Banner for LabNotes
From Lab Notes
Contact Information
Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
Fax: (608) 231-9592


You are here: FPL Home  / Information Products & Services  / Publications

Requested Product

Title: Maleic acid as a dicarboxylic acid hydrotrope for sustainable fractionation of wood at atmospheric pressure and ≤100 °C: mode and utility of lignin esterification

Source: Green Chemistry. 22(5): 1605-1617.

Author(s)Cai, Cheng ; Hirth, Kolby ; Gleisner, Rolland ; Lou, Hongming ; Qiu, Xueqing ; Zhu, J. Y.

Publication Year: 2020  View PDF »

Category: Journal Articles
Associated Research Project(s):   FPL-4709-1B

Abstract: This study evaluated maleic acid (MA) as a green hydrotrope for efficient wood fractionation at atmospheric pressure and ≤100 °C. MA hydrotropic fractionation (MAHF) resulted in esterified lignin with a low degree of condensation and a very light color. 2D 1H–13C HSQC and HMBC NMR analyses of reaction products of a lignin model compound guaiacylglycerol-beta-guaiacyl ether with MA identified bonding through the γ-OH group. The surface charge of lignocellulosic MAHF water insoluble solids (WIS), induced by lignin esterification (carboxylation), enhanced enzymatic sugar yield by reducing nonproductive cellulase binding to lignin through pH-mediated electrostatic repulsion and also enhanced the lubrication effect of lignin in mechanical nanofibrillation for producing cellulose nanofibrils from WIS. Preliminary studies indicated that disssolved xylan can be dehydrated into furfural by MA in the fractionated liquor at a good yield of 70% and MA can be reused for repeated fractionation with minimal loss of less than 5%.

Keywords: Maleic acid hydrotropic fractionation (MAHF); lignin esterification (carboxylation); 2D NMR; enzymatic hydrolysis; lignin containing cellulose nanofibrils (LCNF)

Publication Review Process: Formally Refereed

File size: 6,144 kb(s)

Date posted: 04/03/2020

This publication is also viewable on Treesearch:  view
RITS Product ID: 97494
Current FPL Scientist associated with this product
Zhu, JunYong
Research General Engineer

Additional items that might interest you
View the video celebrating FPL's 100 years of public service in 2010, from the producers of the Greatest Good....view

Research Highlights from FPL....view

Termite Eradication: A search for the Holy Grail.... view

Moisture Management in Residential Construction Series videos...view

Wood Floor Systems in Residential Construction Series videos....view
- FPL's Mission and Strategic Plan -

FPL's mission is to identify and conduct innovative wood and fiber utilization research that contributes to conservation and productivity of the forest resource, thereby sustaining forests, the economy, and quality of life. ... ..more »

- FPL Research Emphasis Areas -
Advanced Composites

As an integral part of the FPL mission, we improve the long-term sustainability of our Nation's forests by creating valuable composite products from biobased materials ... ..more »

Advanced Structures

The FPL has been in the forefront of wood-frame housing research since 1910 and has long been recognized as a world leader in such housing-related areas as engineered wood ... ..more »

Forest Biorefinery

We all know the compelling reasons that the United States needs to reduce its dependence on fossil fuels. Historically, the greatest increases in energy demand have been for transportation fuels ... ..more »


A leader in wood products research for over a century, the FPL is positioning itself to become the lead Federal research facility for the application of nanotechnology in forest products ... more »

Woody Biomass Utilization

Forests in the United States contain a substantial amount of small-diameter, overstocked, and underutilized material.FPL research projects are exploring the potential of the small-diameter ... ..more »