New methods in biomass depolymerisation: catalytic hydrogenolysis of barks

Abstract

Hydrogenolysis of bark from three different species of tree using heterogeneous platinum group metal catalysts produces two major product streams. Aromatic substituted guaiacols are produced from lignin and the lignin-like regions of suberin and a range of saturated fatty acids and alcohols, including α,ω-functionalised species, are produced from the polyester regions of suberin. Control experiments demonstrate clear advantages of catalytic hydrogenolysis over base hydrolysis, both in terms of conversion and product selectivity.

Importance of suberin biopolymer in plant function, contributions to soil organic carbon and in the production of bio-derived energy and materials

“…Catalysts have been incorporated in other thermochemical routes such as hydrogenolysis and depolymerization processes that have been implemented on barks and suberin-rich materials. Garrett et al performed catalytic hydrogenolysis on various types of biomass barks using two different catalysts to understand the chemistry associated with the production of lipid and aromatic species derived from the suberin and lignin in the barks [ 138 ]. Their study highlighted the differences in suberin depolymerization from different biomass sources, namely spruce, sycamore and cork.…”

“…Their study highlighted the differences in suberin depolymerization from different biomass sources, namely spruce, sycamore and cork. For example, cork produced the highest oil yield from hydrogenolysis using Rh/C (11.5 wt%) but the lowest oil yield using Pd/C (7.2 wt%) whereas the highest oil yield from Pd/C was generated from sycamore (13.3 wt%) [ 138 ]. Various types of fatty acids derived from suberin were produced in yields totaling 2–3 wt% in catalytic runs and aromatics were produced on the order of 1–4 wt% depending on catalysts, feeds and conditions [ 138 ].…”

“…For example, cork produced the highest oil yield from hydrogenolysis using Rh/C (11.5 wt%) but the lowest oil yield using Pd/C (7.2 wt%) whereas the highest oil yield from Pd/C was generated from sycamore (13.3 wt%) [ 138 ]. Various types of fatty acids derived from suberin were produced in yields totaling 2–3 wt% in catalytic runs and aromatics were produced on the order of 1–4 wt% depending on catalysts, feeds and conditions [ 138 ]. In a follow-up study, McCallum et al investigated the hydrogenolysis of cork in the presence of heterogeneous catalyst supported on various bases and in different solvents to optimize yield and environmental impacts of the proposed conversion routes [ 139 ].…”

Reusing, recycling and up-cycling of biomass: A review of practical and kinetic modelling approaches

“…Aroso et al [259] have provided an extensive discussion on possible uses of cork as a sustainable material, though the methods discussed could be applied to other types of woody biomass. Depolymerisation methods to extract value-added chemicals such as waxes and phenolic compounds from cork include chemical (acid/base [260] and catalytic [261], oxypropylation [262], liquefaction [263] and pyrolysis [264].…”

Conversion of birch bark to biofuels

“…In one of the reported procedures, a typical lignin-first approach was applied to a bark sample to partially depolymerize suberin into a range of fatty acids and alcohols. 12 Further depolymerization under alkaline conditions was needed to accomplish the transformation. Another method used FeCl 3 -catalyzed lignin isolation; however, the transformation of suberin was not described in detail.…”