Understanding the role of water in the interaction of ionic liquids with wood polymers

A Roselli; M Hummel; J Vartiainen; K Nieminen; H Sixta

doi:10.1016/j.carbpol.2017.03.013

Understanding the role of water in the interaction of ionic liquids with wood polymers

Carbohydr Polym. 2017 Jul 15:168:121-128. doi: 10.1016/j.carbpol.2017.03.013. Epub 2017 Mar 8.

Authors

A Roselli¹, M Hummel², J Vartiainen³, K Nieminen⁴, H Sixta⁵

Affiliations

¹ Department of Bioproducts and Biosystems, School of Chemical Technology, Aalto University, P.O. Box 16300, 00076 Aalto, Finland. Electronic address: annariikka.roselli@aalto.fi.
² Department of Bioproducts and Biosystems, School of Chemical Technology, Aalto University, P.O. Box 16300, 00076 Aalto, Finland. Electronic address: michael.hummel@aalto.fi.
³ Department of Bioproducts and Biosystems, School of Chemical Technology, Aalto University, P.O. Box 16300, 00076 Aalto, Finland. Electronic address: jnvartia@gmail.com.
⁴ Department of Bioproducts and Biosystems, School of Chemical Technology, Aalto University, P.O. Box 16300, 00076 Aalto, Finland. Electronic address: kaarlo.nieminen@aalto.fi.
⁵ Department of Bioproducts and Biosystems, School of Chemical Technology, Aalto University, P.O. Box 16300, 00076 Aalto, Finland. Electronic address: herbert.sixta@aalto.fi.

PMID: 28457431
DOI: 10.1016/j.carbpol.2017.03.013

Abstract

Hemicellulose lean pulps are a raw material source for numerous high value products. We have previously presented the IONCELL-P(ulp) process, a hemicellulose extraction method, based on a binary mixture of ionic liquid and water. The IONCELL-P process does not suffer from yield losses or polymer degradation and retains the Cellulose I crystalline form. In this paper, a selection of cellulose dissolving ionic liquids is tested, in order to compare their applicability in the process. We demonstrate that the extraction selectivity towards low molar mass polymers is related to the anion's ability to accept hydrogen bonds (Kamlet-Taft β-value), if divided by the water molar fraction of the solvent system. Pulp consistency, solvent system viscosity and pH are investigated in order to identify the factors affecting the extraction efficiency. The results show that all the tested ionic liquid-water mixtures were able to dissolve hemicelluloses, but there were differences in their efficiency, selectivity and the ability to process high pulp consistencies.

Keywords: Dissolving pulp; Fractionation; Ionic liquid; Xylan.