Study of a renewable capping agent addition in lignin base catalysed depolymerisation process

Abstract

The aim of this work was to study the influence of a renewable capping agent (CA) in the production of monomeric compounds from the depolymerization of an organosolv lignin (Pinus radiata) by a base catalyzed depolymerization (BCD) process. After the delignification process of the Pinus radiata sawdust, the lignin contained in the black liquor was subjected to a first mild depolymerization process, without using any catalyst, in order to obtain two different products: a lignin which was the feed in the subsequent BCD process and a phenolic oil which was used as CA in the same BCD process. This process was carried out at 230 °C in three consecutive cycles of 20 min using different amounts of capping agent dissolved in a 4% wt. NaOH solution with a lignin:solvent ratio of 1:20. The use of a renewable capping agent derived from lignin was effective not only in terms of phenolic oil production increasing but also in maximizing the monomeric phenolic compounds concentration. The use of CA: lignin ratio of 1:1 resulted the most effective with 10.64% of oil yield and almost 44% of monomeric phenolic compounds concentration while minimizing de undesired by-products yield.