Identification of nitrogen compounds in RFCC diesel oil by mass spectrometry

This paper describes a simple method to separate and identify the nitrogen compounds in residual fluid catalytic cracking (RFCC) diesel oil. A 2% H2SO4 solution in ethanol was used to enrich nitrogen compounds from RFCC diesel oil. Then, the nitrogen-rich fraction was further separated into four fractions by silica gel column chromatography. Two discrete fractions containing neutral and basic nitrogen compounds were identified by mass spectrometry with atmosphere pressure chemical ionization source (APCI-MS) and gas chromatography–mass spectrometry (GC-MS). The results indicated that the nitrogen compounds in these two fractions of RFCC diesel oil were anilines, quinoline, indole, carbazole and their derivatives.