Hydrogenation of brown coal. 2. Iron-based catalysis.pdfVIP

Hydrogenation of brown coal. 2. Iron-based catalysis Mark R. Hatswell, W. Roy Jackson, Francis P. Larkins, Marc Marshall, Douglas Rash and Donald E. Rogers Department of Chemistry, Monash University, Clayton, Victoria, 3160, Australia (Received 4 June 1980; revised 19 March 1981) Some of the inherent cations of Victorian brown coals have been exchanged for iron by treatment with solutions of iron salts. Coals with various iron contents are obtained by variation of the pH of the solutions used. Hydrogenation of coals treated in this way at 395X, and an initial hydrogen pressure of 10 MPa, give product yields similar to those obtained using commercial cobalt molybdate on alumina catalysts, and greater than those obtained using red mud as a catalyst. The increase in yields compared with non-catalyzed experiments results mainly from increased production of asphaltenes. The amount and composition of gas (80-90 wt%CO,, resulting from decarboxylation) remains constant. Despite the similar conversions, the hydrogen consumption and tetralin/naphthalene ratios for iron-catalysed experiments are less than for cobalt-molybdate-catalysed experiments. (Keywords: coal; hydrogenation; catalysis) Victorian brown coals contain large amounts of oxygen ( - 20 wt% of dry coal), much of which is present as free carboxylic acid groups,’ carboxylate ions in association with sodium, calcium, magnesium or iron cations,2 and phenols. The inherent cations can be replaced by ion- exchange with other cations.3,4 Previous studies5-’ have shown that iron and its compounds may be useful catalysts for the direct hydrogenation of Victorian brown coals. In this paper this was examined by introducing iron into the coal by exchange with the inherent cations associated with carboxylate groups. This gives a very good dispersion of the iron without introduction of foreign anions such as sulphate or chloride. The hydrogenation of these coals containing well-dispersed catalyst ce