3, 4-dihydroxy cinnamic acid의 가수분해 반응에 관한 연구

Abstract

The kinetics for the hydrolysis reaction of 3,4- dihydroxy cinnamic acid have been studied in EtOH sol-ution using UV spectrophotometer, The rate constants were determined by absorbance at various pH (1-10) and temperature (25℃-45℃). The reaction was found to be first order over-all. And the rate constants were proportional to the concen-tration of hydroxide ion. On the basis of rate equation it may be concluded that the reaction was initiated by the addition of hydroxide ion to the double bond in ba-sic pH range. Reaction was dependent of the temperature, the higher the temperature, the more rapid the reaction. And the values of activation energy were determined by Arrhenius equation, The preexpornential factor and activation entropy were proportional to the concentration of hydroxide ion.;3,4-dihydroxy cinnamic acid를 산성과 염기성에 걸친 넓은 pH영역 (1.09∼10.22)에서 온도(25℃∼45℃)를 변화해가며 가수분해 시켜 UV-spectrophotometer로 그 흡광도를 측정하였다. 이 측정한 값으로 반응속도상수를 구하였고, 메카니즘을 밝혔으며, 여기에 따른 반응속도식을 유도하였다. 이 화합물의 가수분해반응은 1차반응이며 염기성 영역으로 감에 따라 hydroxide ion농도에 비례하여 반응속도가 증가하며 이 영역에서는 탄소간의 이중결합에 hydroxide ion이 먼저 첨가되는 Michael형 반응에 해당됨을 알 수 있다. 또 온도가 증가할 수록 반응속도가 빨라지며, Arrhenius식에 의거하여 활성화 에너지를 구하였고 높은 pH일수록 frequency factor (A)가 커져 속도상수가 증가하며, 활성화 엔트로피가 커짐을 알 수 있었다.