Circular Economy

Circular Economy

Reusable, renewable and recyclable products

Circular economy means decoupling growth from resource consumption. The chemistry Industry has a crucial role in helping make the world economy circular by enabling innovative technologies that better use and reuse existing materials and in producing technologies and solutions to create a carbon-neutral, resource-efficient and circular society. Chemical companies can drive growth while helping to shape a greener, cleaner, more sustainable future with reusable, renewable and recyclable products.

At the CoE, we are finding solutions for the circular economy by making the most of the limited resources of our planet: Our solutions keep them in use for as long as possible, minimize waste and create value with renewable resources.

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Hydrodeoxygenation of Bio-Oil to Alkanes

Bio-oil, produced by the destructive distillation of cheap and renewable lignocellulosic biomass, contains high energy density oligomers in the water-insoluble fraction that can be utilised for diesel and valuable fine chemicals productions.

Here we show a highly active and stable hydrodeoxygenation (HDO) catalyst that combines atomically-dispersed Pd on a mixed-valent Mo5/6+ oxide phosphate on silica (Pd/m-MoO3-P2O5/SiO2). Using a wood and bark derived feedstock, Pd/m-MoO3-P2O5/SiO2 performs hydrodeoxygenation of lignin, cellulose and hemicellulose-derived oligomers into liquid alkanes with high efficiency and yield. Using phenol as a model substrate this catalyst is 100% effective and 97.5% selective for hydrodeoxygenation to cyclohexane under mild conditions, showing no decrease in catalytic performance after 63 hours under continuous flow operation. Detailed investigations into the nature of the catalyst shows it combine exceptionally high both Brønsted and Lewis acidic sites and facile Mo redox characteristics, we believe these are key features for the efficient catalytic hydrodeoxygenation behaviour.

Recent publications:

Molecular Nitrogen Promotes Catalytic Hydrodeoxygenation , H. Duan, J.-C. Liu, Y. Zhao, M. Xu, X.-L. Ma, J. Dong, X. Zheng, J. Zheng, C.S. Allen, M. Danaie, Y.-K. Peng, T. Issariyakul, D. Chen, A.I. Kirkland, J.-C. Buffet, D. Ma, J. Li, S.C.E. Tsang and D. O’Hare, Nature Catalysis, (2019), 2, pp. 1078–1087.
Hydrodeoxygenation of Water-Insoluble Bio-Oil to Alkanes using highly Dispersed Pd-Mo Catalyst , H., Duan, J. Dong, Y.-K. Peng, W. Chen, T. Issariyakul, W.K. Myers, M.-J. Li, N. Yi, A.F.R. Kilpatrick, Y. Wang, X. Zheng, D. Chen, S. Ji, Y. Li, J.-C. Buffet, S.C.E. Tsang and D. O’Hare, Nature Communications, (2017), 8, Article number: 591(2017).

Characterisation of the Pd/m-MoO3-P2O5/SiO2 catalyst. a, High-angle annular dark-field scanning transmission electron microscopy image of Pd/m-MoO3-P2O5/SiO2. Inset shows the size distribution of the clusters. Scale bar equals 20 nm. b, Aberration-corrected annular-bright-field scanning transmission electron microscope image and c, corresponding high-angle annular dark-field scanning transmission electron microscopy image of Pd/m-MoO3-P2O5/SiO2. Scale bars equal 5 nm. d, STEM-EDS elemental mapping results for Pd/m-MoO3-P2O5/SiO2, showing a homogeneous distribution of the elements within clusters. Scale bar equals 3 nm

Catalytic performance on hydrodeoxygenation of phenol. a, Comparison of different catalysts at 383 K, 1 Mpa H2 for two hours in batch reaction. Reaction conditions: phenol (0.195 mmol), catalyst (including 0.00045 mmol Pd), decalin (7 mL), reaction mixture stirred at 800 rpm. b, Long-term stability test on the Pd/m-MoO3-P2O5/SiO2 at 453 K, 1 MPa H2 with a weight hourly space velocity of 0.085 h-1 in a continuous flow reaction.

Green Packaging

One of the major challenges in the circular economy relating to food packaging is the elimination of metallised film which is currently the industry standard approach to achieve the necessary gas barrier performance. Here, we report the synthesis of high aspect ratio 2D non-toxic layered double hydroxide (LDH) nanosheet dispersions using a non-toxic exfoliation method in aqueous amino acid solution. High O2 and water vapour barrier coating films can be prepared using food safe liquid dispersions through a bar coating process. The oxygen transmission rate (OTR) of 12 μm PET coated film can be reduced from 133.5 cc·m−2·day−1 to below the instrument detection limit (<0.005 cc·m−2·day−1). The water vapour transmission rate (WVTR) of the PET film can be reduced from 8.99 g·m−2·day−1 to 0.04 g·m−2·day−1 after coating. Most importantly, these coated films are also transparent and mechanically robust, making them suitable for flexible food packing while also offering new recycling opportunities.

We report a method to rationally control the aspect ratio of layered double hydroxide for use as a barrier coating for food packaging films. The reconstruction of a Mg2Al-layered double oxide (LDO) in concentrated aqueous glycine solutions produces dispersions of Mg2Al-LDH nanosheets. The nanosheet thickness decreases and diameter increases with increasing reconstruction time from 16 to 96 h. We observe a limiting nanosheet aspect ratio of ca. 336 ± 170. These Mg2Al-LDH nanosheets can be dispersed in PVA to give a water-based dispersion that can be used to coat flexible polymeric films. Oxygen transmission rate (OTR) of a PET film decreases when the thickness of the dried coated layer increases, an OTR of <0.005 mL·m–2·day–1 is observed for a coating with thickness of 1175 ± 101 nm.

Recent publications:

Aspect Ratio Control of LDH Nanosheets and their Application for High Oxygen Barrier Coating in Flexible Food Packaging, J. Yu, J.-C. Buffet, D. O'Hare, ACS Appl. Mater. Interfaces., (2020), 12(9) 10973-10982.
High oxygen barrier coating using non-toxic nanosheet dispersions for flexible food packaging film, J. Yu, K. Ruengkajorn, D. Georgiana Crivoi, C. Chen, J-C. Buffet, D. O’Hare, Nature Communications, (2019), 10, Article number: 2398.

Slurry phase polymerisation of ethylene & Characterisation of solid catalysts

Slurry phase polymerisation of ethylene

Polyethylene is the most produced plastic in the worlds with a production of over 80 MT every year. Slurry and gas phase plant around the world are the favourite meaning to obtain these polymers. We routinely study slurry phase polymerisation of ethylene using “in-house” inorganic support and complexes. Our target is a popcorn like morphology.

Characterisation of solid catalysts

Our solid catalysts are fully characterised by various techniques, solution and solid NMR spectroscopy, IR spectroscopy, SEM, ICP-MS, XANES, XPDF and EXAFS.

Recent publications:

Molecular Nitrogen Promotes Catalytic Hydrodeoxygenation, H. Duan, J.-C. Liu, Y. Zhao, M. Xu, X.-L. Ma, J. Dong, X. Zheng, J. Zheng, C.S. Allen, M. Danaie, Y.-K. Peng, T. Issariyakul, D. Chen, A.I. Kirkland, J.-C. Buffet, D. Ma, J. Li, S.C.E. Tsang and D. O’Hare, Nature Catalysis, (2019), 2, pp. 1078–1087.
Hydrodeoxygenation of Water-Insoluble Bio-Oil to Alkanes using highly Dispersed Pd-Mo Catalyst, H., Duan, J. Dong, Y.-K. Peng, W. Chen, T. Issariyakul, W.K. Myers, M.-J. Li, N. Yi, A.F.R. Kilpatrick, Y. Wang, X. Zheng, D. Chen, S. Ji, Y. Li, J.-C. Buffet, S.C.E. Tsang and D. O’Hare, Nature Communications, (2017), 8, Article number: 591(2017).
Supported bis(peralkylindenyl) metallocene catalysts for slurry phase ethylene polymerisation, P. Angpanitcharoen, G. Hay, J.-C. Buffet, Z.R. Turner, T.A.Q. Arnold and D. O’Hare, Polyhedron, (2016), 116, 216–222
Polymethylaluminoxane supported zirconocene catalysts for polymerisation of ethylene, T.A.Q. Arnold, Z.R. Turner, J.-C. Buffet and D. O’Hare, J. Organomet. Chem., (2016), 822, 85-90
Synthesis and characterization of solid polymethylaluminoxane “sMAO”; a bifunctional activator and support for slurry-phase ethylene polymerization, A.F.R. Kilpatrick, J.-C. Buffet, S. Sripothongnak, P. Nørby, N.P. Funnell, and D. O’Hare, Chem Mater., (2016), 28 (20), 7444-7450
Ethylene Polymerisation using Solid Catalysts Based on Layered Double Hydroxides, J-C. Buffet, Z.R. Turner, R.T. Cooper, and D. O’Hare, Polymer Chem., (2015), 6, 2493-2503.

Lactide Polymerisation

Permethylindenyl

A series of group 3, 4 and 13 permethylindenyl chrloride, aryloxide, and borohydride complexes have been synthesised and fully characterised. Their activities for the ring-opening polymerisation (ROP) of L-, D-, meso- and rac-lactide have been tested. The ROP of L- and rac-lactide produced isotactic polylactide (PLA) and moderately heterotactic PLA (Pr = 0.68–0.72), respectively. Good agreement between experimental and theoretical molecular weights of PLA (Mn) and relatively narrow dispersities were obtained.

Few initiators displayed second order dependence on monomer concentration and produced isotactic and heterotactic (Pr = 0.81) polylactides for the polymerisation of L-, D- and rac-lactide respectively. The effects of temperature, catalyst concentration, co-initiator concentration, solvent and scale were studied.

“Constrained geometry scandium permethylindenyl complexes for the ring-opening polymerisation of L- and rac-lactide”. N. Diteepeng, J.-C. Buffet, Z. R. Turner and D. O’Hare, Dalton Trans., 2019, 48, 16099.

“Group 4 permethylindenyl complexes for the polymerisation of L-, D- and rac-lactide monomers”. J. V. Lamb, J.-C. Buffet, J. E. Matley, C. M. R. Wright, Z. R. Turner and D. O’Hare, Dalton Trans., 2019, 48, 2510.

Circular Economy