Microwave driven wood liquefaction with glycols

Wood liquefaction with glycols using p-toluenesulfonic acid as the catalyst was carried out under microwave heating. With rapid heating and temperatures in the 190–210 °C range complete liquefaction was achieved in 7 min. Liquefaction efficiency was dependent on the choice of glycol. Simple glycols such as ethylene glycol and propylene glycol were more effective than higher analogues. The use of glycerol in mixtures with glycols showed a synergistic effect. Size exclusion chromatography was used to follow the gradual emergence of liquefaction products in solution as well as the recondensation products that start forming early in the reaction and precipitate from solution when molar masses of approx. 1 × 104 g/mol are reached.