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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

DEVELOPMENT OF A SYNTHETIC METHOD FOR 2-TETRAZENES AND EXAMINATION OF THE MASS SPECTROMETRIC BEHAVIOR OF IONIZED 2-TETRAZENES AND ASPHALTENE MODEL

Hao-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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