Theoretical Studies on the Cationic Polymerization Mechanism of Cyclic Acetals 


Vol. 36,  No. 2, pp. 197-204, Apr.  1992


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  Abstract

Cyclic acetal류 산촉매하의 중합반응에 대해서 반경험적인 MINDO/3, MNDO, AM1방법 등을 사용하여 이론적으로 고찰하였다. Oxacyclic acetal의 친핵성 및 염기성은 고리 아세탈의 산소와 음전하 크기로 설명할 수 있다. 공중합하의 성장단계에서 아세탈의 반응성은 반응 중심 탄소(C2)의 양전하 크기와 친전자체의 낮은 LUMO에너지에 좌우됨을 예측할 수 있다. 2-butyl-1,3-dioxepane의 성장단계의 화학종인 oxonuim 이온과 carbenium 이온 사이의 계산된 안정화 에너지는 5∼7kcal/mole로 carbenium 이온이 더 유리함을 예측할 수 있다. 공중합체의 성장단계에서 두 양이온형이 빠른 속도로 평형에 도달하며, 계산 결과에 의한 반응 좌표는 SN1 메카니즘이 SN2 메카니즘보다 빠르게 진행할 것으로 예측된다. The cationic polymerization of cyclic acetals are investigated theoretically using the semiempirical MINDO/3, MNDO, and AM1, methods. The nucleophilicity and basicity of cyclic acetals can be explained by the negative charge on oxygen atom of cyclic acetals. The reactivity of propagation in the polymerization of cyclic acetals can be represented by the positive charge on C2 atom and the low LUMO energy of active species of cyclic acetals. The reactivity of 2-buthyl-1,3-dioxepane(2-Bu-DOP) of cyclic oxonium and opening carbenium ion form is expected computational stability of the oxonium ion by 5∼7kcal/mole favoring the carbenium ion. Owing to the rapid equilibrium of these cation forms and the reaction coordinate based on calculation that the reaction coordinate based on calculation that the chain growth SN1 mechanism will be at least as fast as that for SN2 mechanism.

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  Cite this article

[IEEE Style]

Y. Cheun and J. Kim, "Theoretical Studies on the Cationic Polymerization Mechanism of Cyclic Acetals," Journal of the Korean Chemical Society, vol. 36, no. 2, pp. 197-204, 1992. DOI: .

[ACM Style]

Young-Gu Cheun and Jae-Kyung Kim. 1992. Theoretical Studies on the Cationic Polymerization Mechanism of Cyclic Acetals. Journal of the Korean Chemical Society, 36, 2, (1992), 197-204. DOI: .

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