2ND ROW TRANSITION-METAL SULFIDES FOR THE HYDROTREATMENT OF COAL-DERIVED NAPHTHA .3. REMOVAL OF INDIVIDUAL NITROGEN-COMPOUNDS

The disappearance of individual nitrogen compounds is followed during the hydrotreatment of a coal-derived naphtha containing a mixture of n itrogen-, sulfur- and oxygen-containing heteroatom compounds over bulk second row transition metal sulfides. The naphtha contains mainly thr ee types of nitrogen compounds: pyridines, anilines and quinolines. Wh ile quinoline is the least reactive of the three simplest compounds in these compound classes, substituted anilines are the compounds most d ifficult to remove from the naphtha. The presence or absence of an alk yl substituent exerts a strong influence on the reactivity of individu al compounds and can overshadow the differences between compound types . The reactivity patterns of the methyl-substituted pyridines indicate a steric hindrance about the nitrogen atom. The order of reactivity b etween alkyl-substituted anilines is different over the various sulfid es with steric hindrance about the nitrogen atom indicated for only th e higher activity catalysts. Except for molybdenum sulfide, the reacti vity of quinoline is less than or equal to that of methyl-substituted quinolines. The individual nitrogen compounds do not disappear accordi ng to a first order rate expression but indicate strong product inhibi tion of the reaction rate. The overall removal of nitrogen does not fo llow simple first, zero or second order kinetics and shows similar kin etic behavior as for the disappearance of individual nitrogen compound s.