Ionic Liquids of Improved Thermal Stability

在这个由化学系化学结构、动力学和机制B计划资助的项目中，南阿拉巴马大学化学系的詹姆斯·戴维斯教授和他的学生将探索一种新型离子液体(液盐)的合成、表征和性质。预计要研究的液体盐具有高度的耐热性，并在很长一段时间内保持其液体性质，不会蒸发、分解或易燃。原则上，这种类型的盐可以用作更传统液体的替代品，应用范围从传热液和高性能润滑剂到生物质加工和半导体等重要电子材料的合成。该项目汇集了化学合成以及材料科学和工程的元素，并为参与其中的学生提供了从一系列活动中获得经验的广泛机会。由于进行研究的机构服务于在科学和工程领域代表性不足的群体中的很大比例的个人，本项目将提供重要的机会，对来自这些社区的个人进行专业培训。离子液体(ILS)是具有相当大的基本兴趣和日益增长的实用价值的材料。由于其不挥发性，离子液体可用于需要高温的应用，如热传递、润滑或高温材料合成。尽管典型的离子液体具有相对较高的热稳定性，但它们仍然不能在200摄氏度以上的温度下长期使用。在本项目中，将使用四苯基膦阳离子及其衍生物来制备ILS。初步研究表明，前一种阳离子可以在300摄氏度以上的温度下稳定数天，不会分解或蒸发。在这些发现的基础上，将研究最终确实发生热分解的机理，并将利用这一知识来创造更高热稳定性的盐。除了创造高热稳定性的新熔盐外，还将研究这些液体在促进生物质快速热解(用于生产生物油)和热合成具有重要电子意义的材料，如硫化锌和硫化镉方面的用途。

In this project, funded by the Chemical Structure, Dynamics and Mechanism B Program of the Chemistry Division, Professor James Davis and his students of the Department of Chemistry at the University of South Alabama will explore the synthesis, characterization, and properties of a new type of ionic liquids (liquid salts). The liquid salts to be investigated are expected to be highly resistant to heat and to retain their liquid character, without evaporation, decomposition, or flammability, for long periods of time. Salts of this type can, in principle, be used as substitutes for more traditional liquids in applications ranging from heat transfer fluids and high-performance lubricants to biomass processing and the synthesis of important electronic materials such as semiconductors. The project brings together elements of chemical synthesis as well as material science and engineering, and offers engaged students a broad opportunity for gaining experience from a spectrum of activities. Since the institution at which the research will take place serves a high proportion of individuals from groups underrepresented in the sciences and engineering, the present project will provide important opportunities to engage in the professional training of individuals from these communities.Ionic liquids (ILs) are materials of considerable fundamental interest and growing practical utility. Because of their non-volatility, ionic liquids can be used in applications requiring high temperatures, such as in heat transfer, lubrication, or high-temperature materials synthesis. Although typical ILs have relatively high degrees of thermal stability, they are still incapable of being used for long durations at temperatures above 200 degrees Celsius. In the present project, ILs will be prepared using the tetraphenylphosphonium cation and derivatives thereof. Preliminary work has revealed that the former cation is stable to temperatures in excess of 300 degrees Celsius for days without decomposition or evaporation. Building on these findings, the mechanism by which thermal decomposition eventually does occur will be studied, and that knowledge will be harnessed to create salts of still higher thermal stability. In addition to creating new molten salts of high thermal stability, the use of these liquids in facilitating the rapid pyrolysis of biomass (for production of bio-oil) and in the thermal synthesis of electronically important materials such as ZnS and CdSe will be investigated.