Simultaneous production of furfural and levulinic acid from pine sawdust via acid-catalysed mechanical depolymerization and microwave irradiation

Abstract

In this work pine sawdust was converted into levulinic acid (LA) and furfural. Sawdust was first pre-treated with sulfuric acid-catalysed mechanical depolymerization. The conversion reactions were then performed with microwave heating at 180 °C. To enhance the furfural yield and the efficient separation of furfural and LA, a biphasic water-toluene reaction system was used. The effect of an additional catalyst, AlCl3, on the yield of LA and furfural was also studied. According to the results the pre-treatment method enhanced the yields of LA. In addition, due to the microwave heating the reaction times were short. Additional AlCl3 catalyst enhanced the LA yield, however excellent furfural yields were achieved even without it. Best LA yield (38%) was achieved with 6 h of milling combined with 30 min of microwave heating while the best furfural yield (85%) was achieved with 4 h of milling and 20 min of microwave heating.