1. Field of the Invention
This invention is directed to improving properties of solid, naturally occurring carbonaceous materials and, in particular, to improving yields and physical characteristics of products derived therefrom.
2. Description of the Prior Art
Much work has been done in recent years to make useful liquids and gases from coal. Various types of liquefaction processes have been developed such as solvent refining, direct hydrogenation with or without a catalyst, catalytic or non-catalytic hydrogenation in the presence of a non-donor solvent and catalytic or non-catalytic liquefaction by the donor solvent method.
Pretreatment processes have been developed, e.g., to increase liquid products from coal liquefaction. Exemplary of such pretreatment processes is U.S. Pat. No. 4,092,235 which discloses pretreatment of coal at the carbon sites by the Friedel-Crafts C-alkylation or C-acylation. The C-alkylation/acylation process destroys the caking properties of caking coals and does not enhance the caking properties of non-caking coals. Other coal conversion processes under extensive investigation include solubilization, gasification and pyrolysis.