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DEVELOPMENT OF A SYNTHETIC METHOD FOR 2-TETRAZENES AND EXAMINATION OF THE MASS SPECTROMETRIC BEHAVIOR OF IONIZED 2-TETRAZENES AND ASPHALTENE MODELHao-Ran Lei (13965753) 17 October 2022 (has links)
<p> 2-Tetrazens are often used as high energy-density materials. Only a few synthetic methods exist for making them. Further, their structure-property relationships remain largely unexplored. Asphaltenes are usually a complex mixture found in the heaviest fraction of heavy crude oil. Their structural characterization and understanding have become a pertinent task for petroleum industry around the world. Mass spectrometry is a powerful analytical tool for the detection and characterization of unknown compounds even in complex mixtures. It features high sensitivity and speed and can provide a variety of valuable information for different types of analytes. This thesis focuses on the development of an effective synthetic method for 2-tetrazenes and the mass spectrometry study of the ionized 2-tetrazenes. In addition, the mass spectrometric behavior of ionized asphaltene model compounds are also discussed in this thesis. Chapter 2 describes the instrumentation and fundamental aspects of the mass spectrometers used in the research discussed in this thesis. Chapter3 introduces an effective synthetic method for 2-tetrazens based on iodine-mediated oxidative N-N coupling reaction of hydrazines. Chapter 4 presents the fragmentation behavior of ionized 2-tetrazenes in tandem mass spectrometry experiments. Upon collision-activated dissociation (CAD), ionized alkyl-substituted linear 2- tetrazenes underwent simpler fragmentation reactions than the ionized aromatic 2-tetrazenes or a cyclic 2-tetrazene. The observations were rationalized by using quantum chemical calculations. Chapter 5 presents the fragmentation behavior of ionized asphaltene model compounds under medium-energy collision-activated dissociation (MCAD). The comparison between the different behaviors of the molecular radical cations of these compounds provided useful information for the identification of related unknown compound </p>
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