Design and Optimization of Non-Fluorous CO2-Philic Polymers: FTIR and Phase Behavior Investigations

二氧化碳在化学加工中的应用继续引起人们的极大兴趣，因为二氧化碳通常比传统有机溶剂造成的危害更小。人们一度认为二氧化碳可以简单地取代许多有机溶剂，但后来的研究表明，二氧化碳是一种相当弱的溶剂，因此需要不切实际的高压来溶解感兴趣的化合物。20世纪90年代S发现的“亲二氧化碳”突然使许多应用在技术上成为可能，极大地提高了人们对二氧化碳作为溶剂的兴趣。这些新的亲二氧化碳聚合物，主要是含氟聚合物，允许二氧化碳的许多新应用，从多相聚合到均相催化。尽管含氟两亲化合物在技术上是成功的，但其高昂的成本使该工艺的经济性变得不利，除非ihCO2-phelo能够以高于99%的效率回收。更复杂的是，回收高压过程中的添加剂既不容易，也不便宜。使用氟化前体所固有的缺陷极大地阻碍了大多数二氧化碳新应用的商业化，因此基于二氧化碳的技术的全部前景尚未实现。PI研究了非氟二氧化碳亲和剂的设计。到目前为止，他已经使用一套简单的启发式方法设计了三种类型的非氟亲二氧化碳分子；他预计最终会发现其他类型的亲二氧化碳分子，极大地扩大了二氧化碳作为溶液的适用性。如果我们继续合成和测试所有潜在有用的结构，可能的设计变量(共聚物组成和拓扑结构)的数量将创建一个不切实际的大程序。此外，传统的热力学模型不能预测所有可能排列的行为。因此，PI将在匹兹堡大学和奥本大学之间开展一项协调计划，其最终目标是充分了解组成和拓扑结构对我们新的二氧化碳亲和体在二氧化碳中的相行为的影响。他将结合定向合成、选定热物理性质的测量、高压FT-IR，以及从第一原理到数学描述HIS材料与二氧化碳混合的热力学的精确势函数的开发。本文描述的项目涉及匹兹堡大学(E.J.Beckman，R.M.Enick，J.K.Johnson)和奥本大学(C.B.Roberts)的一个完全整合的项目。将在奥本大学(C.B.Roberts)执行的任务包括相行为和FTIR研究，其中将使用高压红外测量来评估二氧化碳与我们的模型聚合物中包含的Lewis碱基的特定相互作用的强度。高压红外工作为合成设计和构建二氧化碳-聚合物相互作用的准确势能模型提供了输入。

The application of CO2 to chemical processing continues to elicit significant interest, as CO2 generally poses fewer hazards than conventional organic solvents. At one time it was thought that CO2 could simply replace many organic solvents, but subsequent work showed that CO2 is a rather feeble solvent, and hence unrealistically high pressures are needed to dissolve compounds of interest. The discovery during the 1990's of "CO2-philes" suddenly rendered a number of applications technically possible, greatly raising interest in CO2 as a solvent. These new CO2-philes, primarily fluoropolymers, allowed a host of new applications for CO2, from heterogeneous polymerization to homogeneous catalysis. Although fluorinated amphiphiles were technically successful, their high cost renders the economics of a process unfavorable unless the ihCO2-philelo can be recycled at greater than 99% efficiency. Complicating matters further, recycle of additives from a high-pressure process is neither easy nor inexpensive. The drawbacks inherent to the useof fluorinated precursors have greatly inhibited the commercialization of most new applications for CO2, and thus the full promise of CO2-based technology has yet to be realized. The PI has investigated the design of non-fluorous CO2-philes. To date, he has used a set of simple heuristics to design three types of non-fluorous CO2- phile; he expects that others will ultimately be found, greatly broadening the applicability of CO2 as a solvent.The number of possible design variables (copolymer composition and topology) creates an impractically large program if we continue to synthesize and test all potentially useful structures. Further, conventional thermodynamic models are incapable of predicting the behavior of all of the possible permutations. Consequently, The PI will conduct a coordinated program between the University of Pittsburgh and Auburn University whose ultimate aim is to fully understand the effect of composition and topology on the phase behavior of our new CO2-philes in carbon dioxide. He will to combine targeted synthesis, measurement of selected thermophysical properties, high pressure FT-IR, and development of an accurate potential function from first principles to mathematically describe the thermodynamics of mixing of his materials with CO2. Success will allow himto numerically optimize the structure of non-fluorous CO2-philes.The program described herein involves a fully integrated project at both the University of Pittsburgh (E.J. Beckman, R.M. Enick, J.K. Johnson) and Auburn University (C.B. Roberts). The tasks to be performed at Auburn University (C.B. Roberts) include both phase behavior and FTIR studies, where high pressure IR measurements will be employed to evaluate the strength of specific interactions of CO2 with the Lewis base groups incorporated into our model polymers. The high pressure IR work provides both input to the synthetic design and the construction of an accurate potential model for CO2-polymer interactions.