Toward New Descriptors of Basic Nitrogen Compounds in Middle Distillates by 2D NMR
journal contributionposted on 27.01.2020 by D. Proriol, L. Chahen
Any type of content formally published in an academic journal, usually following a peer-review process.
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.