Valorization of Lignin to Simple Phenolic Compounds over Tungsten Carbide: Impact of Lignin Structure
Citations Over TimeTop 10% of 2016 papers
Abstract
Lignins isolated from representative hardwood, softwood, and grass materials were effectively hydrocracked to aromatics catalyzed by tungsten carbide over activated carbon (W2 C/AC). The effects of botanical species and fractionation methods on lignin structure and the activity of W2 C/AC were studied in detail. Gas permeation chromatography (GPC), FTIR, elemental analysis, and 2 D HSQC NMR showed that all the extracted samples shared the basic skeleton of lignin, whereas the fractionation method significantly affected the structure. The organosolv process provided lignin with a structure more similar to the native lignin, which was labile to be depolymerized by W2 C/AC. Softwood lignins (i.e., spruce and pine) possessed higher molecular weights than hardwood lignins (i.e., poplar and basswood); whereas corn stalk lignin that has noncanonical subunits and exhibited the lowest molecular weight owing to its shorter growth period. β-O-4 bonds were the major linkages in all lignin samples, whereas softwood lignins contained more resistant linkages of β-5 and less β-β than corn stalk and hardwood lignins; as a result, lowest hydrocracking efficiency was obtained in softwood lignins, followed by corn stalk and hardwood lignins. 2 D HSQC NMR spectra of lignin and the liquid oil as well as the solid residue showed that W2 C/AC exhibited high activity not only in β-O-4 cleavage, but also in deconstruction of other ether linkages between aromatic units, so that high yield of liquid oil was obtained from lignin.
Related Papers
- → Strength of individual hardwood fibres and fibre to fibre joints(2016)40 cited
- → Characterisation of hardwood fibres used for wood fibre insulation boards (WFIB)(2021)16 cited
- → Gaseous decomposition products from wood degradation via thermogravimetric and fourier transform infrared analysis during thermal modification of beech and pine woods(2019)12 cited
- → Softening Characteristics of Wet Wood under Quasi Static Loading(2000)29 cited
- → Studies on Water Hydrolysis of Wood(1958)