三聚磷酸钠与柠檬酸钠钙螯合机理和螯合能力的对比分析  

Comparative analysis of calcium chelation mechanism and chelating ability about sodium tripolyphosphate and citric acid sodium

作　　者：何春芳[1] 叶近婷 高阳[1] 刘春宇[1] 潘秀梅[1] 

机构地区：[1]东北师范大学化学学院,吉林长春130024

出　　处：《分子科学学报》2015年第3期198-202,共5页Journal of Molecular Science

基　　金：吉林省科技厅重点资助项目(20120401);国家自然科学基金资助项目(21377021)

摘　　要：选取了常用洗涤助剂三聚磷酸钠(STPP)与柠檬酸钠(NaCA)为研究体系,通过实验测定和理论分析,对洗涤助剂的钙螯合能力进行了研究.实验研究采用铬黑T指示剂络合滴定法,分别测定以上2种助剂的钙螯合能力,结果表明:2种助剂均可与Ca2+离子形成稳定的螯合物,但螯合Ca2+离子的能力不同,三聚磷酸钠螯合能力较强.理论计算运用Gaussian09程序包,采用密度泛函的B3LYP方法,6-31G(d,p)基组,在溶剂化条件下计算出2种洗涤助剂与Ca2+离子形成螯合物的几何结构及其结合能,三聚磷酸钠和柠檬酸钠与Ca2+离子的螯合物均为六配位八面体结构,磷酸基团或羧酸基团与羟基参与配位.实验所得螯合能力的差异可以由理论计算得到的分子结构、结合能及前线分子轨道方面进行解释.Sodium tripolyphosphate（STPP）and sodium citrate（NaCA）were choosed as the common detergent assistants in the paper.Calcium chelating ability of detergent assistants was studied by the experiment and theory analysis.Eriochrome black T indicator for complexometric titration was used to measured the calcium chelating ability in experiment,we find that the above two kinds of additives can be with Ca2＋ions to form stable chelate complexes,but the chelating ability with Ca2＋ions was different,the chelating ability of Sodium tripolyphosphate（STPP）is stronger than sodium citrate（NaCA）.The theoretical study is calculated the geometric structure of each detergent and Ca2＋ions to form chelate and binding energy using B3 LYP method with 6-31＋G（d,p）basis set under the condition of solvation,and all calculations were using the Gaussian 09 program package.The geometric structure and binding energy of the above chelates were calculated,the chelates of sodium tripolyphosphate and sodium citrate with Ca2＋ions are six coordinated eight structure,the phosphate groups or carboxylic acid groups and hydroxyl groups are involved in coordination.The difference of chelating ability can be explained by molecular structure,the binding energy and the frontier molecular orbitals in experiment.

关 键 词：三聚磷酸钠 柠檬酸钠 分子结构 

分 类 号：O641[理学—物理化学]