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

CO2在化学加工中的应用继续引起人们的极大兴趣，因为CO2通常比传统的有机溶剂造成的危害更小。人们一度认为CO2可以简单地取代许多有机溶剂，但随后的工作表明，CO2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。在20世纪90年代发现的“亲CO2”突然呈现了一些应用技术上的可能性，大大提高了对CO2作为溶剂的兴趣。这些新的亲CO2分子，主要是含氟聚合物，允许CO2的许多新应用，从非均相聚合到均相催化。尽管氟化两亲物在技术上是成功的，但是它们的高成本使得方法的经济性是不利的，除非所述hCO2-亲物可以以大于99%的效率再循环。更复杂的是，从高压工艺中回收添加剂既不容易也不便宜。使用氟化前体的固有缺点极大地抑制了CO2的大多数新应用的商业化，因此，基于CO2的技术的全部前景尚未实现。PI研究了非氟亲CO2分子的设计。到目前为止，他已经用一套简单的化学方法设计了三种非氟亲CO2分子;他希望最终能找到其他的亲CO2分子，大大拓宽CO2作为溶剂的应用范围。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）的数量将产生一个不切实际的庞大程序。此外，传统的热力学模型不能预测所有可能的排列的行为。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合物在二氧化碳中的相行为的影响。他将结合联合收割机的目标合成，选定的热物理性能，高压FT-IR的测量，并从第一原理的一个准确的势函数的发展，以数学描述他的材料与CO2混合的热力学。成功将使他能够在数值上优化非氟亲CO2分子的结构。Enick，J.K.约翰逊）和奥本大学（C.B. Roberts）。在奥本大学（C.B. Roberts）包括相行为和FTIR研究，其中将采用高压IR测量来评估CO2与并入我们的模型聚合物中的刘易斯碱基团的特定相互作用的强度。高压IR工作提供了合成设计的输入和CO2-聚合物相互作用的准确的潜在模型的构建。

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.