Kinetics and Mechanism of the Hydrolysis of ${\alpha}$-Cyano-${\beta}$-piperonylacrylic Acid

국문 초록 (Abstract)

${\alpha}$-Cyano-${\beta}$-Piperonylacrylic Acid의 가분해 속도상수를 자외선분광기를 사용하여 구하였으며 아울러 넓은 pH범위에 잘 맞는 반응속도식도 얻었다. 이 식에 의하면 넓은 pH범위에 잘 맞는 반응속도식도 얻었다. 이 식에 의하면 넓은 pH범위, 특히 종전에 잘 규명된 바 없는 산성용매 속에서의 반응 및 hydroxide ion의 촉매역활 등도 정략적으로 잘 설명할 수 있음을 알았다. 즉 pH4.0이하에서의 가수분해반응은 ${\alpha}$-Cyano-${\beta}$-Piperonylacrylic Acid에 물분자가 첨가되므로써 시작되며 pH $5.0{\sim}7.5$ 에서는 ${\alpha}$-Cyano-${\beta}$-Piperonylacrylic Acid와 ${\alpha}$-Cyano-${\beta}$</TEXpiperonylacrylate anion에 물분자가 경쟁적으로 첨가되며 pH 8.0에서는 ${\alpha}$-Cyano-${\beta}$-piperonylacrylate anion에 물분자만이 첨가되며 pH 12.0 이상에서는 hydroxide ion만이 ${\alpha}$-Cyano-${\beta}$-piperonylacrylate anion에 첨가됨을 알았다.

다국어 초록 (Multilingual Abstract)

The rate constants of the hydrolysis of ${\alpha}$-Cyano-${\beta}$-piperonylacrylic acid were determined by Ultraviolet spectrophotometry at various pH and a rate equation which can be applied over wide pH range was obtained. The reaction mechanism of hydrolysis of ${\alpha}$-Cyano-${\beta}$-piperonylic acid and especially the catalytic contribution of hydroxide ion which not studied carefully before in acidic media, can be fully explained by the rate equation obtained. The rate equation reveals that; below pH 4.0, the reaction is initiated by the addition of water molecule to ${\alpha}$-Cyano-${\beta}$-piperonyl acrylic acid. At pH $5.0{\sim}7.5$, ${\alpha}$-Cyano-${\beta}$-piperonylacrylic acid compete with ${\alpha}$-Cyano-${\beta}$-piperonyl acrylate ion in adding of water. At pH 8.0, water is the only nucleophile for ${\alpha}$-Cyano-${\beta}$-piperonylacrylate ion, however, above pH 12.0, hydroxide ion is an addendum and the accepter is ${\alpha}$-Cyano-${\beta}$-piperonylacrylate ion.