• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.3-9
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• 1993

Specific rates of solvolysis of 1-adamantyl fluoroformate in hydroxylic solvents have been measured by an electric conductivity method under various pressures. The activation parameters (${\Delta}V^{\neq}{_o},\;{\Delta}{\beta}^{\neq},\;{Delta}H^{\neq},\;{Delta}S^{\neq}$,/TEX>) and average pressure within the solvation-shell of activated complex (charge development) have been estimated from the rates. Also, the selectivities for the formation of solvolysis products in aqueous ethanol have been determined by response-calibrated GC. The values of ${\Delta}V^{\neq}{_o},\;and\;{\Delta}{\beta}^{\neq}$ are both negative, but ${Delta}H^{\neq}$ is positive and ${Delta}S^{\neq}$, is large negative. This behavior is discussed in terms of electrostriction of solvation. From these results, it could be postulated that the solvolysis of 1-adamantyl fluoroformate have two major reaction pathway.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2697-2701
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• 2013

The solvolysis rate constants of piperonyloyl chloride (1) in 27 different solvents are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale, $Y_{Cl}$ solvent ionizing scale, and I aromatic ring parameter with sensitivity values of $0.30{\pm}0.05$, $0.71{\pm}0.02$, and $0.60{\pm}0.04$ for l, m, and h, respectively. The solvent kinetic isotope effect values (SKIE, $k_{MeOH}/k_{MeOD}$ and $k_{50%MeOD-50%D2O}$) of 1.16 and 1.12 were also in accord with the values for the $S_N1$ mechanism and/or the dissociative $S_N2$ mechanism. The product selectivity values (S) for solvolysis of 1 in alcohol/water mixtures were in the range of 0.5 to 1.9, which is also consistent with the proposed unimolecular ionization mechanism.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2465-2470
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• 2014

The rate constants of solvolysis of phenyl N-phenyl phosphoramidochloridate (PhNHPO(Cl)OPh, Target Compound-TC1) have been determined by a conductivity method. The solvolysis rate constants of TC1 are well correlated with the extended Grunwald-Winstein equation, using the $N_T$ solvent nucleophilicity scale and YCl solvent ionizing scale, and sensitivity values of $0.85{\pm}0.14$ and $0.53{\pm}0.04$ for l and m, respectively. These l and m values were similar to those obtained previously for the complex chemical substances dimethyl thiophosphorochloridate; N,N,N',N'-tetramethyldiamidophosphorochloridate; 2-phenyl-2-ketoethyl tosylate; diphenyl thiophosphinyl chloride; and 9-fluorenyl chloroformate. As with the five previously studied solvolyses, an $S_N2$ pathway is proposed for the solvolyses of TC1. For four representative solvents, the rate constants were measured at several temperatures, and activation parameters (${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$) were estimated. These activation parameters are also in line with the values expected for an $S_N2$ reaction.

• Journal of the Korean Chemical Society
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• v.20 no.5
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• pp.333-339
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• 1976

The rates of solvolysis for 2-thenoyl chloride have been measured in aqueous acetone and aqueous ethanol at various temperatures ranging from 20 to $40^{circ}C$. The activation parameters and the Grundwald-Winstein's slope are determined by the analysis of solvolysis rates. The results indicated that the reaction rates of solvolysis are considerably slower than those of the reaction for benzoyl chloride due to the electron donating effect of thiophene nucleus. The results also showed that the reaction proceeds with the $S_N1$ mechanism in water-rich solvents whereas the $S_N2$ character increases with the decrease of water content, and overall reaction is subject to entropy control.

• Bulletin of the Korean Chemical Society
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• v.9 no.1
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• pp.1-4
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• 1988

Rates of solvolysis of trans-[Co$(N-eten)_2Cl_2$]$^+$ have been investigated using spectrophotometric method at various pressures and temperatures in the mixtures of water with the t-butyl alcohol which possesses a high structure inducing capacity in water. The values of ${\Delta}V^{\neq}$ obtained from pressure effect on the rate constants were 2.55∼ 5.83 $cm^3mol^{-1}$. These values were discussed in terms of dissociative mechanism. Extrema found in the variation of ${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$ with solvent composition correlated with extrema in the variation of the physical properties of the mixtures. The logarithms of rate constants correlated linearly with both Grunwald-Winstein parameter and the reciprocal of dielectric constant ($Ds^{-1}$). The gradient, m of Grunwald-Winstein plot for the trans-[Co$(N-eten)_2Cl_2$]$^+$ was 0.09, which is significantly lower than those for the other cobalt (Ⅲ)-dichloro complexes. It was suggested that the reaction is an Id mechanism with long extension of Co-Cl bond in the transition state, as found for the C-Cl bond in the transition state for the solvolysis of t-butyl chloride.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1761-1766
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• 2005

Solvolysis rates of isopropenyl chloroformate (3) in water, $D_2O$, $CH_3OD$ and in aqueous methanol, ethanol, 2,2,2-trifluoroethanol (TFE), acetone, 1,4-dioxane as well as TFE-ethanol at 10 ${^{\circ}C}$ are reported. Additional kinetic data for pure water, pure ethanol and 80%(w/w) 2,2,2-trifuoroethanol (T)-water (W) at various temperatures are also reported. These rates show the phenomena of maximum rates in specific solvents (30% (v/v) methanol-water and 20% (v/v) ethanol-water) and, variations in relative rates are small in aqueous alcohols. The kinetic data are analyzed in terms of GW correlations, steric effect, kinetic solvent isotope effects (KSIE), and a third order model based on general base catalysis (GBC). Solvolyses based on predominately stoichiometric solvation effect relative to medium solvation are proceeding in 3 and the results are remarkably similar to those for p-nitrobenzoyl chloride (4) in mechanism and reactivity.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3366-3370
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• 2010

The specific rates of solvolysis of t-butyl fluoroformate (1) have been measured at $40.0^{\circ}C$ in 21 pure and binary solvents. These give a satisfactory correlation over the full range of solvents when the extended Grunwald-Winstein equation, with incorporation of the solvent nucleophilicity and the solvent ionizing power, is applied. The actual values are very similar to those obtained in earlier studies of the solvolyses of isopropyl chloroformate and ethyl chlorothioformate in the more ionizing and least nucleophilic solvents, which are believed to proceed by an ionization pathway. The small negative values for the entropies of activation are consistent with the ionization nature of the proposed rate-determining step. These observations are also compared with those previously reported for the corresponding primary and secondary alkyl haloformate esters.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2989-2994
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• 2013

The solvolysis rate constants of 3,4- (1) and 3,5-dimethoxybenzoyl (2) chlorides were measured in various pure and binary solvents at $25.0^{\circ}C$, and studied by application of the extended Grunwald-Winstein (G-W) equation, kinetic solvent isotope effect in methanolysis and activation parameters. The solvolysis of 1 was interpreted as the unimolecular pathway due to a predominant resonance effect from para-methoxy substituent like 4-methoxybenzoyl chloride (3), while that of 2 was evaluated as the dual mechanism, with unimolecular or bimolecular reaction pathway according to the character of solvent systems (high electrophilic/nucleophilic) chosen, caused by the inductive effect by two meta-methoxy substituents, no resonance one. In the solvolyses of 1 and 2 with two $-OCH_3$ groups, the resonance effect of para-methoxy substituent is more important to decide the mechanism than the inductive effect with other corresponding evidences.

• Journal of the Korean Chemical Society
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• v.20 no.5
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• pp.391-397
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• 1976

Substituent effects of leaving group in benzylarenesulfonates solvolysis have been carried out in 10∼50% water-acetone mixtures by electric conductivity method. Results of solvent effects, substituent effects and variable rate difference of water contents, show that $S_N1$ character almost predominates through the substituents, though p-MeO favors more or less $S_N2$ character in low water contents.

• Journal of the Korean Chemical Society
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• v.62 no.4
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• pp.265-268
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• 2018

The solvolyses of anthraquinone-2-carbonyl chloride (1) were studied kinetically in 27 pure and various mixed solvents. The analysis using the extended Grunwald-Winstein equation in the solvolyses of anthraquinone-2-carbonyl chloride (1) obtained the l value of $2.11{\pm}0.11$, the m value of $0.54{\pm}0.06$, and the correlation coefficient of 0.955. The solvolysis reaction of 1 might proceed via an associative $S_N2$ mechanism enhancing bond making than bond breaking in the transition state (TS). This interpretation is further supported by a relatively large solvent kinetic isotope effect (SKIE, 2.27).