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本文研究了配合物KCaFe(SC_2O_3)_3·3H_2O在30、40、50℃的Clark-Lubs缓冲溶液中的酸性水解动力学。测定了不同温度和酸度的准一级速度常数K_(th),K_(th)。与[H~(+1)呈直线关系,K_(th)=K_1[H~+]+k_2,K_1是与平衡常数和速度常数k_1有关的常数,k_2为速度常数。提出的反应机制认为是通过不对称配位原子形成共轭酸,再发生铁-硫键破裂,酸性水解的活化参数△H~(?)=78.81±1.18kJ.mol~(-1),△S~(?)=-46.67±0.68J·K~(-1)·mol~(-1),与文献报导的具有不对称配位原子螯合物的酸性催化离解的数值相近。
In this paper, the kinetics of acid hydrolysis of complex KCaFe (SC_2O_3) _3 · 3H_2O in Clark-Lubs buffer solution at 30, 40 and 50 ℃ was studied. The quasi-first-order velocity constants K_ (th), K_ (th) of different temperature and acidity were determined. Is linear with [H ~ (+1), K_ (th) = K_1 [H ~ +] + k_2, K_1 is a constant related to the equilibrium constant and the velocity constant k_1, and k_2 is the velocity constant. The proposed reaction mechanism is believed to be the formation of conjugate acid by asymmetric coordination atoms, followed by the breakdown of iron-sulfur bonds. The activation parameter of acid hydrolysis is ΔH ~ (?) = 78.81 ± 1.18kJ · mol ~ (-1), △ S ~ (?) = -46.67 ± 0.68J · K ~ (-1) · mol ~ (-1), which is similar to that reported in the literature for acidic catalytic dissociation of asymmetric coordination chelates.