Ionic Liquids: Radiation Chemistry, Solvation Dynamics and Reactivity Patterns.

Wishart, J. F.

Technical Information Center Oak Ridge Tennessee

关键词: Radioactive waste processing;    Ionic liquids;    Radiolysis;    Solvation;    Nuclear fuels;   

RP-ID  :  DE2008939945

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

Ionic liquids (ILs) are a rapidly expanding family of condensed-phase media with important applications in energy production, nuclear fuel and waste processing, improving the efficiency and safety of industrial chemical processes, and pollution prevention. ILs are generally nonvolatile, noncombustible, highly conductive, recyclable and capable of dissolving a wide variety of materials. They are finding new uses in chemical synthesis, catalysis, separations chemistry, electrochemistry and other areas. Ionic liquids have dramatically different properties compared to conventional molecular solvents, and they provide a new and unusual environment to test our theoretical understanding of charge transfer and other reactions. We are interested in how IL properties influence physical and dynamical processes that determine the stability and lifetimes of reactive intermediates and thereby affect the courses of chemical reactions and product distributions. Successful use of ionic liquids in radiation-filled environments, where their safety advantages could be significant, requires an understanding of ionic liquid radiation chemistry. For example, characterizing the primary steps of IL radiolysis will reveal radiolytic degradation pathways and suggest ways to prevent them or mitigate their effects on the properties of the material. An understanding of ionic liquid radiation chemistry will also facilitate pulse radiolysis studies of general chemical reactivity in ILs, which will aid in the development of applications listed above. Very early in our radiolysis studies it became evident that slow solvation dynamics of the excess electron in ILs (which vary over a wide viscosity range) increases the importance of pre-solvated electron reactivity and consequently alters product distributions. Parallel studies of IL solvation phenomena using coumarin-153 dynamic Stokes shifts and polarization anisotropy decay rates are done to compare with electron solvation studies and to evaluate the influence of ILs on charge transport processes. Picosecond pulse radiolysis studies at BNL's Laser-Electron Accelerator Facility (LEAF) are used to identify reactive species in ionic liquids and measure their solvation and reaction rates.