scholarly journals Reductive Cleavage of Acetals and Ketals by Borane. Part II. The Kinetics of the Reaction

1975 ◽  
Vol 53 (19) ◽  
pp. 2818-2821 ◽  
Author(s):  
Henry I. Bolker ◽  
Bruce I. Fleming
Keyword(s):  
Transition State ◽  
High Order ◽  
Reductive Cleavage ◽  
Hydrogen Atoms ◽  
Third Order ◽  
Subsequent Formation ◽  
First Order ◽  
Kinetics Of

The reductive cleavage of acetals with borane in tetrahydrofuran was found to be first order in acetal and close to third order in borane. The high order in borane may be due to the participation of three BH3 units in the transition state with subsequent formation of a B2H7− ion. All the hydrogen atoms of borane are available for the reduction of excess acetal at 30 °C.

Evidence for general base catalysis by protic solvents in a kinetic study of alcoholyses and hydrolyses of 1-(phenoxycarbonyl)pyridinium ions under both solvolytic and non-solvolytic conditions

2009 ◽  
Vol 74 (1) ◽  
pp. 43-55 ◽  
Author(s):  
Dennis N. Kevill ◽  
Byoung-Chun Park ◽  
Jin Burm Kyong
Keyword(s):  
Second Order ◽  
Base Catalysis ◽  
Substitution Reactions ◽  
Third Order ◽  
Methoxy Derivative ◽  
First Order ◽  
General Base ◽  
Protic Solvents ◽  
Kinetics Of ◽  
Pyridinium Ions

The kinetics of nucleophilic substitution reactions of 1-(phenoxycarbonyl)pyridinium ions, prepared with the essentially non-nucleophilic/non-basic fluoroborate as the counterion, have been studied using up to 1.60 M methanol in acetonitrile as solvent and under solvolytic conditions in 2,2,2-trifluoroethan-1-ol (TFE) and its mixtures with water. Under the non- solvolytic conditions, the parent and three pyridine-ring-substituted derivatives were studied. Both second-order (first-order in methanol) and third-order (second-order in methanol) kinetic contributions were observed. In the solvolysis studies, since solvent ionizing power values were almost constant over the range of aqueous TFE studied, a Grunwald–Winstein equation treatment of the specific rates of solvolysis for the parent and the 4-methoxy derivative could be carried out in terms of variations in solvent nucleophilicity, and an appreciable sensitivity to changes in solvent nucleophilicity was found.

scholarly journals The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate

2000 ◽  
Vol 65 (12) ◽  
pp. 857-866
Author(s):  
Mladjen Micevic ◽  
Slobodan Petrovic
Keyword(s):  
Kinetic Data ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Activation Entropy ◽  
Second Order Reaction ◽  
Third Order ◽  
First Order ◽  
Kinetics Of

The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate (soman) was examined with a series of alkoxides and in corresponding alcohols: methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol and 2-ethoxyethanol. Soman reacts with the used alkoxides in a second order reaction, first order in each reactant. The kinetics of the reaction between 1,2,2-trimethylpropyl-methylfluorophosphonate and ethanol in the presence of diethylenetriamine was also examined. A third order reaction rate constant was calculated, first order in each reactant. The activation energy, frequency factor and activation entropy were determined on the basis of the kinetic data.

Kinetics and mechanism of aminolysis of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones

1992 ◽  
Vol 70 (10) ◽  
pp. 2515-2519 ◽  
Author(s):  
Sharifa S. Alkaabi ◽  
Ahmad S. Shawali
Keyword(s):  
Rate Constants ◽  
Activation Parameters ◽  
Order Conditions ◽  
Kinetics And Mechanism ◽  
Hammett Equation ◽  
Third Order ◽  
First Order ◽  
Different Temperatures ◽  
Pseudo First Order ◽  
Kinetics Of

The kinetics of the reactions of a series of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones 1 with n-butylamine and piperidine were studied spectrophotometrically in dioxane, ethanol, and cyclohexane under pseudo-first-order conditions and at different temperatures. The relation k1(obs) = k2[amine] + k3[amine]2 was found applicable for all reactions studied in either dioxane or ethanol. However, in cyclohexane the n-butylaminolysis of 1 followed only third-order kinetics k1(obs) = k3[n-BuNH2]2. The kinetics of the reaction of 1 with n-butylamine in the presence of catalytic amounts of triethylamine in dioxane followed the equation: k1(obs)k2 = [n-BuNH2] + k3[n-BuNH2]2[Formula: see text] [Et3N]. The rate constants k2 and k3 correlated well with the Hammett equation and the corresponding activation parameters were determined. The results were interpreted in terms of a mechanism involving solvent- and amine-catalyzed processes.

scholarly journals Consensus Conditions for High-Order Multiagent Systems with Nonuniform Delays

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Mengji Shi ◽  
Kaiyu Qin ◽  
Ping Li ◽  
Jun Liu
Keyword(s):  
Multiagent Systems ◽  
Time Delays ◽  
Second Order ◽  
High Order ◽  
Sixth Order ◽  
Multiple Time ◽  
State Variables ◽  
Third Order ◽  
First Order ◽  
The Third

Consensus of first-order and second-order multiagent systems has been wildly studied. However, the convergence of high-order (especially the third-order to the sixth-order) state variables is also ubiquitous in various fields. The paper handles consensus problems of high-order multiagent systems in the presence of multiple time delays. Obtained by a novel frequency domain approach which properly resolves the challenges associated with nonuniform time delays, the consensus conditions for the first-order and second-order systems are proven to be nonconservative, and those for the third-order to the sixth-order systems are provided in the form of simple inequalities. The method revealed in this article is applicable to arbitrary-order systems, and the results are less conservative than those based on Lyapunov approaches, because it roots in sufficient and necessary criteria of stabilities. Simulations are carried out to validate the theoretical results.

scholarly journals Nonenzymatic NADH-Dependent Reduction of Keggin-Type 12-Tungstocobaltate(III) in Aqueous Medium

2011 ◽  
Vol 8 (3) ◽  
pp. 1152-1157
Author(s):  
Prabla Kumari ◽  
Alaka Das ◽  
Dillip Kumar Baral ◽  
A. K. Pattanaik ◽  
P. Mohanty
Keyword(s):  
Electron Transfer ◽  
Transition State ◽  
Aqueous Medium ◽  
Transfer Reaction ◽  
Activation Parameters ◽  
Electron Transfer Reaction ◽  
Transfer Reactions ◽  
Electron Transfer Reactions ◽  
First Order ◽  
Kinetics Of

The kinetics of the electron transfer reaction of NADH with 12-tungstocobaltate(III) has been studied over the range 5.07 ≤ 104[NADH] ≤ 15.22 mol dm-3, 7.0 ≤ pH ≤ 8.0 and 20 ≤ t ≤ 35oC in aqueous medium. The electron transfer reaction showed first-order dependence each in [NADH]Tand [12-tungstocobaltate(III)]T. The products of the reaction were found to be NAD+and 12-tungstocobaltate(II). The activation parameters ΔH#(kJ mol-1) and ΔS#(JK-1mol-1) of the electron transfer reactions were found to be 64.4±1.8 and -48.86±6.0. Negative value of ΔS#is an indicative of an ordered transition state for the electron transfer reaction.

Acetoxylation by aryliodoso acetates. II. Kinetics of the reaction of phenyliodoso acetate with aceto-p-toluidide

1958 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
WD Johnson ◽  
NV Riggs
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Transition State ◽  
Arrhenius Equation ◽  
First Order ◽  
Temperature Range ◽  
Polar Transition ◽  
Kinetics Of

The reaction of phenyliodoso acetate and aceto-p-toluidide in acetic acid is first order in each reactant and measured rates fit the Arrhenius equation in the temperature range 15-45 �C. Addition of water to the solvent markedly accelerates the reaction, whereas addition of benzene lowers the rate and acetic anhydride has little effect. A polar transition state is indicated.

Oxidation of aromatic secondary and tertiary amines by peroxydisulphate. A kinetic study

1971 ◽  
Vol 24 (8) ◽  
pp. 1633 ◽  
Author(s):  
A Sabesan ◽  
N Venkatasubramanian
Keyword(s):  
Transition State ◽  
Kinetic Study ◽  
Tertiary Amines ◽  
Steric Strain ◽  
First Order ◽  
Kinetics Of

The kinetics of the oxidation of aromatic secondary and tertiary amines by peroxydisulphate ion under aqueous basic conditions have been investigated. The reaction is first order in amine and first order in S2O82- ion. The order of the reactivity is found to be: N-methylaniline > N,N-dimethylaniline > aniline and N-ethylaniline > N,N-diethylaniline > aniline, and among each class: N-methylaniline > N-ethylaniline and N,N-dimethylaniline > N,N-diethylaniline. This reactivity is explained on the basis of a steric strain in the transition state super- imposed over the usual polar effects.

The measurement of the rate of recombination of hydrogen atoms at room temperature by means of e. s. r. spectroscopy

1968 ◽  
Vol 305 (1483) ◽  
pp. 553-574 ◽  
Keyword(s):  
Gas Flow ◽  
Room Temperature ◽  
Statistical Treatment ◽  
Resonance Spectroscopy ◽  
Small Contribution ◽  
Hydrogen Atoms ◽  
Third Order ◽  
Spin Resonance ◽  
Viscous Pressure ◽  
Kinetics Of

Electron spin resonance spectroscopy has been used to determine the absolute concentrations of hydrogen atoms in a gas-flow system at room temperature and at total pressures between 1 and 10 Torr. The kinetics of the decay of hydrogen atoms in the presence of undissociated molecular hydrogen have been extensively analysed on the basis of a statistical treatment of errors for a model which includes first- and second-order decay processes and axial diffusion of the atoms. Care has been taken to consider the effects of high (up to about 20%) dissociation of hydrogen, of viscous pressure drop along the reaction tube, and of other possible decay processes. The predominant rate of removal of hydrogen atoms was by the reaction K 2 H+H+H 2 →H 2 +H 2 , and the value of k 2 was 2·7±0·4x10 15 cm 6 mole -2 s -1 . A small contribution from a first-order reaction K 1 H→ 1 / 2 H 2 (presumably a wall reaction) was also found. The rate constant, k 1, was 0·21±0·15s -1 , which corresponds, in the case of a wall process, to a wall efficiency of 6·5±4·6x10 -7 . No evidence could be found for the presence of the third-order process K 2 H+H+H→H 2 +H, and an upper limit for k 3 could therefore be set at 5·0x1015 cm 6 mole -2 s -1

Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methyl Orange ◽  
Solution Ph ◽  
Vanadium Concentration ◽  
Limiting Behavior ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetic Pattern ◽  
Triton X ◽  
Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

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