One Step Liquefaction of Hardwood Lignin to Oligomers Soluble in Polymerizable Solvents

Today technical lignins produced from different industrial processes are underutilized because they possess recalcitrant C‒C bonds and reduced proportion of ether bonds, making it difficult to produce building block compounds in high yields. Current methods being developed to process technical lignin and improve its usefulness involve multiple steps and the use of toxic chemicals. We report an innovative cleave and couple one step catalytic process on eucalyptus lignin (EUL) to form unique aromatics oligomers with aliphatic side chains using KOH/HCOOH mixture with methanol as the solvent. Under optimum condition, 71 wt% of predominantly dimers and oligomers are formed which are readily soluble in polymerizable solvents such as methyl methacrylate. In this one pot process, the KOH not only acts as the catalyst but ensures complete solubilization of EUL, allowing easier cleavage of bonds to form phenolic monomers and quinone groups (which undergo ring opening) followed by repolymerization to form oligomers. The study has opened pathways towards sustainable catalytic conversion of technical lignin to reactive macromolecular building blocks to produce soft nanomaterials

Catalytic Conversion of Organosolv Lignins to Phenolic Monomers in Different Organic Solvents and Effect of Operating Conditions on Yield with Methyl Isobutyl Ketone

9 páginas.-- 8 figuras.-- 2 tablas.-- 35 referencias.-- The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acssuschemeng.7b02721Catalytic depolymerization of organosolv lignin to phenolic monomers with zeolites was investigated under various operating conditions. H-USY (Si/Al molar ratio = 5) outperformed H-USY with Si/Al ratios of 50 and 250, H-BEA, H-ZSM5, and fumed SiO2 to produce the highest phenolic monomer yield from a commercial organosolv lignin in methanol at 300 °C for 1 h. It was then further investigated in the presence of acetone, ethyl acetate, methanol, and methyl isobutyl ketone (MIBK) on the depolymerization of organosolv bagasse lignin (BGL). The total highest phenolic monomer yield of 10.6 wt % was achieved with MIBK at 350 °C for 1 h with a catalyst loading of 10 wt %. A final total phenolic monomer yield of 19.4 wt % was obtained with an initial H2 pressure of 2 MPa under similar processing conditions. The main phenolic monomers obtained are guaiacol (7.9 wt %), 4-ethylphenol (6.0 wt %), and phenol (3.4 wt %). The solvent properties were used to account for the differences in phenolic monomer yields obtained with different organic solvents.The authors express their sincere appreciation to the Joint raduate School of Energy and Environment (JGSEE), Petchra Pra Jom Klao Doctoral Scholarship, King Mongkut’s University of Technology Thonburi (KMUTT), Thailand Research Fund (RTA5980006), and the Queensland University of Technology (QUT), Australia, for financing this project. The authors thank Dr. Jorge Rencoret and Dr. Ana Gutierrez, who were partly funded by the Spanish projects AGL2014-53730-R and CTQ2014-60764-JIN (cofinanced by FEDER funds), for PyGC/MS analysis of the lignins.Peer reviewe

Lignin Nanoparticles for Enhancing Physicochemical and Antimicrobial Properties of Polybutylene Succinate/Thymol Composite Film for Active Packaging

The natural abundance, polymer stability, biodegradability, and natural antimicrobial properties of lignin open a wide range of potential applications aiming for sustainability. In this work, the effects of 1% (w/w) softwood kraft lignin nanoparticles (SLNPs) on the physicochemical properties of polybutylene succinate (PBS) composite films were investigated. Incorporation of SLNPs into neat PBS enhanced Td from 354.1 °C to 364.7 °C, determined through TGA, whereas Tg increased from −39.1 °C to −35.7 °C while no significant change was observed in Tm and crystallinity, analyzed through DSC. The tensile strength of neat PBS increased, to 35.6 MPa, when SLNPs were added to it. Oxygen and water vapor permeabilities of PBS with SLNPs decreased equating to enhanced barrier properties. The good interactions among SLNPs, thymol, and PBS matrix, and the high homogeneity of the resultant PBS composite films, were determined through FTIR and FE-SEM analyses. This work revealed that, among the PBS composite films tested, PBS + 1% SLNPs + 10% thymol showed the strongest microbial growth inhibition against Colletotrichum gloeosporioides and Lasiodiplodia theobromae, both in vitro, through a diffusion method assay, and in actual testing on active packaging of mango fruit (cultivar “Nam Dok Mai Si Thong”). SLNPs could be an attractive replacement for synthetic substances for enhancing polymer properties without compromising the biodegradability of the resultant material, and for providing antimicrobial functions for active packaging applications

Phase speciation and surface analysis of copper phosphate on high surface area silica support by in situ XAS/XRD and DFT: Assessment for guaiacol hydrodeoxygenation

International audienc

Corn stover-derived biochar supporting dual functional catalyst for direct sorbitol production from cellulosic materials

Sorbitol is one of the top twelve platform chemicals and is industrially produced via glucose hydrogenation reaction. Direct sorbitol production from cellulosic material using a low-cost catalyst is a current challenge. In this study, corn stover-derived biochar supporting dual functional catalyst (Ru/S-CCS) was prepared and extensively characterized. The Ru/S-CCS catalyst was used for direct sorbitol production from microcrystalline cellulose at various reaction temperatures (180–220 °C), times (3–18 h), H2 pressures (1–5 MPa), and Ru contents (1–5 %). The maximum sorbitol yield (66.3 wt%) and selectivity (66.1 %) were achieved at 220 °C for 6 h under 5 MPa H2 with 5 % Ru. Various catalyst characterization techniques revealed that the acidic characteristics and metal hydrogenation sites of the Ru/S-CCS played a vital role in direct sorbitol production from cellulose. The sorbitol yield and selectivity could be enhanced by the vigorous interactive effect of sulfonic groups and Ru metal sites. The recycling performance of the Ru/S-CCS catalyst was explored under the optimal reaction conditions. Moreover, sorbitol production from glucose, raw CS, and pretreated CS was further investigated. Overall, the results of this study show that the CS biochar used in Ru/S-CCS preparation can be a competitive material for the catalyst preparation in sorbitol production, which may subsequently be used for designing large-scale sugar alcohol production