Coal hydroliquefaction using highly dispersed catalyst precursors

Abstract

In order to discuss the hydrogen transfer process in coal liquefaction with a catalyst in the presence of a donor solvent, hydroliquefaction of Yallourn, Wyoming, Illinois No. 6, and Mi-ike coals and cracking of benzyl phenyl ether (BPE) were carried out in tetralin or tetralin/naphthalene mixed solvent under a hydrogen atmosphere with highly dispersed catalyst precursors such as Fe(CO) 5S, Mo(CO) 6S, and Ru 3(CO) 12. In the absence of the catalyst, more than 70% of hydrogen was transferred from tetralin, as determined by the formation of naphthalene. In the presence of Mo(CO) 6S and Ru 3(CO) 12, however, the amount of hydrogen transferred from tetralin decreased to 15–40% of the total hydrogen and that from gas phase increased to 60–85% of the hydrogen required to stabilize coal fragment radicals even with an excess amount of tetralin. When the reaction was carried out in the tetralin/naphthalene mixed solvent, little hydrogenation of naphthalene occurred even with the active catalyst. This strongly supports the assertion that a decrease in the amount of naphthalene in the catalyzed liquefaction of coal in tetralin with a catalyst can be ascribed to the direct hydrogen transfer from molecular hydrogen to coal fragment radicals. In the presence of coal or benzyl phenyl ether, little or no hydrogenation of naphthalene occurred.