$alpha$-Cyano-$eta$-piperonylacrylic acid에 대한 n-Propylmercaptan의 친핵성 첨가반응 속도 상수를 측정하여 넓은 pH 범위에서 잘 맞는 반응속도식을 구하였다. 이 식에 의하면 넓은 pH 범위에서 일어나는 복잡한 반응메카니즘을 정량적으로 잘 설명할 수 있었다. 즉 pH4.5이하에서는 $alpha$-Cyano-$eta$-piperonylacrylic acid에 mercaptan이 직접 첨가되며 pH 4.5∼6.5 사이에서는 주로 $alpha$-Cyano-$eta$-piperonylacrylic ion에 mercaptan 분자가 첨가되고 pH 7.5 부터는 $alpha$-Cyano-$eta$-piperonylacrylic ion에 mercaptan 분자와 mercaptide ion의 첨가가 경쟁적으로 일어나며 pH 10이상에서는 $alpha$-Cyano-$eta$-piperonylacrylic anion에 mercaptide ion의 첨가만이 일어남을 알 수 있었다.
The rate constants of the nucleophilic addition of n-propyl-mercaptan to $alpha$-cyano-$eta$-piperonylacrylic acid were determined at various pH and a rate equation which can be applied over wide pH range is obtained. The rate equation reveals that below pH 4.5 the reaction is initiated by the attack of n-propylmercaptan to $alpha$-cyano-$eta$-piperonylacrylic acid. At pH 4.5~6.5, however, n-propylmercaptan is added to $alpha$-cyano-$eta$-piperonylacrylate ion; at pH 7.04~9.5 the competitive reaction between n-propylmercaptan and n-propylmercaptide ion is anticipated to occur. Above pH 10 the addendum is n-propylmercaptide ion and the acceptor is $alpha$-cyano-$eta$-piperonylacrylate ion.
