The Effect of Pressure on the Rate of Solvolysis(Ⅱ). Reactions of Methyl-, Phenyl Chloroformate and 1-Adamantyl Derivatives

가용매분해반응에 대한 압력의 영향(Ⅱ). Methyl-, Phenyl Chloroformate와 1-Adamantyl 유도체에 대한 반응

  • Published : 19960500

Abstract

The rates of solvolylsis of methyl chloroformate, phenyl chloroformate and 1-adamantyl derivatives in binary solvent mixtures have been measured by conductometric method at various temperatures and pressures. The activation parameters were estimated from the rate constants. The activation volume (${\Delta}V_o^{\neq}$) and the activation entropy (${\Delta}S^{\neq}$) are both negative, but the activation enthalpy (${\Delta}H^{\neq}$) is positive. This behavior is discussed in terms of electrostriction of solvation. The reactivities of these reactions were also estimated from the correlation of the activation volumes with the activation entropies. From these results, it could be estimated that the solvolyses of 1-adamantyl fluoroformate (in aqueous TFE) and 1-adamantyl tosylate have pathway involving unimolecular reaction, while the reaction of methyl chloroformate, phenyl chloroformate and 1-adamantyl fluoroformate (in aqueous alcohol) proceed through a bimolecular reaction.

이성분혼합용매내에서 Methyl-, Phenyl Chloroformate와 1-adamantyl 유도체들의 가용매분해반응속도를 여러 온도와 압력하에서 전도도방법에 의하여 측정하였다. 이들 속도상수로부터 활성화 부피(${\Delta}V_o^{\neq}$), 활성화 엔탈피(${Delta}H^{\neq}$), 활성화 엔크로피 (${\Delta}S^{\neq}$) 값을 구하였다. 이때 모든 혼합물내에서 ${\Delta}V_o^{\neq}$${\Delta}V_s^{\neq}$는 음의 값을 나타내었으며, ${\Delta}H^{\neq}$는 양의 값을 얻었다. 이 현상을 용매구조변화에 대하여 논의하였다. 또한 활성화 부피와 활성화 엔트로피 값들을 플로트하여 본 반응에 대한 반응 경향성을 조사하였다. 이들 결과로부터 Methyl-, Phenyl Chloroformate와 1-adamantyl fluoroformate(알코올수용액)는 이분자반응이, 1-adamantyl fluoromate(TFE수용액)와 1-adamantyl tosylate는 일분자반응이 일어나는 것으로 추정할 수 있었다.

Keywords

References

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