Selective depolymerization of industrial lignin-containing stillage obtained from cellulosic bioethanol processing

• Published in: Fuel processing technology Vol. 173; pp. 165 - 172
• Main Authors: Gómez-Monedero, Beatriz, Pilar Ruiz, M., Bimbela, Fernando, Faria, Jimmy
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.05.2018; Elsevier Science Ltd
• Subjects: 1-D catalyst; Activated carbon; Agglomerates; Carbon nanotubes; Catalysis; Catalysts; Depolymerization; Fine chemicals; Fuel additives; Hydrogen; Hydrogenolysis; Industrial engineering; Industrial plants; Lignin; Manufacturing engineering; Molecular chains; Multi wall carbon nanotubes; Nanotubes; NMR; Nuclear magnetic resonance; Organic chemistry; Stillage; Weight reduction; Zirconium dioxide; Depolymerization; Carbon nanotubes; Lignin; 1-D catalyst; Stillage; Hydrogenolysis
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2018.01.021

Reductive depolymerization of lignin-containing stillage (LA lignin) from 2nd generation bioethanol industrial plants have been studied over two different families of catalysts: conventional porous Ru catalysts supported on ZrO2 or activated carbon, and 1-dimensional Ru catalysts supported on multi-walled carbon nanotubes (MWCNT). The lignin depolymerization degree using conventional porous catalysts resulted in values of 42 and 53%, for Ru/ZrO2 and Ru/C, respectively. Strikingly, when using 1D-supported catalysts (Ru/MWCNT and Ru/ZrO2/MWCNT), the extent of lignin depolymerization measured by 1H13C HSQC NMR, reached values of c.a. 80% of β-O-4 bond disappearance and a reduction of the average molecular weight from 3600 Da to ~ 1900 Da. The higher accessibility of the lignin agglomerates to the 1-D catalyst nanoparticles substantially improves the lignin depolymerization degree, which make this approach of great interest in the production of fine chemicals and fuel additives. [Display omitted] •Lignin stillage has been depolymerized up to 80% of β-O-4 bond disappearance.•Selective depolymerization of β-O-4 ether bonds has been achieved on Ru catalysts.•1-D Ru/MWCNT catalysts show the highest depolymerization extent.•1-D Ru/MWCNT catalysts increase accessibility of the lignin molecules to the catalyst.