β—二酮合钴配合物在各种溶剂中与氧反应的热力学性质和动力学

THERMODYNAMICAL PROPERTY AND KINETICS OF REACTION OF β- DIKETONE COBALT (Ⅱ) COORDINATION COMPOUND WITH OXYGEN IN SEVERAL SOLVENTS

本文研究了二甲亚砜(DMSO),二甲替甲酰胺(DMF)吡啶(py)等溶剂对[Co(acac)_2·2H_2O]载氧和氧化性能的影响.实验证明[Co(acac)_2·2H_2O]与O_2的反应第一步为可逆载氧,而第二步为不可逆载氧.用元素分析和波谱研究了[Co(acac)_2·2H_2O]在溶剂中的存在形态和热力学性质。用配位场理论计算了[Co(acac)_2·2H_2O]在溶剂中的各种配位场参数。动力学的研究表明,[Co(acac)_2·2H_2O]在DMF溶剂中O_2的反应发生一级半过程,一级为[Co(acac)_2·2H_2O]半级为O_2.反应的动力学方程为v=k[Co(acac)_2·2H_2O]·P_(o_2)^(0.41).反应的表观活化能为44.8千焦/摩尔,波谱的分析结果证实,氧化反应的主要产物为[Co(acac)_3]

In this paper the influence of three solvents of DMSO, DMF and py on Co(acac)2 ·2H2O carrying oxygen and oxidation susceptibility was studied by spectrophotometer and absorption oxygen instrument. That first step reaction of Co(acac)2 ·2H2O with O2 is reversible carrying oxygen and the following step of them is irreversible oxidation have also been testified by electronic spectra and magnetic susceptibility measurement. Kinetic on the reaction of Co(acac)2 ·2H2O with O2in dimethylformamide solvent show that the reaction takes place by a first and half-order process, first-order in Co(acac)2 ·2H2O and half-order in O2. The kinetic equation v=k [Co(acac)2 ·2H2O] ·Po2(0.41)has been obtained. The observed rate constants at different temperatures were determined by determination oxygen rate v, and the observed activation energy was determined to be 44.8 kJ/mol from Arrhenius equation by the least-square method. There are a few products in the reaction process of Co(acac)2 ·2H2O with O2, one of them, Co(acac)3, has been confirmed by elemental analysis, IR and NMR.