scholarly journals Kinetic Oxidation Studies of Pentoxifylline by N-Chlorosuccinimide in Acidic Medium Using Iridium(III) Chloride as Inhibitor

2021 ◽  
Vol 34 (1) ◽  
pp. 162-168
Author(s):  
Rakesh Patel ◽  
Ravi Prakash ◽  
Ritu Swamini Bala ◽  
Brijesh Kumar Prajapati ◽  
Rupam Yadav
Keyword(s):  
Activation Energy ◽  
Activation Parameters ◽  
First Order Kinetics ◽  
Free Energy Of Activation ◽  
Enthalpy Of Activation ◽  
Rate Of Reaction ◽  
Entropy Of Activation ◽  
Acidic Conditions ◽  
Kinetic Oxidation

In present study, the kinetics and mechanism of oxidation of pentoxifylline (PTX) by N-chlorosuccinimide (NCS) in acidic conditions at 40 ± 0.1 ºC is reported. The reaction depicts first-order kinetics in regard to [NCS], [PTX] and [HClO4]. The reaction rate goes on decreasing as the concentration of iridium(III) chloride is increased. This shows that iridium(III) chloride plays the role of an inhibitor in the reaction under investigation. Nil impact of [Hg(OAc)2], [NHS] and dielectric constant (D) of the medium on the rate of oxidation of pentoxifylline have been observed. This reaction has been investigated from 308-323 K and the monitored rate of reaction suggests a direct relationship between temperature and the rate of reaction. From the graph between log k and 1/T, value of activation energy (Ea) was numerated and more activation parameters like enthalpy of activation (ΔH#), entropy of activation (ΔS#) and free energy of activation (ΔG#) were calculated with the help of activation energy (Ea). On account of experimentally determined the kinetic orders and activation parameters, a most plausible reaction path has been suggested for the oxidation of pentoxifylline in presence of Ir(III) as an inhibitor.

The role of formaldehyde in the oxidation of ethylene

1952 ◽  
Vol 212 (1110) ◽  
pp. 291-311 ◽  
Keyword(s):  
Activation Energy ◽  
Ethylene Oxide ◽  
Induction Period ◽  
Maximum Rate ◽  
Reaction Scheme ◽  
Stationary Concentration ◽  
Rate Of Reaction ◽  
A Minor ◽  
Close Parallelism

The oxidation of ethylene at temperatures in the region of 400° C has been studied manometrically and analytically, and compared with the oxidation of formaldehyde under similar conditions. The observations of previous authors have been confirmed and extended with particular reference to the factors controlling the maximum rate of reaction. The oxidation of ethylene is closely dependent on the development of formaldehyde, which shows the behaviour to be expected of an agent for degenerate branching. There is a close parallelism between the variation of the activation energy of the oxidation of ethylene from 25 kcal at 350° C to 53 kcal at 550° C and of formaldehyde from 21 kcal at 350° C to more than 40 kcal at 500° C. Formaldehyde is produced in the oxidation of ethylene and attains a maximum concentration which is proportional to the ethylene pressure and independent of the oxygen pressure. The addition of formaldehyde to the reaction mixture reduces or removes the induction period without affecting the maximum rate of the reaction. Ethylene oxide plays a minor but significant part; it attains a stationary concentration in the reaction but is less effective than formaldehyde in reducing the induction period. A reaction scheme based on that proposed by Axford & Norrish (1948) for the oxidation of formaldehyde has been developed; it accounts satisfactorily for the observed facts.

scholarly journals Synthesis and Characterization of Nanometric Pure Phase SnO2 Obtained from Pyrolysis of Diorganotin(IV) Derivatives of Macrocycles

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Mala Nath ◽  
P. K. Saini
Keyword(s):  
Particle Size ◽  
Preexponential Factor ◽  
Energy Of Activation ◽  
Activation Free Energy ◽  
First Order Kinetics ◽  
Free Energy Of Activation ◽  
Transmission Electron ◽  
Entropy Of Activation ◽  
20 Nm ◽  
Derivatives Of

Thermal decomposition of diorganotin(IV) derivatives of macrocycles of general formula, R2Sn(L1) and R2Sn(L2) (where R = n-butyl (1/4), methyl (2/5), and phenyl (3/6); H2L1 = 5,12-dioxa-7,14-dimethyl-1,4,8,11-tetraazacyclotetradeca-1,8-diene and H2L2 = 6,14-dioxa-8,16-dimethyl-1,5,9,13-tetraazacyclotetradeca-1,9-diene), provides a simple route to prepare nanometric SnO2 particles. X-ray line broadening shows that the particle size varies in the range of 36–57 nm. The particle size of SnO2 obtained by pyrolysis of 3 and 5 is in the range of 5–20 nm as determined by transmission electron microscope (TEM). The surface morphology of SnO2 particles was determined by scanning electron microscopy (SEM). Mathematical analysis of thermogravimetric analysis (TGA) data shows that the first step of decomposition of compound 4 follows first-order kinetics. The energy of activation (), preexponential factor (A), entropy of activation (), free energy of activation (), and enthalpy of activation () of the first step of decomposition have also been calculated. Me2Sn(L2) and Ph2Sn(L1) are the best precursors among the studied diorganotin(IV) derivatives of macrocycles for the production of nanometric SnO2.

scholarly journals A Fast, Inexpensive, and Safe Method for Residue Analysis of Meptyldinocap in Different Fruits by Liquid Chromatography/Tandem Mass Spectrometry

2010 ◽  
Vol 93 (6) ◽  
pp. 1957-1964 ◽  
Author(s):  
Kaushik Banerjee ◽  
Soma Dasgupta ◽  
Manjusha R Jadhav ◽  
Dattatraya G Naik ◽  
Axel Patrick Ligon ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Residue Analysis ◽  
First Order ◽  
First Order Kinetics ◽  
Free Energy Of Activation ◽  
Subsequent Hydrolysis ◽  
Liquid Chromatography Tandem Mass ◽  
Rate Kinetics ◽  
Entropy Of Activation ◽  
Hydrolysis Of

Abstract An analytical method is reported for residue analysis of the fungicide meptyldinocap in different fruit matrixes that involves extraction with ethyl acetate, hydrolysis of the residues with ethanolamine, and determination by LC/MS/MS. The method involves extraction of 10 g sample with 10 mL ethyl acetate; evaporation of the ethyl acetate phase to dryness, and subsequent hydrolysis of the residues to 4,6-dinitro-2-(1-methylheptyl) phenol on reaction with 1 ethanolamine. The pH of this hydrolyzed product was neutralized with formic acid and analyzed by LC/MS/MS. The hydrolysis reaction followed pseudo-first-order kinetics, and the reaction product was spectroscopically confirmed as 2-(1-methylheptyl)-4,6-dinitrophenol. The method offered >80 recoveries at an LOQ of 10 ng/g for grape and mango, 25 ng/g for pomegranate with intralaboratory Horwitz ratio <0.5, and measurement uncertainties <10 at LOQ levels. Considering first-order rate kinetics, activation energy, enthalpy of activation, and entropy of activation varied as solvent > mango > grape > pomegranate. Free energy of activation at 298 K was higher than at 280 K and was similar for solvent and three matrixes at both temperatures.

Applications of proton magnetic resonance to rotational isomerism in halotoluene derivatives. IV. α,α,2,4,6-Pentachlorotoluene in carbon disulfide, an exchanging ABC system

1970 ◽  
Vol 48 (24) ◽  
pp. 3877-3881 ◽  
Author(s):  
Helen G. Gyulai ◽  
B. J. Fuhr ◽  
H. M. Hutton ◽  
T. Schaefer
Keyword(s):  
Carbon Disulfide ◽  
Activation Parameters ◽  
Frequency Factor ◽  
Kcal Mole ◽  
Hindered Rotation ◽  
Line Shapes ◽  
Line Shape Analysis ◽  
Enthalpy Of Activation ◽  
Carbon Carbon Bond ◽  
Entropy Of Activation

The p.m.r. of α,α,2,4,6-pentachlorotoluene in carbon disulfide solution displays hindered rotation about the sp2–sp3 carbon–carbon bond, causing broadening and collapse of the proton resonance spectrum. A full line-shape analysis using the computer program DNMR gives an activation energy of 14.2 ± 0.3 kcal/mole, a frequency factor of 11.9 ± 0.2, an enthalpy of activation of 13.7 ± 0.3 kcal/mole, and an entropy of activation of −4.4 ± 1 e.u. These data are compared with the activation parameters obtained in methylcyclohexane and toluene-d8 solutions from different line shapes.

scholarly journals Kinetics and Mechanism of Oxidation of Malic Acid by N-Bromonicotinamide (NBN) in the Presence of a Micellar System

2015 ◽  
Vol 52 ◽  
pp. 111-119
Author(s):  
L. Pushpalatha
Keyword(s):  
Malic Acid ◽  
Reaction Rate ◽  
Activation Parameters ◽  
Zero Order ◽  
Micellar System ◽  
First Order ◽  
First Order Kinetics ◽  
Rate Of Reaction ◽  
Different Temperatures ◽  
Experimental Findings

The oxidation of malic acid by N-bromonicotinamide in the presence of micellar system is studied. First order kinetics with respect to NBN is observed. The kinetics results indicate that the first order kinetics in hydroxy acid at lower concentrations tends towards a zero order at its higher concentrations. Inverse fractional order in [H+] and [nicotinamide] are noted throughout its tenfold variation. Variation of [Hg (OAc)2] and ionic strength of the medium do not bring about any significant change in the rate of reaction. Rate of the reaction increases with a decrease in the percentage of acetic acid. Decrease in the rate constant was observed with the increase in [SDS]. The values of rate constants observed at four different temperatures were utilized to calculate the activation parameters. A suitable mechanism consistent with the experimental findings has been proposed.

scholarly journals Kinetics and Thermodynamic Studies of Depolymerization of Nylon Waste by Hydrolysis Reaction

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
D. B. Patil ◽  
S. V. Madhamshettiwar
Keyword(s):  
Arrhenius Plot ◽  
Hydrolysis Reaction ◽  
Energy Of Activation ◽  
Pure Substance ◽  
Reaction Yield ◽  
First Order ◽  
Free Energy Of Activation ◽  
Enthalpy Of Activation ◽  
Entropy Of Activation ◽  
Kinetics Of

Depolymerization reaction of nylon waste was carried out by hydrolysis reaction. Yield of depolymerization products was up to 72.20% for a two-hour reaction time. The products obtained were characterized by melting point and FTIR spectra. The values obtained for dibenzoyl derivative of hexamethylenediamine (DBHMD) agreed with those of the pure substance. Chemical kinetics of this reaction shows that it is a first-order reaction with respect to hexamethylenediamine (HMD) concentration with velocity constant 7.32×10-3 min−1. The energy of activation and Arrhenius constant obtained by Arrhenius plot were 87.22 KJg−1 and 0.129, respectively. The other thermodynamic parameters such as enthalpy of activation (ΔH‡) and entropy of activation (ΔS‡) and free energy of activation were 5975.85 J and −270.86 J·K−1·mol−1 and 101.59 KJ·mol−1, respectively.

scholarly journals A kinetic and mechanistic study of the osmium(VIII)-catalysed oxidation of crotyl alcohol by hexacyanoferrate(III) in aqueous Alkaline medium

2020 ◽  
Vol 44 (5-6) ◽  
pp. 295-300
Author(s):  
Priyamvada Sharma ◽  
Riya Sailani ◽  
Anita Meena ◽  
Chandra Lata Khandelwal
Keyword(s):  
Reaction Mechanism ◽  
Alkaline Medium ◽  
Activation Parameters ◽  
Mechanistic Study ◽  
Aqueous Alkaline Medium ◽  
Crotyl Alcohol ◽  
Catalysed Oxidation ◽  
Entropy Of Activation ◽  
Eyring Equation

The kinetics and mechanism of the osmium(VIII)-catalysed oxidation of crotyl alcohol by hexacyanoferrate(III) in aqueous alkaline medium is studied. The role of the osmium(VIII) catalyst is delineated to account for the experimental observations. A plausible reaction mechanism is suggested. Activation parameters such as the energy and entropy of activation are evaluated by employing the Eyring equation and are found to be 36.833 kJ mol−1 and −141.518 J K−1 mol−1, respectively.

Kinetic Investigation of Thermal Decomposition Reaction of Ethane-1,2-Diamine Copper(II) Chloride, C2H8N2CuCl2

2014 ◽  
Vol 665 ◽  
pp. 255-259
Author(s):  
Pu Hong Wen
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Decomposition Reaction ◽  
Kinetic Investigation ◽  
Thermal Decomposition Process ◽  
Exponential Factor ◽  
Free Energy Of Activation ◽  
Enthalpy Of Activation ◽  
Entropy Of Activation ◽  
Temperature Programmed

:The thermal behavior and thermal decomposition kinetic parameters of ethane-1,2-diamine copper (II) chloride (EDCC) in a temperature-programmed mode have been investigated by mean of TG-DTG. There are four stages in the thermal decomposition process. The kinetic parameters of the apparent activation energyEa(130.2, 143.6 and 158.9 KJ·mol–1) and per-exponential factorA(1011.80, 1012.18and 1011.83s–1) in II, III and IV stages were obtained from analysis of the TG-DTG curves by Kissinger method. The values ofEaindicated that the difficulty coefficient of pyrolysis in II, III and IV stages was increased in the order: II < III < IV. The values of the entropy of activation ΔS≠, enthalpy of activation ΔH≠and free energy of activation ΔG≠of the reaction were estimated.

The Influence of Sodium Benzoate on the Alkaline Hydrolysis of Fuchsin: Inhibition Study

2021 ◽  
Vol 46 (1) ◽  
Author(s):  
D. F Latona ◽  
A.E Akinola
Keyword(s):  
Alkaline Hydrolysis ◽  
Sodium Benzoate ◽  
Activation Parameters ◽  
First Order ◽  
First Order Kinetics ◽  
Free Energy Of Activation ◽  
Hydrolytic Reaction ◽  
Presence And Absence ◽  
Gibb’S Free Energy ◽  
Hydrolysis Of

Kinetics of alkaline hydrolysis of Fuchsin in the absence and presence of sodium benzoate was investigated at 546.5 nm by pseudo first order kinetics. The reaction was found to be first order each in [Fuchsin] and [NaOH] in the presence and absence of sodium benzoate. Double reciprocal plot indicates the presence of an intermediate complex in the course of the reaction. Activation parameters were obtained from Erying’s equation as ΔH# 24.70 kJmol-1, ΔS# -0.193 kJK-1mol-1 and ΔG# 82.21 kJ mol-1 in the absence of sodium benzoate and ΔH# 27.59 kJmol-1, ΔS# -0.185 kJ K-1mol-1 and ΔG# 82.72 kJ mol-1in the presence of sodium benzoate. Sodium benzoate plays an inhibitory role in the hydrolysis reaction. The values of the change in Gibb’s free energy of activation shows same mechanism for the hydrolytic reaction in the presence and absence of sodium benzoate. A plausible mechanism is proposed. Keywords: Sodium benzoate, Fuchsin, NaOH, rate law, mechanism

Role of solvation and desolvation in polymer ‘catalysis’. I. The influence of high pressures on the spontaneous and Ag+-induced aquations of Co(NH 3 )5Br 2+ catalysed by macro-ions

1980 ◽  
Vol 370 (1743) ◽  
pp. 485-500 ◽  
Keyword(s):  
Free Energy ◽  
High Pressures ◽  
Energy Of Activation ◽  
Elevated Pressures ◽  
Free Energy Of Activation ◽  
Entropy Of Activation ◽  
Activated Complex

The spontaneous and Ag+-induced aquation reactions of Co(NH 3 ) 5 Br 2 + were examined in the presence of polyelectrolytes and at high pressures. The aquation reactions were enhanced by addition of anionic polyelectrolytes, i.e. sodium polyethylenesulphonate and sodium polystyrenesulphonate. The polyelectrolyte-accelerated reactions were retarded at elevated pressures. The volumes of activation, ΔT≠, were negative in the absence of the macro-ions and positive in their presence for both aquations. The results indicate that the activated complex is dehydrated by the macro-ions to a much larger extent than the reactants. Correspondingly, the entropy of activation was increased by addition of the macro-ions, causing a decrease in the free energy of activation. The dehydration of the activated complex is thus considered to be one of the important factors of polyelectrolyte ‘catalysis’. The implications of these findings are discussed.

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