Conversion of saturated cyclic and noncyclic amines over a sulphided NiMo/Al 2O 3 catalyst : mechanisms of carbon - nitrogen bond cleavage

Abstract

The objective of this work was to provide comprehensive hypotheses concerning the mechanisms operative in the CN bond cleavages occurring during the catalytic conversion of amines over a conventional hydrotreating catalyst, so as to account for experimental observations and to help in developing better hydrodenitrogenation catalysts. The approach consists in a study of the relations between the structure and the reactivity of two series of amines with different numbers of hydrogen atoms on the carbon atoms in the α and β positions with respect to their nitrogen atom. It was found that the hydrogen atoms on the carbon atom in the β position are involved in the formation of hydrocarbons, and that neither the hydrogen atoms on the carbons in the α position nor those on the carbon atoms in the β position are involved in the formation of condensation products. On the basis of these results, two mechanisms are proposed for the formation of the different reaction products.