Title
Hydrogenation of aspen ethanol lignin in supercritical ethanol in the presence of Ni/C catalyst
Authors
ALEKSANDR S. KAZACHENKO, ANGELINA V. MIROSHNIKOVA, YURIY N. MALYAR, ANDREY M. SKRIPNIKOV, VALENTIN V. SYCHEV, SERGEY V. BARYSHNIKOV and OLGA S. SELEZNEVA

Received January 29, 2025
Published Volume 59 Issue 5-6 May-June
Keywords ethanol lignin, aspen, hydrogenation, nickel catalyst

Abstract
Lignin is the largest renewable source of aromatic chemicals and has great potential for the production of high value added chemicals. In this work, we describe the process of hydrogenation of aspen wood ethanol-lignin in supercritical ethanol in the presence of Ni/C catalyst and in the absence of added catalysts. It is shown that at a temperature of 250 °C, the catalyst reduces the yield of solid residue from 7.3 to 1.9 wt%. The total yield of phenolic compounds during non catalytic hydrogenation does not exceed 5.8 wt%. The bifunctional nickel-containing catalyst increases almost twofold (up to 10.1 wt%) the yield of liquid phenolic products, among which 4-propylsyringol predominates. Increasing the process temperature of catalytic hydrogenation to 300 °C leads to an increase in the yields of monomeric phenolic compounds to 13.4 wt%. In the presence of a catalyst, the molecular weight distribution of liquid products of ethanol lignin hydrogenation shifts to the low molecular weight region, due to an increase in the content of monomeric phenolic compounds in the liquid products.