Lignins isolated from pine milled wood, milled wood lignin (MWL), and residual enzyme lignin (REL) were compared using modified thioacidolysis, modified DFRC, gel permeation chromatography (GPC), two-dimensional Heteronuclear Multiple Quantum Coherence (HMQC) NMR, and quantitative C NMR. Dissolution of the lignin for solution-state NMR was accomplished by utilizing the recently reported DMSO/N-...

residual lignin of wood after mwl isolation was dissolved with 1-butyl-3-methylimidazolium chloride ionic liquid. chemical structure of isolated mwl from poplar wood (popolus deltiodes) and dissolved residual lignin were characterized with gas chromatography and 1d, 2d nmr techniques. analytical results showed that  popolus deltoides wood has more 4-(3-hydroxy-1-propenyl)-2-methoxy phenol units...

To define the abundance and comprehend the reactivity of dibenzodioxocins in lignin, model compound studies, specific degradation experiments on milled wood lignin, and molecular modeling calculations have been performed. Quantitative (31)P NMR measurements of the increase of biphenolic hydroxyl groups formed after a series of alkaline degradations in the presence of hydrosulfide anions (kraft ...

The recently developed protocol for isolating enzymatic mild acidolysis lignins (EMAL) coupled with the novel combination of derivatization followed by reductive cleavage (DFRC) and quantitative (31)P NMR spectroscopy were used to better understand the lignin isolation process from wood. The EMAL protocol is shown to offer access at lignin samples that are more representative of the overall lig...

A simplified procedure for the identification and measurement of single-ring aromatic products of lignin acidolysis is described. The procedure employed a 6-h hydrolysis of spruce milled wood lignin in acidic dioxane at 87 degrees C, followed by a series of organic extractions to recover acidolysis products which were quantified by gas chromatography of trimethylsilyl derivatives. Complex gel p...

Vessels White oak cell types, fibers, rays, and vessels, were isolated from high-yield chemimechanical, neutral Rays sulphite semichemical (NSSC), and kraft pulps. Milled wood lignins (MWL) from NSSC fiber and ray Fibers cell fractions analyzed by ultraviolet and infrared spectroscopy were found to have similar syringyl/ Cell wall guaiacyl ratios. Methoxyl analyses of MWL’s were also similar an...

Eleven gram-negative aerobic bacteria (Pseudomonadaceae and Neisseriaceae) out of 122 soil isolates were selected for their ability to assimilate poplar dioxane lignin without a cosubstrate. Dioxane lignin and milled wood lignin degradation rates ranged between 20 and 40% of initial content after 7 days in mineral medium, as determined by a loss of absorbance at 280 nm; 10 strains could degrade...

Pyrolysis-gas chromatography-mass spectrometry was performed on milled wood lignins (MWLs) and wood samples. Among the major pyrolysis products identified from loblolly pine lignin were guaiacol, 4-methylguaiacol, 4-vinylguaiacol, vanillin, coniferal­ dehyde, and coniferyl alcohol. White oak lignin pyrolysis products also included guaiacol, 4-methylguaiacol, and vanillin and addi­ tionally 2,6-...

Advanced solid-state NMR was employed to investigate differences in chemical structure and heterogeneity between milled wood lignin (MWL) and residual enzyme lignin (REL). Wiley and conventional milled woods were also studied. The advanced NMR techniques included 13C quantitative direct polarization, various spectral-editing techniques, and two-dimensional 1H-13C heteronuclear correlation NMR w...

The process of cooking with solid alkali is a novel and efficient technology. In the present work, milled wood lignin (MWL) and water-soluble milled wood lignin (WMWL) were used as the raw materials to research their properties when cooking with MgO and active oxygen. Before and after cooking, the lignin content of the samples was estimated using attenuated total reflectance-Fourier transform i...