Separation of mass law and solvent effects in kinetics of solvolyses of p-nitrobenzoyl chloride in aqueous binary mixtures

Bentley, T. William; Harris, H. C.

doi:10.1021/jo00239a004

Cited by 55 publications

(34 citation statements)

References 1 publication

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“…These values are remarkably similar to those observed in the corresponding solvolyses of benzyl chloroformate (S=2.0-4.1), 30 benzyl fluoroformate (S=2.2-3.6), 31 and psubstituted benzoyl chlorides (S=2.0-4.2), 36,37 which are believed to follow the addition-elimination pathway.…”

supporting

confidence: 85%

Rate and Product Studies of 1-Adamantylmethyl Haloformates Under Solvolytic Conditions

Park¹,

Lee²,

Lee³

et al. 2012

Bulletin of the Korean Chemical Society

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Reactions of 1-adamantylmethyl chloroformate (1-AdCH 2 OCOCl, 1) and 1-adamantylmethyl fluoroformate (1-AdCH 2 OCOF, 2) in hydroxylic solvents have been studied. Application of the extended Grunwald-Winstein (G-W) equation to solvolyses of 1 in a variety of pure and binary solvents indicates an addition-elimination pathway in the majority of the solvents except an ionization pathway in the solvents of relatively low nucleophilcity and high ionizing power. The solvolyses of 2 show an addition-elimination pathway in all of the mixed solvents. The leaving group effects (k F /k Cl ), the kinetic solvent isotope effects (KSIEs, k MeOH /k MeOD ), and the enthalpy and entropy of activation for the solvolyses of 1 and 2 were also calculated. The selectivity values (S) for each solvent composition are reported and discussed. These observations are compared with those previously reported for other alkyl haloformate esters.

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supporting

confidence: 85%

Rate and Product Studies of 1-Adamantylmethyl Haloformates Under Solvolytic Conditions

Park¹,

Lee²,

Lee³

et al. 2012

Bulletin of the Korean Chemical Society

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“…There is probably general-based catalysis [20,21] to the nucleophilic attack, leading to a relatively high l value of 1.7 for phenyl chloroformate solvolyses. The addition-step is believed to be rate-determining, largely on the basis of the very similar rates for fluoroformates and chloroformates, despite the much stronger carbon-fluorine bond [22].…”

Section: Introductionmentioning

confidence: 99%

Application of the Extended Grunwald-Winstein Equation to Solvolyses of n-Propyl Chloroformate

Kyong

Won

Kevill

2005

IJMS

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Application of the extended Grunwald-Winstein equation to solvolyses of n-propyl chloroformate in a variety of pure and binary solvents indicates an addition-elimination pathway in the majority of the solvents but an ionization pathway in the solvents of highest ionizing power and lowest nucleophilicity. For methanolysis, a solvent deuterium isotope effect of 2.17 is compatible with the incorporation of general-base catalysis into the substitution process. Activation parameters are consistent with the duality of mechanism. Very modest positive salt effects are observed on adding chloride or bromide salts to the ethanolysis.

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“…However, considering the result obtained (Table 7) for the substituent effect and the leaving group effect, 23 unfortunately we have no evidence for the nucleophilic attack on carbocations by third order reaction model type (based on a general base catalytic reaction) 7,8 Therefore, the k MAP terms may be estimated as 3rd order rate constant which depends on the number of free molecules of methanol caused by the cleavage of the H-bond, as a non-hydrogen bonding aprotic solvent (hydrogen bonding donor acidity, HBDA; α = 0.23 for MeNO 2 , 015 for MeCN) 24 is added to the bulk structure of methanol (α = 0.98) and the k MM , these values may be the only ones which are connected with a molecule of methanol without adding an aprotic solvent.…”

Section: Resultsmentioning

confidence: 80%

“…1c However, rate maxima in alcohol-water mixtures have also been observed, and explained by general base catalysed nucleophilic attack on carbonyl carbon (third order reactions in which changes in solvent stiochiometry are the dominant solvent effect). 7,8 In addition to examples relevant to our work (see below), there are a few other examples of rate maxima for solvolyses in binary mixtures: e.g. S N 1 reactions of 1-adamantyl picrate in methanol-tetramethylene sulfone, 9 and of 2-adamantyl perchlorate in methanol-acetone; 10 S N 2 reactions of methyl perchlorate in methanol-acetone, 10 acetone-water 11 and dioxane-water.…”

Section: Introductionmentioning

confidence: 99%

Stoichiometric Solvent Effect on S_N1 Solvolytic Reactivity Accounting for Phenomenon of Maximum Rates in Methanol-Nitromethane Mixtures

2004

Bulletin of the Korean Chemical Society

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Pseudo-first order rate constants (k obs ) are reported for the following solvolyses in approximately isodielectric mixtures: 3-and 4-methoxybenzyl chloride, bromo-and chlorodiphenylmethane, and 4-chloro-, 4,4'-dichloroand 4-methyl-chlorodiphenylmethane in 0-80% v/v nitromethane-methanol mixtures; and bromo-and chlorodiphenylmethane and 4-methyl-chlorodiphenylmethane in various acetonitrile-methanol mixtures (in the range 0-50% v/v) at 25 ºC. These data, and literature data for t-butyl halides (Cl, Br, and I), and for p-methoxybenzoyl chloride, show rate maxima in solvent compositions of ca. 30% aprotic cosolvent, explained by a stoichiometric solvent effect on electrophilic solvation. Linear relationships are observed between (k obs )/ [MeOH] 2 and [AP]/[MeOH], where [AP] refers to the molar concentration of aprotic cosolvent. The results are consistent with competing third order contributions to kobs, kMM [MeOH] 2 with hydrogen-bonded methanol as electrophile, and kMAP [MeOH][AP] with hydrogen-bonding disrupted by the aprotic solvent.

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Separation of mass law and solvent effects in kinetics of solvolyses of p-nitrobenzoyl chloride in aqueous binary mixtures

Cited by 55 publications

References 1 publication

Rate and Product Studies of 1-Adamantylmethyl Haloformates Under Solvolytic Conditions

Rate and Product Studies of 1-Adamantylmethyl Haloformates Under Solvolytic Conditions

Application of the Extended Grunwald-Winstein Equation to Solvolyses of n-Propyl Chloroformate

Stoichiometric Solvent Effect on S_N1 Solvolytic Reactivity Accounting for Phenomenon of Maximum Rates in Methanol-Nitromethane Mixtures

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Separation of mass law and solvent effects in kinetics of solvolyses of p-nitrobenzoyl chloride in aqueous binary mixtures

Cited by 55 publications

References 1 publication

Rate and Product Studies of 1-Adamantylmethyl Haloformates Under Solvolytic Conditions

Rate and Product Studies of 1-Adamantylmethyl Haloformates Under Solvolytic Conditions

Application of the Extended Grunwald-Winstein Equation to Solvolyses of n-Propyl Chloroformate

Stoichiometric Solvent Effect on SN1 Solvolytic Reactivity Accounting for Phenomenon of Maximum Rates in Methanol-Nitromethane Mixtures

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Stoichiometric Solvent Effect on S_N1 Solvolytic Reactivity Accounting for Phenomenon of Maximum Rates in Methanol-Nitromethane Mixtures