TITLE:
Production of Bio-Phenols for Industrial Application: Scale-Up of the Base-Catalyzed Depolymerization of Lignin
AUTHORS:
Björn Rößiger, Robert Röver, Gerd Unkelbach, Daniela Pufky-Heinrich
KEYWORDS:
Lignin, Base-Catalyzed Depolymerization, Phenolic Monomers, Phenolic Oligomers
JOURNAL NAME:
Green and Sustainable Chemistry,
Vol.7 No.3,
August
3,
2017
ABSTRACT: Objective of this study was the investigation on the up-scaling of base-catalyzed depolymerization (BCD) of lignin to pilot plant dimension. The cleavage process was carried out in dilute alkaline solution at temperatures up to 340°C and a pressure of 25 MPa in a continuously operated tubular flow reactor with throughputs up to 20 kg/h. Investigations included the proof of the feasibility of the scale-up as well as a parameter study on the cleavage of hardwood Organosolv lignin and softwood Kraft lignin within the established pilot plant. Yields and molecular compositions of the isolated product fractions BCD-oil (liquid phenolic fraction) and BCD-oligomers (solid phenolic fraction) are similar to those described in technical lab scale, showing a good scalability. Here, BCD-oils rich in phenolic monomers such as guaiacol, catechol and/or syringol were obtained with a content of up to 13.3 wt% and 14.5 wt% from Organosolv lignin and Kraft lignin, respectively. Formation of BCD-oligomers strongly depends on temperature and residence times within the reactor.