Whether lignin benzyl hydroxyl shielding could promote its pyrolysis to phenolic compounds was investigated in this paper. Lignin benzyl hydroxyl was first preoxidized by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and stabilized by propionaldehyde respectively, then pyrolysis was conducted with milled wood lignin as a control. Organic stable radicals in pyrolytic chars were further detected to reveal lignin pyrolysis chemistry. Results showed that benzyl hydroxyl shielding process weakened lignin thermal stability, and decreased liquid yields regardless of the frequency of lignin β-O-4 linkages. In addition, char yield grew after benzyl hydroxyl shielding. Radical concentration was inversely proportional to β-O-4 content which indicated the non-negligible impact of shielded benzyl hydroxyl on lignin pyrolysis. Furthermore, gases from propionaldehyde stabilized lignin quenched its radicals. This work confirmed that lignin β-O-4 linkages and shielded benzyl hydroxyl both played the great role in radical-mediated pyrolysis, but the enhancement of liquid products could not be achieved via benzyl hydroxyl shielding.
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http://dx.doi.org/10.1016/j.biortech.2021.125944 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
University of Toronto, Dept. of Chemistry, 80 St. George Street, M5S 3H6, Toronto, CANADA.
A copper-catalyzed enantioselective synthesis of borylated 1-pyrrolines from γ,δ-unsaturated oxime esters is reported. Twenty-four novel 1-pyrroline derivatives are reported in yields ranging from 26% to 96% and enantioselectivities from 74.5:25.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Key Laboratory of Biomass Materials Science and Technology of Jilin Province, Beihua University, Binjiang East Road, Jilin City, Jilin Province, PR China; Collaborative Innovation Center of Forest Biomass Green Manufacturing of Jilin Province, Beihua University, Binjiang East Road, Jilin City, Jilin Province, PR China; Key Laboratory of Wooden Materials Science and Engineering of Jilin Province, Beihua University, Binjiang East Road, Jilin City, Jilin Province, PR China. Electronic address:
Lignin, as the largest renewable aromatic resource, has significant opportunities for producing high-value products via catalytic depolymerization. However, its complex structure and stable chemical bonds present challenges to its transformation. This study explores the catalytic depolymerization of lignin to aromatic monomers by means of Dawson-type phosphomolybdovanadate polyoxometalates (POMs), understanding the underlying mechanisms.
View Article and Find Full Text PDFCurr Med Chem
January 2025
School of Pharmacy, North Sichuan Medical College, Nanchong, 637000, China.
Objectives: Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder, but no drugs can cure this disease. Chalcones possess good antioxidant activity, anti-neuroinflammatory activity, neuroprotective effects, inhibitory effects on Aβ aggregation, and Aβ disaggregation ability. Therefore, chalcones are ideal lead compounds, and the discovery of novel anti-AD agent-based chalcones is necessary.
View Article and Find Full Text PDFResearch (Wash D C)
January 2024
School of Resources and Environment, Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 611731, China.
Solar-driven CO photoreduction holds promise for sustainable fuel and chemical productions, but the complex proton-coupled multi-electron transfer processes and sluggish oxidation half-reaction kinetics substantially hinder its efficiency. Here, we devised a rational catalyst design to address these challenges by fabricating ferrocene carboxylic acid-functionalized CsSbBr nanocrystals (CSB-Fc NCs), which facilitate simultaneous benzyl alcohol oxidation and CO reduction reactions under visible-light irradiation. The synchronized proton-coupled electron transfer processes between the reduction and oxidation half-reactions on CSB-Fc NCs resulted in a 5-fold increase in the CO reduction rate (45.
View Article and Find Full Text PDFChemistry
December 2024
Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan.
Grafting carbon-based nanomaterials (CNMs) with polyglycerol (PG) improves their application potentials in biomedicine and electronics. Although "grafting from" method offers advantages over "grafting to" one in terms of operability and versatility, little is known about the reaction process of glycidol with the surface groups onto CNMs. By using graphene oxide (GO) as a multi-functional model material, we examined the reactivity of the surface groups on GO toward glycidol molecules via a set of model reactions.
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