CHEMISTRY AND REACTIVITY OF CYCLIC OLEFINS AS DONORS IN COAL-LIQUEFACTION

A new set of hydrogen-donor compounds, cyclic olefins, has been evaluated to determine their effectiveness as hydrogen donors to coal. These cyclic olefins are hydroaromatic species that do not contain aromatic rings. The reactivity and hydrogen donability of these cyclic olefins have been compared to those of conventional hydroaromatics. The cyclic olefins under study are 1,4,5,8-tetrahydronaphthalene, also known as isotetralin, and 1,4,5,8,9,10-hexahydroanthracene. Cyclic olefins are much more reactive, releasing more hydrogen than their conventional hydroaromatic analogues, both with and without coal. In this paper, the thermal and catalytic reactivity of cyclic olefins under nitrogen and hydrogen at coal liquefaction temperatures is demonstrated and reaction pathways are proposed. The reactivity and hydrogen donability of the cyclic olefins and their conventional hydroaromatic analogues, tetralin, 9,10-dihydroanthracene, and octahydroanthracene, with Western Kentucky No. 9 coal using a nitrogen atmosphere at liquefaction conditions are also determined and compared.