Evaluation of Structural and Compositional Changes of a Model Monoaromatic Hydrocarbon in a Benchtop Hydrocracker Using GC, FTIR, and NMR Spectroscopy

Abstract

Hydrogenation is a catalytic process that has the potential to facilitate sustainable chemical production. In this work, a model monoaromatic hydrocarbon, phenyldodecane (PDD), comprising an aromatic ring with a long aliphatic side chain has been chosen as representative of a typical species involved in hydrogenation and hydrocracked at a high pressure and temperature over a platinum catalyst in a bespoke benchtop mini-reactor. Gas chromatography–mass spectrometry (GC–MS), Fourier transform infrared (FTIR) spectroscopy, UV–vis spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy were employed to analyze the changes that took place after hydrocracking for different time periods. By combining the results from these sensitive spectroscopic tools, it was found that along with the saturation of the aromatic ring of PDD by hydrogen addition, new molecules were formed via ring opening and catalytic cracking. For comparison purposes, the spectra of the samples post hydrogenation were compared with those of cyclohexylnonadecane (CHND), which has a saturated six-membered ring and a long aliphatic tail.