含水量对胆碱基低共熔溶剂的微观结构、密度及黏度影响的分子动力学研究  

Molecular dynamics simulation of the effect of water addition on the microscale structure and density and viscosity of deep eutectic solutions

作　　者：田琳 聂文洁 王剑飞 武广剑 赵贯甲[1] TIAN Lin;NIE Wen-Jie;WANG Jian-Fei;WU Guang-Jian;ZHAO Guan-Jia(College of Electrical and Power Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Provincial Key Laboratory of High Efficiency Heat Storage and Low Carbon Heat Supply,Taiyuan 030008,China;Jinneng Datuhe Thermal Power Co.,Ltd,Lüliang 033099,China)

机构地区：[1]太原理工大学电气与动力工程学院,太原030024 [2]高效储热与低碳供热山西省重点实验室,太原030038 [3]晋能大土河热电有限公司,吕梁033099

出　　处：《四川大学学报(自然科学版)》2025年第2期480-485,共6页Journal of Sichuan University(Natural Science Edition)

基　　金：国家自然科学基金(51976132)。

摘　　要：低共熔溶剂(DES)是一种类离子液体的绿色溶剂,具有蒸汽压低、热稳定性好、制备简单等优点,但高黏度特性制约了其工业应用,同时DES具有强吸湿性,因此探究体系中水的存在对其黏度的影响至关重要.本文利用分子动力学模拟的方法,在GAFF力场下分别模拟了氯化胆碱^(+)乙二醇/甘油/尿素等三种DES水合物在293.15~353.15 K温度范围内的密度和黏度,通过分析氢键数目和径向分布函数,研究了含水量对DES微观结构及宏观性质的影响.结果表明,水的存在破坏了DES内胆碱基阳离子(CHO^(+))与阴离子(Cl^(−))、阴离子(Cl^(−))与氢键供体(HBD)、氢键供体间形成的氢键;同时,水与CHO^(+)、Cl^(−)、HBD形成新的弱氢键从而降低原有DES体系的黏度.当上述三种体系内的含水质量分数分别达到8 wt%、10 wt%、10 wt%时,仍能维持以DES为中心的氢键体系,且对应黏度分别降低了58.3%、73.78%、89.41%.因此,可以通过添加少量水来调节DES的黏度,进而扩大其工业应用范围.Deep eutectic solution(DES)is a kind of ionic liquid-like green solvent,has the advantages of being eco-friendly and low vapor pressure,strong thermal stable and simple preparation.However,the high viscosity restricts its industrial application,and DES is strongly hygroscopic,so it is important to investigate how the presence of a small amount of water in the system affects its viscosity.In this study,the density and viscosity values of three DES hydrates,including choline chloride with ethylene glycol,glycerol and urea were simulated by using molecular dynamic simulation under GAFF force field in the temperature range from 293.15 K to 353.15 K,respectively.The effect of water content on the microstructure and macroscopic properties of DES was also analyzed using the number of hydrogen bonds and radial distribution function.The results showed that the presence of water disrupted the hydrogen bonds formed between the choline-based cation(CHO^(+))and the anion(Cl^(−)),the anion(Cl^(−))and the hydrogen bond donor(HBD),and the hydrogen bond donor within the DES.Then the water molecules can form new weak hydrogen bonds with CHO^(+),Cl^(−),and HBD,which can lead to a reduction in viscosity.When the water content is around 8 wt%,10 wt%and 10 wt%,the above three hydrates can still maintain the hydrogen bonding system centered on DES,and at the same time,the viscosity is reduced by 58.3%,73.78%and 89.41%.Therefore,a small amount of water can be added to adjust the physical properties of DES,thus expanding its industrial applications.

关 键 词：低共熔溶剂 密度 黏度 氢键 分子动力学模拟 

分 类 号：O55[理学—热学与物质分子运动论]