Coals ionic hydrogenation

Different types of other coal liquefaction processes have been also developed to convert coals to liqnid hydrocarbon fnels. These include high-temperature solvent extraction processes in which no catalyst is added. The solvent is usually a hydroaromatic hydrogen donor, whereas molecnlar hydrogen is added as a secondary source of hydrogen. Similar but catalytic liquefaction processes use zinc chloride and other catalysts, usually under forceful conditions (375-425°C, 100-200 atm). In our own research, superacidic HF-BFo-induced hydroliquefaction of coals, which involves depolymerization-ionic hydrogenation, was found to be highly effective at relatively modest temperatnres (150-170°C). 

The second, catalytic liquefaction process is similar to the first except that there is a catalyst in direct contact with the coal. ZnCl2 and other Friedel-Crafts catalysts, including AICI3, as well as BFj-phenol and other complexes catalyze the depolymerization-hydrogenation of coals, but usually forceful conditions (375 t25°C, 100-200 atm) are needed. Superacidic HF-BF3-induced liquefaction of coals8 involves depolymerization-ionic hydrogenation at relatively modest 150-170°C. 

Ionic hydrogenations have substantial interest as, in contrast to metal-catalyzed hydrogenation, they are not affected by many impurities poisoning catalysts, which is of significance in fuels processing, particularly in coal liquefaction.40... 

An extreme case of the effectiveness of ionic hydrogenation is the HF-BF3 superacid-promoted hydrogenation of coals at 170°C with 36-atm hydrogen giving efficiently liquid products under these relatively mild conditions.245,246... 

Thiosulphates occur in natural waters only exceptionally. They are of natural origin in some mineral waters in which they accompany hydrogen sulphide and its ionic forms. Their artificial origin in wastewaters comes from the thermal processing of coal, dying plants, leather plants, etc. 

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