THE KINETICS OF THE DECOMPOSITION AND SYNTHESIS OF SOME DITHIOCARBAMATES

1962 ◽  
Vol 40 (2) ◽  
pp. 246-255 ◽  
Author(s):  
D. M. Miller ◽  
R. A. Latimer
Keyword(s):  
Kinetic Study ◽  
Rate Constants ◽  
Reaction Mechanisms ◽  
Dissociation Constants ◽  
Activation Energies ◽  
Spectral Evidence ◽  
Kinetics Of

Rate constants, activation energies, and dissociation constants were determined in a kinetic study of the synthesis and decomposition of a number of N-substituted dithiocarbamates. These data combined with certain spectral evidence are evaluated and reaction mechanisms suggested.

THE REACTION OF 2,2-DIPHENYL-1-PICRYLHYDRAZYL WITH SECONDARY AMINES

1958 ◽  
Vol 36 (12) ◽  
pp. 1729-1734 ◽  
Author(s):  
J. E. Hazell ◽  
K. E. Russell
Keyword(s):  
Secondary Amine ◽  
Rate Constants ◽  
Reaction Mechanisms ◽  
Hydrogen Abstraction ◽  
Activation Energies ◽  
Major Product ◽  
The Other ◽  
Secondary Amines ◽  
First Order ◽  
Kinetics Of

The reaction of DPPH (2,2-diphenyl-1-picrylhydrazyl) with N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, diphenylamine, and methylaniline has been studied and has been shown to be primarily a hydrogen abstraction process. Two moles DPPH react with 1–1.15 moles secondary amine to give 1.7–1.8 moles 2,2-diphenyl-1-picrylhydrazine and further products.The reaction between DPPH and N-phenyl-1-naphthylamine is first order with respect to each reactant. The reaction of DPPH with the other amines is retarded by the major product 2,2-diphenyl-1-picrylhydrazine and the kinetics of the over-all reaction are complex. However second-order rate constants and activation energies have been obtained using initial rates of reaction. Possible reaction mechanisms are discussed.

Kinetics of esterification of monoisopropylphenols with phosphoryl trichloride

1989 ◽  
Vol 54 (5) ◽  
pp. 1311-1317
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Ján Ilavský
Keyword(s):  
Liquid Phase ◽  
Rate Constants ◽  
Reaction Rates ◽  
Activation Energies ◽  
The Individual ◽  
Kinetics Of

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.

scholarly journals Theoretical investigation of the reaction mechanisms and kinetics of CFCl2CH2O2 and ClO in the atmosphere

RSC Advances ◽  
2020 ◽  
Vol 10 (44) ◽  
pp. 26433-26442
Author(s):  
Yunju Zhang ◽  
Bing He
Keyword(s):  
Theoretical Investigation ◽  
Rate Constants ◽  
Reaction Mechanisms ◽  
Basis Sets ◽  
Thermal Rate Constants ◽  
Product Distributions ◽  
Kinetics Of

The reaction between CFCl2CH2O2 radicals and ClO was studied using the B3LYP and CCSD(T) methods associated with the 6-311++G(d,p) and cc-pVTZ basis sets, and subsequently RRKM-TST theory was used to predict the thermal rate constants and product distributions.

Kinetic Study of the Oxidation of Alcohols with Quaternary Ammonium Permanganates

1993 ◽  
Vol 58 (8) ◽  
pp. 1777-1781 ◽  
Author(s):  
Robert Šumichrast ◽  
Vladislav Holba
Keyword(s):  
Kinetic Study ◽  
Catalytic Reaction ◽  
Rate Constants ◽  
Quaternary Ammonium ◽  
Iterative Procedure ◽  
Activation Parameters ◽  
Reaction Products ◽  
Thermodynamic Activation Parameters ◽  
Oxidation Of Alcohols ◽  
Kinetics Of

Kinetics of the oxidation of 2-propanol, 1-butanol, and 1-pentanol with tetraalkylammonium permanganates have been investigated as function of temperature. The studied reactions are partly autocatalytic, colloidal manganese dioxide as one of the reaction products has been identified as the autocatalyst.A computerized iterative procedure has been used in order to obtained the rate constants of both non-catalytic and catalytic reaction steps together with the thermodynamic activation parameters.

Mechanism of bromination of a quaternary pyrimidinium cation. Change of rate determining step with acidity

1978 ◽  
Vol 56 (23) ◽  
pp. 2970-2976 ◽  
Author(s):  
Oswald S. Tee ◽  
David C. Thackray ◽  
Charles G. Berks
Keyword(s):  
Kinetic Study ◽  
Rate Constants ◽  
Aqueous Media ◽  
Stopped Flow ◽  
Flow Method ◽  
High Acidity ◽  
Rate Determining Step ◽  
Kinetics Of ◽  
Good Agreement

The kinetics of bromination of the 1,2-dihydro-1,3-dimethyl-2-oxopyrimidinium cation (Q+) in aqueous media (pH 0–5) have been studied using the stopped-flow method. At the higher acidities (pH < 2) the results are consistent with rate determining attack by bromine upon the pseudobase (QOH), whereas at low acidities (pH > 4) it appears that pseudobase formation is rate determining. The change occurs because at high acidity the reversal of the pseudobase QOH to the cation is fast relative to bromine attack, whereas at low acidity the converse is true. Results obtained at intermediate acidities (pH 2–4) are consistent with this interpretation.A separate kinetic study of pseudobase formation (and decomposition) yielded rate constants in good agreement with those derived from the bromination study.

Esterification kinetics of phenol with phosphoryl trichloride

1989 ◽  
Vol 54 (3) ◽  
pp. 608-615 ◽  
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Eva Zemanová ◽  
Alexander Kaszonyi ◽  
Ján Ilavský
Keyword(s):  
Liquid Phase ◽  
Linear Regression ◽  
Rate Constants ◽  
Optimization Method ◽  
Activation Energies ◽  
System Of Differential Equations ◽  
Consecutive Reactions ◽  
Esterification Rate ◽  
The Given ◽  
Kinetics Of

The liquid-phase esterification kinetics of phenol with POCl3 has been studied at isothermal conditions within the temperature interval from 90 to 110 °C. The esterification rate constants of the first, second, and third esterification steps and the activation energies of these steps have been calculated. The given system of competitive consecutive reactions can be described by a system of differential equations which has been solved by the Gauss-Newton optimization method of non-linear regression in the Marquardt modification. In the sequence of the first, second, and third step the esterification rate constants have been found to gradually decrease, whereas the activation energies uncrease in the same sequence.

scholarly journals Kinetic study of the hydration of propylene oxide in the presence of heterogeneous catalyst

2017 ◽  
Vol 23 (4) ◽  
pp. 573-580 ◽  
Author(s):  
Sema Akyalcin
Keyword(s):  
Kinetic Study ◽  
Heterogeneous Catalyst ◽  
Propylene Oxide ◽  
Rate Constants ◽  
Reaction Rate ◽  
Batch Reactor ◽  
Catalyst Loading ◽  
Catalyzed Reactions ◽  
Kinetics Of ◽  
Homogeneous Mechanism

The kinetics of the hydration of propylene oxide was studied using a pressurized batch reactor for both uncatalyzed and heterogeneously catalyzed reactions. Lewatit MonoPlus M500/HCO3 - was used as heterogeneous catalyst, which showed better performance than Dowex Marathon A/HCO3 -. The effects of the parameters, namely internal and external diffusion resistances, temperature, catalyst loading and mole ratios of reactants, on the reaction rate were studied. The uncatalyzed and heterogeneously catalyzed reactions were proven to follow a series-parallel irreversible homogeneous mechanism. The temperature dependencies of the rate constants appearing in the rate expressions were determined.

Computational study on the mechanisms and kinetics of the CH2CCl + O2 reaction

2020 ◽  
Vol 98 (8) ◽  
pp. 395-402
Author(s):  
Yunju Zhang ◽  
Bing He ◽  
Yuxi Sun
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Pressure Dependence ◽  
Rate Constants ◽  
Reaction Mechanisms ◽  
Energy Surface ◽  
Computational Study ◽  
Tddft Calculations ◽  
Temperature And Pressure ◽  
Kinetics Of

The potential energy surface for the CH2CCl + O2 reaction has been investigated by using the CCSD(T)/cc-pVTZ//B3LYP/6-311++G(d,p) method. Two type reaction mechanisms have been located. The H-abstraction of CH2CCl by O2 generates CHCCl + HO2 surmounting a 20.86 kcal/mol barrier. The addition between O2 and CH2CCl proceeds to an intermediate CH2CClO2 (IM1t and IM1c) without a barrier, which can further dissociate or isomerize to various products with the complicated processes. The temperature and pressure dependence rate constants for the CH2CCl + O2 reaction were computed by means of multi-channel RRKM-TST theory. Moreover, TDDFT calculations imply that IM1t, IM1c, IM2, IM4, IM5t, and IM5c will photolyze under the sunlight.

The non-stationary polymerization of styrene by HCIO 4 in CH 2 CI 2

1976 ◽  
Vol 351 (1667) ◽  
pp. 551-568 ◽  
Keyword(s):  
Rate Constants ◽  
Methylene Chloride ◽  
Dissociation Constants ◽  
Propagation Rate ◽  
Polymer Chains ◽  
Stage I ◽  
Electrically Conducting ◽  
Steady Stage ◽  
Ionic Components ◽  
Kinetics Of

The non-stationary precursor reaction (stage I) in the polymerization of styrene by perchloric acid in methylene chloride has been examined, by stopped-flow methods over the range 0 to –80 °C. At all temperatures there is evidence of a transient, electrically conducting, intermediate species, absorbing at 340 nm, which reaches its peak concentration at times ranging from 0.1s at 0° C to 0.5–3s at –80 °C (variable with reagent concentra­tions). At the low monomer concentrations (< 0.2M) accessible to the technique, stage I can be quantitatively discriminated from the subsequent steady stage II only below ca . –60 °C. At these low temperatures, contrary to expectations, the conversion during stage I proves to be by a dual mech­anism, the ionic reaction producing no more than about half the mass of polymer and a much smaller fraction of the number of polymer chains. The overall time-scale of stage I appears to be determined primarily by that of removal of free HCIO 4 by the non-ionic mechanism, rather than by the kinetics of the ionic polymerisation. The overall conversions cannot therefore be analysed to yield ionic rate constants. In reactions in presence of the salt n -Bu 4 NCIO 4 , the instantaneous rates can be separated into their non-ionic and ionic components, and approxi­mate values derived for the paired-ion propagation rate constants. k ± p 2000 at –80 °C; 4000–5000 at –60 °C; (unit: dm 3 mol –1 s –1 ). A more speculative analysis of the rates in salt-free systems permits estimates of the free ion propagation constants some 10–20 times the above values, and of ion-pair dissociation constants in the region of 1–5 x 10 –7 mol dm –3 at –60 to –80 °C.

Kinetics of oxidation of thiocyanate by aqueous iodine

1973 ◽  
Vol 26 (9) ◽  
pp. 1863 ◽  
Author(s):  
GT Briot ◽  
RH Smith
Keyword(s):  
Rate Constants ◽  
Activation Energies ◽  
Stopped Flow ◽  
Kinetics Of Oxidation ◽  
Rate Law ◽  
General Base ◽  
Present Rate ◽  
Rapid Equilibrium ◽  
Ph Range ◽  
Kinetics Of

The kinetics of oxidation of thiocyanate to sulphate by aqueous iodine in the pH range 9.2-12.5 have been studied using a spectrophotometric stopped flow technique. The reaction is general base-catalysed, having the rate law ��������������������� -d[I2]a/dt = ([SCN-][I3-]/[I-]2)Σ kB[B] where [I2]a is the total analytical concentration of iodine, [B] is the concentration of base, and where the summation is taken over all bases present. Rate constants, kB, and activation energies have been measured for the bases, OH-, PO43- and CO32-. ��� A mechanism involving the initial steps ����������������� I2+SCN- ↔ ISCN+I- �����������������(rapid equilibrium) ������������� ISCN+H2O+B → HOSCN+I- + HB+ �����������(rate determining) followed by rapid reactions of HOSCN with itself or with iodine is proposed.

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