Low molecular weight nitrogen bases of natural asphaltite and liquid products of its conversion in supercritical water
V. R. ANTIPENKO, S. S. ZHBANOVA
Institute of Petroleum Chemistry, Siberian Branch of the Russian Academy of Sciences, omsk, Russia
Keywords: natural asphaltite, autoclave conversion in supercritical water, liquid products, low molecular weight nitrogen bases, analysis, composition
Abstract
Results of the comparative gas chromatographic - mass spectrometric analysis of the structural-group and molecular compositions of nitrogen-containing basic compounds, isolated by acid extraction from the deasphaltisates of high-sulphur natural asphaltite and the liquid products of its conversion in supercritical water (SCW) at 400 °C and 40 MPa in the presence of potassium hydroxide are presented for the first time. The higher yield of the acid extract in conversion products in comparison with initial asphaltite suggests that an additional portion of low-molecular nitrogen bases is generated during the destruction of asphaltenes and resins of asphaltite under the process conditions. In both extracts, the compounds of homologous series of quinoline, thiophenoquinolines, benzoquinolines, benzothiophenoquinolines, benzoacridines, azapyrenes were identified. It has been determined for the liquid products of SCW conversion that the content of benzoquinolines and benzoacrydines with respect to quinolines increases by a factor of 1.5, and thiophenoquinolines - by a factor of 1.2. Furthermore, among most of the nitrogen base types, the fraction of unsubstituted compounds and/or compounds containing a smaller total number of carbon atoms in the aromatic ring substituents is observed to increase in the conversion products. A change in the content of nitrogen bases or their appearance in conversion products suggests the presence of such nitrogen- and nitrogen-sulphur-containing structural fragments in the molecules of resin-asphaltene substances (RAS) of natural asphaltite.
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