The chemical building blocks that comprise petroleum asphaltenes were determined by cracking samples under conditions that minimized alterations to aromatic and cycloalkyl groups. Hydrogenation conditions that used tetralin as hydrogen-donor solvent, with an iron-based catalyst, allowed asphaltenes from different geological regions to yield 50-60 wt% of distillates (<538°C fraction), with coke yields below 10 wt%. Control experiments with phenanthrene and 5αcholestane confirmed low

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... catalytic activity, and preservation of the cycloalkyl structures. Quantitative recovery of cracking products and characterization of the distillates, by gas chromatography-field ionization-time of flight high resolution mass spectrometry, displayed remarkable similarity in molecular composition for the different asphaltenes. Paraffins and 1-3 ring aromatics were the most abundant building blocks. The diversity of molecules identified, and the high yield of paraffins were consistent with high heterogeneity and complexity of molecules, built up by smaller fragments attached to each other by bridges. The sum of material remaining as vacuum residue and coke was in the range of 35-45 wt%; this total represents the maximum amount of large clusters in asphaltenes that could not be converted to lighter compounds under the evaluated cracking conditions. These analytical data for Cold Lake asphaltenes were transformed into probability density functions that described the molecular weight distributions of the building blocks. These distributions were input for a Monte Carlo approach that allowed stochastic construction of asphaltenes and simulation of their cracking reactions to First and foremost, I would like to express my deepest gratitude to Dr. Murray R. Gray. His extraordinary experience and knowledge have always been admirable, and it has been an honor and a privilege for me to have worked under his mentorship and guidance. I am very grateful for his continuous support and encouragement, and his valuable comments and suggestions to my work. Thanks to his help and diligence this work has been possible.