强磁场原位检测装置及离子液体的物性研究
文献类型：学位论文
| 作者 | 姚宏玮 |
| 学位类别 | 博士 |
| 答辩日期 | 2012-05-25 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 张锁江 |
| 关键词 | 离子液体 磁性离子液体 超导磁场 原位研究装置 黏度 |
| 其他题名 | Study on in situ high magnetic field equipment and properties of ionic liquids |
| 学位专业 | 化学工艺 |
| 中文摘要 | 离子液体的独特结构和性质使得其作为溶剂或介质广泛应用于催化反应、有机合成、分离过程和电化学等领域。然而，由离子液体的黏度高、传递效率低、难分散、难分离等问题成为其工业化应用的瓶颈。因此，通过外场强化以提高传质效率的研究成为离子液体研究的新热点。磁场作为一种有效的外场强化手段，在物质的固定、选择、反应等方面已经得到了很好的应用，但是目前针对离子液体的磁场强化研究未见报道。原因之一是普通的磁场装置最高只能产生2 T的磁场强度，只对铁磁性的物质起作用，而对于离子液体来说，只有更高磁场才能激发其响应。原因之二是如此高的磁场，必然对分析仪器和测试手段有特殊的要求。基于上述背景，本论文研制了强磁场原位研究装置（10 T），合成了9种常规离子液体及7种磁性离子液体，针对离子液体在强磁场环境中黏度变化特性开展了系统的实验研究，论文的主要创新性工作和成果如下： 1. 研制了首套强磁场原位研究装置。该装置包含强磁场控制系统、反应器控制系统/物性测试系统、在线分析系统和数据采集系统。创新点是：采用超导线圈，可产生10 T强磁场；采用冷热硅油替换加热丝的控温手段，达成了强磁场下的温度控制，精度为±0.1 K；设计建造了三维移动支架（带磁屏蔽罩），即可以遥控调节磁体、反应器和分析仪器的相对位置，又可以屏蔽强磁场对分析仪器及其信号的影响；改良了毛细管黏度计的测试方法，通过光路设计，实现了在强磁场有限空间内液体黏度的测量。该装置经过安装及调试后，可达到全部预定指标，运行良好。 2. 合成了9种常规的离子液体和7种磁性离子液体，并对离子液体及其有机溶剂二元体系的密度和黏度进行了测量、计算和拟合。研究发现：常规离子液体的密度受阴离子的影响更大，阴离子体积越大，离子液体的密度越大；常规离子液体的黏度也受阴离子的影响大于阳离子，但是与阴离子的体积或质量无相对关系。磁性离子液体的密度和黏度均比常规的离子液体偏低。离子液体-有机溶剂二元体系的超摩尔体积根据有机溶剂的不同而分为正负两种，与氮甲基吡咯烷酮有机溶剂的超摩尔体积为正，与乙醇有机溶剂的超摩尔体积为负；离子液体-有机溶剂二元体系的超摩尔黏度一般为负，说明混合有机溶剂一般会使体系的黏度降。 3. 采用强磁场原位研究装置，首次对常规离子液体、磁性离子液体及其有机溶剂二元体系在强磁场下的黏度进行了研究，考察了磁场强度、温度、磁化率、官能团和溶剂组分对黏度的影响规律，建立了预测离子液体的黏度的经验关联式。该式可以较准确的预测温度、磁场与离子液体黏度的关系。研究结果表明：对于非磁性（常规）的离子液体，随着磁场的增加黏度降低，磁场与黏度成二次关系；磁场对黏度的影响机理是磁场破坏了离子液体原来的氢键网络结构，从而使离子液体的黏度降低，故对于氢键网络越强的离子，磁场的影响也就越明显。对于磁性离子液体，随着磁场的增加黏度升高，磁场越强磁场对黏度的影响越大；其机理为可以将磁性基团看成是带磁性的小球，磁力的作用使小球之间产生吸引力作用，故流动过程中黏度明显增加。 |
| 英文摘要 | As novel green media and catalysts, ionic liquids （ILs） have been applied to catalysis, organic synthesis, separation, electrochemistry, and so on. However, high viscosity and low transfer efficiency, become the bottlenecks in industrial application of ILs. In order to solve this problem, researches on outfield intensifying have become a new focus. As an effective method in the outfield intensifying, magnetic field has already shown a great number of good applications in material’s capture, selection and reaction. A new equipment is developed in this work for in situ detecting the physicochemical properties or reactions of ILs under high magnetic fields. The main innovations and results of the dissertation are as follows: 1. The first high magnetic field in situ research equipment in the world has been designed and established, which contains superconducting magnet control system, physicochemical property test system, on-line analysis system and data acquisition system. There are four innovations. First of all, the superconducting coil is adopted, which can produce 10 T magnetic fields. Secondly, hot and cold oil mean is used to control temperature, with an accuracy of ± 0.1 K. Thirdly, the 3D supporting bracket （with magnetic shield） is designed and built, which not only can adjust magnet, reactor and analysis apparatus remotely, but also can shield the influences of high magnetic field on signal analysis instrument. Finally, the capillary viscometer test method is improved. Through the optical path design, the measurement of viscosity of ILs under high magnetic field is realized. 2. 9 kinds of conventional ionic liquids and 7 kinds of magnetic ionic liquids were synthesized and characterized. The density and viscosity of 11 kinds of pure ionic liquids and the binary mixture systems of [emim][NTf2] + organic solvents have been tested, calculated and fitted. The results indicate that the densities and viscosities of the conventional ionic liquids are both considerably affected by anions, and the densities increase as the mass of anions increase. The binary mixture’s excess molar volumes are positive or negative according to the different organic solvents. The cyclic organic solvent, such as NMP, makes the excess molar volume positive, and chain organic solvent, such as ethanol, makes the excess molar volumes negative. 3. The viscosity principles of 9 kinds of conventional ionic liquids, as well as a magnetic ionic liquid [bmim][FeCl4], have been investigated for the first time under high magnetic fields from 293.15 K to 232.15 K. Meanwhile, the viscosities of binary mixture system of [bmim][FeCl4] and ethanol are researched in identical situations. The influences of magnetic fields, temperatures, magnetic susceptibilities, functional groups and mixture concentrations on the viscosities of ILs have been investigated. Then the correlation equation is established for predicting ionic liquid’s viscosity and the squared correlation coefficients are more than 0.9999. The results show that the viscosities of conventional ionic liquid increase as the magnetic field increases. And the influence of the magnetic fields enhances with increasing of the magnetic field. The mechanism reveals that magnetic fields destroy the hydrogen-bonded network structure of ILs, resulting in reducing of ionic liquid viscosities. The magnetic field effect is more obvious if the hydrogen bond in IL is stronger. Furthermore, a magnetic ionic liquid [bmim][FeCl4] has been synthesized and measured by viscomer under the magnetic fields. Contrast with the conventional ionic liquids, the magnetic ionic liquid demonstrates the viscosity increases as the magnetic field increases. The magnetic functional groups can be considered as magnetic particles, between which there are attractive forces leading to viscosity increasing significantly. |
| 语种 | 中文 |
| 公开日期 | 2013-09-25 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1827]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 姚宏玮. 强磁场原位检测装置及离子液体的物性研究[D]. 中国科学院研究生院. 2012. |
入库方式： OAI收割
来源：过程工程研究所
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