Ethanollignin isolated from aspen wood was characterized by FTIR spectroscopy, elemental and thermogravimetric analysis. IR spectrum of ethanollignin contains adsorption bands characteristic for phenolic structural units of guaiacyl and syringyl types as well as aliphatic fragments and carboxylic groups. According to thermogravimetric data, the thermal decomposition of ethanollignin proceeds in two stages. This is indicated by the appearance on the differential curve on the mass loss the peak of low intensity at 300 °C and the intensive peak at 390 °C.

The influence of temperature on the conversion of ethanollignin in supercritical ethanol and on the yield and composition of liquid and gaseous products was investigated. The highest conversion of lignin (74 wt.%) was achieved at temperature 280 °C as well as the maximum yield of benzene-soluble fraction of liquid products (42 wt.%) – at 300 °C.

It was defined by GC-MS that the rise of the temperature of ethanollignin depolymerization in supercritical ethanol from 280 °C to 300 °C increases in the obtained liquid products the relative content of methoxyphenols (by 1,6 times) and methoxybenzene (by 2,3).