페놀류의 해리상수에 미치는 온도, 압력의 영향

呂壽東,朴鍾煥 慶北大學校 物理化學硏究所 1985 硏究論文集 Vol.6 No.-

약산의 해리도는 전해질의 종류, 용매의 종류에 따라 달라진다. 또 같은 용매같은 전해질일지라도 온도나 압력에 따라서도 그 해리도가 달라진다. 압력이 증가할때의 약산의 해리상수는 증가하는 것과 감소하는 것이 있다. 증가하는 경우는 하전을 갖지 않은 산으로서 해리할때에 생성되는 이온의 용매화 작용에 의해서 부피가 감소되기 때문이다. 그러나 처음부터 이온으로 존재하고 반응 전후에 전하의 증가가 없는 경우에는 오히려 부피가 증가하여 압력이 높아지면 해리상수가 감소한다.

Phenyl Chloroformate와 置換아닐린의 아미드化 反應

呂壽東,文泰守,沈光澤 慶北大學校 1985 論文集 Vol.39 No.-

The second-order rate constants of carbamate formation from phenyl chloroformate and substituted anilines were determined conductometrically in acetone. The effect of substituent of substituted anilines were discussed. The amidation of phenyl chloroformate with several anilines of electron-donating groups are faster than that of anilines of electron-withdrawing groups. 〔For example, k_2 values: 1.91(p-Me, at 0℃), 1.22×10 exp (-2)(p-NO_2, at 0℃)〕. Hammett-type plots of the rate data with σ(σ^-) gave two straight lines 〔for anilines with electron-donating groups: log k_2=-4.61σ(σ^-)+1.77(r=0.98) in acetone at 10℃, for anilines with electron-withdrawing groups: logk_2=-0.73σ(σ^-)+1.12(r=0.98) in acetone at 10℃ Based on the Hammett plots, Bronsted plots and activation entropy, we assume an addition-elimination mechanism for the amidation of phenyl chloroformate with substituted anilines. In the case of anilines with electron-donating substituents, the rate of C-N bond formation increase and also assist the rate of Cl^- elimination. Therefore, the rate determining step seems to be Cl^- elimination. On the other hand, in the case of anilines with electron-withdrawing groups, they decrease not only the rate of C-N bond formation but the rate of Cl^- elimination. Thus C-N bond formation become rate-determining step.

各種 알코올 용매에서 Benzyl Benzenesulfonate와 Pyridine의 西次化 反應

呂壽東,權成旭 경북대학교 과학교육연구소 1989 科學敎育硏究誌 Vol.13 No.-

The reaction rate of Benzylbenzenesulfonate with pyridine was measured in various solvents by conductivity method. The reaction rate was increased by the increment of dielectric constant of aliphatic alcohols. On the while, in acetonitrile, the reaction rates were slow in contrast to dielectric constant. It has been known that the reaction rate is more affected by dissociation of leaving-group rather than bond-fromation of the nuclophile in the transition state. The results suggest that the reaction has dissociative S_N2 transition state in aliphatic alcohols.

Methanol과 DMF용매에서의 Phenacyl bromide와 치환피리딘類의 置換基效果에 關한 硏究

呂壽東,趙舜煥,沈光澤 경북대학교 과학교육연구소 1979 科學敎育硏究誌 Vol.3 No.-

The rates of the reaction of phenacyl bromide with substituted pyridines in MeOH and DMF were measured by electric conductivity method. The rates of reaction were increased with the electron donation power of substituents of pyridiness and the results were more increased in DMF than MeOH The isokintic relationship was seen between Ea and ΔS^≠, it's temperature was 401˚K in MeOH and 202˚K in DMF. Bro¨nsted linear relationship was shown as log k=0.28pka -2.47 (r=0.988) in MeOH at 45℃ log k=0.37pka -1.79 (r=0.981) in DMF at 45℃ The Hammett polt showed a linearity about substituent except for 4-NH_2, 4-CN. This deviations of above 2 groups were considered to be attributed to the localization of π-electrone on pyridine ring induced by the nuclear nitrogen atom, resonauce effects and solvent effects.

Benzyl arenesulfonate類와 Pyridine과의 反應速度論的 硏究

呂壽東 경북대학교 교육대학원 1973 논문집 Vol.4 No.-

The kinetics of the substituent effects for the reaction of benzyl arenesulfonates with pyridine in acetone at various temperature have been studied. From the kinetics, it is concluded that the rate of reaction could be ruled by the activation entropy of sulfonate groups and the reaction described as S_N2 displacement with the benzyl carbon of benzyl arenesulfonates as the reaction center. It may, however, indicate a small in bond formation and thus a tighter transition state, in benzyl p-chlorobenzensulfonate compared with benzyl m-nitrobenzenesulfonate.

2, 4-Dinitrofluorobenzene과 置換 Aniline類와의 反應에 關한 反應速度論的 硏究

呂壽東,李五錫,朴聖植 慶北大學校 1982 論文集 Vol.33 No.-

The rates and the activation parameters for the reactions of 2,4-Dinitrofluorobenzene with substituted Anilines in ethanol and dimethylformamide were studied. The effects of substituent and solvent on the reactivity of substituted anilines were discussed. The rate of the reaction was increased with the electron-donating power of substituent. The isokinetic relationship was obsevred between ΔH^≠ and ΔS^≠. The excellent linear relationship was found between logk and pka of substituted anilines. The reaction rates in ethlalcohol are faster than that in dimethylformamide, which was explained in terms of the specific solvation. From the results, bond-formation is rate-determining step of this reactions in each solvents.

Benzylbenzenesulfonate와 Dimethylaniline類와의 反應에 關한 硏究 : 擴張Hammett式의 適用에 關하여

呂壽東 慶北大學校 1976 論文集 Vol.22 No.-

The kinetics of the reaction of m-or p-substituted N,N·dimethyl anilines with benzyl benzenesulfonate in acetone have been determined by an electric conductivity method. The Hammett rule has been adopted for these reactions. It has been observed that an electrondonating substituent accelerates the reaction while an electron-attracting substituent retards the reaction. In acetone, the Hammett constant of p·MeO in nucleophile was expected·0.35 compared with other Menschutkin reaction in DMF.

Phenacyl Arensulfonate와 치환 Pyridine類의 반응에 관한 반응속도론적 연구

呂壽東,李五錫 慶北大學校 1983 論文集 Vol.35 No.-

The rates and activation parameters for the reactions of phenacyl tosylate with pyridines in acetonitrile were measured. The effects of substituents were increased with electron-donating power of pyridines and Brψnsted linear relationship was shown. The isoenthalpic relationship was observed and reactivity is mainly ruled by entropy change.

β-phenylethyl P-bromobenzenesulfonate와 피리딘과의 고압반응에 관한 반응속도론적 연구

여수동,박종환 慶北大學校 物理化學硏究所 1983 硏究論文集 Vol.4 No.-

β-phenylethyl brosylate와 피리딘을 아세토니트릴 용매 중에서 40∼60℃와 1∼1500bar의 압력에서 전기전도도 법으로 측정하였다. 반응속도는 온도 및 압력이 증가함에 따라 커졌으나 본 반응의 경우가 benzylbenzenesulfonate와 피리딘의 아세톤 용매 중에서의 반응보다 적었다. 활성화 엔탈피, 활성화 부피를 반응속도로부터 구했다. 특히 활성화 부피는 β-phenylethyl계와 benzyl계가 거의 같은 값을 가졌으나, 활성화 엔트로피는 전자의 경우가 (-)값으로 컸다. 이 현상은 β-phenylethyl계가 전이상태에서 보다 S_N2성임을 입증한다. 이 반응에서 압력 변화에 따라 ΔH^≠와 ΔS^≠사이에는 등속관계가 성립되었고 등속온도는 388˚K였다. 이상의 모든 결과를 종합하면 이 반응은 이 분자 과정의 전형적인 S_N2 반응을 거친다고 설명할 수 있다. Kinetics of the reaction of β-phenylethyl brosylate with pyridine in acetonitrile were investigated by an electric conductivity method under 1 to 1500 bars and at 40 - 60℃. The rates of reaction were increased with increasing temperature and pressure, but less than that of the reaction of benzyl benzenesulfonate with pyridine in acetone. The activation enthalpy, activation entropy an activation volume of the reaction are obtained by the kinetic runs. The activation volumes were about same value in both of β-phenylethyl and benzyl system, but activation entropies were more negatively large in the former systems in particular. These phenomena can be deduced that β-phenylethyl system has more firmly S_N2 character in transition state. The isokinetic relationship between ΔH^≠ and ΔS^≠ for pressure change in the reaction was shown and its temperature was 388˚K. From all the above results, the reaction can be adequately described as typical S_N2 bimolecular process.

Phenacylbromide와 3次아민의 反應에 對한 溶媒效果

呂壽東,趙舜煥,李五錫 慶北大學校 1982 論文集 Vol.33 No.-

The kinetics of the quarterization reaction of phenacylbromide with tertiary amines including pyridine 3.5-lutidine and triethylamine in the media of acetonitrile, dimethylformamide, methanol, acetone and tetratydrofuran have been measured at 25℃, 35℃ and 45℃. The results of experiments show that the rate of quarternization are greatly affected by polarity of solvent except methanol. Activation parameters obtained in this study have the values we can expect for usually S_N2 mechanism. A linear relationship has been obtained between pK_a and logk, though such relationship is not clear in triethylamine. The good linear relationship has also been obtained between activation entropy and enthalpy. The linear relationship between logk and solubility parameters has turned out to be better than that dielectric constants.