Nitrogen compound determination and distribution in three source fuels by GC/MS

Three middle distillate fuels from Kenya, Kuwait, and Sweden were studied for the identification and comparison of their nitrogen content.. The organic nitrogen compounds were isolated by mild acid extraction, and three extracts were obtained from each source fuel: a basic nitrogen extract in methylene chloride (BNC), a nonbasic nitrogen extract in methylene, chloride (NBNC), and a nonbasic nitrogen extract in methanol (NBNC). The major constituents of each extract were determined by gas chromatography/mass spectrometry (GC/MS). The largest number of nitrogen compounds of the BNC extracts were pyridines and pyrroles in the Kuwait fuel, indoles and pyrroles in the Swedish fuel, and pyrroles and quinolines in the Kenya fuel. The Kenya fuel had carbazoles present in the BNC extract, whereas, the other two fuels didn't have this compound. The predominant organic nitrogen compounds in the NBNC extracts in methylene chloride for Kuwait and Kenya were tetrahydroquinolines and quinolines, respectively. The analysis of the NBNC extracts in methanol showed the following prevalent organic nitrogen compounds: indoles for Kuwait, quinolines for Sweden, and pyrroles for Kenya. All three fuels had short chain alkyl substituted indoles. Kenya had the lowest nitrogen content, followed by Kuwait and Sweden.