Environmentally-Benign Ionic Liquid Production: Mechanistic Understanding and Novel Synthesis Methods

摘要：Aaron M.Scurto研究所：堪萨斯大学提议编号：0626313题目：环境友好的离子液体生产：机理理解和新的合成方法项目摘要：离子液体是环境友好的溶剂，因为它们缺乏蒸汽压和分子可调性质。关于它们合成的报道几乎总是包括据称它们将被取代的溶剂。此外，离子液体目前在大规模工业过程中用作替代溶剂的成本太高。这主要是由于小批量生产和很少的动力学和热力学数据的合成。为了让离子液体真正做到绿色环保并得到广泛使用，它们必须以相应的良性方式大量生产，而且成本较低。这个项目解决了这些问题，首先在分子水平上优化了传统的合成路线，然后利用新的压缩或超临界二氧化碳生产作为环境友好的连续反应和分离方案的替代方案。智力上的优点：离子有机化合物通常是由亲核的含氮和含磷的化合物(如咪唑等)季胺化而形成的。与亲电反应物(如卤代烷等)反应。这些新的有机盐被用作IL溶剂或进行额外的阴离子交换反应。这些步骤中的每一步都有自己的动力价值，都有自己的分离问题。从初步数据来看，季胺化步骤非常依赖于溶剂，并且似乎具有非二级动力学速率。本项目将探索液体溶剂结构对反应速率的影响及其机理，以优化其产率。在压缩或超临界流体中合成可能是生产和分离的最佳方法，与目前的技术相比具有明显的优势。在压缩的二氧化碳中，可以通过改变温度、压力、浓度和存在的相数来调节和优化反应速度(即相平衡)。单容器反应器/分离器可能是可能的，因为离子液体在压缩的二氧化碳中是无限不溶的，但通过了解它们的相行为，可以使反应物变得可混溶。计划使用二氧化碳进行CO2阴离子交换过程，以实现从阴离子交换水溶液中难以分离所需的ILS。适当选择可溶于二氧化碳的金属络合剂，压缩的二氧化碳也可以去除残留的有机物和金属卤化物盐杂质。这项研究将把这些间歇反应扩展到连续反应器/分离器场景。更广泛的影响：彻底了解离子液体合成和处理的基本原理，以及后续的反应器/工艺工程，将导致以环境友好的方式生产成本较低的IL溶剂。离子液体在各种工业中的使用增加可能会导致人类和环境暴露在传统挥发性溶剂中的机会减少。压缩的二氧化碳，或者在某些情况下，明智地选择传统溶剂，可能会导致离子液体的全部环境优势可能得到实现。这个项目将向学生介绍必要的研究和分析技能，以开发一种对环境无害的替代品，并将其与传统技术进行批判性比较。此外，整个过程将导致将案例研究纳入科罗拉多大学目前的课程：环境友好反应工程和化学加工环境评估。

ABSTRACTPI: Aaron M. Scurto Institution: University of KansasProposal Number: 0626313Title: Environmentally-Benign Ionic Liquid Production: Mechanistic Understanding and Novel Synthesis Methods.Project Summary:Ionic liquids are environmentally friendly solvents due to their lack of vapor pressure and molecularly tunable properties. Reports of their synthesis almost always include the very solvents that they will purportedly replace. Moreover, ionic liquids are currently too costly for utilization as alternative solvents in large-scale industrial processes. This is primarily due to small batch production and little kinetic and thermodynamic data of their synthesis. For ionic liquids to be truly green and to be used ubiquitously, they must be made in a corresponding benign way in potentially large quantities and for low cost. This project addresses these problems by first optimizing conventional synthesis routes down to the molecular level and then utilizing novel compressed or supercritical CO2 production as an environmentally benign alternative for a continuous reaction and separation scheme.Intellectual Merit:Ionic organic compounds are usually formed by quaternization of nucleophilic N- andP-containing compound (e.g. imidazoles, etc.) with an electrophilic reactant (e.g. haloalkane, etc.). These new organic salts are used as an IL solvent or undergo an additional anion exchange reaction. Each of these steps has its own kinetic value and has its own separation issues. From preliminary data, the quaternization step is very solvent dependent and appears to have non-2nd order kinetic rates. This project will explore the effect of liquid solvent structure on the reaction rates and mechanism to optimize its production rate. Synthesis in compressed or supercritical fluids may be the optimal method for production and separation with clear advantages over current technology. The reaction rate can be tuned and optimized in compressed CO2 by changes in temperature, pressure, concentration and number of phases present (i.e. phase equilibria). A one-vessel reactor/separator may be possible as ionic liquids are immeasurably insoluble in compressed CO2, but the reactants can be made miscible by understanding their phase behavior. A CO2 anion exchange process is planned using CO2 to perform the difficult separation of the desired ILs from an aqueous anion exchange solution. Compressed CO2 may also be capable of removing residual organics and metal halide salt impurities with the proper choice of CO2-soluble metal-complexing agents. This research will extend these batch reactions to continuous reactor/separator scenarios.Broader Impact:A thorough understanding of the fundamentals of ionic liquid synthesis and processingand subsequent reactor/process engineering will lead to a less expensive IL solvent that is produced in an environmentally-benign manner. The increased use of ionic liquids in a variety of industries could lead to a decrease in the exposure of both humans and the environment to conventional volatile solvents. Compressed CO2 or, in some cases, a wise choice of conventional solvents may lead to a time where the full environmental advantage of ionic liquids may be realized. This project will introduce students to the necessary research and analysis skills to develop an environmentally benign alternative and critically compare it to conventional technology. Moreover, the entire process will lead to incorporation of case studies in current courses at KU: Environmentally-Benign Reaction Engineering, and Environmental Assessment of Chemical Processing.