Aqueous Gel Permeation Chromatographic Methods for Technical Lignins

ABSTRACT:We studied the enhancement of lignin reactivity in an alkaline medium, using sodium hydroxide in a microreactor set. The chemical composition and structural characterization of the reacted lignosulfonate in terms of the phenolic hydroxyl groups, aromatic protons, weight-average molecular weight, number-average molecular weight, and lignosulfonate content of all reacted lignins were determined. The techniques that we used were ultraviolet spectroscopy, proton nuclear magnetic resonance spectroscopy, and aqueous gel permeation chromatography. Using response surface methodology, we studied how the temperature and reaction time affected the lignin properties. The reaction conditions were temperatures between 116 and 1808C and reaction times between 18 and 103 min. Modeled response surfaces showed that the two factors affected the lignin properties within the studied ranges. The phenolic hydroxyl groups, aromatic protons, and lignosulfonate content increased when the severity of the treatment increased. The weight-average molecular weight, number-average molecular weight, and solid yield (%) decreased when the severity of the treatment increased. The reactivity of the modified lignins was studied with a formaldehyde reactivity test: more severe conditions produced greater improvements in the formaldehyde reactivity.

show abstract

“…The range of molecular weights measured (4634-6917 g/mol) was lower than others reported in the literature for lignosulfonates. 26,27 M n…”

Section: Wmentioning

confidence: 99%

Structural modification and characterization of lignosulfonate by a reaction in an alkaline medium for its incorporation into phenolic resins

Mansouri

Farriol

Salvadó

2006

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…Besides, the GPC technique has proven earlier to be reliable in determining the molecular weight distribution of kraft lignin and alkali lignin [26]. The GPC analysis using PEG standards and NaOH as eluent was performed to follow the molecular weight distribution of LignoBoost lignin and alkali-treated lignin samples.…”

Section: Molecular Weightmentioning

confidence: 99%

Physicochemical Characterisation of Technical Lignins for Their Potential Valorisation

Abdelaziz

Hulteberg

2016

Waste Biomass Valor

View full text Add to dashboard Cite

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.

show abstract

“…Columns at 30 C were eluted at 0.5 mL min À1 with aqueous 0.1 M NaNO 3 /0.01 M NaOH. 19 Samples were dissolved in 0.01 M NaOH (aq), passed through 0.45 mm PTFE lters and sample aliquots of 50 mL were injected using a type 1260 ALS autosampler (Agilent, Germany). Column effluent was monitored with an Agilent 1260 VWD detector set at 280 nm and a refractive index (RI) detector connected in series.…”

mentioning

confidence: 99%

Autohydrolysis and aqueous ammonia extraction of wheat straw: effect of treatment severity on yield and structure of hemicellulose and lignin

et al. 2014

View full text Add to dashboard Cite

show abstract

Aqueous Gel Permeation Chromatographic Methods for Technical Lignins

Cited by 49 publications

References 5 publications

Structural modification and characterization of lignosulfonate by a reaction in an alkaline medium for its incorporation into phenolic resins

Structural modification and characterization of lignosulfonate by a reaction in an alkaline medium for its incorporation into phenolic resins

Physicochemical Characterisation of Technical Lignins for Their Potential Valorisation

Autohydrolysis and aqueous ammonia extraction of wheat straw: effect of treatment severity on yield and structure of hemicellulose and lignin

Contact Info

Product

Resources

About