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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 34, Number 1
JKCSEZ 34(1)
February 20, 1990 

The Solvolytic Reaction Mechanism of p-Substituted Benzyl Bromides

파라-치환 브롬화 벤질의 가용매 분해반응 메카니즘
Ikchoon Lee, Tae-Seop Uhm, Dae-Dong Sung, Jong-Pal Lee, Hyun-Seok Park

이익춘, 엄태섭, 성대동, 이종팔, 박현석
파라-치환 브롬화 벤질의 가용매 분해반응을 DMSO-H2O과 DMF-H2O 혼합용매계에서 속도론적으로 연구 하였다. 이 두 혼합용매계의 이온화력(Y)와 친핵도(NBS를 결정하기 위하여 같은 혼합용매속에서 1-adamantyl halides, t-butyl halides 그리고 methyl tosylate를 가용매 분해반응시켰다. 각 DMSO-H2O 혼합용매에 대한 분광용매화 파라미터는 측정된 νmax를 Taft의 관계식에 대입시켜 결정하였다. 파라-치환 브롬화 벤질의 가용매 분해반응은 m, l값과 β,ρs값으로 보아 전이상태에서 결합형성이 약간 우세한 경계반응 메카니즘으로 진행함을 알았다.

Solvolyses of p-substituted benzyl bromides have been studied in dimethylsulfoxide-water and N,N-dimethylformamide-water mixtures by kinetic method. To determine the ionizing power, Y and the nucleophilicity, NBS, the solvolyses of 1-adamantyl halides, t-butyl halides, and methyl tosylate in the same solvent mixtures have been investigated. The solvatochromic parameters for each dimethylsulfoxide-water mixtures have been determined by substituting into the Taft's linear solvatochromic energy relationships with measured νmax. The solvolyses of p-substituted benzyl bromides have been found to proceed by borderline mechanism in which bond formation is more advanced than bond cleavage in the transition state based on the m, l values and β,ρs, values.

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