In the course of the Ioncell-P process, hemicelluloses are extracted from wood pulps by a mild treatment with an ionic liquid (IL) water mixture, and the result is a high-purity dissolving pulp. The aim of the present work is to study the influence of pulp origin concerning different wood species and pulping processes on the resulting pulp purity and yield after extraction with IL/water, while the IL is 1-ethyl-3-methylimidazolium acetate ([emim][OAc]). The raw materials were chosen from commercial alkaline kraft and acid sulfite paper and dissolving pulps prepared from both hardwood (HW) and softwood (SW). The extraction was followed by a filtration step to separate the cellulose and the hemicellulose fractions. The hemicelluloses were precipitated from the IL/water filtrate. In general, the Ioncell-P process proved to be more selective toward the removal of xylan as compared to glucomannan indicating that HW pulps are easier to purify than those of SW. It was possible to reach high alpha pulp qualities by the extraction process.
Eucalyptus globulus wood originating from plantations in Uruguay was subjected to continuous batch kraft cooking (CBC), applying mill-like conditions. Pulp samples were taken at different stages of CBC cooking being representative for all three cooking phases. The residual lignin was successfully isolated in a reasonable yield by a new method, the dissolved wood lignin (DWL) protocol, which is based on the total dissolution of ball milled wood and pulp samples in dimethylsulfoxide and N-methylimidazole (DMSO/NMI) followed by precipitation in dioxane/ water to separate lignin and carbohydrate fractions. For comparative reasons, the lignin was also isolated by a conventional mild acidolysis (AL) method. Extensive structural lignin characterization using 1D and 2D NMR revealed that the DWL protocol allows the isolation of less altered lignin than the AL method. During bulk and residual delignification, the S/G ratio of lignin remaining in the fibers continuously decreased, while the content of b-O-4 units and phenolic OH groups remained almost unaffected, suggesting that the CBC process permits enhanced delignification efficiency and good bleachability.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.