Development of a Synthetic Method For 2-tetrazenes and Examination of the Mass Spectrometric Behavior of Ionized 2-Tetrazenes and Asphaltene Model
Abstract
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
Degree
Ph.D.
Advisors
Kenttämaa, Purdue University.
Subject Area
Energy|Analytical chemistry|Atmospheric sciences|Chemistry|Optics
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