Using Isopropanol as a Capping Agent in the Hydrothermal Liquefaction of Kraft Lignin in Near-Critical Water
Journal article, 2021

In this study, Kraft lignin was depolymerised by hydrothermal liquefaction in near-critical water (290-335 degrees C, 250 bar) using Na2CO3 as an alkaline catalyst. Isopropanol was used as a co-solvent with the objective of investigating its capping effect and capability of reducing char formation. The resulting product, which was a mixture of an aqueous liquid, containing water-soluble organic compounds, and char, had a lower sulphur content than the Kraft lignin. Two-dimensional nuclear magnetic resonance studies of the organic precipitates of the aqueous phase and the char indicated that the major lignin bonds were broken. The high molar masses of the char and the water-soluble organics, nevertheless, indicate extensive repolymerisation of the organic constituents once they have been depolymerised from the lignin. With increasing temperature, the yield of char increased, although its molar mass decreased. The addition of isopropanol increased the yield of the water-soluble organic products and decreased the yield of the char as well as the molar masses of the products, which is indicative of a capping effect.

hydrothermal liquefaction

alkaline catalyst

Kraft lignin

isopropanol

Author

Anders Ahlbom

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Forest Products and Chemical Engineering

Marco Maschietti

Aalborg University

Rudi Nielsen

Aalborg University

Huyen Lyckeskog

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Forest Products and Chemical Engineering

Merima Hasani

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Forest Products and Chemical Engineering

Hans Theliander

Chalmers, Chemistry and Chemical Engineering, Chemical Technology, Forest Products and Chemical Engineering

Energies

1996-1073 (ISSN)

Vol. 14 4 932

Från lignin till biobränslen och specialkemikalier

Swedish Energy Agency (45395-1), 2018-01-01 -- 2021-12-31.

Subject Categories

Food Engineering

Other Chemistry Topics

Geochemistry

DOI

10.3390/en14040932

More information

Latest update

3/30/2021