Pore structure and reactivity of chars obtained by pyrolysis of coking coals containing MoCl5

Three coking coals were pyrolysed in the presence of the Lewis acid MoCl5 u nder an inert atmosphere at a final temperature of 750 degrees C, the ultim ate aim of this work being the elaboration of active carbon supported catal ysts for use in hydrodenitrogenation reactions. The values of the parameter s characterizing the porous structure of the chars before and after steam a ctivation were determined using CO2 and C6H6 sorption measurements at 25 de grees C. Char from the lowest rank coal had the most developed ultramicropo rosity (pore width < 0.4 nm) and the presence of MoCl5 in the precursor doe s not seem to exert much influence. In the case of the higher rank coals, a significant development of the ultramicroporosity was observed in the moly bdenum enriched chars before activation and their reactivity toward steam w as increased. After steam activation, the structure of the activated chars was mainly microporous, but a significant development of the mesoporosity w as observed. (C) 1999 Elsevier Science Ltd. All rights reserved.