Formation of lignin alkyl-O-alkyl ether structures 1,6-addition of aliphatic alcohols to β-O-4-aryl ether quinone methides.

Quinone methides (QMs) are formed as the intermediates during lignin biosynthesis and chemical transformation; the chemical structure of the resulting lignin can then be significantly modified the corresponding aromatization. Herein, the structure-reactivity relationship of β-O-4-aryl ether QMs (GS-QM, GG-QM and GH-QM, which are 3-monomethoxylated QMs carrying syringyl, guaiacyl and -hydroxyphenyl β-etherified aromatic rings, respectively) was investigated to clarify the formation of alkyl-O-alkyl ether structures in lignin. The structural features of these QMs were characterized by NMR spectroscopy, and their alcohol-addition experiment was well performed at 25 °C to generate alkyl-O-alkyl/β-O-4 products.

Exploring Alkyl-O-Alkyl Ether Structures in Softwood Milled Wood Lignins.

Recent studies have suggested that there are significant amounts of various alkyl ether (Alk-O-Alk; Alk = alkyl) moieties in a spruce native lignin preparation, milled wood lignin (SMWL). However, the comprehensive NMR assignment to these moieties has not been addressed yet. This study focused on investigating different types of Alk-O-Alk structures at the α- and γ-positions of the lignin side chain in an heteronuclear single-quantum coherence (HSQC) spectrum of SMWL using experimental NMR data of lignin and synthesized model compounds.

Stereo-Recognition of Hydrogen Bond and Its Implications for Lignin Biomimetic Synthesis.

The hydrogen bond (H-bond) is essential to stabilizing the three-dimensional biological structure such as protein, cellulose, and lignin, which are integral parts of animal and plant cells; thus, stereo-recognition of the H-bond is extremely attractive. Herein, a methodology combining the variable-temperature H NMR technique with the density functional theory was established to recognize the underlying H-bonding patterns in lignin diastereomers. This method successfully classified the intramolecular and intermolecular H-bonds with slope values varying between 50.

Structural Analysis of Lignin-Based Furan Resin.

The global "carbon emission peak" and "carbon neutrality" strategic goals promote us to replace current petroleum-based resin products with biomass-based resins. The use of technical lignins and hemicellulose-derived furfuryl alcohol in the production of biomass-based resins are among the most promising ways. Deep understanding of the resulting resin structure is a prerequisite for the optimization of biomass-based resins.

Transparent, smooth, and sustainable cellulose-derived conductive film applied for the flexible electronic device.

A high-performance flexible conductive substrate is one of the key components for developing promising wearable devices. Concerning this, a sustainable, flexible, transparent, and conductive cellulose/ZnO/AZO (CZA) film was developed in this study. The cellulose was used as the transparent substrate.

Effect of Tungsten Species on Selective Hydrogenolysis of Glycerol to 1,3-Propanediol.

Glycerol, as the major byproduct of biodiesel industry, is a cheap and green chemical feedstock. Following the expanded production of biodiesel, the oversupply of glycerol has led to increasing research of the catalytic conversion of glycerol. The selective hydrogenolysis of glycerol is an economical and sustainable way to produce 1,3-propanediol, which experiences a global growing demand, and valorize glycerol.

Stereoselective Formation of β-O-4 Structures Mimicking Softwood Lignin Biosynthesis: Effects of Solvent and the Structures of Quinone Methide Lignin Models.

p-Quinone methide (QM) is formed as an intermediate during lignin biosynthesis. The aromatization of the QM by the attack of a nucleophile at the α-position of its side chain generates a phenolic hydroxy group in a growing polymer and creates stereoisomeric forms in the side chain. A series of β-O-4-aryl ether QMs was reacted with water at 25 °C to replicate the formation of p-hydroxyphenyl (H) and guaiacyl (G) β-O-4 structures in plant cell walls.

Lignin-Biosynthetic Study: Reactivity of Quinone Methides in the Diastereopreferential Formation of p-Hydroxyphenyl- and Guaiacyl-Type β- O-4 Structures.

p-Quinone methides are involved in lignin biosynthesis as transient intermediates, and the aromatization step has a great impact on the chemical structure of the resulting lignin. A series of quinone methides (QMs) were synthesized and allowed to react with water in pH 3-7 buffers at 25 °C to mimic the formation of p-hydroxyphenyl- and guaiacyl-type (H- and G-type, respectively) β- O-4 structures in gymnosperm-plant cell walls. Water addition occurred in 3-methoxy-substituted QMs (G-type QMs) with half-lives of 1.

TEMPO-oxidized cellulose nanofibers (TOCNs) as a green reinforcement for waterborne polyurethane coating (WPU) on wood.

In this work, TEMPO-oxidized cellulose nanofibers (TOCNs) were investigated as a green additive to the waterborne polyurethane (WPU) based coating, for improving its mechanical properties. The structure, morphology, mechanical properties and performances of the WPU/TOCNs coating were determined. Results showed that TOCNs had good compatibility to the WPU coating, and significantly enhanced the mechanical properties of the coating.

Cationic amphiphilic microfibrillated cellulose (MFC) for potential use for bile acid sorption.

In this work, Micro-fibrillated Cellulose (MFC) was cationically modified by quaternary ammonium groups with different chemical structures aiming to improve the sorption capacity to bile acid. The in-vitro bile acid sorption was performed by investigating various factors, such as quaternary ammonium group content and length of its alkyl substituent of the modified cationic MFC (CMFC), ionic strength, initial concentration and hydrophobicity of bile acid. The results showed that the sorption behavior of the modified CMFC was strongly influenced by the quaternary ammonium group content and the lengths of its alkyl substituent, the sorption capacity for the modified CMFC with a C18 alkyl substituent, was approximately 50% of that of Cholestyramine.

Adsorption of polyethylene glycol (PEG) onto cellulose nano-crystals to improve its dispersity.

In this work, the adsorption of polyethylene glycol (PEG) onto cellulose nano-crystals (CNC) was investigated for preparing re-dispersible dried CNC. Results showed that the re-dispersity of CNC in water can be significantly enhanced using a PEG1000 dosage of 5wt% (based on the dry weight of CNC). The elemental analysis confirmed the adsorption of PEG onto the CNC surface.