As the supplies of petroleum diminish, it will become necessary to search for other sources of liquid fuels. Because of the relatively large coal reserves available worldwide, this appears to be thelogical source of additional quantities of liquid fuels.
Recently, much attention has been focussed on coal liquification and as recently as September, 1982, the Division of Fuel Chemistry of the American Chemical Society sponsored a Symposium on Coal Liquification [7].
In contrast with petroleum, the components of coal, coal liquids and other coal-derived products are primarily aromatic in nature and as a result present considerably greater health hazards when produced and handled on a large scale. There have been many different structures proposed for coal.