Wood liquefaction using dibasic organic acids and glycols

Liquefaction of Central European hardwoods was performed using a number of different glycols in combination with dibasic organic acids and a minor addition of ortho-phosphoric acid as a catalyst. The reaction carried outat 190 °C resulted in liquefaction of 15-56% of the original wood. The best effects were achieved using propylene glycol as the solvolytic reagent and maleic anhydride as the the acidic reagent. The unsolubilized solid remains were investigated using scanning electron microscopy. The liquefaction product examined by size exclusion chromatography and infrared spectroscopy was composed of low molar mass oligomeric polyesters.