Thermal Transformations of Organic Nitrogen Bases in Resin Components of Oils of Various Types

Abstract

The composition and the structure of organic nitrogen bases of resins of low- and high-resin oils are studied before and after thermal exposure (450 °C, 30 minutes, inert medium). It is found that most of the bases in all samples of resins under study are high-molecular compounds, but their content in thermolized resins is significantly lower. Thermally transformed bases are characterized by lower values of average molecular weights, minority and smaller sizes of structural blocks constituting their mean molecules. A decrease in the overall size of the structural blocks is mainly due to a decrease in the number of saturated cycles in the naphtheno-aromatic system and carbon atoms in alkyl substituents. According to GC-MS data, the bases of all the resins under study are represented by the same sets of alkyl derivatives of quinoline, benzoquinoline, dibenzoquinoline, and azapirene. Alkyl derivatives of thiophenoquinoline and benzothiophenoquinoline are present in the composition of bases of highsulfur oil resins in significant amounts. In all cases, the maximum in the distribution of identified compounds falls to alkyl benzoquinolines. The special feature of organic nitrogen bases of thermally transformed resins is a high content in alkylquinolines and alkylthiophenoquinolines, as well as a higher percentage of structures with a lower number of carbon atoms in alkyl substituents. Thus, the chemical nature of oils is not responsible for main patterns of thermal transformation of organic nitrogen bases in oil resins