Green Chemistry Blog

Solvent selection guide for medicinal chemists

23 Mar 2011

Scientists at GlaxoSmithKline (GSK) have recently published a revised “solvent selection guide” which is designed to aid the decision-making process associated with choosing a solvent for a chemical transformation. The original solvent selection guide published in 1998 assessed the use of 47 solvents in organic chemistry reactions. The updated version of the solvent selection guide now includes 110 solvents (each with a life cycle score), thus providing a more comprehensive comparative and relative assessment of the solvents.

The guide also contains information on solvent recycling, environmental impact, health and flammability issues amongst others. The broad range of issues covered in the guide will enable scientists to make an objective decision on which solvents to use based on multiple paramenters – this will help truly assess which solvent is the most sustainable for a particular procedure.

Click the link below to read the article in full – free access until 21st April

Expanding GSK’s solvent selection guide – embedding sustainability into solvent selection starting at medicinal chemistry

Richard K. Henderson, Concepcion Jimenez-Gonzalez, David J. C. Constable, Sarah R. Alston, Graham G. A. Inglis, Gail Fisher, James Sherwood, Steve P. Binks and Alan D. Curzons, Green Chem., 2011, DOI: 10.1039/c0gc00918k

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Read the best ionic liquid research from the Asia-Pacific region

18 Mar 2011

By Kathleen Too, Deputy Editor.

Green Chemistry has collated a number of ionic liquid research presented at the recent 2nd Asia Pacific Conference on Ionic Liquids and Green Processes held in Dalian, China, on 7-10 September 2010. The selection of articles below represents some of the best ionic liquid research from the Asia-Pacific region. You can access the web-themed issue online.

Fangmin Jin and co-workers demonstrate the reduction of NaHCO3 to formate using isopropanol as a reducing agent. Yields of about 70% were acheived.

Green Chemistry reviews some of the challenges

15 Mar 2011

By Kathleen Too, Deputy Editor.

Green Chemistry has recently published a series of critical reviews that have been highly downloaded. These reviews aim to cover the trends and progress in the fields and also set the scene for cutting-edge research and innovations for a greener and sustainable future. More importantly the reviews highlight the challenges that need to be urgently addressed in each of those research areas.

Use of carbon dioxide in chemical syntheses via a lactone intermediate
A. Behr and G. Henze
Green Chem., 2011, 13, 25-39
DOI: 10.1039/C0GC00394H

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
DOI: 10.1039/C0GC00639D

Processing of metals and metal oxides using ionic liquids
Andrew P. Abbott, Gero Frisch, Jennifer Hartley and Karl S. Ryder
Green Chem., 2011, 13, 471-481
DOI: 10.1039/C0GC00716A

Viable methodologies for the synthesis of high-quality nanostructures
Jonathan M. Patete, Xiaohui Peng, Christopher Koenigsmann, Yan Xu, Barbara Karn and Stanislaus S. Wong
Green Chem., 2011, 13, 482-519
DOI: 10.1039/C0GC00516A

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
DOI: 10.1039/C0GC00595A

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, Advance Article
DOI: 10.1039/C0GC00401D

Greener solvents for ruthenium and palladium-catalysed aromatic C–H bond functionalisation
Cedric Fischmeister and Henri Doucet
Green Chem., 2011, Advance Article
DOI: 10.1039/C0GC00885K

The irruption of polymers from renewable resources on the scene of macromolecular science and technology
Alessandro Gandini
Green Chem., 2011, Advance Article
DOI: 10.1039/C0GC00789G

You may also be interested in some of the review articles published in 2010:

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

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

Vegetable oil-based polymeric materials: synthesis, properties, and applications
Ying Xia and Richard C. Larock
Green Chem., 2010, 12, 1893-1909
DOI: 10.1039/C0GC00264J

Glycerol as a sustainable solvent for green chemistry
Yanlong Gu and François Jérôme
Green Chem., 2010, 12, 1127-1138
DOI: 10.1039/C001628D

Synthesis of cyclic carbonates from epoxides and CO2
Michael North, Riccardo Pasquale and Carl Young
Green Chem., 2010, 12, 1514-1539
DOI: 10.1039/C0GC00065E

Enzymes in neoteric solvents: From one-phase to multiphase systems
Pedro Lozano
Green Chem., 2010, 12, 555-569
DOI: 10.1039/B919088K

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Are microwave reactions really green?

03 Mar 2011

By Kathleen Too, Deputy Editor.

Jonathan Moseley and Oliver Kappe provide some pertinent answers to the question: “Why should microwave chemistry be green?”.

There has been over 5000 microwave-assisted syntheses reported in the last 25 years and most of the scientific reports assume that microwave reactions are green, sustainable, environmentally friendly (“ecofriendly”), benign etc. A lot of the times, authors do not provide a clear rationalization and justification why the respective protocols are green because most researchers assume that microwave heating is more energy efficient than classical heating methods.

Here, Moseley and Kappe critically assess the energy efficiency of microwave-assisted transformations in the context of scaling-up this technology to production quantities, taking into account the twelve principles of green chemistry, with a focus on the 6th principle: design for energy efficiency.

“Microwave heating process performed in laboratory-scale single-mode microwave reactors is appallingly energy inefficient,” claim Moseley and Kappe.

However, they agree that when moving from the lab scale to the kilogram scale, microwave technology is more efficient that conventional heating processes.

The full perspective can be freely downloaded until the 3rd April 2011.

A critical assessment of the greenness and energy efficiency of microwave-assisted organic synthesis
Jonathan D. Moseley and C. Oliver Kappe
Green Chem., 2011, Advance Article
DOI: 10.1039/C0GC00823K, Perspective

This perspective has also been highlighted in Chemistry World. It can be read here:

Microwave chemistry – green or not?

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Changing the properties of biocompatible polymers

25 Feb 2011

By Emma Eley, Deputy Editor.

Polymer scientists from Aachen, Germany, have developed a novel and green method to produce biocompatible polyesters using Novozyme 435 as the catalyst.

The polyester poly(pentadecalactone) (PPDL) investigated in this work is a non-toxic, highly crystalline and hydrophobic material – similar to polyethylene. By copolymerizing pentadecalactone with functional e-caprolactones and macrolactones containing C=C double bonds, epoxide rings and amide functionalities, it was found that the properties of PPDL could be tuned and crystallinity was reduced – increasing the biocompatibility of the material which is necessary for applications in drug-delivery devices or scaffolds.

Using the Novozyme 435 enzyme catalyst, copolymerization of PDL with two 7-membered lactones leads to a near quantitative monomer conversion.

To find out more, click the link below to read the Green Chemistry article in full – free to access until 21st March 2011.

Tailor-made polyesters based on pentadecalactone via enzymatic catalysis by C. Vaida, H. Keul and M. Moeller
DOI: 10.1039/C1GC15044H

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Finding the optimum conditions – screening solvents and catalysts

21 Feb 2011

By Kathleen Too, Deputy Editor.

Scientists from the Netherlands and the UK have conducted a solvent screening study aimed at identifying greener alternatives for the commonly used solvent dichloromethane in N-oxy catalysed bleach oxidations of various alcohol substrates.

The team found that environmentally acceptable ester solvents, notably isopropyl acetate and methyl acetate, gave results comparable to or better than dichloromethane.

However, there was no apparent correlation between common solvent properties and performance.

A comparison of two co-catalysts, NaBr and borax, revealed that borax gave better results with cinnamyl alcohols whereas NaBr was generally better with the other alcohols.

The team also studied the effect of catalyst loading. In the oxidation of 3-phenyl-1-propanol the amount of N-oxy catalyst could be effectively reduced to a mere 0.1 mol%.

They concluded that due to the complex nature of these systems, there is not a single set of conditions that gives good results for all alcohols. However, by employing a simple screening approach to assess solvent, catalyst and co-catalyst combinations, similar or even better results can often be achieved in solvents other than dichloromethane.

Read more about this article:

Towards greener solvents for the bleach oxidation of alcohols catalysed by stable N-oxy radicals
M H A Janssen, J F Chesa Castellana, H Jackman, P J Dunn and R A Sheldon, Green Chem., 2011, DOI:10.1039/c0gc00684j

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New editorial policy on the publication of Ionic Liquid studies in Green Chemistry

16 Feb 2011

By Emma Eley, Deputy Editor.

“Not all ionic liquids are green!” is what we often hear at Green Chemistry conferences. Indeed there have been many debates about ionic liquid toxicity and more importantly how we determine if an ionic liquid is “green”. However, we increasingly receive a number of articles merely reporting the properties of an ionic liquid or its toxicity with no insight on its impact on green processes.

In the new editorial by Tom Welton, he clarifies the Journal’s policy on the publication of ionic liquid toxicity studies. While it is, of course, a very important area of research for the ionic liquid community, the new guidelines in the editorial state that articles purely on ionic liquid toxicity will no longer fall within the scope of Green Chemistry. However, if an article on ionic liquid toxicity demonstrates that the design of the ionic liquid improves a green process or product then that article is within the redefined scope of the Journal. In the same way that studies on the physical properties of ionic liquids are useful to practitioners of Green Chemistry, the actual work in itself is not “green chemistry” – the same applies to ionic liquid toxicity studies.

Click here to read the full editorial by Tom Welton.

Whether it is an ionic liquid or not, choosing the right solvent is very important when attempting to make a chemical process “greener”. Read the latest perspective by Phil Jessop on searching for green solvents.

Is the green solvents research community investing time and effort in the areas of research that will give the maximum environmental benefit? What areas of research would increase the benefit?

Philip G. Jessop

Green Chem., 2011, Advance Article, DOI: 10.1039/C0GC00797H, Perspective

You may also be interested in reading our 2009 themed issue on “Green solvents – Progress in science and application” published in Green Chemistry.

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Processing of metals and metal oxides using ionic liquids – a review

16 Feb 2011

By Mary Badcock, Deputy Editor.

Andrew Abbott and co-workers at the University of Leicester have reviewed the use of ionic liquids for the processing of metals and metal oxides.

Processing of metals and metal oxides using ionic liquids

The processing and reprocessing of metals is possibly one of the largest energy consumers and generators of waste in the industry sector. Typically, metal extract and recovery (also known as hydrometallurgy) in solution is done in melts or very basic or acidic solutions, as metal oxides are insoluble in most molecular solvents. However, these methods have disadvantages due to their high energy demands, the amount of waste generated, and the numerous steps involved.

Ionic liquids, salts which are liquid below 100 °C, possess useful physical properties which allow them to be applied to many different reactions and processes. In this case, some ionic liquids have demonstrated much higher solubilities for metal salts than most organic solvents. Potential advantages of using ionic liquids in this field include the ability to simplify processing techniques and avoid the formation of oxide and hydroxide products during processing.

In this review Abbott and co-workers critically review the potential efficacy of ionic liquids in metal and metal oxide processing over existing methods.

This article is freely available until the 16 March 2011:

Processing of metals and metal oxides using ionic liquids, Andrew P. Abbott, Gero Frisch, Jennifer Hartley and Karl S. Ryder, Green Chem., 2011, DOI: 10.1039/C0GC00716A.

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Green Chemistry Blog

Top ten most accessed articles in February

Top ten most accessed articles in January

Solvent selection guide for medicinal chemists

Read the best ionic liquid research from the Asia-Pacific region

Green Chemistry reviews some of the challenges

Are microwave reactions really green?

Changing the properties of biocompatible polymers

Finding the optimum conditions – screening solvents and catalysts

New editorial policy on the publication of Ionic Liquid studies in Green Chemistry

Processing of metals and metal oxides using ionic liquids – a review

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