Conversion of tetralin over sulphided iron catalysts, in connection with coal liquefaction

Abstract

The gas phase dehydrogenation of tetralin under atmospheric pressure was studied at 660 K using reduced, reduced and sulphided or directly sulphided iron oxide catalysts. It was found that, in tetralin conversion, metallic iron - possesses activity for dehydrogenation and hydrogenolysis simultaneously, - is strongly poisoned, even at very low S/Fe ratios, - is sulphided, more slowly than the initial oxide, to a S/Fe ratio near unity, where it shows good intrinsic activity and its selectivity is oriented to the dehydrogenation reaction. Directly sulphided iron oxides have a higher specific catalytic activity with the same (100%) selectivity for dehydrogenation. The tetralin dehydrogenation activity of the catalyst depends strongly on the stoichiometry of the Fe 1-x S sulphide. These results are in agreement with the fact that the iron-based catalysts used in the liquefaction of coal are more active if they are not pre-reduced and used with the addition of a sulphiding agent, particularly in the case of sulphur poor coals.