2 research outputs found
Composition Analysis of Organosolv Lignin and Its Catalytic Solvolysis in Supercritical Alcohol
The structural analysis and catalytic
solvolysis performance of
organosolv lignins from Chinese fir (softwood) and maple (hardwood)
were investigated. Fourier transformation infrared spectroscopy (FTIR)
analysis revealed that both Chinese fir lignin and maple lignin exhibited
a guaiacyl–syringyl structure. Chinese fir lignin consisted
of guaiacyl units principally, while maple lignin consisted of syringyl
units mainly. The ratios of guaiacol-/syringol-type products obtained
by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS)
were 2.53 for Chinese fir lignin and 0.29 for maple lignin, respectively.
The catalytic solvolysis degradation was studied in supercritical
ethanol/1-butanol at 300 °C with Ru/C to produce phenolic compounds.
The degradation products of Chinese fir lignin were mainly guaiacol-type
products, while the products of maple lignin consisted of both guaiacol-
and syringol-type compounds. The yields of most products of maple
lignin were much higher than those of Chinese fir lignin. The results
show that the organosolv maple lignin is a potential feedstock for
producing phenolic products through the solvolytic method
Hydrogen Transfer Hydrogenolysis of Organosolv Chinese Fir Lignin to Monophenols over NiZnAlO<sub><i>x</i></sub> Catalyst
Lignin
is the only naturally renewable aromatized polymer
consisting
of several phenyl propane structures linked by C–O and C–C
bonds, so lignin can be depolymerized into value-added chemicals or
liquid fuels. In this study, M5Zn5AlOx (M = Co, Ni and Cu) catalysts were obtained by the
co-precipitation method and then were used in organosolv lignin depolymerization.
Among these catalysts, the Ni5Zn5AlOx catalyst possessed the largest surface area and
abundant surface oxygen vacancies as well as strong acidic sites on
the surface, giving the highest yield of monophenols (about 14.49
wt %). The effect of Ni/Zn ratios on the lignin depolymerization was
also investigated, and it was found that the surface area and the
proportion of surface oxygen vacancies and strong acidic sites of
the NiZnAlOx catalysts increased and then
decreased with the Ni/Zn ratios increasing. Similarly, the yield of
monomeric compounds increased and then decreased with the Ni/Zn ratios
increasing. The highest yield of monophenols was 17.18 wt % obtained
over the Ni3Zn7AlOx catalyst, a remarkable monomer yield from organosolv lignin. The
two-dimensional 1H-13C heteronuclear single-quantum
coherence nuclear magnetic resonance spectroscopy of bio-oil revealed
that the linkage bonds in lignin could be effectively broken over
the Ni3Zn7AlOx catalyst.
This study provided an effective route to obtain high-value chemicals
from organosolv lignin under nickel-based catalysts