Low-field benchtop versus high-field NMR for routine 31P analysis of lignin, a comparative study

Gracia-Vitoria, Jaime; Rubens, Maarten; Féghali, Elias; Adriaensens, Peter; Vanbroekhoven, Karolien; Vendamme, Richard

doi:10.1016/j.indcrop.2021.114405

Cited by 17 publications

(16 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The hydroxyl content of the fractionated lignin was determined by 31 P NMR as described in the literature. 36,37,42,43 The relative polarities of the three solvents used for the fractionations range are as follows: polarity (EtOAc) < polarity (EMK) < polarity (MeOH). We can observe from Table 1 that both the extraction yields and the molecular weights decrease together with the solvent polarities.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The hydroxyl content of the different lignin fractions was determined by 31 P NMR spectroscopy as reported previously. 36,37 The spectra were recorded at room temperature on a Varian Inova 400 spectrometer using a 5 mm probe. The chemical shift scale (δ) in ppm was calibrated relative to the reaction product of water and the phosphorylating agent (132.2 ppm), and cyclohexanol was used as an internal standard.…”

Section: ■ Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stabilization of Hybrid Adhesives and Sealants by Thermodynamic Tuning of Molecularly Optimized Lignin Bio-Additives: Small Changes, Big Effects

et al. 2022

View full text Add to dashboard Cite

The use of lignin as a functional additive has long been a promising topic in both industry and academia, but the development of such systems is still limited by the considerable challenges posed by the incompatibility of lignin with common polymers. Herein, we designed modified silicone (MS) sealants with enhanced UV and thermal stability by incorporating molecularly engineered lignin bio-additives while establishing robust design principles to finely adjust the morphology of such blends by tailoring the molecular structures of lignin fractions. To that end, we first constructed a library of lignin fractions with various molecular weights (obtained by fractionating Kraft lignin and by using a lignin model compound) and with several chemical modifications (acetylation, butyrylation, and silylation). The lignin bio-additives were then melt-blended with MS polyethers. The experimental phase diagrams of the resulting blends were established and rationalized with a thermodynamic framework combining Hansen solubility parameters and Flory−Huggins theory, unraveling fascinating insights into the complex solubility behavior of lignin fractions and notably, for the first time, the subtle interplay between molecular weight (entropic effects) and chemical modifications (enthalpic effects). A molecularly optimized lignin additive was then selected to achieve full solubility while providing better thermal stability and UV-blocking properties to the resulting MS material. Overall, this article provides robust design principles for the elaboration of functional biomaterials with optimized morphologies based on rationally engineered lignin fractions.

show abstract

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Stabilization of Hybrid Adhesives and Sealants by Thermodynamic Tuning of Molecularly Optimized Lignin Bio-Additives: Small Changes, Big Effects

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The amount of aliphatic and phenolic OH groups in all the lignin fractions (before and after esterification) was quantified by 31 P-NMR (Spinsolve 80 MHz ULTRA, Magritek, Aachen, Germany) in CDCl 3 /pyridine after sample derivatization with the phosphorylating reagent TMDP, using NHND as a reactive internal standard, as previously described [ 23 ]. Data was processed using Mnova software (version 14.3.0, Mestrelab, Santiago de Compostela, Spain).…”

Section: Methodsmentioning

confidence: 99%

Selective Enzymatic Esterification of Lignin-Derived Phenolics for the Synthesis of Lipophilic Antioxidants

et al. 2023

View full text Add to dashboard Cite

Lignin is an abundant and renewable source of phenolic compounds that can be used as natural antioxidants to substitute synthetic, petroleum-based alternatives. The development of lignin depolymerization techniques has improved the accessibility of low-molecular-weight phenolic fractions with enhanced antioxidant activity compared to native lignin. The selective esterification of the aliphatic OH groups in these compounds is necessary in order to increase their compatibility with hydrophobic product matrixes, while preserving their antioxidant capacity. In the present work, lipase was chosen as a selective catalyst for the esterification of the monolignol dihydroconiferyl alcohol (DCA), in order to target the esterification of aliphatic OHs without modifying the aromatic groups. The reaction was studied under solvent-assisted and solvent-free conditions, using different fatty acids and substrate ratios. A product yield of 97% could be obtained after 24 h in a solvent-assisted reaction with 2 molar equivalents of fatty acid, or after 3 h in a solvent-free reaction with 10 molar equivalents of the fatty acid. The esterified monolignol showed relevant long-term radical scavenging activity, comparable to other commercial, petroleum-based antioxidants. Different lignin fractions were also used as substrates for enzymatic esterification with different fatty acids, resulting in esterification degrees of 20–58% (of the total aliphatic OH), depending on the specific combination of fatty acid–lignin fractions.

show abstract

“…Work on this topic was recently published by Gracia-Vitoria et al using an 80 MHz NMR spectrometer ( 31 P Larmor frequency = 32.4 MHz), highlighting the usefulness of benchtop NMR for the analysis of technical, depolymerized, and modified lignins. 23 While the authors describe a similar approach to the one presented in this work, the use of regular 1 H decoupling technique as opposed to an inverse-gated decoupling means that the obtained integration areas might not be quantitative, depending on the proximity of protons to the observed 31 P signals. 24 During an inverse-gated decoupling experiment, the nuclear Overhauser effect (NOE) is avoided and more accurate integration areas can be obtained.…”

Section: Introductionmentioning

confidence: 92%

Analysis of lignins using ³¹P benchtop NMR spectroscopy: quantitative assessment of substructures and comparison to high-field NMR

Araneda¹,

Burton

Paleologou

et al. 2022

Can. J. Chem.

View full text Add to dashboard Cite

Lignin is quickly emerging as a biomass-derived source for the production of some crucial organic chemistry building blocks, typically obtained from unsustainable and non-renewable petroleum feedstocks. As a complex polymer, lignin characterization is often challenging, due to its random structure and multitudes of different repeating substructures. Over the last 20 years, advances in our understanding and processing of lignin, as well as important work on its characterization using 31P NMR, have led to numerous publications highlighting the many potential uses for this material. With the emergence of high-resolution benchtop NMR instruments, these types of analyses can now be accessed by many laboratories and industries that have historically not been able to take advantage of NMR due to cost or size constraints. Herein, we demonstrate that benchtop NMR is a viable technique for the 31P NMR analysis of lignin and compare our results to those obtained on a traditional high-field instrument.

show abstract

Low-field benchtop versus high-field NMR for routine 31P analysis of lignin, a comparative study

Cited by 17 publications

References 40 publications

Stabilization of Hybrid Adhesives and Sealants by Thermodynamic Tuning of Molecularly Optimized Lignin Bio-Additives: Small Changes, Big Effects

Stabilization of Hybrid Adhesives and Sealants by Thermodynamic Tuning of Molecularly Optimized Lignin Bio-Additives: Small Changes, Big Effects

Selective Enzymatic Esterification of Lignin-Derived Phenolics for the Synthesis of Lipophilic Antioxidants

Analysis of lignins using ³¹P benchtop NMR spectroscopy: quantitative assessment of substructures and comparison to high-field NMR

Contact Info

Product

Resources

About

Low-field benchtop versus high-field NMR for routine 31P analysis of lignin, a comparative study

Cited by 17 publications

References 40 publications

Stabilization of Hybrid Adhesives and Sealants by Thermodynamic Tuning of Molecularly Optimized Lignin Bio-Additives: Small Changes, Big Effects

Stabilization of Hybrid Adhesives and Sealants by Thermodynamic Tuning of Molecularly Optimized Lignin Bio-Additives: Small Changes, Big Effects

Selective Enzymatic Esterification of Lignin-Derived Phenolics for the Synthesis of Lipophilic Antioxidants

Analysis of lignins using 31P benchtop NMR spectroscopy: quantitative assessment of substructures and comparison to high-field NMR

Contact Info

Product

Resources

About

Analysis of lignins using ³¹P benchtop NMR spectroscopy: quantitative assessment of substructures and comparison to high-field NMR