| 浓氯化钙水溶液中高配位Ca-Cl离子团簇:分子动力学模拟研究 |
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| 引用本文： | 王语林,唐剑峰,张宁.浓氯化钙水溶液中高配位Ca-Cl离子团簇:分子动力学模拟研究[J].盐湖研究,2020,28(3):34-42. |
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| 作者姓名： | 王语林 唐剑峰 张宁 |
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| 作者单位： | 中国石油兰州化工研究中心,甘肃兰州 730060;中南林业科技大学理学院,湖南长沙 410004 |
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| 基金项目： | 湖南省教育厅一般项目(17C1639)；湖南省自然科学基金青年项目(2018JJ3883);国家自然科学基金青年基金(51704338) |
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| 摘 要： | 采用分子动力学(MD)模拟研究了5.55 mol·kg~(-1)氯化钙溶液的微观结构特征,尤其是溶液中高配位Ca-Cl离子团簇的结构与性质,探究了温度对于高配位Ca-Cl离子团簇的影响。结果显示,5.55 mol·kg~(-1)氯化钙溶液中,除形成CaCl]~+、CaCl_2]~0离子对外,还存在一些高配位CaCl_x]~(2-)~x(x=3～6)离子团簇。高配位CaCl_x]~(2-)~x(x=3～6)离子团簇在5.55 mol·kg~(-1)氯化钙溶液中介稳存在,易解离或进一步缔合形成更大Ca-Cl离子团簇,这可能与溶液中大量未完全水合Ca~(2+)对高配位CaCl_x]~(2-)~x(x=3～6)离子团簇水壳层的扰动破坏有关。温度升高,氯化钙溶液中Ca-Cl离子缔合增强,但高配位Ca-Cl离子团簇的平均存在时间(t_(av))减小,这表示高温下溶液中Ca-Cl离子团簇频繁地解离与缔合,离子团聚趋势更为显著。本工作观测到的高配位CaCl_x]~(2-)~x(x=3～6)离子团簇可能是浓氯化钙溶液Ca-Cl离子缔合过程中一种热力学不稳定结构,但这些高配位Ca-Cl离子团簇的形成可能对溶液结晶及相关化学过程产生不利影响。
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| 关 键 词： | 氯化钙 离子团簇 缔合 温度 分子动力学模拟 |
| 收稿时间： | 2019/3/8 0:00:00 |
| 修稿时间： | 2019/4/10 0:00:00 |
High Coordinated Ca(II) Chloro Ion Clusters in the Concentrated CaCl2 Aqueous Solution:A Molecular Dynamics Simulation Study |
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| WANG Yu Lin,TANG Jian Feng,ZHANG Ning.High Coordinated Ca(II) Chloro Ion Clusters in the Concentrated CaCl2 Aqueous Solution:A Molecular Dynamics Simulation Study[J].Journal of Salt Lake Research,2020,28(3):34-42. |
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| Authors: | WANG Yu Lin TANG Jian Feng ZHANG Ning |
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| Institution: | Lanzhou Petrochemical Research Center,Petro China,Lanzhou,College of Science,Central South University of Forestry and Technology,Changsha,College of Science,Central South University of Forestry and Technology,Changsha |
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| Abstract: | Molecular dynamics simulation was employed to investigate the structural characteristics of 5.55 mol·kg?1 CaCl2 solution, especially the high?coordinated Ca?Cl ion clusters observed in the solution. The results show that there may be some highly coordinated CaClx]2?x (x=3?6) ion clusters formed in 5.55 mol·kg?1 CaCl2 solution, apart from the CaCl]+ and CaCl2]0 ion pairs. The highly coordinated Ca?Cl ion clusters remain meta?stable in 5.55 mol·kg?1 CaCl2 solution and easily disassociate into smaller structures or associate with other ions to form the larger Ca?Cl ion clusters, which may be related to the disturbing damage of the numerous Ca2+, without adequate hydration, to the outer shells of the high?coordinated Ca?Cl ion clusters in the concentrated CaCl2 solution. As the temperature rises, Ca?Cl ion association increases in 5.55 mol·kg?1 CaCl2 solution, but the average lifetime (tav) of the CaClx]2?x (x=3?6) ion clusters decreases, indicating that at elevated temperature the Ca?Cl ion clusters frequently disassociate and associate, and the tendency of ionic aggregation in the solution is more pronounced. The highly coordinated CaClx]2?x(x=3?6) ion clusters observed in this work may be a thermodynamically unstable structure during the ion association in 5.55 mol·kg?1 CaCl2 solution, but the formation of the high?coordinated Ca?Cl ion clusters can exert some negative influences on the crystallization of the CaCl2 solution and other related chemical processes. |
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| Keywords: | Calcium chloride Association Ion cluster Temperature Molecular dynamics simulation |
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