Archive for May, 2011

Bimetallic catalyst for hydrocarbon fuels, and styrene oxidation by hydrogen peroxide in ionic liquids

Production of liquid hydrocarbon fuels by catalytic conversion of biomass-derived levulinic acid. Dumesic and co-workers report the use of a highly active bimetallic catalyst  for the conversion of levuilinic acid to γ-valerolactone (GVL).  The RuRe/C catalyst used in this work is significantly more active that the traditional Ru/C, and shows stable activity and stereoselectivity in the presence of sulfuric acid.  A model techno-economical analysis has shown that this new calaytic process can be integrated with the catalyic conversion of GVL to butene, followed by alkene oligomerization, and could provide a cost effective route for converting biomass into liquid hydrocarbon fuels.  (Green Chem., 2011, DOI:10.1039/c1gc15047b)

Styrene oxidation by hydrogen peroxide in ionic liquids: the role of the solvent on the competition between two Pd-catalyzed processes, oxidation and dimerization. In this work, Chiappe and her team investigated the role of solvent in the Wacker oxidation of styrene, in ionic liquids (ILs).  They found that the nature of the IL has a strong influence on the outcome of the reaction.  In the hydrophillic ILs, a homogeneous solution is formed and gives the expected product with high selectivity, and only a small amount of by-products. However, in hydrophobic ILs, the aqueous solution of hydrogen peroxide is immiscible and so forms a biphasic system.  In this case side reactions occur, and the palladium catalyst is reduced from Pd(II) to Pd(0) and reoxidation back to Pd(II) is disfavoured. (Green Chem., 2011, DOI:10.1039/c0gc00945h)

Read these articles for free until 24th June

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Top ten most accessed articles in April

This month sees the following articles in Green Chemistry that are in the top ten most accessed:-

Expanding GSK’s solvent selection guide – embedding sustainability into solvent selection starting at medicinal chemistry 
Richard K. Henderson, Concepción Jiménez-González, 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, 13, 854-862 DOI: 10.1039/C0GC00918K, Paper 

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 

Greener solvents for ruthenium and palladium-catalysed aromatic C-H bond functionalisation 
Cedric Fischmeister and Henri Doucet 
Green Chem., 2011, 13, 741-753 DOI: 10.1039/C0GC00885K  

Searching for green solvents
Philip G. Jessop 
Green Chem., 2011, Advance Article DOI: 10.1039/C0GC00797H, Perspective 

Algae as a source of renewable chemicals: opportunities and challenges 
Patrick M. Foley, Evan S. Beach and Julie B. Zimmerman 
Green Chem., 2011, Advance Article DOI: 10.1039/C1GC00015B  

A critical assessment of the greenness and energy efficiency of microwave-assisted organic synthesis 
Jonathan D. Moseley and C. Oliver Kappe 
Green Chem., 2011, 13, 794-806 DOI: 10.1039/C0GC00823K, Perspective 

One-pot preparation of magnetic N-heterocyclic carbene-functionalized silica nanoparticles for the Suzuki-Miyaura coupling of aryl chlorides: improved activity and facile catalyst recovery 
Hengquan Yang, Yunwei Wang, Yong Qin, Yanzhu Chong, Qiaozhen Yang, Guang Li, Li Zhang and Wei Li 
Green Chem., 2011, 13, 1352-1361 DOI: 10.1039/C0GC00955E  

The 13 Principles of Green Chemistry and Engineering for a Greener Africa 
Nigist Asfaw, Yonas Chebude, Andinet Ejigu, Bitu B. Hurisso, Peter Licence, Richard L. Smith, Samantha L. Y. Tang and Martyn Poliakoff 
Green Chem., 2011, 13, 1059-1060 DOI: 10.1039/C0GC00936A  

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, Critical Review 

Production of liquid hydrocarbon fuels by catalytic conversion of biomass-derived levulinic acid 
Drew J. Braden, Carlos A. Henao, Jacob Heltzel, Christos C. Maravelias and James A. Dumesic 
Green Chem., 2011, Advance Article DOI: 10.1039/C1GC15047B  

Why not take a look at the articles today and blog your thoughts and comments below.

Fancy submitting an article to Green Chemistry? Then why not submit to us today or alternatively email us your suggestions.

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15th Annual Green Chemistry Conference

Have you registered for the 15th Annual Green Chemistry Conference?   With over 600 attendees expected, this premier Conference showcases innovations in all aspects of sustainable chemistry.  From June 21-23, mingle with US government representatives, Business executives, R&D managers, marketing and communication experts, sustainability thought leaders, chemical engineers, chemists, international & local students.  Attend numerous breakout sessions, networking events while exploring Washington D.C in the summer.

Visit the conference website, www.gcande.org, for updated conference information and to:  

Posted on behalf of Shefali Algoo, ACS Green Chemistry Institute.

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Using sunlight to drive electrochemical oxidations

Cheap and readily available photovoltaic cells have been used to conduct electrochemical oxidation reactions by Kevin D Moeller and co-workers from the Washington University in St Louis.

Connecting the dots: using sunlight to drive electrochemical oxidations

Connecting the dots

Oxidation reactions are among the most powerful tools available to synthetic chemists because they increase the level of functionality in a molecule.  This study demonstrates that the energy efficiency of sunlight-driven reactions can be combined with the versatility of electrochemistry to create new, sustainable methods for conducting oxidation reactions.

Interested in knowing more?  Read the full article here.

Connecting the dots: using sunlight to drive electrochemical oxidations
Laura A. Anderson, Alison Redden and Kevin D. Moeller
Green Chem., 2011, Advance Article
DOI: 10.1039/C1GC15207F

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Green Chemistry Editorial Board Chair Martyn Poliakoff nominated as Foreign Secretary of the Royal Society

Martyn Poliakoff CBE FRS

Martyn Poliakoff CBE FRS

Professor Martyn Poliakoff CBE has been nominated as the next Foreign Secretary of the Royal Society. Professor Poliakoff is the Chair of the Green Chemistry Editorial Board.

Foreign Secretary of the Royal Society is one of its most prestigious positions and the holder is responsible for building relationships around the world, particularly with other scientific academies, and ensuring that British Science and the Royal Society is recognised and promoted internationally. The post dates back to 1723 – predating the post of Foreign Secretary in the UK government by sixty years.

The appointment will not be official until the 7th of July when a ballot will be held and Fellows of the Royal Society asked to indicate their support, however, in keeping with tradition Professor Poliakoff is the only nominee.

As well as his duties for Green Chemistry, Professor Poliakoff is Research Professor of Chemistry at the University of Nottingham and one of the developers and regular presenters of the YouTube channel The Periodic Table of Videos where you can view a video in which Professor Poliakoff explains more about this appointment.  You can also read a recent interview with Professor Poliakoff on the Green Chemistry blog.

Professor Poliakoff’s current research interests involve chemical applications of supercritical fluids, with particular emphasis on green chemistry, and a selection of his most recent Green Chemistry articles have been made free until the 7th of July when his post will be made official.

The 13 Principles of Green Chemistry and Engineering for a Greener Africa
Nigist Asfaw, Yonas Chebude, Andinet Ejigu, Bitu B. Hurisso, Peter Licence, Richard L. Smith, Samantha L. Y. Tang and Martyn Poliakoff
Green Chem., 2011, 13, 1059-1060, DOI: 10.1039/C0GC00936A, Editorial

Continuous heterogeneous catalytic oxidation of primary and secondary alcohols in scCO2
Adrian O. Chapman, Geoffrey R. Akien, Nicholas J. Arrowsmith, Peter Licence and Martyn Poliakoff
Green Chem., 2010, 12, 310-315, DOI: 10.1039/B913434D, Paper

Solubilisation of α-chymotrypsin by hydrophobic ion pairing in fluorous systems and supercritical carbon dioxide and demonstration of efficient enzyme recycling
Karima Benaissi, Martyn Poliakoff and Neil R. Thomas
Green Chem., 2010, 12, 54-59, DOI: 10.1039/B904761A, Paper

Strategies for cleaner oxidations using photochemically generated singlet oxygen in supercritical carbon dioxide
Xue Han, Richard A. Bourne, Martyn Poliakoff and Michael W. George
Green Chem., 2009, 11, 1787-1792, DOI: 10.1039/B914074C, Paper

A critical look at reactions in class I and II gas-expanded liquids using CO2 and other gases
Geoffrey R. Akien and Martyn Poliakoff
Green Chem., 2009, 11, 1083-1100, DOI: 10.1039/B904097H, Critical Review

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Photosynthesis inspired photoreactor

Scientists from China have developed a way to intensify photocatalytic processes, and they have utilised it for efficient photoreactor design.

Currently, photocatalysis has few commercial or industrial applications because of the complex configuration of the photoreactor that would be required, and thus difficult engineering and scale-up issues.  However, Zhuhong Yang and co-workers from Nanjing University of Technology, China have developed a new photoreactor design which separates the process into two parts and has been inspired by photosynthesis in plants.

Photosynthesis can be considered as a tandem reaction consisting of the light reaction and the dark reaction. In the reactor designed by Yang, the first part of the reactor is the heterogeneous reaction, where surface-bound radical species are generated (the ‘light’ reaction) and the second part is the homogeneous reaction mediated by the radicals generated in part one (the ‘dark’ reaction).  The team used a static mixer which greatly improved the overall efficiency of the reaction by increasing radical mobility in the solution.

By separating the illumination and mixing parts of the photoreactor, scale-up and engineering applications will be made much easier.

For more information, please see the full article, free to read until 13th June:

Photosynthesis-inspired design approach of a liquid phase heterogeneous photoreactor, Dong Li, Kui Xiong, Kangzhong Shi, Zhuhong Yang, Chang Liu, Xin Feng and Xiaohua Lu, Green Chem., 2011, DOI: 10.1039/C1GC15082K.

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Predicting ionic liquid toxicity

Rapid screening of ionic liquids to determine their toxicity is now possible thanks to a modelling technique by scientists in Spain.

Ionic liquids (IL) – salts with low melting points – are being investigated as green alternatives to solvents, because their negligible vapour pressures result in minimal atmospheric contamination. However, their slight solubility in water poses a potential risk to aquatic ecosystems, as the toxicity of ILs is still relatively unknown.

Methods to predict the toxicity of unknown ILs would be very useful in IL research. Unfortunately, the only currently investigated method, quantitative structure-activity relationships, is labour intensive and time consuming.

Design of ionic liquids: an ecotoxicity (Vibrio fischeri) discrimination approach

The green fluorescent protein Vibrio fischeri in the background with ionic liquid structures

Now, Manuel Alvarez-Guerra and Angel Irabien at the University of Cantabria, in Santander, have devised a model to screen the toxicity of unknown ILs towards Vibrio fischeri, a standard bacterial assay for IL toxicity. 

The technique uses toxicity data from 64 known cations and 30 known anions that can be combined to theoretically make 1920 unique ionic liquids. By applying partial least squares-discriminant analysis and using the toxicity of toluene as a threshold value, the potential hazards of all the possible ILs can be predicted. After ‘training’ their model using a standard set of toxicity data, the team was able to confirm the model’s accuracy with a test set, obtaining a non-error rate of 93 per cent.

‘This tool could easily guide the design effort [of ILs] from the earliest steps of the process,’ says Alvarez-Guerra, ‘so we can direct the effort towards ionic liquids that we think will be less toxic than the conventional solvents that they may replace.’ 

Gloria Elliott, an expert in the biocompatibility of ionic liquids at the University of North Carolina at Charlotte, US, praises the novelty of the work. ‘Most of the [current] work has been looking at the structures and trying to deduce what functional groups or chain lengths would give rise to an enhanced toxicity,’ she explains. ‘But this takes the next step and starts to put it into computer language and enable more high-throughput processing,’ she adds.

However, she highlights that before the model can fulfil its potential, it needs to be tested against other datasets, such as toxicity data for cells of other species and higher organisms. Alvarez-Guerra agrees that this is the next step, but would rely on the availability of data.

Reproduced from a Chemistry World story written by Yuandi Li

Read the full article here:

Design of ionic liquids: an ecotoxicity (Vibrio fischeri) discrimination approach
Manuel Alvarez-Guerra and Angel Irabien, Green Chem., 2011
DOI: 10.1039/c0gc00921k

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Ionic liquids as dual functional anti-microbial agents and plasticisers in medical devices

Dual functional ionic liquids as plasticisers and antimicrobial agents for medical polymers

Chemical structures of the IL precursors used in this study: (a) 1-ethylpyridinium, (b) tributyl(2-hydroxyethyl)phosphonium and (c) bis(2-ethylhexyl)sulfosuccinate (docusate)

In this study Tony McNally and co-workers in Northern Ireland, Spain and the USA show that dual functional ionic liquids can uniquely provide both a plasticising effect for medical polymers, and exhibit antimicrobial and antibiofilm-forming activity to a range of antibiotic resistant bacteria.

Poly(vinyl chloride) (PVC) is widely used in the manufacture of a range of medical devices, including endotracheal tubes and catheters. The unique flexibility of PVC for use in such applications is derived from the use of phthalate esters as plasticisers. However, the possible carcinogenic and reprotoxic effects of phthalates has been a concern for some decades since their identification as an environmental contaminant.  Another problem with medical devices is the risk of infection of indwelling medical devices as bacteria can colonise and form a biofilm on the surface. As device-related infections are recalcitrant to conventional antimicrobial therapy and host defences, alternative agents for their treatment are required. Ionic liquids have been shown in separate experiments to have antimicrobial activity and a plasticising effect on polymeric materials.

This study reports the design of two dual functional ionic liquids which uniquely provide a plasticising effect, and exhibit antimicrobial and antibiofilm-forming activity to a range of antibiotic resistant bacteria. The design approach adopted will be useful in developing ionic liquids as multi-functional additives for polymers.

Interested in knowing more?  Read the full article here. Free until June 3rd.

Dual functional ionic liquids as plasticisers and antimicrobial agents for medical polymers
Seong Ying Choi, Héctor Rodríguez, Arsalan Mirjafari, Deirdre F. Gilpin, Stephanie McGrath, Karl R. Malcolm, Michael M. Tunney, Robin D. Rogers and Tony McNally
Green Chem., 2011, Advance Article
DOI: 10.1039/C1GC15132K

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