• Journal of the Korean Chemical Society
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• v.30 no.2
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• pp.188-194
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• 1986

The rate constants for the solvolysis reactions of p-chlorobenzyl chloride in ethanol-water mixtures were determinded at 30${\circ}\;and\;40{\circ}$C up to 1,600bar. Rates of reaction were increased with increasing temperature and pressure, and decreased with increasing solvent composition of ethanol mole fraction. The plots of ln k against pressure are fitted to a second-order function in P, and values of ${\Delta}V^{\neq}\;and\;${\Delta}{\beta}^{\neq}$ are obtained. The values of ${\Delta}V^{\neq}\;and\;${\Delta}{\beta}^{\neq}$ extremum behavior at about 0.20 mole fraction of ethanol. This behavior is discussed in terms of solvent structure variation. From the relation between the plots of ln k versus the solvent parameter, q ≡ (D-1)/(2D+1), or the logarithmic molar water concentration, In $C_w$, it could be estimated that the reaction proceeds through $S_N1(2)$ mechanism.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.462-469
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• 2012

Cr(VI)-4,4'-bipyridine complex(4,4'-bipyridinium dichromate) was synthesized by the reaction of 4,4'-bipyridine with chromium trioxide in H2O, and characterized by IR, ICP. The oxidation of benzyl alcohol using 4,4'-bipyridinium dichromate in various solvents showed that the reactivity increased with the increase of the dielectric constant(${\varepsilon}$), in the order: cyclohexene$CH_3$, H, m-Br, m-$NO_2$) smoothly in N,N'-dimethylformamide. Electron-donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant(${\rho}$) was -0.63(303K). The observed experimental data have been rationalized as follows; the proton transfer occurs after the prior formation of a chromate ester in the rate determining step.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.6039-6046
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• 2013

Cr(VI)-heterocyclic complex[Cr(VI)-2-methylpyrazine] was synthesized by the reaction between of heterocyclic compound(2-methylpyrazine) and chromium trioxide, and characterized by IR and ICP analysis. The oxidation of benzyl alcohol using Cr(VI)-2-methylpyrazine in various solvents showed that the reactivity increased with the increase of the dielectric constant(${\varepsilon}$), in the order : cyclohexene${\rho}$) was Cr(VI)-2-methylpyrazine= -0.65(308K). The observed experimental data have been ratiolized. The hydride ion transfer causes the prior formation of a chromate ester in the rate-determining step.

• Journal of the Korean Chemical Society
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• v.33 no.6
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• pp.651-656
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• 1989

The catalytic effects of several phase-transfer catalysts (PTC) on the liquid-liquid heterogeneous nucleophilic displacement reaction of thiocyanate on benzyl chloride have been determined. Reactions followed a pseudo-first order dependency on the benzyl chloride concentration and the observed rate constant $(k_{obsd})$ were linearly related to the concentration of catalyst and varied with variables such as reaction temperature and solvent. The sequences of catalytic activity of the displacement were $NH_4Cl$ < BTMAC < 18-crown-6 < BTEAC < PEG < TBAC < CTMAB. Enthalpies and entropies of activation associated with the displacement were 15∼20 Kcal$mo^{l-1}$, -12∼-29 eu. respectively and the reaction occurs in the interphase comprising of microemulsion.

• Applied Chemistry for Engineering
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• v.25 no.6
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• pp.648-653
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• 2014

Cr(VI)-heterocyclic complex (2,4'-bipyridinium chlorochromate) was synthesized by the reaction between heterocyclic compound(2,4'-bipyridine) and chromium trioxide, and characterized by IR and ICP analysis. The oxidation of benzyl alcohol using 2,4'-bipyridinium chlorochromate in various solvents showed that the reactivity increased with the increase of the dielectric constant (${\varepsilon}$), in the order : N,N-dimet-hylformamide (DMF) > acetone > chloroform > cyclohexene. In the presence of DMF solvent with acidic catalyst such as hydrochloric acid (HCl solution), 2,4'-bipyridinium chlorochromate oxidized benzyl alcohol (H) and its derivatives (p-$CH_3$, m-Br, m-$NO_2$). Electron-donating substituents accelerated the reaction rate, whereas electron acceptor groups retarded the reaction rate. The Hammett reaction constant (${\rho}$) was -0.67 (303 K). The observed experimental data have been rationalize the proton transfer occurred followed the formation of a chromate ester in the rate-determining step.

• Journal of the Korean Chemical Society
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• v.32 no.3
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• pp.179-185
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• 1988

The reaction of VO_2\;^+$ with benzyl alcohol in perchloric acid and aqueous dimethylformamide leads to the formation of $VO^{2+}$ and benzaldehyde. The products, $VO^{2+}$ and benzaldehyde, are identified by infrared spectroscopy and gas chromatography. Kinetic studies on the reaction of VO_2\;^+$ with benzyl alcohol have been carried out using visible spectroscopy. The empirical rate equation can be expressed as $-d[VO_2\;^+]/dt=2\{\\{k_O+k_H[HClO_4]\}\[VO_2\;^+][C_6H_5CH_2OH]$ The rate determining step for the reaction is the process for the formation of $VO^{2+}$ and $C_6H_5CHOH$. The activation parameters are ${\Delta}H^{\neq}=13.32{\pm}1.73\;kcalmol^{-1}$ and ${\Delta}S^{\neq}=-31.02{\pm}0.09\;calmol^{-1}K^{-1}$ for the oxidation of benzyl alcohol in aqueous dimethylformamide.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5990-5996
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• 2011

6-Methylquinolinium dichromate[$(C_{10}H_9NH)_2Cr_2O_7$] was synthesized by the reaction of 6-methylquinoline with chromium trioxide in $H_2O$, and characterized by IR, ICP. The oxidation of benzyl alcohol using 6-methylquinolinium dichromate in various solvents showed that the reactivity increased with the increase of the dielectric constant(${\varepsilon}$), in the order: cyclohexene < chloroform < acetone < N,N- dimethylformamide. In the presence of hydrochloric acid($H_2SO_4$ solution), 6-methylquinolinium dichromate oxidized benzyl alcohol and its derivatives(p-$OCH_3$, m-$CH_3$, H, m-$OCH_3$, m-Cl, m-$NO_2$) smoothly in DMF. Electron-donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant(${\rho}$) was -0.67(303K). The observed experimental data was used to rationalize the hydride ion transfer in the rate-determining step.

• Applied Chemistry for Engineering
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• v.23 no.2
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• pp.241-246
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• 2012

Cr(VI)-heterocyclic complex (2,2'-bipyridinium dichromate) was synthesized by the reaction between of 2,2'-bipyridine and chromium trioxide in $H_2O$, and characterized by IR and ICP. The oxidation of benzyl alcohol using 2,2'-bipyridinium dichromate in various solvents showed that the reactivity increased with the increase of the dielectric constant, in the order: cyclohexene < chloroform < acetone < N,N-dimethylformamide. In the presence of DMF solvent with acidic catalyst such as $H_2SO_4$ solution, 2,2'-bipyridinium dichromate oxidized the benzyl alcohol and its derivatives (p-$p-OCH_3$, $m-CH_3$, H, $m-OCH_3$, m-Cl, $m-NO_2$). Electron-donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant was -0.66 (303 K). The observed experimental data was used to rationalize the hydride ion transfer in the rate-determining step.

• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.281-285
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• 2014

$Pd/TiO_2$ particles were prepared by wet impregnation for aerobic benzyl alcohol oxidation. Catalysts were prepared by the impregnation of 10 wt% palladium on $TiO_2$ after calcination at various temperatures. The surface areas of the catalysts were changed with calcination temperature. The catalyst calcined at $300^{\circ}C$ possessed the highest surface areas. Catalytic activity of the prepared samples was examined for aerobic benzyl alcohol oxidation. Among the samples, $Pd/TiO_2$ calcined at $300^{\circ}C$ showed the highest catalytic activity. Moreover, the catalysts with various Pd concentrations from 5 wt% to 15 wt% were prepared to investigate an optimum catalyst. 10 wt% $Pd/TiO_2$ was the most active in this reaction due to its higher surface areas and metal dispersion.

• Elastomers and Composites
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• v.40 no.1
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• pp.53-58
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• 2005

Carbon tetrachloride is very reactive chain transfer agent due to the resonance stability of the trichlorocarbon radicals after breaking of C-Cl bond. Effect of benzylic radical comparing to trichlorocarbon radicals in the chain tranrfer reactions was investigated. From the structural point of view, cumyl chloride is a good candidate because it has the C-Cl bond with benzylic radicals after displacement of C-Ci bond. The reactivity of free radical polymerization of styrene in the presence of cumyl chloride was compared with that of carbon tetrachloride by calculating chain transfer constants. Results show that the cumyl chloride acts as a stronger chain transfer agent than carbon tetrachloride. The calculated chain transfer constant of cumyl chloride shows higher value (0.0463) than that of carbon tetrachloride (0.0011) in the styrene polymerization. High reactivity of cumyl chloride comparing to that of carbon tetrachloride is probably due to the higher resonance stability or benzylic radical than that or trichlorocarbon radicals after breaking of C-Cl bond. Monte Carlo simulation method is applied for characterizing the validity of kinetic constants according to the ratio of chain transfer agent to monomer.