Kinetic and Equilibrium Studies of the Reactions of Cyanide Ion with 1,3,5-Trinitrobenzene, 2,4,6-Trinitroanisole, and 2,4,6-Trinitrotoluene in Isopropanol

1974 ◽  
Vol 52 (1) ◽  
pp. 8-17 ◽  
Author(s):  
Leong Huat Gan ◽  
Albert Richard Norris
Keyword(s):  
Standard Enthalpy ◽  
Equilibrium Constants ◽  
Activation Parameters ◽  
Stopped Flow ◽  
Cyanide Ion ◽  
Equilibrium Studies ◽  
Kinetics Of Formation ◽  
Kinetics Of

Equilibrium constants for the formation of 1:1 cyanide ion σ-complexes with 1,3,5-trinitrobenzene, 2,4,6-trinitroanisole, and 2,4,6-trinitrotoluene have been determined spectrophotometrically over a range of temperatures. Standard enthalpy (ΔH0) and entropy (ΔS0) changes associated with each reaction have been evaluated. The kinetics of formation of the σ-complexes have been investigated by means of a stopped-flow technique and the activation parameters characterizing the formation of each complex have been determined. Evidence is presented which indicates the cyanide ion – 2,4,6-trinitroanisole σ-complex formed in isopropanol contains the cyanide ion bonded exclusively at the C-3 position.

Kinetic and equilibrium studies of the acid dissociation of the cobalt(II) complexes of N,N'-dialkyl- 1,10-phenanthroline-2,9-dimathanamine ligands

1999 ◽  
Vol 77 (9) ◽  
pp. 1471-1475 ◽  
Author(s):  
Hongwei Sun ◽  
Zhifen Zhou ◽  
Huakuan Lin ◽  
Guanghua Zhao ◽  
Shourong Zhu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Key Words ◽  
Dissociation Rate ◽  
Acid Dissociation ◽  
Stopped Flow ◽  
Isokinetic Temperature ◽  
Dissociation Kinetics ◽  
Equilibrium Studies ◽  
Complexation Property ◽  
Kinetics Of

The complexation property and the acid dissociation kinetics of four N,N'-dialkyl-1,10-phenanthroline-2,9-dimathanamine complexes with cobalt(II) were studied using a pH meter and a stopped-flow spectrophotometer. In 6.6 × 10-3~0.5 mol dm-3 HCl (I = 0.5 mol dm-3 HCl + NaCl), the dissociation rate follows the law kobs = kK2[H+]/(1 + K2[H+]). The acid dissociation can be rationalized in terms of a four-step kinetic process involving two rapid pre-equilibrium protonations and rate-determining cleavage of the Co(II)-N(phenanthroline) bond. The temperature dependence of the rate was determined, and the appropriate thermodynamic parameters were obtained. The linear relationship between ΔH not equal and ΔS not equal suggests that an isokinetic temperature, Tiso of 282 ± 2 K exists. Key words: N,N'-dialkyl-1,10-phenanthroline-2,9-dimathanamine, complexation property, acid dissociation kinetics, mechanism, cobalt(II) complex.

Kinetic studies of the reactions of 4-nitrobenzofuroxan with cyanide ion and isopropoxide ion in isopropanol

1980 ◽  
Vol 58 (16) ◽  
pp. 1691-1696 ◽  
Author(s):  
Michael E. Moir ◽  
Albert R. Norris
Keyword(s):  
Rate Constants ◽  
Activation Parameters ◽  
Kinetic Studies ◽  
Specific Rate ◽  
Stopped Flow ◽  
Cyanide Ion ◽  
Temperature Range ◽  
Flow Reaction

Kinetic studies of the reactions in isopropanol of 4-nitrobenzofuroxan with cyanide ion and isopropoxide ion have been carried out over the temperature range 15.0 to 35.0 °C. For both bases, the first species identifiable using stopped-flow reaction techniques is postulated to be a C-7 σ-complex of 4-nitrobenzofuroxan and base. Specific rate constants and activation parameters for the formation of these σ-complexes are compared to corresponding data relating to the formation of cyanide ion and isopropoxide ion—σ-complexes of 1,3,5-trinitrobenzene in isopropanol.

scholarly journals Kinetics and Thermodynamics of the Adsorption of Lead (II) on a Activated Carbon from Coconut Shells

2013 ◽  
Vol 15 (4) ◽  
pp. 283 ◽  
Author(s):  
L. Largitte ◽  
P. Lodewyckx
Keyword(s):  
Activated Carbon ◽  
Standard Enthalpy ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Activation Parameters ◽  
Effect Of Temperature ◽  
Standard Entropy ◽  
Exponential Factor ◽  
Different Temperatures ◽  
Coconut Shells

The effect of temperature on the adsorption of lead by an activated carbon from coconut shells is investigated. The pseudo second order equation is applied to the kinetic data obtained at different temperatures in order to determine the adsorption rate constants at these temperatures. Then, the Arrhenius equation is applied to the rate constants to determine the activation energy of the sorption reaction and the pre-exponential factor. By applying the Eyring equation to the rate constants, the standard thermodynamic activation parameters of the sorption reaction can also be calculated. In addition, the isotherms of lead adsorption on the activated carbon from coconut shells, at different temperatures, are determined and fitted by the Langmuir equation. The Van’t Hoff equation is applied to the Langmuir equilibrium constants in order to determine the standard enthalpy of the sorption reaction. The other standard thermodynamic parameters<br />(Gibbs standard enthalpy and standard entropy) are deduced. The isosteric standard sorption enthalpy is also determined by using both the classical approach and an adapted Clausius Clapeyron equation. The results are identical. The value obtained is higher, but more correct than that of Langmuir. On the basis of these<br />thermokinetic parameters, the activated carbon from Coconut shells can be considered as a very efficient carbon for the sorption of lead and its sorption efficiency (rate and quantity) increase with the temperature.

Absolute Light Scattering Calibration of the Stopped-Flow Spectrophotometer with Application to the Kinetics of Formation of Monodispersed Colloidal Hematite

1987 ◽  
Vol 41 (3) ◽  
pp. 402-407 ◽  
Author(s):  
Wan Peter Hsu ◽  
Ramesh C. Patel ◽  
Egon Matijevic
Keyword(s):  
Colloidal Silica ◽  
Temperature Jump ◽  
Scattered Light ◽  
Calibration Method ◽  
Stopped Flow ◽  
Flow Temperature ◽  
Hydrous Oxides ◽  
Solid Iron ◽  
Kinetics Of Formation ◽  
Kinetics Of

A calibration method based on absolute intensities of scattered light from colloidal silica was developed to standardize the stopped-flow temperature jump spectrophotometer (SFTJ). The need for such calibration was exemplified by the study of the temperature effect on the Rayleigh ratio changes during the formation of solid iron (hydrous) oxides.

Kinetics of the Anation Reaction of Nickel(II) and 1,10-Phenanthroline in Ethanol

1972 ◽  
Vol 50 (23) ◽  
pp. 3861-3865 ◽  
Author(s):  
M. L. Sanduja ◽  
W. MacF. Smith
Keyword(s):  
Rate Constant ◽  
Sodium Perchlorate ◽  
Order Rate Constant ◽  
Stopped Flow ◽  
Tetrabutyl Ammonium ◽  
Kinetics Of Formation ◽  
Kinetics Of ◽  
Nickel Perchlorate ◽  
Anation Reaction ◽  
Made In

The kinetics of formation of the monophenanthroline complex of nickel(II) in ethanol has been studied using stopped-flow methods over the temperature range 7 to 35 °C. Tetrabutyl ammonium perchlorale in concentration 0.044 M does not affect the rate appreciably, sodium perchlorate at the same concentration depresses the rate significantly. Most measurements were made in the absence of electrolytes other than nickel perchlorate and a trace of perchloric acid. The second order rate constant is not significantly dependent on the nickel(II) concentration over a four-fold change in value indicating that the concentration of encounter pairs is small relative to the concentration of the free reactants. The rate constant at 25 °C (31 × 103 M−1 s−1)is consistent with a dissociative interchange mechanism and the rate constant for ethanol exchange on nickel. However, the value of ΔH≠ for the overall reaction (15.9 ± 1.0 kcal mol−1) is about 5 kcal mol−1 higher than that reported for ethanol exchange.

Ion Pairing and the Reaction of Alkali Metal Ferrocyanides and Persulfates

1971 ◽  
Vol 49 (18) ◽  
pp. 2943-2947 ◽  
Author(s):  
R. W. Chlebek ◽  
M.W. Lister
Keyword(s):  
Alkali Metal ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Ion Pairs ◽  
Activation Parameters ◽  
Ion Pairing ◽  
Similar Rate ◽  
Thermodynamic Quantities ◽  
Kinetics Of

Osmometric measurements have been made on the alkali metal persulfates, and these are interpreted in terms of formation of ion pairs, MS2O8−, by means of the method of Masterton and Berka (5). Equilibrium constants, and the derived thermodynamic quantities are deduced for the reactions [Formula: see text]. These results are applied to the interpretation of the kinetics of the reactions[Formula: see text]With M = K+, Rb+, and Cs+, the reacting species are MFe(CN)63− + MS2O8−, with very similar rate constants; with M = Li+, Na+ the species are MFe(CN)63− + S2O82−; and for lithium the reaction of Fe(CN)64− + S2O82− is also important. Rate constants and activation parameters are deduced.

Kinetics of Formation of Vesicles from Lecithin/Sodium Xylenesulfonate Micelles from Stopped-Flow Measurements

Langmuir ◽  
1998 ◽  
Vol 14 (3) ◽  
pp. 590-594 ◽  
Author(s):  
Samuel E. Campbell ◽  
Zhiqiang Zhang ◽  
Stig E. Friberg ◽  
Ramesh Patel
Keyword(s):  
Stopped Flow ◽  
Flow Measurements ◽  
Kinetics Of Formation ◽  
Kinetics Of

Etude cinétique du système Cu(II)–adénine

1973 ◽  
Vol 51 (20) ◽  
pp. 3322-3328
Author(s):  
G. Boivin ◽  
M. Zador
Keyword(s):  
Exchange Reaction ◽  
Reaction Rates ◽  
Stopped Flow ◽  
Parallel Reaction ◽  
Kinetics Of Formation ◽  
Protonated Species ◽  
Kinetics Of

The kinetics of formation and dissociation of Cu(II)–adenine complexes have been studied by stopped flow and relaxation methods.Between pH 3.5 and 5 the formation of Cu(II)•aH is too fast to be measured; formation of Cu(II)•(aH)2 has been studied and rate parameters have been determined. At pH < 3 protonated species make an important contribution to measured reaction rates. In basic media two different complexes have been investigated. The exchange reaction with EDTA proceeds by two parallel reaction paths.The mechanism of these reactions is discussed and compared with that proposed for the Cu(II)–adenosine system.La cinétique de la formation et de la dissociation de divers complexes Cu(II)–adénine a été étudiée par les méthodes de la relaxation thermique et du "flux stoppé".

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