Lignin and Lignans

Heitner, C.; Dimmel, Donald R.; Schmidt, John A.

doi:10.1201/ebk1574444865

Cited by 158 publications

(29 citation statements)

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“…NMR of the underivatized (i.e., un-acetylated) isolated lignin was made difficult due to the high levels of iron in this sample, as previously reported [65]; unfortunately, we were not able to sufficiently effect its removal by complexation with EDTA. Nevertheless, 13 C NMR (Fig. 1) readily revealed the presence of p-hydroxybenzoates, assumed at this point to be on lignins.…”

Section: Resultsmentioning

confidence: 92%

“…Distinguishing whether p-hydroxybenzoates are attached to S or G units requires long-range 1 H-13 C correlation experiments [13]. The heteronuclear multiple bond correlation Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Spectra have been run over many years on a variety of Bruker instruments, including DP 360 and Avance 400, 500 and 600 MHz instruments, using standard experiments and conditions [13]. The 3D total correlation spectroscopy-heteronuclear single-quantum coherence (TOCSY-HSQC) experiment was run as described previously [60,55].…”

Section: Nmr Of Ligninsmentioning

confidence: 99%

“…Beyond the monolignol biosynthetic pathway, various monolignol conjugates have also been shown to participate in lignification [12][13][14]. Acylated lignins of four types have been encountered in various plants to date.…”

Section: Introductionmentioning

confidence: 99%

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Naturally p-Hydroxybenzoylated Lignins in Palms

et al. 2015

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The industrial production of palm oil concurrently generates a substantial amount of empty fruit bunch (EFB) fibers that could be used as a feedstock in a lignocellulosebased biorefinery. Lignin byproducts generated by this process may offer opportunities for the isolation of value-added products, such as p-hydroxybenzoate (pBz), to help offset operating costs. Analysis of the EFB lignin by nuclear magnetic resonance (NMR) spectroscopy clearly revealed the presence of bound acetate and pBz, with saponification revealing that 1.1 wt% of the EFB was pBz; with a lignin content of 22.7 %, 4.8 % of the lignin is pBz that can be obtained as a pure component for use as a chemical feedstock. Analysis of EFB lignin by NMR and derivatization followed by reductive cleavage (DFRC) showed that pBz selectively

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Section: Resultsmentioning

confidence: 92%

“…Distinguishing whether p-hydroxybenzoates are attached to S or G units requires long-range 1 H-13 C correlation experiments [13]. The heteronuclear multiple bond correlation Fig.…”

Section: Resultsmentioning

confidence: 99%

Section: Nmr Of Ligninsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Naturally p-Hydroxybenzoylated Lignins in Palms

et al. 2015

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“…Lignin is a high potential feedstock for value-added chemicals and high quality biofuel because it is abundant, readily available, and renewable (Heitner et al 2010). The conversion of this unique and natural aromatic polymer has attracted increasing attention during the last few decades because of the increasingly serious depletion of fossil fuels and associated environmental problems, such as the greenhouse effect and acid rain.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal Depolymerization of Lignin: Understanding the Structural Evolution

Long¹,

Xu²,

Wang³

et al. 2014

BioResources

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The structural evolution of Panicum virgatum lignin during hydrothermal depolymerization was investigated. Product distribution from various temperatures was studied using gas chromatography-mass spectrometry (GC-MS) and gel permeation chromatography (GPC) analysis. The physical-chemical properties of initial lignin, tetrahydrofuran soluble fraction, and char were also comparatively characterized by elemental analysis, scanning electron microscopy (SEM), thermogravimetry (TG), and Fourier transform infrared (FT-IR) spectroscopy. Results showed that both the depolymerization and repolymerization were significantly temperature-dependent. The undesired char formation becomes obvious when the temperature is greater than 180 °C. Further investigation demonstrated that H lignin is the most accessible for hydrothermal depolymerization, whereas S lignin is the most recalcitrant. Moreover, under the thermal effect and the dissolution of the subcritical water, the basic structure of lignin was first collapsed and then further decomposed into low-molecular weight products by the fracture of ether bonds, accompanied by char formation after repolymerization and dehydration.

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