Self-inhibition observed during indole and o-ethylaniline hydrogenation in the presence of dibenzothiophene

Abstract An unexpected self-inhibiting effect of indole and o -ethylaniline in their hydrogenation process during dibenzothiophene hydrodesulphurization at conditions commonly used in the hydrotreatment of diesel feedstocks has been experimentaly determined. The self-inhibition behavior of these compounds is non-linear, showing strong inhibition at concentrations as low as 22 ppm (as nitrogen). The experimental data for the hydrogenation of indole and o -ethylaniline was quantitatively represented by a Langmuir–Hinshelwood type rate equation, showing that indole self-inhibition is 10 times stronger than o -ethylaniline self-inhibition.