Ligand substitution kinetics of iron(III) in aprotic solvents

1983 ◽  
Vol 36 (5) ◽  
pp. 843 ◽  
Author(s):  
JT Carr ◽  
PA Treloan
Keyword(s):  
Ionic Strength ◽  
Dimethyl Sulfoxide ◽  
Activation Parameters ◽  
Forward Rate ◽  
Dimethyl Formamide ◽  
Activation Entropy ◽  
Aprotic Solvents ◽  
Forward Rate Constant ◽  
Temperature Activation ◽  
Complexation Reactions

The complexation reactions of NCS- and Br- with iron(III) have been studied in N,N-dimethyl-formamide, and the temperature activation parameters determined. The observed forward rate constants are 114±5 and 69±31, mol-1 s-1, the activation enthalpies are 48+±3 and 74±4 kJ mol-1, and the activation entropies are -45±8 and 40±10 J K-1 mol-1, respectively, at 298 K and 0.5 M ionic strength. The complexation reactions of NCS- with iron(III) in dimethyl sulfoxide have been studied at ionic strengths of 0.1, 0.3 and 0.5 M, and over a range of temperatures. The observed forward rate constant is 55±31. Mol-1 s-1, the activation enthalpy is 42±3 kJ mol-1, and the activation entropy is -70±30 J K-1 mol-1 at 298 K and 0.5 M ionic strength. It is proposed that the substitution reactions of iron(111) in the aprotic solvents N,N-dimethyl- formamide and dimethyl sulfoxide proceed through an associative interchange (Ia) mechanism.

scholarly journals Electropolymerization of N,N'-Diphenylguanidine in Non-Aqueous Aprotic Solvents and Alcohols

2020 ◽  
Vol 65 (1) ◽  
pp. 139-147
Author(s):  
László Kiss ◽  
Ferenc Kovács ◽  
Sándor Kunsági-Máté
Keyword(s):  
Cyclic Voltammetry ◽  
Dimethyl Sulfoxide ◽  
Benzyl Alcohol ◽  
Polymer Films ◽  
Platinum Electrode ◽  
Anodic Peak ◽  
Dimethyl Formamide ◽  
Aprotic Solvents ◽  
Permeability Studies ◽  
Voltammetric Peak

Electrooxidation of N,N’-diphenylguanidine (1,3-diphenylguanidine) was investigated in aprotic (acetonitrile, acetone, dimethyl sulfoxide, dimethyl formamide, propyleneoxide, nitromethane) and alcoholic (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, benzyl alcohol) non-aqueous solvents at platinum electrode with cyclic voltammetry. Its concentration was 5 mM in most cases. In acetonitrile and acetone a sharp voltammetric peak appeared around 1 V vs. reference and currents measured in the subsequent scans showed that the electrode fouled quickly. In dimethyl formamide, the anodic peak heights decreased slowly in the subsequent scans but in dimethyl sulfoxide weak deactivation could be observed both in smaller and in higher concentration. In alcohols, continuous deactivation could be also observed during electrooxidation of N,N’-diphenylguanidine. The permeability studies showed that the structure of the formed polymer films varied significantly according to the solvent used for electrodeposition.

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.

Kinetic and Equilibrium Studies of the Reactions of 2,4,6-Trinitrotoluene and 2,4,6-Trinitrotoluene-d3 with Sodium and Potassium t-Butoxide in t-Butanol

1974 ◽  
Vol 52 (12) ◽  
pp. 2306-2315 ◽  
Author(s):  
Erwin Buncel ◽  
Albert Richard Norris ◽  
Kenneth Edwin Russell ◽  
Harold Wilson
Keyword(s):  
Initial Rate ◽  
Forward Rate ◽  
Specific Rate ◽  
Equilibrium Studies ◽  
Proton Abstraction ◽  
Kinetic Isotope ◽  
Forward Rate Constant ◽  
Hydrogen Deuterium ◽  
Reaction In Solution ◽  
Sodium And Potassium

The reactions of 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrotoluene fully deuterated at the methyl position (TNT-d3) with sodium and potassium t-butoxide in t-butanol have been studied. With TNT as the substrate, proton abstraction by ion-paired sodium or potassium t-butoxide appears to be the predominant reaction in solution. With sodium t-butoxide as base, the forward rate constant for proton abstraction at 30.0 °C (Kf,ip) is 6000 ± 400 M−1 s−1 while ΔH≠ and ΔS≠ for the reaction are 4.2 ± 0.3 kcal mol−1 and −27 ± 2 cal deg−1 mol−1, respectively. With TNT-d3 as the substrate, formation of a TNT-d3-t-butoxide ion σ-complex occurs simultaneously with deuteron abstraction. Specific rate constants for the two processes have been determined at 30.0 °C. Initial rate studies establish a hydrogen-deuterium kinetic isotope effect of 8 ± 1 for the formation of the anion in t-butanol.

Comparisons of Pressure and Temperature Activation Parameters for Amide Hydrogen Exchange in T4 Lysozyme†

Biochemistry ◽  
2000 ◽  
Vol 39 (1) ◽  
pp. 248-254 ◽  
Author(s):  
Michelle E. Dixon ◽  
T. Kevin Hitchens ◽  
Robert G. Bryant
Keyword(s):  
Hydrogen Exchange ◽  
Activation Parameters ◽  
T4 Lysozyme ◽  
Amide Hydrogen ◽  
Amide Hydrogen Exchange ◽  
Temperature Activation

Solvation of the halide anions in dimethyl sulfoxide. Factors involved in enhanced reactivity of negative ions in dipolar aprotic solvents

1984 ◽  
Vol 106 (21) ◽  
pp. 6140-6146 ◽  
Author(s):  
Tom F. Magnera ◽  
Gary Caldwell ◽  
Jan Sunner ◽  
Sigeru Ikuta ◽  
Paul Kebarle
Keyword(s):  
Dimethyl Sulfoxide ◽  
Negative Ions ◽  
Aprotic Solvents ◽  
Halide Anions ◽  
Dipolar Aprotic Solvents

Electron-transfer reactions in non-aqueous media. VII. Reduction of CoF(NH3)52+ and Co(HCOO)(NH3)52+ by copper(I) in dimethyl sulfoxide-water mixtures

1983 ◽  
Vol 36 (10) ◽  
pp. 1923 ◽  
Author(s):  
JMB Harrowfield ◽  
L Spiccia ◽  
DW Watts
Keyword(s):  
Electron Transfer ◽  
Dimethyl Sulfoxide ◽  
Aqueous Media ◽  
Mixed Solvents ◽  
Transfer Reactions ◽  
Aprotic Solvents ◽  
Aqueous Mixtures ◽  
Electron Transfer Reactions ◽  
Dipolar Aprotic Solvents ◽  
Sphere Mechanism

Previous work on the reduction of a series of cobalt(III) complexes by iron(II) in dipolar aprotic solvents and in aqueous mixtures has been extended to reduction by copper(I). The greater stability of copper(I) to disproportionation in these media has permitted the study of the reduction of CoF(NH3)52+ and Co(HCOO)(NH3)52+ in range of solvents over a number of temperatures with a precision not possible in previous studies in water. The results are consistent with an inner-sphere mechanism in which the copper(I) reductant is preferentially solvated by dimethyl sulfoxide to the exclusion of water in mixed solvents.

Kinetic Studies on the Polymerization of Dicyclohexylmethylmethane-4,4'-Diisocyanate with Polyoxytetramethylene Diol

2013 ◽  
Vol 791-793 ◽  
pp. 32-35
Author(s):  
Jian Cheng Wang
Keyword(s):  
Rate Constant ◽  
Arrhenius Equation ◽  
Activation Enthalpy ◽  
Kinetic Studies ◽  
Activation Entropy ◽  
Dimethyl Acetamide ◽  
Different Temperatures ◽  
Ft Ir ◽  
Temperature Activation

Dicyclohexylmethylmethane-4,4'-diisocyanate is used to react with polyoxytetramethylene diol at different temperatures. N,N-Dimethyl acetamide is used as solvent.In situFT-IR is used to monitor the reaction to work out rate constant, Arrhenius equation and Eyring equation. The polymerization has been found to be a second order reaction, and the rate constant increases with the rise of temperature. Activation energy (Ea), activation enthalpy (ΔH) and activation entropy (ΔS) for the polymerization are respectively calculated out, which are very useful to reveal the reaction mechanism.

Dimethyl sulfoxide and dimethyl formamide increase lifespan of C. elegans in liquid

2013 ◽  
Vol 134 (3-4) ◽  
pp. 69-78 ◽  
Author(s):  
Harald Frankowski ◽  
Silvestre Alavez ◽  
Patricia Spilman ◽  
Karla A. Mark ◽  
Joel D. Nelson ◽  
...  
Keyword(s):  
Dimethyl Sulfoxide ◽  
Dimethyl Formamide ◽  
C Elegans
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