Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI

Antonino, Leonardo Dalseno; Gouveia, Júlia Rocha; Sousa, Rogério Ramos de; Garcia, Guilherme Elias Saltarelli; Gobbo, Luara Carneiro; Tavares, Lara Basílio; Santos, Demétrio Jackson dos

doi:10.3390/molecules26082131

Cited by 46 publications

(34 citation statements)

References 49 publications

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“…The higher ratio of phenolic to aliphatic hydroxyl groups in the LHO-MD polyol (1.5:1) compared to those of the other lignin-derived polyols (0.9:1 to 1.2:1) may have contributed to the lower hydroxyl group reactivity of the LHO-MD polyol. Aliphatic hydroxyl groups, in general, have been shown to be more reactive toward isocyanate groups than phenolic groups. − …”

Section: Results and Discussionmentioning

confidence: 99%

Preparation of Mechanically Robust Bio-Based Polyurethane Foams Using Depolymerized Native Lignin

Quinsaat

Féghali

Pas

et al. 2021

ACS Appl. Polym. Mater.

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Native lignin, a major structural polymer in lignocellulosic biomass, offers unique advantages as a feedstock for high-performance biobased polymeric materials. In this work, depolymerized native lignin was utilized as a polyol in the synthesis of rigid bio-based polyurethane (PU) foams. Lignin in Pinus radiata wood was subjected to a pilot-scale hydrogenolysis process to obtain a depolymerized native lignin oil that was composed of monomers, dimers, and oligomers of predominant dihydroconiferyl alcohol and 4-propyl guaiacol. These lignin-derived polyols had low molecular weight, high hydroxyl group content, and good copolyol solubility, all of which were advantageous factors in preparing PU foams. The whole lignin oil, or fractions of the oil, was incorporated into PU foams by substituting sorbitol polyether polyol at 12.5−50 wt % to boost the bio-based content. Substituting with lignin-derived polyols led to foams with similar densities and thermal properties and substantially improved compression properties. The monomeric-/dimeric-rich fraction of the lignin oil, when incorporated at 33 or 50 wt % of the polyol, led to 100 and 61% improvements in compression modulus and strength in the resulting PU foams. The dimeric polyols in the lignin oil were principally responsible for enhancing the resistance of the foam to mechanical compression. These findings provide insights into how native lignin can be valorized via a lignin-first approach to produce rigid PU foam materials with an enhanced mechanical robustness and bio-based content.

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Section: Results and Discussionmentioning

confidence: 99%

Preparation of Mechanically Robust Bio-Based Polyurethane Foams Using Depolymerized Native Lignin

Quinsaat

Féghali

Pas

et al. 2021

ACS Appl. Polym. Mater.

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“…For example, the use of a rich aliphatic hydroxyl Biolignin TM , as WS Biolignin TM , could be a real advantage in polyurethanes synthesis. Indeed, the reactivity of aliphatic hydroxyl groups can be up to 1000 times greater than phenolic hydroxyl, in noncatalyzed reactions with isocyanates at room temperature, mainly due to steric hindrance effects (Antonino et al 2021) With an average of 0.44 mmol g -1 , the amount of carboxylic moieties in the studied Biolignins TM seemed to be higher than in other organosolv lignin references (milled wood lignins, cellulolytic enzymatic lignins, enzymatic mild acidolysis lignins) (Pu et al 2011).…”

Section: P Nmr Analysismentioning

confidence: 90%

Comparison of organic acid-based organosolv lignins extracted from the residues of five annual crops

Cachet

Benjelloun-Mlayah

2021

BioRes

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Organosolv lignins were extracted from corn stover, wheat, rice straw, reed straw, and sugarcane bagasse using a mixture of acetic and formic acids, at relatively low temperature and atmospheric pressure. Lignin content, residual carbohydrates, ash levels, proteins, and molecular weights were determined in each extracted lignin. The lignin content of all samples was relatively high, confirming the performance of the pretreatment process. The low molecular weights were in a narrow range, in accordance with the organosolv lignin molar masses. However, some differences between studied lignins were highlighted, in particular in rice straw lignin, which contained the highest silica, calcium, and nitrogen contents. Nuclear magnetic resonance spectroscopies (31P and semi-quantitative Heteronuclear Single Quantum Correlation) underlined the structural similarities and differences between these organosolv lignins. Corn stover and sugarcane bagasse lignins were rich in non-methoxylated (H-Unit) or mono-methoxylated (G-Unit) phenolic units, making them the best promising candidates for production of phenolic resins. Wheat straw lignin was richer in aliphatic OH than in phenolic OH. This is an advantage for use as polyol substitute in polyurethane synthesis. Reed straw lignin was less specific, with a balanced content of OH groups. However, it contained a high concentration of β-O-4 linkages, which is favorable for depolymerization.

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“…The FTIR spectra of kraft lignin is plotted in Figure 1c,d and compared to that of the Ni-lignin composites. A strong peak at 3368 cm −1 and two small peaks at 2937 and 2841 cm −1 are assigned to stretching vibrations of hydroxyl, methyl and methylene groups in lignin, respectively [19,20]. The IR peak at 1710 cm −1 is associate with carbonyl groups.…”

Section: Catalytic Carbonization Of Ni-lignin Composite To Few-layer Graphene Encapsulated Nickel Nanoparticles (Ni@g)mentioning

confidence: 99%

“…Peaks at 1597, 1511, and 1417 cm −1 are due to stretching vibrations of aromatic rings in lignin [13]. The stretch absorptions of C-C, C-O, and C=O are located at 1265 and 1215 cm −1 , respectively [16,19]. The IR band at 1078 cm −1 is associated with C-O deformation of secondary alcohol of the side chains [21].…”

Section: Catalytic Carbonization Of Ni-lignin Composite To Few-layer Graphene Encapsulated Nickel Nanoparticles (Ni@g)mentioning

confidence: 99%

Production of COx-Free Hydrogen and Few-Layer Graphene Nanoplatelets by Catalytic Decomposition of Methane over Ni-Lignin-Derived Nanoparticles

2022

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Nickel (Ni)-lignin nanocomposites were synthesized from nickel nitrate and kraft lignin then catalytically graphitized to few-layer graphene-encapsulated nickel nanoparticles (Ni@G). Ni@G nanoparticles were used for catalytic decomposition of methane (CDM) to produce COx-free hydrogen and graphene nanoplatelets. Ni@G showed high catalytic activity for methane decomposition at temperatures of 800 to 900 °C and exhibited long-term stability of 600 min time-on-stream (TOS) without apparent deactivation. The catalytic stability may be attributed to the nickel dispersion in the Ni@G sample. During the CDM reaction process, graphene shells over Ni@G nanoparticles were cracked and peeled off the nickel cores at high temperature. Both the exposed nickel nanoparticles and the cracked graphene shells may participate the CDM reaction, making Ni@G samples highly active for CDM reaction. The vacancy defects and edges in the cracked graphene shells serve as the active sites for methane decomposition. The edges are continuously regenerated by methane molecules through CDM reaction.

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Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI

Cited by 46 publications

References 49 publications

Preparation of Mechanically Robust Bio-Based Polyurethane Foams Using Depolymerized Native Lignin

Preparation of Mechanically Robust Bio-Based Polyurethane Foams Using Depolymerized Native Lignin

Comparison of organic acid-based organosolv lignins extracted from the residues of five annual crops

Production of COx-Free Hydrogen and Few-Layer Graphene Nanoplatelets by Catalytic Decomposition of Methane over Ni-Lignin-Derived Nanoparticles

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