Thermal Decomposition Mechanisms of Molecules Relevant to Chemical Vapor Deposition and Fuel Combustion by Flash Pyrolysis Photoionization Time-of-Flight Mass Spectrometry

• Main Author: Shao, Kuanliang
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01.01.2023
• Subjects: Analytical chemistry; Chemistry; Physical chemistry
• ISBN: 9798379957599

Flash pyrolysis microreactor coupled with molecular beam extraction and photoionization time-of-flight mass spectrometry along with theoretical calculations are employed to study the pyrolysis of gas phase molecules with relevance to chemical vapor deposition (CVD) and fuel combustion. This dissertation presents a comprehensive exploration of the flash pyrolysis mechanisms of various organosilanes and hydrocarbons, including allyltrichlorosilane, allyltrimethylsilane, 1,1,2,2-tetraethylsilane, trimethylchlorosilane, tetraethylsilane, cyclohexane, and cycloheptane.Chapters 3 to 6 of this dissertation focus on investigating the decomposition pathways and identifying key reaction products of various CVD precursors through a combination of experimental observations and theoretical analyses. The study specifically examines allyltrichlorosilane, allyltrimethylsilane, 1,1,2,2-tetramethylsilane, trimethylchlorosilane, and tetraethylsilane. The findings reveal that allyltrichlorosilane decomposes primarily through Si-C bond homolysis, while the thermal decomposition of allyltrimethylsilane proceeds primarily via molecular eliminations. The pyrolysis of 1,1,2,2-tetramethylsilane involves molecular elimination reactions, Si-Si bond fission, H2 elimination, and decomposition to trimethylsilane and methylsilylene. Trimethylchlorosilane predominantly undergoes HCl molecular elimination, while tetraethylsilane follows Si-C bond homolysis. These studies have conducted a thorough examination of the pyrolysis mechanism of organosilane precursors, providing a comprehensive overview, and investigating their potential applications in SiC thin film production.Additionally, Chapters 7 and 8 explore the thermal decomposition mechanisms of cyclohexane and cycloheptane, elucidating the diradical mechanism in the primary initiation reactions. These comprehensive studies provide valuable insights into the intricate pyrolysis mechanisms of organosilanes and aviation fuel prototypes, facilitating the development of accurate models and efficient utilization strategies for these compounds.