FRACTIONATION OF ACID- AND ALKALI-PRETREATED BIRCH WOOD INTO METHOXYPHENOLS AND CELLULOSE USING ETHANOL AS A REDUCING AGENT AND A BIFUNCTIONAL Ru/C CATALYST

The effect of alkaline and acid pretreatments on the yield and composition of thermal transformation products of treated birch wood in an ethanol medium at a temperature of 225 °C in the presence of a bifunctional catalyst containing nanodispersed ruthenium particles on the acidic carbon support Sibunit has been established. The yields of liquid products of catalytic fractionation of wood subjected to alkaline and acid pretreatments reach 39 and 34 wt.%, respectively. In the presence of the Ru/C catalyst, a shift in the molecular weight distribution curves of the liquid products and an increase in the yield of monomeric methoxyphenols are observed. The highest yield of monomeric methoxyphenols (18.2 wt.%) was achieved during thermal catalytic transformation of wood subjected to acid pretreatment. In this case, the highest quality cellulose product was also obtained with a cellulose content of 88.5 wt.% and a crystallinity index of 0.72. A scheme for catalytic fractionation of birch wood into xylan, xylose, monomeric methoxyphenols and microcrystalline cellulose using ethanol as a reducing agent is proposed.