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Recycling rare earth elements using ionic liquids

Recycling old magnets, so that rare-earth metals can be re-used, could help to solve an urgent raw material supply problem in the electronics industry. Researchers from the University of Leuven, Belgium, have used ionic liquids to separate neodymium and samarium from transition metals like iron, manganese and cobalt – all elements that are used in the construction of permanent rare-earth magnets, which are found in electronic devices ranging from hard drives to air conditioners and wind turbines.

‘The process involves the liquid-liquid extraction of rare-earth metals from the other elements present in neodymium-iron-boron and samarium-cobalt magnets,’ explains Koen Binnemans who leads the group developing the process. ‘These other elements – including iron, cobalt, manganese, copper and zinc – are extracted into the ionic-liquid phase, while the rare-earth metals are left behind in the aqueous phase,’ he says, adding that the ionic liquid itself – trihexyl(tetradecyl)phosphonium chloride – can also be re-used, after the transition metals have been stripped out.

In traditional liquid-liquid extractions of metal ions, an aqueous phase containing the metal salt is mixed with an organic phase containing an extraction agent. Simple though they are, these processes use organic phases comprising flammable and volatile solvents, like toluene, kerosene or diethyl ether. Ionic liquids are far more environmentally friendly, having very low vapour pressure and non-flammability.

Read the full article in Chemistry World

Read the original journal article in Green Chemistry:

Removal of transition metals from rare earths by solvent extraction with an undiluted phosphonium ionic liquid: separations relevant to rare-earth magnet recycling
Tom Vander Hoogerstraete,  Sil Wellens,  Katrien Verachtert and Koen Binnemans
Green Chem., 2013,15, 919-927

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Green Chemistry Issue 4 now online

Green Chemistry issue 4 is now online and you can read it here.

Issue 4 front coverThe cover features work by François Jérôme and co-workers from France.  Their Paper, ‘Pretreatment of microcrystalline cellulose by ultrasounds: effect of particle size in the heterogeneously-catalyzed hydrolysis of cellulose to glucose’ demonstrates that activity of a sulfonated carbon in the heterogeneously-catalyzed hydrolysis of cellulose was greatly improved by assistance of ultrasound. The paper demonstrates that the sonication method was as effective as conventional pre-treatments such as ball-milling or ionic liquids.

Pretreatment of microcrystalline cellulose by ultrasounds: effect of particle size in the heterogeneously-catalyzed hydrolysis of cellulose to glucose
Qinghua Zhang, Maud Benoit, Karine De Oliveira Vigier, Joël Barrault, Gwenaëlle Jégou, Michel Philippe and François Jérôme, Green Chem., 2013, 15, 963-969

Issue 4 inside cover

The inside front cover highlights a review article entitled ‘Green chemistry and the ocean-based biorefinery’ by Fran Kerton and co-workers at the Memorial University of Newfoundland in Canada.  This review highlights that competition for land use could be minimized if marine sourced feedstocks were used for chemicals and materials production rather than crops grown on fertile land. It focuses on achievements and potential opportunities surrounding the use of algae and waste from shellfish and finfish processing.

Green chemistry and the ocean-based biorefinery
Francesca M. Kerton, Yi Liu, Khaled W. Omari and Kelly Hawboldt, Green Chem., 2013, 15, 860-871

These articles are free to access for 6 weeks!

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‘Super solvents’ shortlisted for most important British innovation of the 21st Century

Work by scientists from Queen’s University Belfast on ionic liquid chemistry is in the running to be named the most important British innovation of the 21st Century. 

The work of staff in the Queen’s University Ionic Liquid Laboratories (QUILL) Research Centre is up against 11 other innovations from across the United Kingdom battling it out in a public vote to find the one that will have the greatest impact in the coming century. The vote is part of the Science Museum’s Initiative on Great British past and future Innovations. 

Ionic liquids are salts which can remain liquid at room temperature and do not form vapours, and so can be used as non-polluting alternatives to conventional solvents.  At QUILL, a team of nearly 100 scientists are exploring the potential of these green solvents and Fortune 100 energy giant Petronas is already using the technology in its plants.  The mercury removal unit, using 15 tons of supported ionic liquid, was developed by a team led by Professor Ken Seddon, Co-Director of QUILL at Queen’s, and Dr John Holbrey also from QUILL, who were listed last year as the number one and two chemists in the UK based on citations of their work.Professor Ken Seddon said: “Being shortlisted for the most important British innovation of the 21st century is recognition of the high calibre of research being undertaken at QUILL and throughout the University.  We would encourage people to take a moment to vote for our research as its application will eventually have a bearing on most of our lives.”

Other notable British innovations in the hunt for the prize are Quantum Dots, Graphene, Raspberry Pi and the discovery of the Higgs-Boson – you can vote for your favourite here.  Update Monday 25th March – Ionic Liquid Chemistry was voted the recent innovation that is most likely to shape the coming century.

Why not take a look at a collection of high quality research in this area from across RSC Journals – Increadible ionic liquids: an article collection.

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Top 10 most accessed articles in 2012

Do you want to know what your colleagues were reading during 2012? The following articles in Green Chemistry were the most accessed over the course of the year:

Multicomponent reactions in unconventional solvents: state of the art
Yanlong Gu
Green Chem., 2012,14, 2091-2128
DOI: 10.1039/C2GC35635J, Critical Review

Characterization and comparison of hydrophilic and hydrophobic room temperature ionic liquids incorporating the imidazolium cation
Jonathan G. Huddleston, Ann E. Visser, W. Matthew Reichert, Heather D. Willauer, Grant A. Broker and Robin D. Rogers
Green Chem., 2001,3, 156-164
DOI: 10.1039/B103275P, Paper

Catalytic conversion of biomass to biofuels
David Martin Alonso, Jesse Q. Bond and James A. Dumesic
Green Chem., 2010,12, 1493-1513
DOI: 10.1039/C004654J, Critical Review

Transition metal based catalysts in the aerobic oxidation of alcohols
Camilla Parmeggiani and Francesca Cardona
Green Chem., 2012,14, 547-564
DOI: 10.1039/C2GC16344F, Tutorial Review

Evolution of asymmetric organocatalysis: multi- and retrocatalysis
Raffael C. Wende and Peter R. Schreiner
Green Chem., 2012,14, 1821-1849
DOI: 10.1039/C2GC35160A, Critical Review

Green synthesis of metal nanoparticles using plants
Siavash Iravani
Green Chem., 2011,13, 2638-2650
DOI: 10.1039/C1GC15386B, Critical Review

Technology development for the production of biobased products from biorefinery carbohydrates—the US Department of Energy’s “Top 10” revisited
Joseph J. Bozell and Gene R. Petersen
Green Chem., 2010,12, 539-554
DOI: 10.1039/B922014C, Critical Review

Continuous flow reactors: a perspective
Charlotte Wiles and Paul Watts
Green Chem., 2012,14, 38-54
DOI: 10.1039/C1GC16022B, Tutorial Review

Catalytic conversion of biomass using solvents derived from lignin
Pooya Azadi, Ronald Carrasquillo-Flores, Yomaira J. Pagán-Torres, Elif I. Gürbüz, Ramin Farnood and James A. Dumesic
Green Chem., 2012,14, 1573-1576
DOI: 10.1039/C2GC35203F, Communication

5-Hydroxymethylfurfural (HMF) as a building block platform: Biological properties, synthesis and synthetic applications
Andreia A. Rosatella, Svilen P. Simeonov, Raquel F. M. Frade and Carlos A. M. Afonso
Green Chem., 2011,13, 754-793
DOI: 10.1039/C0GC00401D, Critical Review

Take a look at the articles and then post your thoughts and comments below.

Interested in submitting your own work to Green Chemistry? Submit online today, or email us with your suggestions.

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Green Chemistry issue 3 now online

The latest issue of Green Chemistry is now available to read online.

Green Chemistry, issue 3, 2013, front coverThe front cover of this issue highlights a Critical Review by Tom Welton and colleagues from Imperial College London (UK) and Umeå University (Sweden) on the deconstruction of lignocellulosic biomass with ionic liquids.  The review begins by providing background information on ionic liquids and lignocellulosic biomass before going on to explore the solubility of lignocellulosic biomass in ionic liquids.  The also describes the destruction effects brought about by the use of ionic liquids as a solvent, before finally looking at the practical considerations for design of ionic liquid based deconstruction processes.

Deconstruction of lignocellulosic biomass with ionic liquids, Agnieszka Brandt, John Gräsvik, Jason P. Hallett and Tom Welton, Green Chem., 2013, 15, 550-583

The inside front cover features work by Robert Brown and Kaige Wang from Iowa State University, USA, who report the catalytic pyrolysis of microalgae for production of valuable petrochemicals and ammonia.  This promising microalgae biorefinery pathway (both from an economical and environmental point-of-view) used the HZSM-5 catalyst for pyrolysis to convert whole microalgae into aromatic hydrocarbons.  The ammonia produced in the process can be recycled as a fertilizer for microalgae cultivation.

Catalytic pyrolysis of microalgae for production of aromatics and ammonia, Kaige Wang and Robert C. Brown, Green Chem., 2013, 15, 675-681

These articles are free to access for 6 weeks!

Keep up-to-date with the latest content in Green Chemistry by registering for our free table of contents alerts.

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Ohmic heating for efficient green synthesis

With environmental issues increasingly in the news, overcoming the challenges associated with greener chemistry has become a major focus of scientific research. To this aim, Portuguese scientists have developed a new ohmic-heating reactor for organic syntheses ‘on water,’  ie chemistry using an aqueous suspension of the reactants.

With ohmic heating the reaction medium itself serves as an electrical resistor, and is heated by passing electricity through it. Internal energy transformation occurs, from electrical to thermal energy, thanks to ion movement and friction within the reaction medium. Since the heating process depends on the resistivity of the medium, the exact conditions vary from reaction to reaction.

Lightning bolts hitting water, to illustrate ohmic heating

© Shutterstock

Read the full article in Chemistry World

Read the original journal article in Green Chemistry:
Ohmic heating as a new efficient process for organic synthesis in water
Joana Pinto, Vera L. M. Silva, Ana M. G. Silva, Artur M. S. Silva, José C. S. Costa, Luís M. N. B. F. Santos, Roger Enes, José A. S. Cavaleiro, António A. M. O. S. Vicente and José A. C. Teixeira
Green Chem., 2013, Advance Article
DOI: 10.1039/C3GC36881E
 

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Green Chemistry Issue 2 now online!

Green Chemistry issue 2, 2013, is now available to read online.

Green Chemistry, issue 2, 2013 - front coverThis issue features work by Enrique Herrero Acero, Georg Guebitz and co-workers from Austria who report the replacement of heavy-metal catalysts from paints.  Alkyd resins are polyesters containing unsaturated fatty acids which are used as binding agents in paints and coatings.  The chemical drying of these resins is based on crossing-linking the unsaturated fatty acid moieties using heavy-metal catalysts.  However, these catalysts have been proven to be carcinogenic and so research has been focused on finding less toxic and environmentally friendly alternatives.  The team here have developed a laccase-mediator system which not only performs well in aqueous media, but also in solid film.

Banning toxic heavy-metal catalysts from paints: enzymatic cross-linking of alkyd resins, Katrin J. Greimel, Veronika Perz, Klaus Koren, Roland Feola, Armin Temel, Christian Sohar, Enrique Herrero Acero, Ingo Klimant and Georg M. Guebitz, Green Chem., 2013, 15, 381-388

Green Chemistry, issue 2, 2013 - inside front coverThe inside front cover features work by Michael Meier and Maulidan Firdaus who have derived renewable polyamides and polyurethanes from limonene.  Addition of cysteamine hydrochloride to (R)-(+)- and (S)-(+)-limonene presented a versatile method to produce functionalised renewable monomers for polyamide and polyurethane synthesis.  Through various combinations, fatty acid, limonene and Nylon 6,6 copolymers were prepared. Diamines derived from limonene were efficiently transformed into dicarbamates viaa phosgene-free route, and linear renewable polyurethanes, with molecular weights of up to 12.6 kDa, were obtained through an isocyanate-free route.  The structure-thermal property relationships of these compounds were also studied.

Renewable polyamides and polyurethanes derived from limonene, Maulidan Firdaus and Michael A. R. Meier, Green Chem., 2013, 15, 370-380

Read these articles for free for 6 weeks!

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Environmentally friendly alternative to toxic heavy metals in paint

Austrian scientists have shown that an environmentally friendly enzyme, laccase, can be used to replace toxic drying agents in paint.

Currently, water-based paints contain heavy metals that dry the alkyd (polyester) resin films that are used as binding agents by catalysing the oxidative cross-linking of unsaturated fatty acid moieties in the films. Heavy metals are often toxic, and the commonly used cobalt-based catalysts have recently proved to be carcinogenic, and so alternative materials are being sought.

Laccase on painted background

An enzyme system could be an environmentally friendly alternative to toxic heavy metal drying agents in paints

Enrique Herrero Acero at the Austrian Centre of Industrial Biotechnology, Graz, and colleagues, decided to replace the heavy metal catalysts with a laccase enzyme–mediator-based, non-toxic biocatalyst. Laccases, found in fungi, bacteria and plants, can catalyse the oxidation of mainly phenolic substances, and are already used in other fields, including the food, pulp and paper, and textile industries.

Read the full article in Chemistry World

Read the original article online:
Banning toxic heavy-metal catalysts from paints: enzymatic cross-linking of alkyd resins
Katrin J. Greimel, Veronika Perz, Klaus Koren, Roland Feola, Armin Temel, Christian Sohar, Enrique Herrero Acero, Ingo Klimant and Georg M. Guebitz
Green Chem., 2013, Advance Article
DOI: 10.1039/C2GC36666E

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Top 10 cited review articles in 2012

A green chemistry coverAs the year draws to a close, here is a list of the top 10 cited review articles in Green Chemistry in 2012 – all free to access until the end of January 2013!

Technology development for the production of biobased products from biorefinery carbohydrates—the US Department of Energy’s “Top 10” revisited, Joseph J. Bozell and Gene R. Petersen, Green Chem., 2010, 12, 539-554

 Converting carbohydrates to bulk chemicals and fine chemicals over heterogeneous catalysts, Maria J. Climent, Avelino Corma and Sara Iborra, Green Chem., 2011, 13, 520-540

Catalytic conversion of biomass to biofuels, David Martin Alonso, Jesse Q. Bond and James A. Dumesic, Green Chem., 2010, 12, 1493-1513

Green chemistry by nano-catalysis, Vivek Polshettiwar and Rajender S. Varma, Green Chem., 2010, 12, 743-754

Synthesis of cyclic carbonates from epoxides and CO2, Michael North, Riccardo Pasquale and Carl Young, Green Chem., 2010, 12, 1514-1539

Searching for green solvents, Philip G. Jessop, Green Chem., 2011, 13, 1391-1398

5-Hydroxymethylfurfural (HMF) as a building block platform: Biological properties, synthesis and synthetic applications, Andreia A. Rosatella, Svilen P. Simeonov, Raquel F. M. Frade and Carlos A. M. Afonso, Green Chem., 2011, 13, 754-793

Vegetable oil-based polymeric materials: synthesis, properties, and applications, Ying Xia and Richard C. Larock, Green Chem., 2010, 12, 1893-1909

Glycerol as a sustainable solvent for green chemistry, Yanlong Gu and François Jérôme, Green Chem., 2010, 12, 1127-1138

Enzyme-mediated oxidations for the chemist, Frank Hollmann, Isabel W. C. E. Arends, Katja Buehler, Anett Schallmey and Bruno Bühler, Green Chem., 2011, 13, 226-265

Stay up-to-date with the latest news and content in Green Chemistry by registering for our free table of contents alerts.

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Green Chemistry issue 1, 2013 – now online!

The first issue of Green Chemistry for 2013 is now available to read online.  Click here to read the Editorial by the Chair of the Editorial Board, Professor Walter Leitner, and Editor, Sarah Ruthven.

The front cover of this month’s issue highlights the work of Bruce Lipshutz and colleagues from the University of California, Santa Barbara, USA.  The team reported the use of a nonionic amphiphile which efficiently enabled Stille couplings in water.  TPGS-750-M is a commercially available ‘designer’ surfactant which self-assembles to form nano-micelles in water.  Within each of these micelles, several coupling reactions can take place.  This procedure, which in most cases could be performed at room temperature, could be applied to a wide variety of substrates and leads to minimal waste generation.

Stille couplings in water at room temperature, Guo-ping Lu, Chun Cai and Bruce H. Lipshutz, Green Chem., 2013, 15, 105-109

The inside front cover features the work by Robert Davis and colleagues from the University of Virginia, USA.  In this Critical Review, the team evaluate the literature surrounding the use of supported metal nanoparticle catalysts for the selective oxidation of alcohols and aldehydes.  They compare the performances of the catalysts studied in this review by categorising reaction rates based on the turnover frequency as a common, consistent denominator.   The authors also look at factors that can affect the evaluation of reaction kinetics, such as catalyst deactivation, and give suggestions regarding how to obtain the best data.

Selective oxidation of alcohols and aldehydes over supported metal nanoparticles, Sara E. Davis, Matthew S. Ide and Robert J. Davis, Green Chem., 2012, 15, 17-45.

Read both of these article for free!

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