LIQUEFACTION OF WYODAK COAL WITH PHOSPHOMOLYBDIC ACID

Phosphomolybdic acid (PMA) has been found to be a very effective catal yst precursor for direct liquefaction of Wyodak coal. A concentration of 300 mg Mo/kg maf coal of PMA imparts greater activity when impregna ted onto the coal compared to adding the crystalline solid directly to the reaction mixture. Significant improvement in the reaction occurre d only when H2S was added to the reaction mixture, suggesting that the Keggin anion does not act as the catalyst. Impregnated PMA is at leas t as active as organically soluble molybdenum di(2-ethylhexyl)phosphor odithioate or oxothiomolybdenum N,N-dibutyldithiocarbamate. The method of impregnating the PMA from aqueous solution onto the coal did not h ave any significant influence on THF solubilization or resid conversio n. It was also found that neither THF solubilization nor conversion to distillate was affected by impregnating the Mo precursor onto only 10 % of the feed coal. However, if the PMA is impregnated onto a carbon c arrier, which is then mixed with coal, very poor THF solubilization oc curs.