99/00265 Hydrogen transfer from hydrogen donors and molecular hydrogen to aromatic hydrocarbons

Abstract

The hydrogen transfer from hydrogen donors and molecular hydrogen to aromatic hydrocarbons such as 1-methylnaphthalene (1-MN), acenaphthene, phenanthrene, anthracene, pyrene and di(1-naphthyl) methane (DNM) was studied under pressurized nitrogen or hydrogen in the temperature range of 300--425 C. In non-catalytic runs, hydrogen transfer is easier from tetralin (THN) than from decalin (DHN) to some substrates. Only anthracene hydrogenation proceeded at 300 C in DHN, whereas the hydrogen transfer from THN to 1-MN and acenaphthene did not occur even at 425 C. The reactivities of the polycyclic arenes toward hydrogenation decreased in the order: 1-MN, acenaphthene < phenanthrene < pyrene < anthracene, which can be interpreted in terms of the superdelocalizabilities (Sr) of the substrates. The extent of hydrogen transfer during the thermal dissolution step in coal liquefaction can be inferred from the above facts to be related not only to the hydrogen donatabilities of solvents, but also to the hydrogen acceptabilities of aromatic rings in coal and coal-derived radical fragments. Metallic Fe, Ni, Pd/C, Zn, Al and Cu were used for the catalytic reaction. The catalytic activities for the hydrogenation of 1-MN and DNM decreased in the order: Fe < Ni < Pd/C, whereas Zn, Al and Cu show nomore » catalytic activity. The addition of sulfur or hydrogen donors such as THN and 9,10 dihydroanthracene inhibited catalytic hydrogenation of the substrates, but sulfur addition promote catalytic hydrocracking of DNM.« less