Recently, natural chabazite was identified as a catalyst for a novel thermocatalytic oil upgrading process. To further develop this process, it is essential to understand the chemical reactions involved. In this study, up to 67.5% vanadium removal from oil sands bitumen is obtained without adding hydrogen. Using model compounds, vanadium removals up to 47.9% and nickel removals up to 3.4% were obtained after a 1h reaction at 400 degrees C. Nickel removal up to 90.0% at equilibrium and room temperature was observed. Evidence of free-base porphyrin formation is presented. It was also found that chabazite can catalyze the dealkylation of octaethylporphyrins. The results presented here allow for a better understanding of the chemical properties of chabazite and open the possibility for the creation of pretreatment processes that can remove metals and modify the structure of petroleum-derived fractions without using hydrogen or rejecting substantial amounts of usable oil.