Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - CatASus (Cleave and couple: Fully sustainable catalytic conversion of renewable resources to amines)

Teaser

The problem addressed is the fully sustainable conversion of renewable resources to bio-based chemicals for future manufacturing of polymers, drugs, materials. Lignocellulose is produced in large (~160MT/year) quantities as part of agricultural and forestry waste, (not...

Summary

The problem addressed is the fully sustainable conversion of renewable resources to bio-based chemicals for future manufacturing of polymers, drugs, materials. Lignocellulose is produced in large (~160MT/year) quantities as part of agricultural and forestry waste, (not competing with food), but currently it is not valorized because of its challangeing structure. This proposal aims to tackle this. Two fundamental challanges addressed: 1. efficient depolymerization of lignocellulose to platform chemicals (also lignin) and the conversion of these platform chemicals into useful compounds, primarily amines. Amines are ubiquitous in the chemical industry, they are highly demanded in medicinal, polymer chemistry or as fine chemical intermediates. In this proposal the sustainable production of amines is foreseen.The aim of this research program will deliver groundbreaking approaches in catalysis that are necessary to establish an entirely new lignin valorization platform.

The development of entirely novel waste-to-value chains would bring significant environmental and economic benefits overall, whilst also creating revenues for the agricultural and chemical industry sectors and various other stakeholders in the European Bioeconomy.
In the next decade, the chemical industry needs to undergo a crucial transition from a fossil-based to a renewables-based enterprise. Equally important is to train PhD students in the novel research areas that are strongly related to the European bioeconomy where biofuel and biomaterials sector will see large demand in terms of new jobs and employment - skilled empolyess will be highly sought after.

Energy and resource security and environmental pollution are major societal challenges and chemistry will play a central role in solving these in the coming decades. Research in green and sustainable chemistry urges to redesign traditional processes not only with the goal to provide a more sustainable future for the society, but also knowing that such innovations will have beneficial economic impact. The chemical industry is a factor of economic growth in Europe, thus it is imperative that we chemist engage in re-shaping our chemical landscape. The utilization of renewable resources, and the development of sustainable catalytic transformations, especially with earth-abundant metals, are vital focus areas where significant innovations are desired.


Importantly, the project will identify fundamentally novel approaches in catalysis - combining valrious fields (homogeneous, heterogeneous, nanoscale catalysis). focus will be devoted to catalysts replying on cheap, Earth-abundant materials in contrast to methods taht use expensive, noble metals that are scarce and will run out in the coming decades.
Moreover, the project will seek to bridge fundamental research directly with industrial relevance by identifying concrete building blocks, products which can be valorised and are interesting for industrial partners.

Globally, a much more efficient, sustainable, green utilization of agricultural waste materials will be proposed as alternative to current methods that are largely inefficient.

Work performed

Scientific reporting – CatASus
Period covered by the report: from 01/05/2016 to 31/01/2018
Narrative
Excellent progress has been achieved.
WP1 – lignin depolymerization:
All objectives of WP1 have been achieved and breakhrough papers published.
Line 1: A new process “Ligno-flex” was invented. Aromatic monomer 4-(propanol) guaiacol in high selectivity. Mechanistic investigation and catalyst strcutural investigation performed. Several catalyst compositions were investigated, CuPMO (Cu/Mg/Al). [Nature Catalysis, 2018, 1, 82-92.]
Line 2: Correlation between acidolysis and b-O-4 linkage content established [Green Chemistry, 2017, 19(12), 2774-2782], high yield of aromatic monomers with this method was achieved ethylene glycol acetals with metal triflates.[ChemSusChem, 2016, 9(20), 2974-2981.] And mechanistic understanding related to other types of linkages was elucidated [J. Am. Chem. Soc., 2016,138(28), pp 8900–8911].
Line 3: Because in Line 1 solid residues were converted to aliphatic alcohols (Ligno-Flex). The alcohols so obtained were converted to Jet-Fuel range alkanes CuNiPMO [ACS Sustainable Chemistry & Engineering, 2017, 5(2), 1738-1746.]
In addition, high impact review on lignin was published [Chem Rev. 2017, 10.1021/acs.chemrev.7b00588]
Goals achieved related to WP2 – cellulose/HMF:
Line 1: the conversion of HMF and Furfural to bio-derived solvents partially accomplished. Line 3: ring opening of HMF investigated and direct conversion to pyrrole derivatives achieved. Aliphatic alcohols are under investigation. Line 2: Because in the meantime this was reported in literature, the Diels-alder chemistry was replaced by ABA to BTX.
Goals achieved related to WP3 – amination of alcohols:
Research is well on the way and publication in Nature Catalysis shows for the first time lignin-derived amines. Line 1: Aminations with ammonia investigated, also reported in Nature Catalysis. Line 2: ahead of time, reactive separation working, manuscript in ACS CEntral Science; phenol to aniline done. Line 3: Mechanistic studies partially accomplished, and more planned. New ligand structures have been prepared, research underway. Line 4: Increase diversity of products from lignin aromatics, in progress. Selective alkylation of amino acids with alcohols, breakthrough paper published in: [Science Advances 2017, Vol. 3, no. 12, eaao6494], also in A. Afanasenko, et. al, Catal. Sci. Technol., 2018, 10.1039/C8CY01200H.]
WP4 – many concrete products collaborations with polymer chemist, separation chemistry, medicinal chemistry. Original concept: Cleave and couple has been put forward and discussed in talks and perspective articles: [Z. Sun, K. Barta, Chem Commun, 2018, 54, 7725-7745.]

Final results

The efficient depolymerization of lignin, to well defined aromatic monomers is a daunting challange. One of the fundamental problems in lignin depolymerization is the recalcitrant structure of lignin. Lignin consists of tightly linked aromatic subunits.
Our focus is to not only develop novel catalytic methods capable of depolymerizing lignin by cleavage of specific bonds, but also to prevent the recondensation processes that otherwise lead to the formation of undesired char.
We developed fundamentally new methods from lignin to aromatics. One solution is the stabilization of reactive C2-aldehydes as acetals or by tandem catalysis (In WP1, Line 2).
The C2 acetals provide valuable novel lignin derived platform. In Wp1, Line 1 the CuPMO catalysed reductive fractionation of lignocellulose to obtain 4-propanol guaiacol in high selectivity. Integrated catalyst recylcing via catalytic conversion of all process residues in supercricital methanol to aliphatic alcohols. The intermadiate alcohols are ideally set up for further C-C or C-N bond formation to get valuable products.

The project developed concrete valorization pathways from the aromatics and aliphatics obtanined. Cellulose derived aliphatics to jet fuels/ Lignin derived aromatics to valuable amines (pharma and polymer building blocks).

By the end of the project, we will identify novel catalytic mehtods, and concrete products that can be used by industrial partners. ERC PoC has been awarded to facilitate this.

Website & more info

More info: http://bartagroup.org/.