Mechanism on the Hydrolysis of Cinnamonitrile in Strong Acid 


Vol. 28,  No. 6, pp. 418-424, Dec.  1984


PDF
  Abstract

Cinnamonitrile의 산-가수분해 반응속도상수를 25℃, HClO4 1 ∼ 5M의 센산성 용액속에서 UV분광법으로 측정하고 Bunnett관계식에 적용하여 w = 9.8, w* = 0.42 및 ψ=1.6등의 hydration parameter를 구하였다. 이는 질소원자에 양성자화가 이루어진 짝산에 대하여 속도결정단계에서 친핵체로 물분자가 첨가된 다음에 양성자 전달체로 작용한다는 것을 시사한다. Cinnamonitrile 분자의 궤도함수를 CNDO/2방법으로 계산한 바, 형태이성체의 안정도는 (E)-planar＞(Z)-planar이였으며 음하전의 크기는 C8(β)≪N이였고 전이상태에서 물분자는 짝산의 양하전이 큰 C7(α)원자에 대하여 σ접근함을 알았다. 이상의 결과로 부터, 센산성속에서 cinnamonitrile의 가수분해반응은 특정 산-촉매작용을 수반하는 A-2형의 산-가수분해 반응메카니즘에 의하여 진행됨을 알았다. Rate constants for the hydrolysis of cinnamonitrile in the concentration range of 1 ∼ 5M of perchloric acid at 25℃ have been determined by UV spectrophotometry and from the Bunnett equations, hydration parameters (w = 9.8, w* = 0.42 & ψ=1.6) were obtained. CNDO/2 MO calculations were performed to determine relative stability, net charges, and overlap population of various conformational isomers. The results show that the (E)-planar is more stable than the (Z)-planar and protonation is favored on the nitrogen atom. On the basis of above findings, the acid hydrolysis is initiated by the protonation of the nitrogen atom of cinnamonitrile and then water molecule acting as nucleophile and as a proton transfer agent in the rate determining step. In the transition state of the acid hydrolysis, nucleophilic addition of water molecule occurs by sigma approach to the positively charged C7(α) atom of the conjugate acid. As the results, we may conclude that the hydrolysis of cinnamonitrile in the strong acidic media proceeds through the A-2 type mechanism.

  Statistics
Cumulative Counts from November, 2022
Multiple requests among the same browser session are counted as one view. If you mouse over a chart, the values of data points will be shown.


  Cite this article

[IEEE Style]

K. Kwon, N. Sung, Y. Cheun, T. Kim, "Mechanism on the Hydrolysis of Cinnamonitrile in Strong Acid," Journal of the Korean Chemical Society, vol. 28, no. 6, pp. 418-424, 1984. DOI: .

[ACM Style]

Ki-Sung Kwon, Nack-Do Sung, Young-Gu Cheun, and Tae-Rin Kim. 1984. Mechanism on the Hydrolysis of Cinnamonitrile in Strong Acid. Journal of the Korean Chemical Society, 28, 6, (1984), 418-424. DOI: .

Search
(IN TITLE, AUTHOR, ABSTRACT,KEYWORDS)

Advanced Search ▼

POPULAR KEYWORDS
(TOP 10 KEYWORDS)

Recent Publications
(LAST 3 YEARS)

ISSN(Print) 1017-2548
ISSN(Online) 2234-8530