TY - JOUR
T1 - Monitoring Molecular Weight Changes during Technical Lignin Depolymerization by Operando Attenuated Total Reflectance Infrared Spectroscopy and Chemometrics
AU - Khalili, Khaled N.M.
AU - de Peinder, Peter
AU - Donkers, Jacqueline
AU - Gosselink, Richard J.A.
AU - Bruijnincx, Pieter C.A.
AU - Weckhuysen, Bert M.
N1 - Publisher Copyright:
© 2021 The Authors. ChemSusChem published by Wiley-VCH GmbH
PY - 2021
Y1 - 2021
N2 - Technical lignins are increasingly available at industrial scale, offering opportunities for valorization, such as by (partial) depolymerization. Any downstream lignin application requires careful tailoring of structural properties, such as molecular weight or functional group density, properties that are difficult to control or predict given the structure variability and recalcitrance of technical lignins. Online insight into changes in molecular weight (Mw), to gauge the extent of lignin depolymerization and repolymerization, would be highly desired to improve such control, but cannot be readily provided by the standard ex-situ techniques, such as size exclusion chromatography (SEC). Herein, operando attenuated total reflectance infrared (ATR-IR) spectroscopy combined with chemometrics provided temporal changes in Mw during lignin depolymerization with high resolution. More specifically, ex-situ SEC-derived Mw and polydispersity data of kraft lignin subjected to aqueous phase reforming conditions could be well correlated with ATR-IR spectra of the reaction mixture as a function of time. The developed method showed excellent regression results and relative error, comparable to the standard SEC method. The method developed has the potential to be translated to other lignin depolymerization processes.
AB - Technical lignins are increasingly available at industrial scale, offering opportunities for valorization, such as by (partial) depolymerization. Any downstream lignin application requires careful tailoring of structural properties, such as molecular weight or functional group density, properties that are difficult to control or predict given the structure variability and recalcitrance of technical lignins. Online insight into changes in molecular weight (Mw), to gauge the extent of lignin depolymerization and repolymerization, would be highly desired to improve such control, but cannot be readily provided by the standard ex-situ techniques, such as size exclusion chromatography (SEC). Herein, operando attenuated total reflectance infrared (ATR-IR) spectroscopy combined with chemometrics provided temporal changes in Mw during lignin depolymerization with high resolution. More specifically, ex-situ SEC-derived Mw and polydispersity data of kraft lignin subjected to aqueous phase reforming conditions could be well correlated with ATR-IR spectra of the reaction mixture as a function of time. The developed method showed excellent regression results and relative error, comparable to the standard SEC method. The method developed has the potential to be translated to other lignin depolymerization processes.
KW - ATR-IR spectroscopy
KW - chemometrics
KW - lignin valorization
KW - operando spectroscopy
KW - size exclusion chromatography
U2 - 10.1002/cssc.202101853
DO - 10.1002/cssc.202101853
M3 - Article
AN - SCOPUS:85119663070
VL - 14
SP - 5517
EP - 5524
JO - ChemSusChem
JF - ChemSusChem
SN - 1864-5631
IS - 24
ER -