Ferrocenylmethyl Benzoate류의 가용매분해에 대한 반응속도론적 연구 = Kinetics for the Solvolysis of Ferrocenylmethyl Benzoates

국문 초록 (Abstract)

여러 가지 p- 혹은 m- 치환 ferrocenylmethyl benzoate를 합성하였다. 이들 에스테르의 가용매 분해반응 속도를 여러 혼합비의 methanol, ethanol, acetone 및 1,4-dioxane 수용액에서 pH metric method로 측정하였다. 반응 속도는 용매의 유전상수가 클수록 빠르고 Kirkwood-Onsager 관계식에 잘 맞았다. Grunwald-Winstein 식을 적용시킬 때 substrate parameter m 값이 0.5 -0.6으로 나타나며 aprotic solvent에서 보다 protic solvent에서 약간 더 크게 나타났다. 이들 가용매 분해반응은 전자 끄는 치환기에 의해 촉진되며 Hammett 반응 상수가 ＋0.622 (80% EtOH)와 ＋0.882 (80% 1,4-dioxane)로 나타났다. 또한 이들 반응에 관여하는 몇 가지 활성화 parameter를 산출하였다. 이상의 반응 속도론적 연구결과로부터 이들 에스테르의 가용매 분해반응은 ?? (alkyl-oxygen fission)과 ?? (acyl-oxygen fission)의 혼합과정으로, 그러나 ??쪽이 약간 우세한 과정으로 진행한다는 사실을 알 수 있었다.

다국어 초록 (Multilingual Abstract)

Several ferrocenylmethyl p-or m- substituted benzoates were synthesized. Rates of solvolysis of these esters in aqueous methanol, ethanol, acetone or 1,4-dioxane of various compositions were measured by a pH metric method. Rates of reaction were increased with increasing dielectric constant of solvent and these reactions obeyed Kirkwood-Onsager equation well. Substrate parameter (m) derived from Grunwald-Winstein equation was found to be 0.4-0.6 in these solvolyses, and the value (m) in protic solvent was slightly larger than that in aprotic solvent. Reactions were accelerated by electron-withdrawing substituents and Hammett substituent constants (ρ) of ＋0.622 (in 80% EtOH) and ＋0.882 ( in 80% 1, 4-dioxane) were obtained. Some activation parameters relevant to these reactions were also calculated. From the observed kinetics, it was concluded that ferrocenylmethyl benzoates solvolyze by a combination of ?? (alkyl-oxygen fission) and ?? (acyl-oxygen fission) pathways, in which ?? mode predominates slightly over ?? mode.