Lignin and Lignans as Renewable Raw Materials

Calvo‐Flores, Francisco G.; Dobado, José A.; Isac‐García, Joaquín; Martín‐Martínez, Francisco J.

doi:10.1002/9781118682784

Cited by 173 publications

(127 citation statements)

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“…1). These units are linked together randomly by different types of ether/aryl ether (C-O) and carbon-carbon (C-C) bonds [7,8], where the aryl ether linkages are spotted to be more easily cleaved [9] in comparison to the stable C-C linkages that are considered to be much more resistant towards chemical depolymerisation.…”

Section: Introductionmentioning

confidence: 99%

Continuous catalytic depolymerisation and conversion of industrial kraft lignin into low-molecular-weight aromatics

Abdelaziz

Tunå

et al. 2017

Biomass Conv. Bioref.

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Base-catalysed depolymerisation of lignin using sodium hydroxide has been shown to be an effective approach towards exploiting industrial (technical) lignins within the pulp and paper industry. In the present work, a pine kraft lignin (Indulin AT) which is precipitated from black liquor of linerboard-grade pulp was depolymerised via base catalysis to produce lowmolecular-mass aromatics without any organic solvent/capping agent in a continuous-flow reactor setup for the first time. The catalytic conversion of lignin was performed/screened at temperatures varying from 170 to 250°C, using NaOH/lignin weight ratio ≈ 1 with 5 wt% lignin solids loadings for residence times of 1, 2 and 4 min, respectively, with comprehensive characterisation of substrate and produced reaction mixtures. The products were characterised using size exclusion chromatography (SEC), nuclear magnetic resonance spectroscopy (NMR) and supercritical fluid chromatography-diode array detector-tandem mass spectrometry (SFC-MS). The optimum operating conditions for such depolymerisation appeared to be at 240°C and 30 h −1 , yielding the highest concentration of low-molecular-weight phenolics below the coking point. It was also found that the depolymerised lignin products exhibited better chemical stability during long-term storage at lower temperatures (~4°C).

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Section: Introductionmentioning

confidence: 99%

Continuous catalytic depolymerisation and conversion of industrial kraft lignin into low-molecular-weight aromatics

Abdelaziz

Tunå

et al. 2017

Biomass Conv. Bioref.

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“…This process typically uses different sulphurous acid salts like sulphites and bisulphites, in which the lignin recovered contain about 4-8 % sulphur and are termed lignosulfonates, due to the sulfonate groups' presence in its structure [12]. Soda pulping is another existing pulping process, where biomass treatment made using an aqueous solution of NaOH or lime at temperatures of almost B160°C.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Characterisation of Technical Lignins for Their Potential Valorisation

Abdelaziz

Hulteberg

2016

Waste Biomass Valor

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Lignin, the second most abundant natural polymer, has emerged as a potential alternative material to petroleum-based chemicals and renewable resource for the production of diverse forms of aromatics, biofuels, and biobased materials. Thus, it is becoming important to understand its structure and properties to provide key features and insights for better/efficient lignin valorisation. In this work, the physicochemical characterisation of two types of industrial (technical) lignins, namely LignoBoost lignin and alkali-treated lignin was performed. Characterisation has been conducted using Brunauer-Emmett-Teller N 2 adsorption, particle size distribution, Fourier transform infrared spectroscopy, ultraviolet-visible absorption spectroscopy, gel permeation chromatography, and thermogravimetric analysis. It was found that the pretreatment severity considerably influenced the lignin composition and functional properties. The measured physicochemical properties helped in proposing potential valorisation routes for these lignins in the context of a biorefinery, focusing on their depolymerisation and subsequent biological conversion to value-added chemicals and fuels.

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“…Lignin consists of several aromatic sub-units: p-hydroxyphenyl type (H), guaiacyl type (G) and syringyl type (S) and they are the result of the polymerization of three types of phenylpropane units that are considered to be the primary building blocks of lignin and are called as monolignols [17]. The monolignols differs from each other in the number of methoxy groups attached to the aromatic ring (none, one or two methoxy groups in the p-coumaryl, coniferyl and synapyl alcohol respectively) (Fig.…”

Section: Biorefineries and Lignin Valorisationmentioning

confidence: 99%

“…In general, hardwood lignin contains mainly G and S units and traces of H units, whereas softwood lignin contains G units predominantly with very low H units, and in the case of grass based lignin nearly equal amounts of G and S units are found with very less H units. Compared to hardwood and softwood lignins, grass lignins contain more H units [7,17,20]. For any given lignin sample, the H:G:S ratio can be calculated using wet chemical methods such as acidolysis, nitrobenzene oxidation (NBO), permanganate oxidation, cupric oxide and thioacidolysis [21][22][23] or spectroscopic techniques such as FT-IR [24] or 2D-NMR [25,26].…”

Section: Biorefineries and Lignin Valorisationmentioning

confidence: 99%

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Review on Catalytic Cleavage of C–C Inter-unit Linkages in Lignin Model Compounds: Towards Lignin Depolymerisation

2018

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Lignin and Lignans as Renewable Raw Materials

Cited by 173 publications

References 0 publications

Continuous catalytic depolymerisation and conversion of industrial kraft lignin into low-molecular-weight aromatics

Continuous catalytic depolymerisation and conversion of industrial kraft lignin into low-molecular-weight aromatics

Physicochemical Characterisation of Technical Lignins for Their Potential Valorisation

Review on Catalytic Cleavage of C–C Inter-unit Linkages in Lignin Model Compounds: Towards Lignin Depolymerisation

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