Kinetics and Mechanism of Reaction of 2,4-Dinitrobenzaldehyde with Hydroxide Ion

1994 ◽  
Vol 59 (10) ◽  
pp. 2262-2268 ◽  
Author(s):  
Vladimír Macháček ◽  
Jana Manová ◽  
Miloš Sedlák ◽  
Vojeslav Štěrba
Keyword(s):  
Reaction Mechanism ◽  
Equilibrium Constant ◽  
Reaction Order ◽  
Kinetics And Mechanism ◽  
Hydroxide Ion ◽  
First Order ◽  
Mechanism Of Reaction

The reaction of 2,4-dinitrobenzaldehyde with hydroxide ion in water is first order in the substrate. The reaction order in hydroxide ion varies from one to two at lower and higher OH- concentrations, respectively. The reaction mechanism has been suggested, the pKa value of reaction product 2-nitro-4-nitrosophenol and the equilibrium constant of formation of the Meisenheimer adduct from 2-nitro-4-nitrosophenoxide and hydroxide ion have been determined.

scholarly journals REACTION KINETICS OF Cu ELECTRO-DEPOSITION ON THE SURFACE OF TiO2/GRAPHITE

2015 ◽  
Vol 8 (2) ◽  
pp. 116
Author(s):  
Fitria Rahmawati ◽  
Wanodya Anggit Mawasthi ◽  
Patiha
Keyword(s):  
Equilibrium Constant ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Order ◽  
Electrode Reaction ◽  
Deposition Process ◽  
Anodic Reaction ◽  
Electro Deposition ◽  
First Order ◽  
Kinetics Of

Research on the kinetics of electrode reaction during copper electro-deposition on the surface of TiO2/graphite has been conducted. The aims of this research are to determine the ratio of anodic reaction rate to cathodic reaction rate , the ratio of anodic rate constant to cathodic rate constant , the equilibrium constant when the reaction reach equilibrium condition and to study the polarization in the electro-deposition reaction. Copper was deposited electrochemically from CuSO4 solution at various concentration i.e. 0.1 M; 0.2 M; 0.3 M; 0.4 M; 0.5 M. In every 5 minutes during electro-deposition process, the pH changes in anode cell was recorded and the change of Cu2+ concentration was also analyzed by spectrophotometric method. The result shows that the reaction order of Cu2+ reduction is first order and the oxidation of H2O in anodic cell is zero order. The ratio of anodic rate constant to cathodic rate constant, is 4.589´10-3 ± 0.071´10‑3. It indicates that the reaction rate  in cathode is larger than the reaction rate in anode and it allowed polarization.  The electrochemical cell reached equilibrium after 25 minutes with the equilibrium constant is 8.188´10-10 ± 1.628´10-10.

Kinetics and mechanism of the oxidation of formaldehyde by hexacyanoferrate(III) ion

1969 ◽  
Vol 47 (6) ◽  
pp. 1051-1056 ◽  
Author(s):  
V. N. Singh ◽  
M. C. Gangwar ◽  
B. B. L. Saxena ◽  
M. P. Singh
Keyword(s):  
Alkaline Medium ◽  
Kinetics And Mechanism ◽  
Hydroxide Ion ◽  
First Order ◽  
Order Rate ◽  
Rapid Reaction ◽  
Kinetics Of

The kinetics of the reaction between formaldehyde and hexacyanoferrate(III) ion in alkaline medium has been investigated at four temperatures. The data show that the reaction is rapid initially, then follows a simple first order rate with respect to each of the hexacyanoferrate(III) ion, formaldehyde, and hydroxide ion. Calculations reveal that only 0.27% of the formaldehyde corresponds to the initial rapid reaction; the remaining 99.73% follows the kinetics described. The net rate of the oxidation of formaldehyde as measured by the consumption of hexacyanoferrate(III) ion, is given by[Formula: see text]

Oxygen transfer reactions. 3. The oxidation of sulfides by sodium perruthenate

1995 ◽  
Vol 73 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Donald G. Lee ◽  
Huifa Gai
Keyword(s):  
Reaction Mechanism ◽  
Transition Metal ◽  
Transition State ◽  
Oxygen Transfer ◽  
Coordination Shell ◽  
Transfer Reactions ◽  
Hydroxide Ion ◽  
First Order ◽  
Order Dependence ◽  
Substituent Constants

The transfer of oxygen from transition metal oxidants to sulfur (MO4− + R2S → MO3− + R2SO) has been studied using the oxidation of alkylthio or arylthioacetic acids (RSCH2CO2H) by perruthenate as models. These reactions exhibit a first-order dependence on the concentrations of both the oxidant and the reductant, and are directly proportional to the basicity of the medium. The Hammet ρ value is negative (ρ = −0.66), a better correlation being obtained when σ, rather than σ+, substituent constants are used. The entropies of activation for the reactions are large and negative, indicating that the transition state is highly structured. A reaction mechanism involving an activating expansion of the ruthenium coordination shell through incorporation of a hydroxide ion is proposed. Oxygen transfer is then initiated by reaction of a nonbonding pair of sulfur electrons with either a vacant ruthenium d-orbital or a Ru=O π*-orbital. Keywords: perruthenate, sulfides, oxygen transfer, oxidation.

Kinetics and mechanism of the oxidation of alcohols by tetrapropylammonium perruthenate

2005 ◽  
Vol 83 (9) ◽  
pp. 1212-1221 ◽  
Author(s):  
W David Chandler ◽  
Zhao Wang ◽  
Donald G Lee
Keyword(s):  
Reaction Mechanism ◽  
Isotope Effects ◽  
Second Order ◽  
Kinetics And Mechanism ◽  
Ruthenium Dioxide ◽  
Effective Catalyst ◽  
First Order ◽  
Oxidation Of Alcohols ◽  
Autocatalytic Process ◽  
Deuterium Isotope Effects

2-Propanol is oxidized by tetrapropylammonium perruthenate (TPAP) in a reaction that is second order in TPAP and first order in 2-propanol. One of the products, believed to be ruthenium dioxide, is an effective catalyst for the reaction, making it an autocatalytic process. The rate of oxidation is relatively insensitive to the presence of substituents. Primary kinetic deuterium isotope effects are observed when either the hydroxyl or the α hydrogen is replaced by deuterium. The only product obtained from the oxidation of cyclobutanol is cyclobutanone, indicating that the reaction is a two-electron process. Tetrahydrofuran is oxidized at a rate that is several orders of magnitude slower than that observed for 2-propanol, suggesting that the reaction of TPAP with alcohols may be initiated by formation of perruthenate esters. A tentative mechanism consistent with these observations is proposed.Key words: oxidation, alcohols, tetrapropylammonium perruthenate, reaction mechanism, autocatalysis.

Complete monotonicity of entropy production in chemical reaction

1981 ◽  
Vol 46 (2) ◽  
pp. 452-456
Author(s):  
Milan Šolc
Keyword(s):  
Entropy Production ◽  
Equilibrium Constant ◽  
Chemical Reaction ◽  
Relative Entropy ◽  
Order Reaction ◽  
Complete Monotonicity ◽  
First Order Reaction ◽  
First Order ◽  
Completely Monotonic ◽  
Derivatives Of

The successive time derivatives of relative entropy and entropy production for a system with a reversible first-order reaction alternate in sign. It is proved that the relative entropy for reactions with an equilibrium constant smaller than or equal to one is completely monotonic in the whole definition interval, and for reactions with an equilibrium constant larger than one this function is completely monotonic at the beginning of the reaction and near to equilibrium.

The kinetics of hydration of tricalcium silicate

1970 ◽  
Vol 48 (21) ◽  
pp. 3291-3299 ◽  
Author(s):  
K. G. McCurdy ◽  
B. P. Erno
Keyword(s):  
Reaction Mechanism ◽  
Intermediate Product ◽  
Activation Energies ◽  
Tricalcium Silicate ◽  
Rate Data ◽  
Large Excess ◽  
First Order ◽  
Kinetics Of ◽  
Subsequent Decomposition

An investigation has been made of the kinetics of hydration of tricalcium silicate at several temperatures in a large excess of water in the presence of various added ions. The rate data have been interpreted by a reaction mechanism which involves: (a) the first order hydration of tricalcium silicate to form an intermediate product, 1.5CaO•SiO2, which can react by two pathways, (b) the direct first order decomposition of intermediate, 1.5CaO•SiO2, to form lime and silica or (b′) complexing of intermediate with silica and subsequent decomposition to form lime and silica. This reaction mechanism predicts the rate of production of base during the hydration. The effect of various added ions is interpreted in terms of the proposed mechanism.Rate constants and activation energies for the various steps in the proposed mechanism are reported.

The reaction of μ-oxo-bis(phthalocyaninato)iron(III) with hydrogen sulphide in the presence of pyridine: Evidence for axial coordination of dichloromethane

2005 ◽  
Vol 09 (03) ◽  
pp. 198-205 ◽  
Author(s):  
Fabrizio Monacelli ◽  
Elisa Viola
Keyword(s):  
Reaction Mechanism ◽  
Linear Function ◽  
Rate Constant ◽  
Hydrogen Sulphide ◽  
Stoichiometric Ratio ◽  
First Order ◽  
Axial Coordination ◽  
Elementary Sulphur ◽  
Increasing Function ◽  
Limiting Value

The oxo-bridged complex ( py ) FePc - O - FePc ( py ) ( py = pyridine , Pc = phthalocyaninato dianion) reacts in dichloromethane with hydrogen sulphide giving elementary sulphur and the reduced ( py )2( FePc ) complex in the stoichiometric ratio 1:1. Under excess py and H2S , the reaction is first-order and the rate constant at a given py concentration is an increasing function of the reducing agent concentration, with asymptotic tendency to a limiting value. This latter depends on the pyridine concentration being higher the lower is the base concentration. When the reaction is carried out in pure pyridine, the rate constant is, instead, a strictly linear function of [ H2S ], with zero intercept. A reaction mechanism is proposed where the dichloromethane is directly involved in the axial coordination about the iron centers and H2S competes efficiently with both pyridine and solvent.

scholarly journals KINETIC INVESTIGATION OF PROPANE DISAPPEARANCE AND PROPENE FORMATION IN PROPANE OXIDATION ON DILUTED AND LEACHED MoVTeNb CATALYST

2010 ◽  
Vol 10 (2) ◽  
pp. 172-176
Author(s):  
Restu Kartiko Widi
Keyword(s):  
Reaction Kinetics ◽  
Partial Order ◽  
Reaction Order ◽  
Propane Oxidation ◽  
Kinetic Investigation ◽  
Formation Kinetic ◽  
Kinetic Reaction ◽  
First Order ◽  
Langmuir Hinshelwood Mechanism

Reaction kinetics for the oxidation of propane over diluted-leached MoVTeNb is described. This paper is focused on the study of products selectivity profile and determination of the orders of propane disappearance and propene formation. The result shows that selective oxidation of propane to propene over this catalyst follows the Langmuir-Hinshelwood mechanism. The disappearance of propane is first order with respect to hydrocarbon and partial order (0.21) with respect to oxygen. The propene formation is first order with respect to hydrocarbon and not depending on oxygen concentration.   Keywords: propane oxidation, propane disappearance, propene formation, kinetic, reaction order

scholarly journals PENGEMBANGAN BAHAN AJAR KIMIA RINTISAN SMA BERTARAF INTERNASIONAL KELAS XI MATERI LAJU REAKSI

2012 ◽  
Vol 13 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Inova Putri Carera ◽  
I Wayan Dasna
Keyword(s):  
High School ◽  
High School Students ◽  
Reaction Mechanism ◽  
Reaction Rate ◽  
Reaction Order ◽  
Average Score ◽  
School Students ◽  
Factors Affecting ◽  
Rate Law

This study was aimed to develop teaching materials about chemical reaction rate which covered materials adapted to A-Level High School students of grade XI in Pioneer International Standard High School (RSMA-BI). The developmental research was adopting the instructional development model 4D which include four stages of development, namely define, design, develop, and disseminate. Instructional materials were written in English consist of seven topics titled: Reaction Rate Concept, The Exchange's Expressions, Rate Law and Reaction Order, Experimental Determination of a Rate Law, Reaction Mechanism, Theories of Reaction Rate, Factors Affecting Reaction Rate. Results of content validation from content experts obtained the average score of 3. 56 of 14 range of scores which means valid / good / decent. Test limited to high school students of RSBI obtained an average score of 3.35 (valid / good / decent). The results of the use of teaching materials obtained a score of 77.8 which is above the minimal passing grade (75). Therefore it can be concluded that the materials were feasible to be used in the classroom.Penelitian ini bertujuan untuk mengembangkan bahan ajar laju reaksi dengan cakupan materi yang disesuaikan dengan A-Level untuk siswa kelas XI Rintisan Sekolah Menengah Atas Bertaraf Internasional (RSMA-BI. Rancangan penelitian pengembangan mengadaptasi model pengembangan bahan ajar Model 4D yang meliputi empat tahap pengembangan, yaitu define, design, develop dan disseminate. Produk pengembangan adalah bahan ajar kimia RSMA-BI kelas XI materi laju reaksi yang ditulis dalam bahasa Inggris menggunakan pendekatan kontekstual. Bahan ajar terdiri atas empat bagian utama yaitu pendahuluan, materi, evaluasi dan penutup. Materi tersusun atas tujuh sub materi yaitu Reaction Rate Concept, The Rates Expressions, Rate Law and Reaction Order, Experimental Determination of a Rate Law, Reaction Mechanism, Theories of Reaction Rate, Factors Affecting Reaction Rate. Hasil validasi isi dari ahli materi diperoleh nilai rata-rata 3,56 dari rentang skor 1-4 dengan kriteria valid/baik/layak. Hasil uji terbatas pada siswa SMA RSBI diperoleh nilai rata-rata 3,35 dari rentang skor 1-4 dengan kriteria valid/baik/layak. Hasil uji penggunaan bahan ajar diperoleh skor sebesar 77,8. Skor ini diatas SKM (Skor Kelulusan Minimal) yaitu 75 sehingga dapat disimpulkan bahwa bahan ajar telah layak dan dapat digunakan dalam pembelajaran di kelas.

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