摘要
和厚朴酚在0．1mol/LNH3－NH4Cl缓冲溶液（pH9．4）中，用线性扫描伏安法得到两个还原峰P1和P2。峰电位分别为Ep1＝－0·23V和Ep2＝-1.18V（vs.Ag／AgCl）。用线性扫描与循环伏安法、脉冲极谱法和恒电位库仑法等手段研究体系的电化学行为及其反应机理。实验表明，P1和P2均为不可逆波。P1和P2的电子转移数均为2。和厚朴酚在汞电极上的吸附具有中性分子吸附的特征，吸附符合Frumkin吸附等温式，吸附系数β＝4．0×105mol/L，吸引因数α＝1．54，饱和吸附量гm=7．4×10-11mol·cm－2。P1的电子转移系数为0．80，非均相电极反应速率常数k1＝3．2×10-4cm／s。通过量化计算，证明P1是分子中酚羟基邻位上的碳碳双键的还原峰，P2是其对位上的碳碳双键的还原峰。
Two reduction peaks P1 and P2 of honokiol were obtained by linear sweep voltammetry in 0.1 mol/L NH3-NH4Cl btffer solution (pH 9.0). The peak potentials were at - o. 23 V and 1. 8 V (vs.Ag/AgCl), respectively. The electrochemical behavior and reaction mechanism of the system have been studied by linear sweep and cyclic votammetry, pulse polarography and constant-poential coulometry.The experiments indicatd that P1 and P2 were irreversible peak, The number of electrons involved in the electroreduction of P1 and Pm was 2. The adsorptive of honokiol at Hg electrode surface was a typical adsorptive characteristics of neutral molecule. The adsorption of the system obeys Frumkin adsorption isotherm. The adsorption coefficient β was 4.0×105 mol/L and the attraction factor α was 1. 54. The maximum of adsorption was 7.70×10-11 mol/cm2. The number of electrode transfer coefficient of P1 was 0. 80. The electrode reaction rate constant k1 = 3.2×10-4 cm/s. Quantum chemical calculation proved that P1 was the reduction of -C=C- in the ortho-phenyl hydroxy; P2 was that in the opposite phenyl hydroxy in the molecule.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
2000年第5期539-543,共5页
Chinese Journal of Analytical Chemistry
