C₁₀–C₅₀ Olefins in Thermal Cracking Products of Heavy Petroleum: Characterization Using Ag⁺ ESI High-Resolution Mass Spectrometry

The characterization of olefin compounds is crucial for elucidating the reaction network in thermal cracking processes. In this study, heavy olefins were selectively characterized by using Ag+ complexation electrospray ionization coupled with high-resolution Orbitrap mass spectrometry. Semiquantitative analysis of the olefin content was conducted using naphthalene-d8 as an internal standard. In thermal cracking products, heavy olefins with carbon numbers ranging from C10 to C50 were detected, with a concentration peak observed in the C20–C25 range. Linear monoalkenes were found to be the most abundant species. The molecular composition of olefins in cracking products under various reaction conditions was investigated, and based on these findings, the thermal cracking reaction network was analyzed. Furthermore, the correlation between the olefin content and the bulk properties of the thermal cracking products was well correlated. This study provides valuable insights into the complex reaction network involved in the residual thermal cracking process, thereby providing a theoretical foundation for process optimization.