Journal of Wood Chemistry and Technology 

About: Journal of Wood Chemistry and Technology is an academic journal published by Marcel Dekker. The journal publishes majorly in the area(s): Lignin & Pulp (paper). It has an ISSN identifier of 0277-3813. Over the lifetime, 1211 publications have been published receiving 25141 citations.

Ionic Liquid as a Green Solvent for Lignin

Abstract: This study examined the application of select ionic liquids (ILs) as aprotic green solvents for lignin. Dissolution experiments were carried out employing lignin isolated from pine kraft pulp. Up to 20 wt% lignin could be dissolved in [hmim][CF3SO3], [mmim][MeSO4] and [bmim][MeSO4]. For the [bmim]+‐containing ionic liquids, the order of lignin solubility for varying anions was: [MeSO4]−>Cl−∼Br−⋙[PF6]−, indicating that the solubility of lignin was principally influenced by the nature of the anions. Ionic liquids containing large, non‐coordinating anions [PF4]− and [PF6]− were unsuitable as a solvent for lignin. 13C nuclear magnetic resonance (NMR) analyses of lignin and model compounds showed that 13C signals using ionic liquid as a solvent were shifted up‐field by δ 0.1 to 1.9 ppm in comparison to 13C NMR data acquired using dimethyl sulfoxide (DMSO) as the solvent.

pKa-Values of Guaiacyl and Syringyl Phenols Related to Lignin

Abstract: The literature relating to the pKa -values of guaiacyl- and syringyl-derived phenols has been thoroughly surveyed and summarized. In addition, the pKa -values of a number of guaiacyl, syringyl and other phenols related to lignin have been determined using a spectrophotometric method combined with multivariate evaluation. Differences and similarities between the acidities of a number of substances are extensively discussed. The pKa -value strongly affects the delignification during pulping, bleaching and leaching of lignin during pulp washing.

Quantitative phosphorus-31 NMR analysis of lignins, a new tool for the lignin chemist

Abstract: A novel quantitative method has been developed for the determination of the various types of hydroxyl groups present in lignins. The syringyl, guaiacyl and p-hydroxyphenyl free phenolic groups, as well as the primary, and the secondary hydroxyl groups (belonging to individual erythro and threo forms of the aryl-glycerol β-O-4 ether strctures) can be quantitatively determined from a 31P NMR experiment. This is made possible by phosphitylating lignins with 1,3,2 dioxaphospholanyl chloride, followed by 31P NMR spectroscopy, in the presence of a relaxation reagent (chromium acetylacetonate) and an internal standard. The various aspects leading to the development of this technique are discussed together with relevant statistical information pertaining to the reproducibility and quantitative validity of the method. This simple and novel form of spectroscopy may become a valuable resource to the lignin chemist, because it can supply detailed quantitative information about the structure of a soluble lign...

Thermal Modifications in Softwood Studied by FT‐IR and UV Resonance Raman Spectroscopies

Abstract: Scots pine planks were heat‐treated under steam in a temperature range of 100–240°C at every 20°C. Changes in chemical structure of the wood samples were examined with UV resonance Raman (UVRR) and Fourier transform infrared (FT‐IR) spectroscopies. Prior to the FT‐IR and UVRR analysis, the heartwood part of wood samples were ground and extracted with acetone. Both the extracts and the extracted samples were analyzed. In addition, Klason lignin contents of the samples were determined. The FT‐IR and UVRR spectroscopy were powerful techniques to monitor chemical changes in the heat‐treated wood samples. Results confirmed most of what determined previously by other research groups using different techniques. The UVRR and FT‐IR spectra of acetone extracts showed that lignin became partly acetone soluble after a heat treatment of 180°C or greater. Increased levels of free phenolic hydroxyl groups were detected in lignin, probably due to cleavages of β‐O‐aryl ether interunit linkages. The amount of extr...

A Rapid Modified Method for Compositional Carbohydrate Analysis of Lignocellulosics by High pH Anion-Exchange Chromatography with Pulsed Amperometric Detection (HPAEC/PAD)

Abstract: During the last decade, high pH anion exchange chromatography with pulsed amperometric detection (HPAEC/PAC) has gained increasing acceptance as the method of choice for analysis of neutral sugars commonly occurring in woods, pulps, and other lignocellulosics. This paper describes modified chromatographic conditions and discusses other critical factors that improve the precision and efficiency of this application. The method involves a controlled loading of acetate onto the column prior to equilibration with water and injection of sample. In-line solid-phase extraction is used to remove hydrophobic substances that have the potential to foul the analytical column. Critical operational parameters for the successful application of the method include a metal-free flowpath and a consistent application of anions with sample. Resolution of rhamnose is achieved while maintaining the resolution of xylose and mannose. Simplified sample pretreatment allows a ca. five-fold increase in sample through-put comp...