Correlation Analysis Of Reactivity Research Articles

Correlation analysis of reactivity in the oxidation of some vicinal and non-vicinal diols by Tributylammonium chlorochromate: A kinetic and mechanistic approach

The kinetics of oxidation of four vicinal, four non-vicinal diols by tributylammonium chlorochromate (TBACC) has been studied in dimethylsulphoxide (DMSO). The main product of oxidation is the corresponding hydroxycarbonyl compound. The reaction is first order each in TBACC. Michaelies-Menten type of kinetics is observed with respect to the diols. The reaction is catalysed by hydrogen ions. The hydrogen ion dependence is taking the form: kobs = a + b[H+]. The oxidation of [1,1,2,2-2H4] ethanediol exhibits a substantial primary kinetic isotope effect (kH/kD = 5.81 at 298 K). The reaction has been studied in nineteen different organic solvents and the solvent effect has been analysed using Taft's and Swain's multiparametric equations. The temperature dependence of the kinetic isotope effect indicates the presence of a symmetrical transition state in the rate-determining step. A suitable mechanism has been proposed.

Correlation analysis of reactivity in oxidation of some aliphatic aldehydes by 2-picolinium chlorochromate: A kinetic study

The oxidation of six aliphatic aldehydes by 2- picolinium chlorochromate (PICC) in dimethyl sulfoxide (DMSO) leads to the formation of corresponding carboxylic acids. The reaction is of first order each in PICC. A Michaelis-Menten type of kinetics is observed with respect to the aldehydes. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form: kobs = a + b[H+]. The oxidation of deuteriated acetaldehyde MeCDO exhibited a substantial primary kinetic isotope effect (kH/kD = 5.69 at 298 K). The oxidation of acetaldehyde has been studied in nineteen different organic solvents. The solvent effect has been analysed using Taft's and Swain's multiparametric equations. The rate constants correlate well with Taft’s * values, reaction constants being negative. A mechanism involving transfer of hydride ion has been suggested.

Kinetics and correlation analysis of reactivity in the oxidation of aliphatic primary alcohols by isoquinolinium dichromate in non-aqueous medium

Mild oxidation in dimethyl sulfoxide (DMSO) medium by isoquinolinium dichromate (IQDC) of aliphatic primary alcohols produces corresponding carbonyl compounds. A Michaelis-Menten kind kinetics noticed as for alcohols while unit dependency on rate observed as for IQDC. At non-identical temperatures the formation constants and the rates of decomposition of alcohol-IQDC complexes have been evaluated. Thermodynamic parameters and activation parameters for formation of the complex and break down of the complexes have been determined respectively. The oxidation process accelerates with increase in proton concentration. An α-C-H bond fisson in the rate-controlling step suggested by the deuterium isotope effect. For oxidation of ethanol, kH/kD = 5.82 at 293 K, was observed. The oxidation rates have been evaluated in 19 organic solvents and greater role of solvating power of the cation is observed. Depended on the kinetic parameters, solvent effect analysis and the outcome of thermodynamic parameters, a mechanism in which rate-controlling break down of the complex is suggested, to give the resulting product through hydride-ion transfer with a cyclic transition state.

Kinetics and Correlation Analysis of Reactivity in the Oxidation of Some α-Hydroxy Acids by Benzimidazolium Dichromate

Kinetic and mechanistic studies of the oxidation of mandelic acid and nine monosubstituted mandelic acids by benzimidazolium dichromate (BIDC) in dimethyl sulfoxide are discussed with an emphasis on correlation of structure and reactivity. The reactions were of first order with respect to BIDC. However, Michaelis-Menten type kinetics were observed with respect to hydroxy acids. The reactions are catalysed by protons. The deuterium isotope effect for the oxidation of mandelic acid ( kH/ kD= 5.91 at 298 K) indicated an α-C-H bond cleavage in the rate-determining step. An analysis of the solvent effect showed that the role of cationsolvation is major. The reaction showed an excellent correlation with the Hammett σ values, the reaction constant being negative. Based on the kinetic data, analysis of the solvent effect and results of structure-reactivity correlation along with some non-kinetic parameters, a mechanism involving rate-determining oxidative decomposition of the complex through hydride-ion transfer via a cyclic transition state to give the corresponding oxoacid is suggested.

Correlation analysis of reactivity in the oxidation of substituted benzyl alcohols by benzimidazolium dichromate – A kinetic and mechanistic aspects

Correlation analysis of reactivity in the oxidation of substituted benzyl alcohols by benzimidazolium dichromate – A kinetic and mechanistic aspects

Correlation analysis of reactivity in the oxidation of aliphatic primary alcohols by imidazolium dichromate

Correlation analysis of reactivity in the oxidation of aliphatic primary alcohols by imidazolium dichromate

Kinetics and Correlation Analysis of Reactivity in the Oxidation of Some Alkyl Phenyl Sulfides by Benzimidazolium Dichromate

Abstract The oxidation of some alkyl phenyl sulfides by benzimidazolium dichromate (BIDC) in dimethyl sulfoxide, to the corresponding sulfoxides, is first order with respect to BIDC. Michaelis–Menten type kinetics was observed with respect to sulfide. Thermodynamic parameters for the complex formation and activation parameters for the decomposition of the complex were calculated. The reaction is proton-catalyzed and the order is less than one. It appears that the BIDCH+ is the active electrophile. An intermediate of composition sulfide–BIDC–H+ has been envisaged. The high value of negative entropy of activation suggests a cyclic transition state in the rate-determining step. The reaction exhibited negative polar reaction constants and a small degree of steric hindrance. The rate of oxidation of sulfide was determined in 19 organic solvents. An analysis of the solvent effect by Swain’s equation indicated that though both the anion and cation solvating powers of the solvent contribute to the observed solvent effect, the role of cation solvation is major. A mechanism involving the rate-determining oxygen atom transfer in complex, formed by a nucleophilic attack of sulfide-sulfur on BIDCH+ in a rapid pre-equilibrium, is suggested to give corresponding sulfoxide via. a cyclic transition state.

Correlation analysis of reactivity in the oxidation of some organic sulfides by tetrabutylammonium tribromide : A kinetic and mechanistic study

Correlation analysis of reactivity in the oxidation of some organic sulfides by tetrabutylammonium tribromide : A kinetic and mechanistic study

Correlation analysis of reactivity in the oxidation of some para- substituted benzhydrols by triethylammonium chlorochromate in non-aqueous media

Triethylammonium chlorochromate (TriEACC) oxidation of some para-substituted benzhydrols (BH) in dimethylsulfoxide (DMSO) leads to the formation of corresponding benzophenones. The reaction was run under pseudo-first-order conditions. The reaction is catalyzed by hydrogen ions. The hydrogen ion dependence has the form: kobs=a+b[H+]. Various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of isokinetic relationship. Oxidation of benzhydrol was studied in 18 different organic solvents. The rate data showing satisfactory correlation with Kamlet–Taft solvatochromic parameters (α, β and π∗) suggests that the specific solute–solvent interactions play a major role in governing the reactivity, and the observed solvent effects have been explained on the basis of solute–solvent complexation. A suitable mechanism of oxidation has been proposed.

Correlation analysis of reactivity in the oxidation of some organic diols by tripropylammonium fluorochromate in non-aqueous media

The kinetics of oxidation of some organic diols by tripropylammonium fluorochromate (TriPAFC) have been studied in dimethylsulfoxide (DMSO). The main product of oxidation is the corresponding hydroxy aldehydes. The reaction is first order with respect to TriPAFC and exhibited Michaelis-Menten type kinetics with respect to organic diols. The reaction is catalyzed by hydrogen ions. The hydrogen ion dependence has the form: kobs=a+b[H+]. Various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of isokinetic relationship. Oxidation of diols was studied in 18 different organic solvents. The rate data are showing satisfactory correlation with Kamlet–Taft solvotochromic parameters (α, β and π∗). A suitable mechanism of oxidation has been proposed.

Correlation analysis of reactivity in the oxidation of methionine by benzimidazolium fluorochromate in different mole fractions of acetic acid–water mixture

The kinetics of oxidation of methionine (Met) by benzimidazolium fluorochromate (BIFC) has been studied in the presence of chloroacetic acid. The reaction is first order with respect to methionine, BIFC and acid. The reaction rate has been determined at different temperatures and activation parameters calculated. With an increase in the mole fraction of acetic acid in its aqueous mixture, the rate increases. The solvent effect has been analyzed using the Kamlet’s multi parametric equation. A correlation of data with the Kamlet–Taft solvatochromic parameters (α, β, π∗) suggests that the specific solute–solvent interactions play a major role in governing the reactivity. The reaction does not induce polymerization of acrylonitrile. A suitable mechanism has been proposed.

Kinetics and correlation analysis of reactivity in the oxidation of organic sulfides by butyltriphenylphosphonium dichromate

The oxidation of a number of monosubstituted aryl methyl, alkyl phenyl, dialkyl, and diphenyl sulfides by butyltriphenylphosphonium dichromate (BTPPD), to the corresponding sulfoxides, is first order with respect to BTPPD and is second order with respect to sulfide. The reaction is catalysed by hydrogen ions and the dependence is of second order. The oxidation of meta- and para-substituted aryl methyl sulfides correlated best in terms of Hammett equation, the reactions exhibited negative polar reaction constant. The ortho-substituted compounds correlated best in terms of Charton’s triparametric equation with negative polar constant and a small degree of steric hindrance. The oxidation of alkyl phenyl sulfides exhibited a good correlation in terms of Pavelich-Taft equation confirming that the electron-donating power of the alkyl group increases the rate, however, the reactivity is not markedly controlled by the bulkiness of the alkyl group. The rates of oxidation of sulfides were determined in nineteen organic solvents. An analysis of the solvent effect by multi-parametric equations indicated the relatively greater importance of the cation-solvating power of the solvents. A mechanism involving a single-step electrophilic oxygen transfer from BTPPD to the sulfide leading to polar transition state has been proposed.

Correlation analysis of reactivity in the oxidation of substituted benzaldehydes by morpholinium chlorochromate

Oxidation of thirty six monosubstituted benzaldehydes by morpholinium chlorochromate (MCC) in dimethylsulphoxide (DMSO), leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to MCC. A Michaelis-Menten type kinetics is observed with respect to benzaldehydes. The reaction is promoted by hydrogen ions; the hydrogen-ion dependence has the form k obs = a + b [H + ]. The oxidation of [ 2 H]benzaldehyde (PhCDO) exhibited a substantial primary kinetic isotope effect. The reaction was studied in nineteen organic solvents and the effect of solvent was analysed using Taft's and Swain's multi-parametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.

Correlation Analysis of Reactivity in the Photo- and Electro-Reduction of Cobalt(III) Complexes in Binary Organic Solvent/Water Mixtures

The photo- and electro-reduction of a series of cobalt(III) complexes of the type cis-β - [Co(trien)(RC6H4NH2)Cl]Cl2 with R = H, p-OMe, p-OEt, p-Me, p-Et, p-F, and m-Me has been studied in binary propan-2-ol/water mixtures. The redox potential (E1/2) and photo-reduction quantum yield (ΦCo(II)) data were correlated with solvent and structural parameters with the aim to shed some light on the mechanism of these reactions. The correlation of E1/2 and ΦCo(II) with macroscopic solvent parameters, viz. relative permittivity, indicated that the reactivity is influenced by both specific and non-specific solute-solvent interactions. The Kamlet-Taft solvatochromic comparison method was used to separate and quantify these effects: An increase in the percentage of organic cosolvent in the medium enhances both reduction processes, and there exists a good linear correlation between E1/2 and ΦCo(II), suggesting a similar solvation of the participants in these redox processes.

Kinetics and Correlation Analysis of Reactivity in the Oxidation of Aromatic Aldehydes by Butyltriphenylphosphonium Dichromate

The oxidation of a number of para-, meta- and ortho-substituted benzaldehydes by butyltriphenylphosphonium dichromate (BTPPD), in dimethyl sulphoxide, leads to the formation of the corresponding benzoic acid. The reaction is first-order with respect to BTPPD. Michaelis-Menten type kinetics were observed with respect to the aldehyde. The formation constants of the aldehyde-BTPPD complexes and the rates of their decomposition were determined at different temperatures. The reactions are catalysed by hydrogen ions and the dependence is of the second order. The oxidation of [2H] benzaldehyde (PhCDO) exhibited the presence of a substantial kinetic isotope effect. The rates of oxidation of meta- and para-substituted benzaldehydes were correlated in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated with tetraparametric LDRS equation. The oxidation of para- and ortho-substituted benzaldehydes are more susceptible to the delocalization effect than is the oxidation of meta-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric hindrance by the ortho-substituents. The rates of oxidation of benzaldehyde were determined in nineteen organic solvents. An analysis of the solvent effect by multiparametric equations indicated the greater importance of the cation-solvating power of the solvents. Suitable mechanisms have been discussed.

Correlation analysis of reactivity in the oxidation of substituted benzyl alcohols by 2,2' -bipyridinium chlorochromate

Oxidation of benzyl alcohol and some ortho-, meta- and para-monosubstituted ones by 2,2'-bipyridinium chlorochromate (BPCC) in DMSO leads to the formation of corresponding benzaldehydes. The reaction is first order in both BPCC and the alcohol. The reaction is promoted by hydrogen ions; the hydrogen-ion dependence has the form : k obs = a + b [H + ]. Oxidation of α,α-dideuteriobenzyl alcohol (PhCD 2 OH) has exhibited a substantial primary kinetic isotope effect (k H /k D = 5.60 at 298 K). The reaction has been studied in nineteen organic solvents and the effect of solvent analysed using Taft's and Swain's multi-parametric equations. The rates of oxidation of para- and meta-substituted benzyl alcohols have been correlated in terms of Charton's triparametric LDR equation whereas the oxidation of ortho-substituted benzyl alcohols with tetraparametric LDRS equation. The oxidation of para-substituted benzyl alcohols is more susceptible to the delocalization effect than that of ortho- and meta-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.

Correlation analysis of reactivity in the oxidation of anilines by nicotinium dichromate in nonaqueous media

AbstractThe kinetics of oxidation of 15 para‐ and meta‐substituted anilines by nicotinium dichromate (NDC) in different organic solvent media in the presence of p‐toluenesulfonic acid (TsOH) has been investigated. The rate of the reaction is zero order with respect to substrate, first order in NDC, and is found to increase with increase in [TsOH]. The various thermodynamic parameters for the oxidation have been reported and discussed along with the validity of the isokinetic relationship. The specific rate of oxidizing species‐anilines reaction (k2) correlates with Hammett's substituent constants affording negative reaction constants. The effect of para‐ and meta‐substituents on the oxidation rates confirms to Swain et al.'s substituent constants F and R, both with negative reaction constants. The rate data failed to correlate with macroscopic solvent parameters such as εr and E while showing satisfactory correlation with Kamlet–Taft's solvatochromic parameters (α, β, and π*). © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 657–665, 2006

Correlation analysis of reactivity in the oxidation of substituted benzyl alcohols by quinolinium bromochromate

Oxidation of benzyl alcohol and some ortho- meta- and para-monosubstituted ones by quinolinium, bromochromate (QBC) in dimethyl sulphoxide (DMSO) leads to the formation of corresponding benzaldehydes. The reaction is first order each in both QBC and the alcohol. The reaction is promoted by hydrogen ions; the hydrogen-ion dependence has the form k o b s = a + b [H + ]. Oxidation of α,α-dideuteriobenzyl alcohol (PhCD 2 OH) has exhibited a substantial primary kinetic isotope effect (k H /k D = 5.60 at 298 K). The reaction has been studied in nineteen organic solvents and the effect of solvent analysed using Taft's and Swain's multi-parametric equations. The rates of oxidation of para- and meta-substituted benzyl alcohols have been correlated in terms of Charton's triparametric LDR equation whereas the oxidation of ortho-substituted benzyl alcohols with tetraparametric LDRS equation. The oxidation of para-substituted benzyl alcohols is more susceptible to the delocalization effect than that of ortho- and meta-substituted compounds which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.

Correlation analysis of reactivity in the oxidation of substituted benzylamines by pyridinium hydrobromide perbromide

The oxidation of benzylamine and twenty-seven ortho-, meta- and para-substituted benzylamines by pyridinium hydrobromide perbromide (PHPB), in dimethylsulphoxide (DMSO), leads to the formation of the corresponding aldimines. The reactions are of first order with respect to both PHPB and the amine. The oxidation of deuterated benzylamine exhibited a substantial kinetic isotope effect (k H /k D = 3.20 at 303 K). An addition of pyridinium bromide does not affect the rate. PHPB itself has been postulated as the reactive oxidizing species. The rates of the oxidation of para- and meta-substituted benzylamines were correlated with Taft's and Swain's field and resonance substituent constants. The oxidation of para-substituted benzylamines showed an excellent correlation with Taft's σ 1 and σ B A R values; the meta-compounds correlated best with σ 1 and σ R 0 values. Rates of the ortho-substituted compounds showed a significant correlation with Charton's triparametric equation. Suitable mechanism has been proposed.

Correlation Analysis of Reactivity in the Oxidation of Substituted Benzyl Alcohols by Hexamethylenetetramine-Bromine

Correlation analyses of the effect of substituents on the oxidation of benzyl alcohols by hexamethylenetetramine-bromine indicate the presence of a carbocationic centre in the transition state and steric acceleration of the reaction.