written as d [ Au ( TMPyP )5+]/ dt = ( k 1[ AuCl 4-] + k2[ AuCl 3( OH )-] + k3[ AuCl 2( OH )2-] + k4[ AuCl ( OH )3-])[ H 2 TMPyP 4+], where k1, k2, k3 and k4 were found to be (2.16 ± 0.31) × 10-1, (6.56 ± 0.19) × 10-1, (1.07 ± 0.24) × 10-1, and (0.29 ± 0.21) × 10-1 M -1. s -1, respectively. The kinetic data revealed that the trichloromonohydroxogold(III) species, [ AuCl 3( OH )]-, is the most reactive. The higher reactivity of [ AuCl 3( OH )]- is explained by hydrogen bonding formation between the hydroxyl group of [ AuCl 3( OH )]- and the pyrrole hydrogen atom of [ H 2( TMPyP )]4+. Furthermore, applying the Fuoss equation to the observed rate constants at different ionic strengths, the apparent net charge of [ H 2( TMPyP )]4+ was calculated to be +3.5.


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