نتایج جستجو برای: lignins
تعداد نتایج: 729 فیلتر نتایج به سال:
Due to the enormous abundance of lignin and its unique aromatic nature, lignin has great potential for the production of industrially useful fuels, chemicals, and materials. However, the rigid and compact structure of the plant cell walls significantly blocks the separation of lignin. In this study, wheat straw was hydrothermally pretreated at different temperatures (120-200 °C) followed by pos...
We have studied the structural modifications of lignins from sisal and flax during their soda-anthraquinone (AQ) pulping and subsequent totally chlorine-free (TCF) and elementary chlorine-free (ECF) bleaching. For this purpose, residual lignins were isolated from pulps, analyzed by Py-GC/MS, 2D-NMR, and GPC, and their characteristics were compared to the “milled-wood” lignin of the raw material...
Lignins are aromatic polymers that are present mainly in secondarily thickened plant cell walls. Several decades of research have elucidated the main biosynthetic routes toward the monolignols and demonstrated that lignin amounts can be engineered and that plants can cope with large shifts in p-hydroxyphenyl/guaiacyl/syringyl (H/G/S) lignin compositional ratios. It has also become clear that li...
A semiquantitative analytical method has been developed for the determination of the total quinonoid content (o-benzoquinones and p-benzoquinones) of soluble lignins. The method is based on detailed measurements and observations made with model oand p-quinones, which in dry organic solvents were shown to form adducts with trimethyl phosphite in quantitative yield. These adducts gave 31P NMR sig...
Protic ionic liquids (PILs) have been established as effective solvents for the selective extraction and recovery of lignin from lignocellulosic biomass. In this study, we utilize extensive analytical techniques to characterize the PIL-extracted lignins to (1) expand on the physical/chemical structure, and to (2) develop a better understanding of the mechanism behind the lignin dissolution proc...
A series of phosphided NiMo catalysts on different supports was tested for the catalytic hydrotreatment lignins to biobased building blocks like alkylphenols.
Variants of modification technical lignins for the production drilling reagents in demand various technological operations during construction wells are considered
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