Chemical characterization of the lignins of corn and soybean agricultural residues

Saliba, Eloísa de Oliveira Simões; Rodriguez, N. M.; Piló‐Veloso, Dorila; Morais, Sérgio Antônio Lemos de

doi:10.1590/s0102-09352002000100007

Cited by 9 publications

(7 citation statements)

References 7 publications

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“…34,60 Based on these results, the general (monomer) molecular formulas of lignins were determined and are tabulated in Table 1. 7,61,62 Since lignin is an organic molecule, it is expected that up on thermal degradation at high temperatures, it will completely disintegrate into CO, CO 2 or CH 4 . 7,61,62 Since lignin is an organic molecule, it is expected that up on thermal degradation at high temperatures, it will completely disintegrate into CO, CO 2 or CH 4 .…”

Section: Characterization Of Ligninmentioning

confidence: 99%

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Lignin Depolymerization into Aromatic Monomers over Solid Acid Catalysts

2014

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It is imperative to develop an efficient and environmentally benign pathway to valorize profusely available lignin, a component of non-edible lignocellulosic materials into value-added aromatic monomers, which can be used as fuel additives and platform chemicals. To convert lignin, earlier studies used mineral bases (NaOH, CsOH) or supported metal catalysts (Pt, Ru, Pd, Ni on C, SiO 2 , Al 2 O 3 etc.) under hydrogen atmosphere but these methods face several drawbacks such as corrosion, difficulty in catalyst recovery, sintering of metals, loss of activity etc. Here we show that under inert atmosphere various solid acid catalysts can efficiently convert six different types of lignins in to value-added aromatic monomers. Particularly, SiO 2 -Al 2 O 3 catalyst gave exceptionally high yields of ca. 60 % for organic solvent soluble extracted products with 95±10 % mass balance in the depolymerization of dealkaline lignin, bagasse lignin, ORG and EORG lignins at 250 o C within 30 min. GC, GC-MS, HPLC, LC-MS, GPC analysis of organic solvent soluble extracted products confirmed the formation of aromatic monomers with ca. 90 % selectivity. In the products, confirmation of retention of aromatic nature as present in lignin and appearance of several functional groups is done by FT-IR, 1 H and 13 C NMR studies. Further, isolation of major products by column chromatography was carried out to obtain aromatic monomers in pure form and their further characterization by NMR is presented. Detailed characterization of six different types of lignins obtained from various sources helped in substantiating the catalytic results obtained in these reactions. Meticulous study on fresh and spent catalysts revealed that the amorphous catalysts are preferred to obtain reproducible catalytic results. . Materials.Dealkaline lignin (TCI Chemicals, product no. L0045), Alkali lignin (Aldrich, product no. 370959), Organosolv lignin (Aldrich, product no. 371017) were purchased and used without any pre-treatment. ORG and EORG lignins are obtained from local industries. Bagasse lignin was isolated in the laboratory by organosolv method. Zeolites, H-USY (Si/Al=15), H-ZSM-5 (Si/Al= 11.5), H-MOR (Si/Al=10), H-BEA (Si/Al=19) were obtained from Zeolyst International. Prior to use, zeolites were calcined at 550 °C for 16 h in air flow. SiO 2 -Al 2 O 3 (Aldrich), K10 clay and Al pillared clay (Aldrich), niobium pentoxide (Spectrochem) were also purchased. Various aromatic monomers were purchased from Aldrich, Alfa Aesar, TCI chemicals and used as received. Solvents like methanol (99.9 %, LOBA), ethanol (99.7 %, LOBA), tetrahydrofuran (99.8 %, LOBA), ethyl acetate (99.9 %, LOBA), chloroform (99.8 %, LOBA), diethyl ether (99.5 %, LOBA), hexane (99 %, LOBA) and dichloro methane (99.8 %, LOBA) were purchased and used as received. NaCl (Merck), H 2 SO 4 (98.5-

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Section: Characterization Of Ligninmentioning

confidence: 99%

“…[61][62][63] We have attempted to do the TPD study with isopropyl amine (IPA) as a probe molecule. have been developed for the characterization of acidity of solid acid catalysts.…”

Section: Characterization Of Solid Acid Catalystsmentioning

confidence: 99%

Lignin Depolymerization into Aromatic Monomers over Solid Acid Catalysts

2014

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“…[12]. The data of nitrobenzene oxidation was vanillin (V) = 49.8 mg%, Syrigaldheide (S) = 50.2 mg% from LIPE® and V = 50.0 mg% and S = 49.18 mg% from feces lignin.…”

Section: Resultsmentioning

confidence: 96%

Characterization of Lignin before and after Exposure to the Gastrointestinal Tract of Ruminants

Saliba¹,

Piló‐Veloso²,

Rodríguez³

et al. 2016

AJAC

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The aim of this study was to investigate the structural composition of lignin (LIPE®) extracted from Eucalyptus grandis, before and after exposure to the gastrointestinal tract of ruminants. For this study lignin was isolated, purified and characterized using 1 H and 13 C Nuclear Magnetic Resonance Spectroscopy, nitrobenzene oxidation, functional groups analysis and gas chromatography with mass spectroscopy. To have a better understanding of lignin morphology and of its ultra structure, electron microscopy in wood cell wall was utilized. The lignin fecal samples showed similar 1 H NMR spectrums and nitrobenzene oxidation products compared with LIPE®. The result of the microanalysis of LIPE® was similar to data shown in the literature. The ultra structure of lignin was similar to that of Bamboo (hard wood). The lignin isolated from feces of sheep was identical to the original LIPE®, which means that this product can be used as an external marker in protein digestibility in sheep.

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“…Until now, its chemical structure is not completely clarified yet. In such situation, one trial to estimate its molecular elements ratio was done by Morais et al [19] and it is estimated as (C 9 H 7.9 O 2.73 (OCH 3 ) 1.5 ) l . Wood is compound of these three constitutions.…”

Section: Chemical Formulae and Reactionmentioning

confidence: 99%

Numerical Analysis on Wood Pyrolysis in Pre-Vacuum Chamber

Homma¹,

Homma²,

Idris³

2014

JSBS

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In the previous experimental work, a new technology system for wood pyrolysis was developed to aim at mitigating climate change, global warming, and energy crisis as well as enhancing low electrification in rural areas in developing countries. The new technology system equipped with a pre-vacuum chamber requires low cost and less maintenance. However, large wood pyrolysis in the pre-vacuum chamber is rather complicated. To obtain a good understanding of the previous experimental results, a numerical analysis taking account of heat-mass transfer and chemical reaction is carried out. Two-step general reaction model is proposed for the numerical analysis. The first stage is volatile and char formation from the wood pieces and the second state is decomposition of the volatile to five species including vapor of tar. In this analysis, chemical formulae of the volatile and the tar are successfully identified hypothetically. The results obtained by this numerical analysis can explain the experimental results reasonably and provide useful information about time evolution of volatile formation, temperature change in pre-vacuum chamber with time, and species mole concentration decomposed from the volatile.

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Chemical characterization of the lignins of corn and soybean agricultural residues

Cited by 9 publications

References 7 publications

Lignin Depolymerization into Aromatic Monomers over Solid Acid Catalysts

Lignin Depolymerization into Aromatic Monomers over Solid Acid Catalysts

Characterization of Lignin before and after Exposure to the Gastrointestinal Tract of Ruminants

Numerical Analysis on Wood Pyrolysis in Pre-Vacuum Chamber

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