Running 13 C eNMR would also require altering the pulse sequence to incorporate

Running 13 c enmr would also require altering the

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this will in turn require a change to a high-gradient strength diffusion probe. Running 13 C eNMR would also require altering the pulse sequence to incorporate 1 H decoupling. As shown in the calibration section of this report, the temperature increase due to Joule heating during eNMR experiments on ionic liquids presents a problem in terms of convection and thus signal attenuation. No continuous build up of heat was measur- able, only induced convection due to temperature gradients. The effects of this could without changing input parameters be reduced by further increasing the air flow in the spectrometer to allow for faster temperature stabilization. Preferably the delay time between scans should also be increased in order to suppress convection. As can be seen from the plots of temperature variation during the eNMR experiments and the result- ing reference phase shifts and cation phase shifts, the convection compensation through added reference gives excellent results. eNMR provides a more direct approach of measuring the degree of dissociation of ionic liquids then reported elsewhere. As shown the results are reproducible and in good agreement with the report by Tokuda et al. [ 1 ]. eNMR provides quick and accurate measurements of dissociation and with proper control of parameters, this method should be applicable to any ionic liquid of interest. Presented in this report is a method of measuring ionic dissociation directly through eNMR. In order to be of benefit, more ionic liquids need to be investigated and categorized if ionic association is to be used as a parameter for systematic categorization of ionic liquids. This is most suitably done initially on previously investigated systems where other physicochemical properties are already known. 26
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Acknowledgements There are several people who deserve being mentioned, without whom this diploma work would not have happened. I would like to thank my supervisor, prof. Istv´ an Fur´ o, for allowing me to do the diploma work at physical chemistry and for his input and ideas throughout the project, prof. Peter Stilbs and ass.prof. Sergey Dvinskikh for their help with problems that has occurred, both practical and theoretical. Thanks Marianne Giesecke who have taught me practical eNMR and been a great help throughout the entire project with everything from helping to build electrodes to proofreading this diploma work. I would also like to thank ˚ Asa ¨ Ostlund for helping me get started on the project and along with Marianne teaching me about practical NMR. All the other members, phd and post-doc alike, in the NMR group, thank you for a great environment to work within and for making me feel part of the group from the very beginning. I would also like to thank Frederick Hallberg for the use of his figures ( 1.5 , 1.6 , 1.8 ) and for some fun dinners together with the rest of the NMR group. 27
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Bibliography [1] H. Tokuda, S. Tsuzuki, Mabh Susan, K. Hayamizu, and M. Watanabe. How ionic are room-temperature ionic liquids? an indicator of the physicochemical properties. Journal Of Physical Chemistry B , 110(39):19593–19600, 2006. ISI Document Delivery No.: 088QJ Times Cited: 244 Cited Reference Count: 88 English Article 1520-6106.
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