Kinetics of reactions of undecacarbonyl(triethyl phosphite)triruthenium with some P- and As-donor ligands

1989 ◽  
Vol 67 (11) ◽  
pp. 1924-1930 ◽  
Author(s):  
Lezhan Chen ◽  
Anthony J. Poë
Keyword(s):  
Rate Equation ◽  
Activation Parameters ◽  
Triethyl Phosphite ◽  
Nucleophilic Attack ◽  
Donor Ligands ◽  
Metal Carbonyls ◽  
Kinetic Characteristics ◽  
Ruthenium Clusters ◽  
Kinetics Of

The kinetics have been studied of reactions of the cluster Ru3(CO)11 (P(OEt)3) with a variety of P- and As-donor nucleophiles, L, in alkane solution. Reactions proceed according to the rate equation: kobsd = k1 + k2 [L] and activation parameters for the two paths have been obtained. When combined with activation parameters for Ru3(CO)12 and some other Ru3(CO)11L′ clusters the values of [Formula: see text] and [Formula: see text] are found to lie on a good isokinetic plot. The changes in the activation parameters are consistent with major and systematic changes in the nature of the Ru3(CO)10L′ moieties left after CO dissociation.Analysis of the dependence of log k2 on the electronic and steric nature of the various nucleophiles leads to the derivation of electronic and steric profiles that are characteristic of the cluster, together with values for the intrinsic or standard susceptibility of the cluster towards nucleophilic attack. These kinetic characteristics are compared with those similarly derived for Ru3(CO)12. Keywords: metal carbonyls, ruthenium, clusters, kinetics, mechanisms.

Acid-Catalyzed Hydration of Prop-2-en-1-ol and 2-Methylprop-2-en-1-ol: Correlation of Reactivity

1989 ◽  
Vol 42 (8) ◽  
pp. 1345 ◽  
Author(s):  
KP Herlihy
Keyword(s):  
Activation Parameters ◽  
Relative Reactivity ◽  
Nucleophilic Attack ◽  
Alternative Mechanism ◽  
Catalysed Reaction ◽  
Acid Catalyzed ◽  
Solvent Isotope ◽  
Kinetics Of

The kinetics of the acid-catalysed reaction of prop-2-en-1-ol and 2-methylprop-2-en-1-ol have been measured. The relative reactivity, solvent isotope ( kH+/kD +) and change in acidity effects, and activation parameters, have been determined and found to be similar to those of other alkenes. While this correlation of results for the hydration of both these alkenols can be interpreted in terms of the conventional Ad-E2 mechanism, computed values for the lifetime of possible carbocation intermediates suggest that an alternative mechanism for the reaction of prop-2-en-1-ol, in which nucleophilic attack by the solvent is concerted with protonation, is feasible.

Cleavage of the Sulfur–Sulfur Bond in 2,4-Dinitrophenyl-4-substituted-phenyl Disulfides by trans-[IrCl(CO) (PPh3)2]. A Kinetic Study

1973 ◽  
Vol 51 (22) ◽  
pp. 3790-3794 ◽  
Author(s):  
Chiu T. Lam ◽  
Caesar V. Senoff
Keyword(s):  
Transition State ◽  
Kinetic Study ◽  
Sulfur Atom ◽  
Activation Parameters ◽  
Initial Step ◽  
Second Order ◽  
Nucleophilic Attack ◽  
Kinetics Of ◽  
Sulfur Bond

The kinetics of the reaction between trans-[IrCl(CO)(PPh3)2] and a series of 2,4-dinitrophenyl-4-substituted-phenyl disulfides, YC6H4SSC6H3(NO2)2 (Y = Br, F, H, CH3, or CH3O) have been investigated in toluene between 70 and 90°. These reactions were found to follow simple second order kinetics, rate = k2[IrCl(CO)(PPh3)2][YC6H4SSC6H3(NO2)2]. The rates of reaction were also found to be insensitive to the nature of the para substituent, Y. This fact together with the observed activation parameters, ΔH≠ ~ 17 kcal mol−1 and ΔS≠ ~ − 19 cal mol−1 deg−1, have been interpreted as indicating that the initial step in these reactions involves a nucleophilic attack by the iridium atom at the sulfur atom bonded to the 2,4-dinitrophenyl group, followed by the formation of a three-centered transition state. An overall mechanism for these reactions is presented and discussed.

STUDYING THE KINETIC CHARACTERISTICS OF THE EXTRACTION OF ANTHOCYANINS FROM THE SQUEEZE OF KRASNOSTOP ZOLOTOVSKY

2020 ◽  
Author(s):  
M.A. Egyan ◽  
Keyword(s):  
Reaction Rate ◽  
Sugar Content ◽  
Extraction Process ◽  
Efficiency Coefficient ◽  
Kinetic Characteristics ◽  
Reaction Rate Constants ◽  
Solids Content ◽  
Kinetics Of ◽  
Process Speed

The article shows studies characterizing the quality of the squeeze: the mechanical composition of the squeeze is determined, the structural moisture of each component is determined, the sugar content in the formed process of sedimentation of the juice and its acidity are determined refractometrically. The kinetics of anthocyanins extraction was determined in two ways, the solids content in the extract was calculated, and the reaction rate constants of the extraction process and the efficiency coefficient of ultrasonic amplification of the extraction process speed were calculated.

Kinetics of catalytic reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst

1983 ◽  
Vol 48 (11) ◽  
pp. 3202-3208 ◽  
Author(s):  
Zdeněk Musil ◽  
Vladimír Pour
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxide ◽  
Rate Equation ◽  
Catalytic Reduction ◽  
Zero Order ◽  
Spectroscopic Measurements ◽  
First Order ◽  
Ir Spectroscopic ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst (8.36 mass % CuO) were determined at temperatures between 413 and 473 K. The reaction was found to be first order in NO and zero order in CO. The observed kinetics are consistent with a rate equation derived from a mechanism proposed on the basis of IR spectroscopic measurements.

Thermodynamic and Kinetic Investigation of the Solvent Effect on the Oxidation of [Co(en)2SCH2COO]+ with S2O82- In Water-Methanol and Water-tert-Butyl Alcohol Mixtures

1993 ◽  
Vol 58 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
Oľga Vollárová ◽  
Ján Benko
Keyword(s):  
Transfer Functions ◽  
Activation Parameters ◽  
Butyl Alcohol ◽  
Oxidation Of Co ◽  
Kinetics Of Oxidation ◽  
Tert Butyl ◽  
Tert Butyl Alcohol ◽  
Alcohol Mixtures ◽  
Kinetics Of

The kinetics of oxidation of [Co(en)2SCH2COO]+ with S2O82- was studied in water-methanol and water-tert-butyl alcohol mixtures. Changes in the reaction activation parameters ∆H≠ and ∆S≠ with varying concentration of the co-solvent depend on the kind of the latter, which points to a significant role of salvation effects. The solvation effect on the reaction is discussed based on a comparison of the transfer functions ∆Ht0, ∆St0 and ∆Gt0 for the initial and transition states with the changes in the activation parameters accompanying changes in the CO-solvent concentration. The transfer enthalpies of the reactant were obtained from calorimetric measurements.

Kinetics and Mechanism of Hexachloroiridate(IV) Oxidation of Arsenic(III) in Acidic Perchlorate Solutions

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Ionic Strength ◽  
Fractional Order ◽  
Activation Parameters ◽  
Order Reaction ◽  
First Order Reaction ◽  
Intermediate Complex ◽  
Constant Ionic Strength ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
Kinetics Of

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.

Kinetics and mechanism of the reaction of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione

1990 ◽  
Vol 55 (8) ◽  
pp. 1984-1990 ◽  
Author(s):  
José M. Hernando ◽  
Olimpio Montero ◽  
Carlos Blanco
Keyword(s):  
Aqueous Solution ◽  
Metal Ion ◽  
Activation Parameters ◽  
Enol Form ◽  
Kinetics And Mechanism ◽  
Kinetic Constants ◽  
Steric Factors ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

The kinetics of the reactions of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione to form the corresponding monocomplexes have been studied spectrophotometrically in the range 5 °C to 16 °C at I 25 mol l-1 in aqueous solution. In the proposed mechanism for the two complexes, the enol form reacts with the metal ion by parallel acid-independent and inverse-acid paths. The kinetic constants for both pathways have been calculated at five temperatures. Activation parameters have also been calculated. The results are consistent with an associative activation for Fe(H2O)63+ and dissociative activation for Fe(H2O)5(OH)2+. The differences in the results for the complexes of heptanediones studied are interpreted in terms of steric factors.

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