【作者】 许艳红；

【导师】 魏刚；

【作者基本信息】 北京化工大学 ， 材料学， 2004， 硕士

【摘要】 本工作是国家科技攻关项目绿色水处理剂聚环氧琥珀酸(PESA)研究的一部分,旨在研究PESA的单体环氧琥珀酸(ESA)的螯合溶解作用,为查明PESA的性能与构效关系提供基础参数。首次采用多种分析、分离方法研究了ESA螯合物中钙离子的测定,发现ESA对钙离子的螯合能力极强,超过了通用的络合滴定指示剂,因而不能用络合滴定法测定,离子交换法、沉淀法、萃取法等分离方法也难以将钙离子从ESA螯合物中有效分离。通过研究,首创了HCl-HNO3消解-络合滴定法、H2O2-HNO3消解-络合滴定法以及复合指示剂-络合滴定法等三种测定ESA螯合物中钙离子的方法,得出分析操作要点。试验结果表明,三种方法都具有标准偏差小、准确度高和简便易行等特点。首次研究了在不同反应条件下ESA对碳酸钙和硫酸钙这两种不溶或难溶固体的螯合溶解性能,发现ESA是一种可以在较高温度下使用的螯合剂,在酸性和中性pH范围内对碳酸钙的螯合溶解性能较好,在接近中性的pH范围内对硫酸钙的螯合溶解性能较好,体系中固液相界面的接触面积对螯合反应有影响,ESA浓度对螯合反应的影响甚微,可以忽略不计。通过反应条件的优化,得出ESA的最大钙螯合值为318.75mg/g,大于EDTA等螯合剂的最大钙螯合值,是一种络合能力极强的螯合剂。首次探讨了ESA与碳酸钙、硫酸钙螯合反应的机理和反应动力学,得出这两种螯合反应均为一级反应,反应的表观速率常数分别为k1=4.47 ×10-3/min和k2=2.292×10-2/min。更多还原

【Abstract】 This work is a part of the research from the Key Technology R&D Programme. We investigated the chelating properties of epoxysuccinic acid (ESA), the monomer of polyepoxysuccinic(PESA), in order to apply the basic datas for the further research on the constructures and properties of PESA. In this article the determination of calcium chelating with ESA have been studied and the reasonable analytical conditions have been selected. HCl-HNO3 pretreatment-complexometric titration, H2O2-HNO3 pretreatment- complexometric titration and complex agent complexometric titration are applied to the determination of chelating calcium in ESA for the first time. The precision and recovery of the three methods have been discussed.The chelating properties and dissolving capability of ESA under different conditions have been studied. We have found that ESA can be used as chelator under high temperatures. The chelating with CaCO3 is prefered to take place in the solution pH≤7, while the chelating with CaSO4 is prefered to happened in the solution pH closed to 7. The chelated calcium is oberserved to improve significantly with the increase of the the interface area to the reaction mixture. The effect of the concentration of ESA is insignificant. In this article, we obtained the maximum dissolving capability of epoxysuccinate by optimized the chelating conditions. The maximum calcium dissovling value is 318.75mg/g which is larger than the maximum value of EDTA. ESA is confirmed to be an excellent chelator for calcium by the results.The kinetics of the chelating of ESA with CaCO3 and CaSO4 have been investigated in this paper for the first time. The investigations have indicated the two reactions to be first order. The numerical values of the constants are obtained as k1=<WP=5>4.47 ×10-3/min, k2=2.292×10-2/min.更多还原