Waste plastics: lignite mixtures co-liquefaction over Si/Al catalysts

The results of an investigation of the conversion of lignite and post-consu mer polymers into liquid products are reported in this paper. At first, a s eries of silica-alumina acidic catalysts were prepared by sol-gel chemistry with different Si/Al compositions and the catalysts ratio of Bronsted to L ewis acid sites was determined. Then thermal and catalytic col-iquefactions were attempted on 1/1 mixtures of lignite and waste plastics, e.g., PS, PI SO and PE. It was found that the catalysts prepared enhanced oil formation in all cases although lignite and polymeric materials demonstrated a variet y of catalytic characteristics. Thermal and catalytic reactions of polystyr ene (PS) and polyisoprene (PISO) showed that both polymers were liquefied e asily at 420 degrees C while polyethylene (PE) did not interact promptly un der the same conditions. The conversion of the solid materials correlated w ith the concentration of Bronsted acidity on the catalysts employed.