论文部分内容阅读
十二钨钴酸钾具有四面体结构,其中金属离子是配合物的中心原子,作为配体的多酸阴离子(W3O10)在四面体顶角,它们具有Keggin结构。本实验用紫外可见光谱测定法,以287nm为测定波长,测定浓度为8 0×10-4mol/L的K5CoW12O40溶液与浓度分别为4 0×10-3、6 0×10-3、8 0×10-3mol/L、12×10-3mol/L的NaNO2溶液进行氧化还原反应时的吸光度。以不同浓度时的ln(A—A∞)对t作图呈线形关系,确定氧化剂反应级数为一。以不同的kobs对还原剂浓度作图,其图形也呈直线,确定还原剂的反应级数也为一,其反应的速率常数K=0 21×103(min-1)。说明K5CoW12O40的氧化还原反应机理是外界反应机理。此法在杂多酸化学中有着重要的意义。
The potassium dodecongungstate has a tetrahedral structure in which the metal ion is the central atom of the complex and the polyacid anion (W3O10) as a ligand has a Keggin structure at the tetrahedral vertex. In this experiment, UV-Vis spectrophotometry was used to determine the wavelength of 287nm. The concentration and concentration of K5CoW12O40 with concentration of 80 × 10-4mol / L were determined as 4 × 10-3, 6 × 10-3 and 80 × 10-3mol / L, 12 × 10-3mol / L NaNO2 solution for redox reaction absorbance. The linear relationship between ln (A-A∞) and t at different concentrations was established, and the reaction order of oxidant was determined to be one. The concentration of reductant was plotted with different kobs and the graph was also linear. The reaction order of the reductant was also determined to be one with a rate constant K = 0 21 × 10 3 (min -1). Description K5CoW12O40 redox reaction mechanism is the external reaction mechanism. This method is of great importance in heteropoly acid chemistry.