高压/超临界原位红外光谱监测系统研制

Environmental pollution caused by the rapid development of the chemical industry cannot be ignored. The explorations of the environmental friendly chemical process have become a target of researchers in recent years. Supercritical carbon dioxide (scCO2) technology has been applied in fields such as catalysis and materials synthesis due to its green properties and low critical temperature and pressure. The adjustable solvent properties of scCO2 endow its unique significance in both theoretical studies and potentially industrial application to catalysis, polymerization and materials synthesis. However, the complicated intermolecular interactions in scCO2 system as well as the insufficiencies in the present high-pressure in-situ monitoring systems have become the "bottleneck" of this green medium further research and application in some other fields. Studying the in-situ spectroscopy techniques in the real pressure, stirring conditions and on-line monitoring in situ spectroscopy of scCO2 system, which will help revealing the secrets of scCO2 microcosmic dynamic process or the intermolecular interaction mechanism and promoting scCO2 techniques well research and applications. This project aimed at the technical defects existing in high pressure in-situ infrared spectrum monitoring process (for example, the lower pressure resistance limitation of sample cell, non-stirring and lower reliability), based on the attenuated total reflection (ATR) FTIR can reduce the infrared optical path down to a few microns and then increase the concentration of reactants, designing and manufacturing a new type of high pressure ATR associated sensor. Designing and developing the modules of the high pressure infrared cell and light path transmission system using systematic concepts. Designing and constructing the high pressure/supercritical in-situ middle infrared spectrum on-line monitoring system through various functions module effective integrated and coalesced. Realizing the on-line monitoring for physical transforms or the chemical reaction induced by microscopic dynamic process of high pressure/scCO2 system under the pressure of 40 MPa, the temperature of 200 oC and fully stirring conditions. To study the mechanism and dynamic kinetics of catalytic reactions, the synthesis of the fluorinated polymers and the material synthesis under the real scCO2 conditions, which will open a new effective way for the investigation of scCO2 process under a real high pressure/scCO2 conditions.

超临界CO2(scCO2)可调节的溶剂性能赋予其独特的理论研究意义和应用潜力，然而scCO2体系复杂多变的分子间相互作用及高压原位监测手段的不足已成为这一绿色技术进一步研究和应用的“瓶颈”。研发在真实条件下在线监测scCO2体系的原位光谱技术，对于揭示scCO2体系微观动态过程的奥秘或作用机制、促进scCO2技术的应用具有重要的意义。本项目拟针对现有高压原位红外光谱系统监测过程中存在的技术缺陷(如样品池耐压限低、无法搅拌及可靠性差等)，基于衰减全反射原理设计新型高压原位红外传感器，设计研制高压红外池及光路传导系统等模块，通过各功能模块间的有效集成与融合，构建高压/超临界原位中红外光谱在线监测系统，实现在线监测40MPa及200C以内在充分搅拌条件下的高压/scCO2体系物理转变或化学反应微观动态过程，为研究真实条件下scCO2体系中催化、聚合和材料合成的机理及动力学等开辟一条新的有效途径。

超临界二氧化碳（scCO2）已被广泛应用于催化、萃取、纳米材料合成。但是，由于分子间相互作用及相行为随高压scCO2体系温度/压力变化而演变，使得高压scCO2体系中的原位表征技术极具挑战性。因此，研发在真实的反应温度/压力和充分搅拌反应体系原位监测技术、揭示scCO2体系中微观动态过程的本质或作用机制，已成为研究者梦寐以求的愿望。.研制一套在较宽压力/温度范围和搅拌条件下，在线监测真实scCO2实验条件下相行为和化学反应微观动态过程的高压原位红外光谱监测装置，建立相应的高压原位红外光谱监测方法。主要研究内容包括设计与研制原位红外样品池和中红外ATR传感器，集成与融合各功能模块或子系统，探究分子间相互作用，在线监测体系中的聚合、催化等化学反应过程，定量测定转化率、研究反应动力学及反应机理等。.(1) 高压/超临界原位红外光谱监测系统：设计构建了一套在 -20～200 ℃、0.1～40 MPa和充分搅拌等条件下能稳定运行的原位红外光谱监测系统，迄今为止报道的同类或相似的仪器，其耐压极限最高、综合性能最好。.(2) 溶解过程及相行为监测：通过可视窗口可以原位监测不同反应物/单体在scCO2介质中溶解性能和相行为演变过程，定性描述分散质的溶解性能。 .(3) 溶剂化及分子间相互作用：发现文献未曾报道过的振动吸收光谱随压力的衍变，特别是分散质分子中官能团振动吸收光谱的蓝移规律。提出了分子间相互作用合力及转变压力PT概念，阐明了TFEMA及PHFPO在scCO2中由于分子间相互作用动态诱导的溶剂化作用机制。.(4) 聚合过程跟踪及动力学研究（定量、近红外）：获得了TFEMA在scCO2中的自由基聚合动力学方程和聚合活化能，从而证明了单体参与链引发过程，并与所提出的scCO2体系中引发剂分解的“去笼效应”相互印证。.(5) 反应进程跟踪及中间体捕捉（水解及催化、中红外）：跟踪酰氟基团（F-C=O）水解进程和柠檬醛加氢反应，提出了酰氟水解机制和Fe(III)对Pt/MWCNT催化柠檬醛选择性加氢反应机理。.该仪器的建成使得高压/超临界体系相关反应的描述由宏观变为微观/分子成为现实，极大地提升了该领域的理论研究水平和扩大了其应用范围。