Towards new descriptors of basic nitrogen compounds in middle distillates by 2D NMR

D. Proriol (1) , L. Chahen (1)

1 IFPEN - IFP Energies nouvelles

Basic nitrogen-compounds (N-compounds), present in middle distillates, can inhibit acidic catalysts used in hydrotreatment processes. A better knowledge of these compounds, especially the environment of the nitrogen atom, may be interesting to improve these processes. Herein, we propose a new promising methodology coupling the extraction of the basic N-compounds by flash chromatography with 2D NMR analysis. The NMR sequence Heteronuclear Single-Quantum Correlation (HSQC) allows to visualize specific C-H correlations and, with the help of the prediction software Advanced Chemistry Development/Laboratory (PS-ACDL), eleven areas of interest have been identified. The representativeness of these areas have been validated with data from literature and with a gas oil (GO) sample analysis. These areas are specific to C-H couples in pyridine, quinoline, isoquinoline and acridine derivatives and give a detailed fingerprint of basic N-compounds in the GO cut. Moreover, certain areas allow to describe the close environment of the nitrogen atom and allow, for example, to differentiate isoquinoline from quinoline derivatives. 2

Keywords: NMR; HSQC; NMR Prediction; isoquinoline; Basic Nitrogen; Middle distillates

Domains: Chemical Sciences

D. Proriol, L. Chahen. Towards new descriptors of basic nitrogen compounds in middle distillates by 2D NMR. Energy & Fuels, 2020, 34 (2), pp.1347-1354. ⟨10.1021/acs.energyfuels.9b03199⟩. ⟨hal-02553541⟩