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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 33, Number 1
JKCSEZ 33(1)
February 20, 1989 

The Nucleophilic Substitution Reactions of the Nitrate Group. The Kinetics of Substituted Benzyl Nitrates with Anilines in Acetonitrile

질산기의 친핵성 치환반응. 아세토니트릴용매에서 질산치환벤질류와 아닐린류와의 반응속도론
Wang Ki Kim, Chang Kook Sohn

김왕기, 손창국
순수한 아세토니트릴용매에서 질산파라-치환 벤질과 파라-치환 아닐린간의 친핵성 치환반응에 대한 2차반응속도상수를 전기전도도법으로 구하여 Hammett ρx와 ρy값 및 BrΦnsted β값을 계산하였다. 이때 아닐린의 치환기 변화에 따르는 ρx는 음의 값으로 주어졌으며 기질의 치환기에 따라서는 U자 모양의 비직선성 Hammett 도시가 얻어졌다. 포텐셜에너지표면 및 양자역학적 모형을 적용하여 치환기 변화에 따른 천이상태 구조의 변화를 고찰하여 본 결과 본 반응은 기질의 치환기의 성질에 따라 결합형성의 정도가 크게 변화하는 SN2 반응 메카니즘으로 진행함을 알 수 있었다.

The second-order rate constants for the nucleophilic substitution reactions of para-substituted benzyl nitrates with para-substituted anilines in acetonitrile were conductometrically determined. Hammett ρx and ρy values and BrΦnsted β values were obtained from these kinetic data. The reactions of Benzyl nitrates with the series of anilines showed linear Hammett plots with negative slopes. For the change of substituents in the benzyl nitrates, nonlinear Hammett plots with a concave upwards curve were obtained. We applied the potential energy surface and the quantum mechanical models in order to examine the transition state variations caused by changes in substituents on the nucleophile and the substrate. The results showed that the reaction was proceeded via the SN2-type reaction mechanism in which the extent of bond-formation was greatly changed depending on the property of the substituents in substrate.

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