Nitrogen compounds in light cycle oils: identification and consequences of ageing

Abstract

Basic and non-basic nitrogen compounds were selectively extracted from different light cycle oils (LCOs). The isolated fractions were analysed by nitrogen selective detector gas chromatography and by gas chromatography/mass spectrometry. The basic compounds are aniline and alkyl derivatives from C 1- to C 4- anilines. The non-basic compounds are indole, C 1- to C 4- alkylindoles, carbazole and C 1- to C 3-alkylcarbazoles. In the four different LCOs that we have investigated, the distributions of the nitrogen compounds are very similar and no other nitrogen compounds were found. It has been shown that after ageing, the distribution of nitrogen compounds is different: the evolution of indoles is more important than the evolution of anilines and carbazoles.