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Toward New Descriptors of Basic Nitrogen Compounds in Middle Distillates by 2D NMR
- Proriol, D., Chahen, L.
- Energy & fuels 2020 v.34 no.2 pp. 1347-1354
- catalysts, chromatography, computer software, distillates, fuel oils, nitrogen, nuclear magnetic resonance spectroscopy, prediction, pyridines, quinoline
- 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 to couple the extraction of the basic N-compounds by flash chromatography with 2D NMR analysis. The NMR sequence heteronuclear single-quantum correlation (HSQC) allows us 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 has 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 us to describe the close environment of the nitrogen atom and allow, for example, to differentiate isoquinoline from quinoline derivatives.