Identification and quantification of lignin monomers and oligomers from reductive catalytic fractionation of pine wood with GC × GC – FID/MS

Abstract

Thorough lignin characterization is vital to understand the physicochemical properties of lignin and to evaluate lignocellulose biorefinery processes. In this study, an in-depth characterization of lignin oil, obtained from reductive...

Highly efficient catalytic transfer hydrogenolysis for the conversion of Kraft lignin into bio-oil over heteropoly acids

“…These dimers and trimers are composed of different G units, mainly linked by C–C units, including β-5 (β-5 γ-OH, β-5 ethyl and β-5 propyl), β-1 (β-1 γ-OH, β-1 ethyl and β-1 propyl), β–β (β–β 2 × γ-OH and β–β), 5–5 and a small amount of β-O-4 and 4-O-5. 17,25 It has been reported 25 that the aliphatic end units in dimer and trimer molecules contain 4-propanol (4-P-γ-OH), 4-propyl, 4-ethyl, 4-(3-methoxy propyl), 4-methyl, 4-propenol alcohol and 4-(3-methoxy propyl-1-en-1-yl), verified by the high temperature GC × GC technique.…”

“…11 In general, apart from lignin monomers, depolymerized lignin oil still contains dimers and oligomers, and many molecules in these fractions have high boiling points. 25…”

“…11 In general, apart from lignin monomers, depolymerized lignin oil still contains dimers and oligomers, and many molecules in these fractions have high boiling points. 25 Thereafter, the more detailed changes in the molecular composition of KL before and after CTH were analyzed using FT-ICR MS with electrospray ionization (ESI) in negative ion mode. EKL has nearly 1275 distinct molecular weights.…”

Isolation and purification of 4-propylguaiacol and 4-propylsyringol by extraction and crystallization from the products of reductive catalytic fractionation processes

“…10,19 Extracting the lignin oil using alkanes can extract and separate monomers (including G-3 and S-3) from larger phenolic compounds. 19,31 Membrane separation is another method based on the mechanism in which the membrane allows smaller molecules to pass through while it blocks larger molecules. 32 Thus, extraction and membrane-based methods only afford a mixture of monomers with minor larger components, and cannot produce pure monomers.…”

Detailed insights into lignin stabilisation and carbohydrate chemical nature in the H-transfer RCF process: On the role of solvent fractionation in the structural profiling of lignin oil

“…Sels group made significant progress characterising lignin dimers and trimers, using ethyl acetate (EtOAc) and n-heptane to work up lignin oil from pine wood. [35,36] However, despite the reported use of solvent fractionation of lignin oil as a work-up method, solvent fractionation has not yet been developed as a method applied to the structural profiling of RCF lignin oligomers/polymers.…”