Issue 24, 2016

Supercritical water hydrolysis: a green pathway for producing low-molecular-weight cellulose

Abstract

This work discusses the suitability of supercritical water treatment (SCWT) for depolymerising microcrystalline cellulose in a controlled way. The SCWT partially hydrolysed cellulose down to a mixture of three valuable products: water-insoluble low-molecular-weight cellulose (WI-LMWC) precipitate, water-soluble low-molecular-weight cellulose (WS-LMWC) oligomers, and glucose. The conditions under which the energy demand for obtaining these products is minimised were identified by adjusting the reaction time inside the continuous reactor and the temperature around the critical point. The optimum conditions were 370 °C and 0.4 seconds for producing WI-LMWC and 360 °C and 0.5 seconds for producing WS-LMWC, with maximum yields of 19 wt% and 50 wt%, respectively. This work also shows that the water-insoluble product precipitates into crystalline cellulose II arrangements. This precipitation phenomenon enabled isolation of cellulose chains of different lengths according to their respective solubilities in ambient water. The results show that SCWT is a relevant process for producing narrowly distributed fractions of low-molecular-weight cellulose using water and heat only.

Graphical abstract: Supercritical water hydrolysis: a green pathway for producing low-molecular-weight cellulose

Supplementary files

Article information

Article type
Paper
Submitted
10 Sep 2016
Accepted
19 Sep 2016
First published
21 Sep 2016
This article is Open Access
Creative Commons BY license

Green Chem., 2016,18, 6516-6525

Supercritical water hydrolysis: a green pathway for producing low-molecular-weight cellulose

J. Buffiere, P. Ahvenainen, M. Borrega, K. Svedström and H. Sixta, Green Chem., 2016, 18, 6516 DOI: 10.1039/C6GC02544G

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