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Eco-friendly chromatography

Spanish scientists have devised a greener form of liquid chromatography by using cyclodextrins as additives in the mobile phase. This results in more water being used in the chromatographic process.

Using cyclodextrins in chromatography could increase the amount of water being used

Cyclodextrins are a natural, renewable compound made from starch and are totally biodegradable. They can be modified and tailor made, and as a result are used in a variety of fields including the pharmaceutical, food and cosmetic industries.

High performance liquid chromatography (HPLC) is a commonly used analytical technique that allows fast separation and quantification of compounds in complex mixtures. Owing to its high resolution and sensitivity, it is widely employed in academic and industrial settings.

Using cyclodextrins in chromatography could increase the amount of water being used
Antonia Martin and colleagues from the Complutense University of Madrid investigated ways of reducing the amount of acetonitrile and developing chromatographic methods that use an increasing amount of water and renewable solvents like ethanol. ‘Due to the toxicity of acetonitrile, these mobile phases have to be treated as chemical waste, so we were interested in using non-toxic solvents, especially alcohols, as an alternative,’ says Martin.

Being greener is only a benefit if the performance of the new system is comparable to current methods. To check this, Martin and her team tested for beta-carbolines, a naturally occurring alkaloid linked to neurological diseases, in human blood serum. The results were as good as non-cyclodextrin modified HPLC in terms of accuracy – in fact the cyclodextrins increased the detection sensitivity.

‘There was a rapid increase in the price of acetonitrile during 2008 so these substitutions will lead to significant cost benefits as well as green chemistry benefits,’ he adds.

Rebecca Brodie

This article is free to access upon a simple registration process:

Eco-friendly liquid chromatographic separations based on the use of cyclodextrins as mobile phase additives
Víctor González-Ruiz, Andrés G. León, Ana I. Olives, M. Antonia Martín and J. Carlos Menéndez, Green Chem., 2011, DOI:10.1039/c0gc00456a

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Read our latest Green Chemistry hot articles

The following hot articles can be freely downloaded until Christmas after a simple registration process: http://pubs.rsc.org/en/account/register

Enjoy the read!

Mechanism of efficient anti-Markovnikov olefin hydroarylation catalyzed by homogeneous Ir(III) complexes
Elucidation of the full mechanism of the hydroarylation reaction between unactivated olefins and benzene carried out by the (acac-O,O)IrIII(R)(L) catalyst.

Gaurav Bhalla, Steven M. Bischof, Somesh K. Ganesh, Xiang Yang Liu, C. J. Jones, Andrey Borzenko, William J. Tenn, III, Daniel H. Ess, Brian G. Hashiguchi, Kapil S. Lokare, Chin Hin Leung, Jonas Oxgaard, William A. Goddard, III and
Roy A. Periana, Green Chem., 2011, Advance Article, DOI:10.1039/C0GC00330A
A renewable gasoline can be prepared directly from biomass sugar solutions in a two-bed reactor system.

Ning Li, Geoffrey A. Tompsett, Taiying Zhang, Jian Shi, Charles E. Wyman and George W. Huber, Green Chem., 2011, Advance Article, DOI: 10.1039/C0GC00501K 

Recycling of hydrophilic, water miscible ionic liquids/deep eutectic solvents by means of pressure driven membrane separation technologies was critically studied.
Kurt Haerens, Stephanie Van Deuren, Edward Matthijs and Bart Van der Bruggen, Green Chem., 2010, 12, 2182-2188, DOI: 10.1039/C0GC00406E

Room temperature ionic liquids containing [OAc] anions, with high Kamlett–Taft β parameter values (β 〉 1), are effective solvents for pretreatment of recalcitrant maple wood flour.

Thomas V. Doherty, Mauricio Mora-Pale, Sage E. Foley, Robert J. Linhardt and Jonathan S. Dordick, Green Chem., 2010, 12, 1967-1975, DOI: 10.1039/C0GC00206B

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Top cited articles in Green Chemistry

Top most cited articles in 2010 published in Green Chemistry:

Arno Behr, Jens Eilting, Ken Irawadi, Julia Leschinski and Falk Lindner
Green Chem., 2008, 10, 13-30, Critical Review

Yukinobu Fukaya, Kensaku Hayashi, Masahisa Wada and Hiroyuki Ohno
Green Chem., 2008, 10, 44-46,  Communication

Green Chem., 2008, 10, 177-182, Paper

Radovan Šebesta, Iveta Kmentová and Štefan Toma
Green Chem., 2008, 10, 484-496,  Critical Review

Hua Zhao, Gary A. Baker, Zhiyan Song, Olarongbe Olubajo, Tanisha Crittle and Darkeysha Peters
Green Chem., 2008, 10, 696-705, Paper

Ayumu Onda, Takafumi Ochi and Kazumichi Yanagisawa
Green Chem., 2008, 10, 1033-1037, Paper

Hydrothermal carbon from biomass: a comparison of the local structure from poly- to monosaccharides and pentoses/hexoses
Maria-Magdalena Titirici, Markus Antonietti and Niki Baccile
Green Chem., 2008, 10, 1204-1212, Paper

Conversion of fructose to 5-hydroxymethylfurfural using ionic liquids prepared from renewable materials
Suqin Hu, Zhaofu Zhang, Yinxi Zhou, Buxing Han, Honglei Fan, Wenjing Li, Jinliang Song and Ye Xie
Green Chem., 2008, 10, 1280-1283, Communication

Complete dissolution and partial delignification of wood in the ionic liquid 1-ethyl-3-methylimidazolium acetate
Ning Sun, Mustafizur Rahman, Ying Qin, Mirela L. Maxim, Héctor Rodríguez and Robin D. Rogers
Green Chem., 2009, 11, 646-655, Paper

Desulfurisation of oils using ionic liquids: selection of cationic and anionic components to enhance extraction efficiency
John D. Holbrey, Ignacio López-Martin, Gadi Rothenberg, Kenneth R. Seddon, Guadalupe Silvero and Xi Zheng
Green Chem., 2008, 10, 87-92, Paper

Join those leading authors by submitting your work to Green Chemistry today!

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Which ionic liquid to use for dissolving cellulose?

German scientists have developed a model to predict the solubility of cellulose in different ionic liquids. 

In the past, ionic liquids have been shown to be promising solvents for cellulose but have you ever wondered which ones to use because the ionic liquid candidates are numerous? Kai Leonhard and co-workers, at the RWTH Aachen University in Germany, used a computing model called COSMO-RS to screen over 2000 ionic liquids with respect to their dissolving power for cellulose. The results are in good agreement with experimental data available in literature. 

Leonhard and his team found that “anions were mainly responsible for the respective dissolving power, suggesting some new ionic liquids as potential candidates for cellulose dissolution”. 

Read more about this article here:

Modelling cellulose solubilities in ionic liquids using COSMO-RS
Jens Kahlen, Kai Masuch and Kai Leonhard, Green Chem., 2010, DOI: 10.1039/C0GC00200C, Paper

 

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Hydrogenolysis without hydrogen gas

“This is the first demonstration of electrochemical hydrogenolysis,” says Richard G. Compton and co-workers.

The UK scientists at Oxford University showed a simple and rapid electrochemical hydrogenolysis process in room temperature ionic liquid requiring no hydrogen gas. 

Hydrogenolysis of N,N¢-bis(benzyloxycarbonyl)-L-lysine was achieved by the electrochemical reduction of a labile proton at a Pd microelectrode,and the hydrogenolysis monitored by the size of the Pd/H oxidation peak. “The extension of this system to hydrogenation reactions should present no great problems, ” claims Compton and co-workers.

Read the article online:

Hydrogenolysis without hydrogen gas: hydrogen loaded palladium electrodes by electrolysis of H[NTf2] in a room temperature ionic liquid

Yao Meng, Leigh Aldous and Richard G. Compton, Green Chem., 2010, DOI: 10.1039/C0GC00450B

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Anti-corrosive acid catalysts minimises reactor contamination

Nishide and Heard reports a novel recyclable acid catalysts for use in esterification, Friedel-Crafts acylation and other condensation reactions. The team from Waseda University in Japan and Monash University in Australia reports the synthesis of high-density poly(vinylsolfonic acid)-grafted solid acid materials with extremely high acid dissociation abilities.

 

They found the catalyst to possess interesting anti-corrosive properties implying that reactor corrosion is minimised. The process introduces “a new avenue to carry out such solid-phase acid catalysed synthetic reactions in a more benign, green chemical manner, whilst minimizing pollution/contamination risks due to leading to minimum risks of reactant contamination due to corrosion”, claims Hearn and co-workers.

Read more here:

Poly(vinylsulfonic acid)-grafted solid catalysts: new materials for acid-catalysed organic synthetic reactions

Teruyuki Okayasu, Kei Saito, Hiroyuki Nishide and Milton T. W. Hearn, Green Chem., 2010, DOI:10.1039/C0GC00241K

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Singing Green Chemistry tools in Germany

The Green Solvents for Synthesis conference started on Sunday the 10th October 2010 with a boat trip on Lake Königsee which I was told was absolutely spectacular with plenty of mountain landscape.  The lake was described as the purest of all “green solvents” being a gorgeous emerald green in colour.

The delegates were then gathered for a welcome reception in the evening and an opening lecture delivered by Phil Jessop (Queen’s University, Canada) where he described the progress made in green solvents and categorised them in three areas: Replacement green solvents, Really green solvents, and Revolutionary green solvents. His comments were that the replacement solvents may not be enough to cover the different needs. Some solvents have been assessed thoroughly and found to be really green, but most “green” solvents have not been assessed.

On the first day of the conference, Peter Dunn of Pfizer Ltd gave us a broad overview of organic reactions carried out in water. Other talks of interest were by Takao Ikariya (Tokyo institute of Technology) on the use carbon dioxide as green solvent and reactant for organic reactions and Tadafumi Adschiri (Tohoku University) who brought along samples of the super hybrid materials made in his lab via supercritical routes. This was followed by a lecture by Andreas Jess (University of Bayreuth, Germany) on the evaporation and thermal decomposition of ionic liquids by thermogravimetry at ambient pressure and UHV.  The afternoon ended with an inspiring lecture by Peter Wassercheid (University of Erlangen-Nuremberg) on ionic liquids and heterogeneous catalysis and his recent progress on supported ionic liquid phase (SILP) and supported catalyst with an ionic liquid layer (SCILL). A poster session then followed with winners to be announced shortly.

The highlights of the second day were talks by Dieter Vogt (TU Eindhoven) on homogeneous catalysis and amine formations, followed by Alberto Puga (QUILL, Belfast) on new 6-membered  piperidine and 7-membered azepane derived ionic liquids. It became clear that toxicity is an important factor in determining the “greenness” of new ionic liquids. Other talks of interest were algae lipids for biodiesel production delivered by Lindsay Soh (PhD student at Yale University) and fluorous solvents for catalyst recovery, activation and product protection given by John Gladysz (Texas A&M University).

The delegates were spoilt for choices for lunch at either traditional Bavarian style restaurants or small cafes with plenty of outdoor seating to soak up the sun and the magnificent mountain views. The afternoon session resumed with an awe-inspiring talk by Steve Howdle (University of Nottingham, UK) where he used supercritical fluids to synthesize green polymers which were used in bone grafting and drug delivery. We later learnt that Steve, who is a keen footballer, had been invited to take a penalty shoot at half-time during the England-Montenegro qualifying match at Wembley Stadium and he had declined the FA invitation to be with us at the Green Solvents conference. Biocatalysis was also on the agenda with a talk from Udo Kragl (University of Rostock, Germany).

The day ended with a traditional Bavarian buffet and music. The atmosphere was light-hearted and spirits high. Walter Leitner, Steve Howdle, Istvan Horvath, Peter Wassercheid and Helen Olivier-Bourbigou grouped on stage for an excellent rendition of the “green chemistry song”, lyrics below:

Always Use Green Chemistry Tools

Music: guitar by Walter Leitner

Lyrics: Walter Leitner and Steve Howdle

Some syntheses are bad

They can really make you mad

Other chemistry just smells and makes a mess!

If the molecule’s a hassle

Don’t crumble- give a whistle

Green Chemistry will change things for the best!

Chorus:

And Always use the Green Chemistry tools

— whistle —

They make science fun and scientists cool

— whistle —

If the process seems absurd

And “waste” is the final word

Green Chemistry will show a better way!

Just save energy and steps

Of course, catalysis can help

And your profits will shoot up to the sky!

Chorus:

And Always use the Green Chemistry tools

— whistle —

They make science fun and scientists cool

— whistle —

Using carbon dioxide

Makes the future look so bright!

And with biomass we make the stuff we need

All the solvents are replaced

There is no more toxic waste

The business model is extremely neat!

Chorus:

And Always use the Green Chemistry tools

— whistle —

They make science fun and scientists cool

— whistle —

Unfortunately, I was unable to attend the last day of the conference but I am sure that the lectures were as inspiring as the previous days. Green solvents 2012 is a must and well done DECHEMA for organising this excellent conference!

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Making fuels from biomass waste

Jet and diesel fuel can be produced in a simple economic process using waste products of wood processing and pulp mills, claim US scientists. 

World decline in fossil fuel resources, rising oil prices, and an increased awareness in environmental impact has made the search for alternative renewable fuel sources extremely important. Sustainable production of fuels has been attempted using non-food biomass (composed of cellulose, hemicellulose, and lignin) and vegetable oils. But these methods only make light alkanes that are not suitable for use as jet and diesel fuel due to their high volatility, so jet and diesel fuels are currently still reliant on petroleum-based crude oils. 

In the search for alkanes more suited for transport fuels, George Huber at the University of Massachusetts in Amherst and colleagues have shown that waste feedstocks from biomass power plants or composite wood manufacturing facilities can be turned into jet fuel in an integrated and economical process. 

four step process

4 step process produces heavy alkanes suitable for diesel

Huber treats a hemicellulose extract from hardwood trees, a common by-product from the wood manufacturing industry, in a four-step process that includes acid hydrolysis and xylose dehydrogenation, aldol condensation, low temperature hydrogenation, and high temperature hydrodeoxygenation. High yields of 76 per cent are obtained and the cost works out to between $2.06/gal and $4.39/gal, depending on initial xylose concentration, refinery size and overall yield. 

‘Our society will always have a critical need to produce renewable liquid transportations fuels that can run heavy machinery like jet or diesel engines. It is imperative that we develop inexpensive routes to produce these liquid fuels from our renewable resources,’ comments Huber. Though in its beginning stages, Huber hopes it can be developed to a commercial level. 

David Shonnard, director of the Sustainable Futures Institute at Michigan Technological University in the US comments, ‘this is a significant step forward in achieving sustainable transportation. The economic analysis is also particularly important and the sensitivity analyses highlight promising pathways for improvement.’ 

Rebecca Brodie

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Hot article: Screening Ionic Liquids for Cellulose Dissolution

Kai Leonhard and co-workers at the Univeristy of Stuttgart, Germany, provide an insight into the solvation mechanism of ionic liquids for cellulose dissolution using COSMO-RS combined with some other modelling studies. From the screening of more than 2200 ionic liquids, it is suggested that the anion as mainly responsible for the respective dissolving power. The German team also identified some new ionic liquids as potential candidates for cellulose dissolution. The results are in good qualitative agreement with those from the experimental data available in the literature.

Graphical abstract image for this article  (ID: c0gc00200c)

Read the full article here: http://dx.doi.org/10.1039/c0gc00200c

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Nominations for the 2011 RSC Prizes and Awards are now open

The RSC currently presents around 60 prestigious Prizes and Awards annually to scientists in all the main chemical science disciplines allowing for the greatest range of scientists to be recognised for their work; individuals, teams and organisations working across the globe.

There are nine categories of awards including specific categories for Industry and Education so whether you work in business, industry, research or education recognition is open to everyone.

Our Prizes and Awards represent the dedication and outstanding achievements in the chemicals sciences and are a platform to showcase inspiring science to gain the recognition deserved.

Do you know someone who has made a significant contribution to advancing the chemical sciences?

View our full list of Prizes and Awards and use the online system to nominate yourself or colleagues.

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