Upgrading of commercial pulps to high-purity dissolving pulps by an ionic liquid-based extraction method

Abstract

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.

History repeats itself again: Will the mistakes of the past for ILs be repeated for DESs? From being considered ionic liquids to becoming their alternative: the unbalanced turn of deep eutectic solvents

“…The IONCELL-P process has been widely used for the separation of Kraft pulp (originated from different biomasses) from hemicellulose, with the aim of increasing its quality to dissolving grade. 286,287 A further interesting system is the organic electrolyte solution (OES) consisting of [C 2 C 1 im]OAc and the biobased solvent GVL, in turn derived from cellulose processing. This system performs well in the presence of water, as the GVL/[C 2 C 1 im] OAc/water mixture in a 2 : 1 : 1 ratio transforms hardwood Kraft pulp into dissolving-grade material under mild conditions.…”

“…The IONCELL-P process has been widely used for the separation of Kraft pulp (originated from different biomasses) from hemicellulose, with the aim of increasing its quality to dissolving grade. 286,287…”