Sustainable recovery of pure natural vanillin from fermentation media in one step

Pure vanillin can be recovered from fermentation media in a single, sustainable, solvent-free pervapouration step.

Vanillin is one of the world’s most important aroma compounds in the profitable market of flavours and fragrances. The majority of vanillin is produced chemically, with only a very small proportion extracted from beans. Vanillin can also be produced from fermentation processes, which have significantly lower production costs and give a high quality product.  However, vanillin produced by this method can only be described as ‘natural’ if its recovery from the fermentation media does not adversely affect the product quality.  This is an important characteristic as ‘natural’ vanillin has a much higher commercial price that synthetic vanillin.

In this work Crespo and co-workers have used an organophilic pervaporation method to recover vanillin from fermentation media.  This process involves a hydrophobic non-porous membrane in which hydrophobic solutes sorb very favourably to it, diffuse across the membrane and desorb under stimulus (e.g. changes in pressure).  This method avoids the use of organic solvents and contamination from adsorbents, and provided quantitative recovery of vanillin.

To find our more, just click the link below!  This article is free to access until 29th August!

Sustainable recovery of pure natural vanillin from fermentation media in a single pervaporation step, Carla Brazinha, Dalje S. Barbosa and João G. Crespo, Green Chem., 2011, DOI: 10.1039/C1GC15308K

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Granting wishes for researchers

Rafael Luque discusses funding for early stage researchers and the importance of green chemistry with Anna Simpson

Rafael Luque

Rafael Luque is the Ramon y Cajal fellow at the University of Cordoba in Spain. His interests range from materials science, nanotechnology and heterogeneous catalysis to biomass valorisation and biofuels.

How did you get to where you are today? 

I was always fascinated by chemistry because it’s in everything. This table that we are sitting at is chemistry! 

I did my undergraduate degree at the University of Cordoba in Spain and I was delighted to receive a grant to do my PhD in the organic chemistry department there. I started to have my own ideas and in pursuing them, my supervisors were always happy. It all worked out really well in the end! 

During my PhD, I spent six months at the green chemistry centre of excellence at the University of York in the UK. I worked with Duncan Macquarrie who had a big impact on my career. I am very grateful to him and to James Clark for this. After my PhD, I returned to York as a green chemistry research associate and spent some of the most wonderful years of my career to date there. Everything went very well in York; however, after three and a half years as a postdoc, I needed to move on with my career and my life. So, due to personal and family pressures, I decided to move back to Cordoba. In the beginning, this was difficult but I managed to get a nice fellowship and now have a small group of four PhD students and a postdoc starting soon. 

What are the biggest challenges facing young researchers and what’s your advice for someone about to embark on the next step after a PhD or postdoc? 

Innovation is the key to success. You can’t get grant money for doing the same thing that we have been doing for over 20 years, it must be new work. 

Getting funding and grants is challenging, but even with a very small group, such as one masters or PhD student, you can start to do more work. I have met lots of innovative and creative people in Europe and Spain. They have lots of interesting ideas and promising research but the problem is they need basic funding to progress. My advice is to keep trying and not lose courage as generally, if you are unsuccessful, you have to carry on and fight for what you want to do. 

You have quite wide ranging research interests but the theme that underpins it all is green and sustainable chemistry. Why is green chemistry important? 

Green chemistry is going to be everything in the future. We will be using green products made using technology with low environmental impact and utilising locally sourced materials and even waste. The perception of waste as a resource rather than a problem is something we have to change in people’s minds. We still have some work to do there. 

After working in both the UK and Spain, what differences did you experience between the chemical research communities in these countries? 

There are lots of differences. In the UK, there are big funding agencies to support researchers. This is something we lack in Spain, but I must stress that in Spain, I have found that we are good and very competitive in terms of publications and research. We are innovative and creative and I was very pleased to see, when I got back, that there were so many people doing such a great job – it is a big inspiration for me. It is especially apparent with young researchers. They lack resources but are still self-motivated to pursue their dreams, which is very encouraging. I take care of students and encourage them to carry on because I can see that this degree of motivation is getting them everywhere. I love teaching – there is always a way to engage the students to learn about chemistry. Being a young academic often helps because students feel closer to you as there is not an age barrier. The language and the way you communicate with the students are not so different. 

Where does your funding come from? 

At the moment it’s mostly national and regional funding. This wasn’t particularly easy to get, but the government supports young researchers with groundbreaking ideas. The funding I received is aimed at early career researchers and for me, after proposing one of these groundbreaking concepts, it was helpful that I could get some funding – it allowed me to go back to Cordoba. 

Hopefully, at the end of October, I will try my best to be successful with a European bid, which could potentially put me in a more stable situation and allow me to grow a bigger group. This funding, called a ‘Starting Research Grant’ is indeed a lot of money – 1.5 million Euros – so it could have a big impact on my career. Its purpose is to allow someone to develop ideas and start an independent research group that could lead to important developments for Europe. We plan to work with lignocellulosics and lignin, one of our main targets. 

What do you like to do when you are not doing chemistry? 

I love travelling – it’s one of my favourite things, so I have been all over the world except for Australia and New Zealand. When I’m at home, I’m addicted to video games; I must admit that I am a big fan. Other than that, I love music, so if I wasn’t a chemist I would probably be a DJ.

Read some of Rafael Luque’s latest work in Green Chemistry by following the links below:

Catalytically active self-assembled silica-based nanostructures containing supported nanoparticles
Camino Gonzalez-Arellano, Alina Mariana Balu, Rafael Luque and Duncan J. Macquarrie
Green Chem., 2010, 12, 1995-2002

Magnetically separable nanoferrite-anchored glutathione: aqueous homocoupling of arylboronic acids under microwave irradiation
Rafael Luque, Babita Baruwati and Rajender S. Varma
Green Chem., 2010, 12, 1540-1543

Highly active and selective supported iron oxide nanoparticles in microwave-assisted N-alkylations of amines with alcohols
Camino Gonzalez-Arellano, Kenta Yoshida, Rafael Luque and Pratibha L. Gai
Green Chem., 2010, 12, 1281-1287

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Efficient and recyclable catalysts for reactions with biomass-derived products

Hydrolytic hydrogenation of cellulose with hydrotreated caesium salts of heteropoly acids and Ru/CHydrolysis of cellulose by an acid catalyst, followed by metal-catalysed hydrogenation gives hexitols, which can be used as renewable chemicals and fuels.  In this study the authors use a combined catalyst of caesium salts of heteropoly acids (HPAs) and Ru/C.  Although HPAs have been used before, they cannot be recovered from the reaction afterwards, which greatly limits their use in industrial processes.

However, in this work Sels and co-workers have found that the caesium salts of HPAs are not only highly selective (giving up to 90% yields of hexitols) and can be performed under mild reaction conditions, the Cs HPA salts could be recovered by simple recrystallisation at room temperature without using organic solvents. (Green Chem., 2011, DOI: 10.1039/c1gc15350a)

Selective oxidation of 5-hydroxymethyl-2-furfural using supported gold-copper nanoparticles. 5-Hydroxymethyl-2-furfural (HMF), formed from the dehydration of sugars, can be oxidised to 2,5-furandicarboxylic acid (FDCA), which recently has been suggested as a substitute for terephthalate acid – the monomer for the production of terephthalate plastic. However, currently many strategies to oxidise HMF to FDCA have various drawbacks, including the use of stoichiometric oxidants. 

In this work Hutchings and colleagues report the use of gold-copper supported nanoparticles as an effective catalyst for the oxidation of HMF to FDCA.  Although supported gold nanoparticles have been applied to this reaction previously, catalyst stability has remained very low. However, the bimetallic nanoparticles reported here, supported on titania, exhibit a remarkable degree of stability, even in the presence of base.  The catalyst could be recovered by filtration and reused several times without significant loss of activity. (Green Chem., 2011, DOI: c1gc15355b)

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Enzymatic reductions for chemists

Biocatalysis has undergone dramatic improvements in recent years, becoming an alternative method to chemocatalysis.  Due to their inherent chirality, enzymes are able to selectively catalyse reactions giving the products with high enantioselectivity.

Reduction reactions with enzymes has developed rapidly in the past few years.  Previously, biocatalytic reductions have been challenging due to the dependency of the enzyme on a co-factor, narrow substrate range and restrictions to reactions in aqueous media.  However, the majority of these challenges have now been, or are about to be, solved.

In this review article, Hollmann and co-workers give an overview of the recent developments in biocatalytic reduction, with a critical view on the green aspects.  To read more, please read the full article, which is free until 12 August, by clicking the link below. 

Enzymatic reductions for the chemist, Frank Hollmann, Isabel W. C. E. Arends and Dirk Holtmann, Green Chem., 2011, DOI: 10.1039/C1GC15424A

You may also be interested in the following review, free until 12 August:

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

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Utilizing natural resources – ethenolysis of natural rubber and pyrolysis of macro-algae

On the ethenolysis of natural rubber and squalene.  Plenio and Wolf report the utilisation of natural rubber and squalene to obtain a set of terminal olefins.  The main focus for producing olefins from renewable resources has been on plant oils. Despite the fact that the annual production (2007) of natural rubber was 9.7 × 106 tons, this polyolefin has not been widely used.  However, due to the high degree of stereoregularity (in terms of double bond geometry and orientation) of natural rubber and squalene, Plenio was able to obtain controlled polymer degradation which resulted in the synthesis of sveral small oligoisoprenes. Future work is going to be directed scaling up this reaction and ultizing the products for the synthesis of flavours, odorants, etc. (Green Chem., 2011, DOI: 10.1039/c1gc15265c)
   
Microwave-mediated pyrolysis of macro-algae. Macro-algae is an abundant but generally underutilised resource – currently less that 1% is used.  Its integration into a biofrinery is challenging as it contains increased levels of halogenated compounds, alkali earth and heavy metals which restrict its use in direct combustion.  In this work, Clark and co-workers report the effective pyrolysis of macro-algae using a microwave. Pyrolysis is an established technique for deconstructing biomass using heat under an inert atmosphere to obtain high-value chemicals and platform molecules.  In this study chemical rich bio-oils were obtained from macro-algae at temperatures lower than those used for conventional biomass and by using microwave irradiation they obtained a higher yield (21%) than that obtained with conventional heating (14%). (Green Chem., 2011, DOI: 10.1039/c1gc15560a)
Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Critical reviews on selective oxidation of glycerol and recycling homogeneous catalysts using mebrane separation.

Selective catalytic oxidation of glycerol – perspectives for high value chemicals. The increasing worldwide production of biodiesel has led to an excess supply of crude glycerol, prompting researchers to investigate its valorisation.  Thanks to its three hydroxyl groups, glycerol is a potential starting material for several high-value fine chemicals.  Various metals can catalyse glycerol oxidation.  However, the selectively of these reactions is dependent on the active phase, metal particle size, pore size of the support and pH of the reaction medium.  In this review, Dumeignil and co-workers look at the recent developments in new catalysts and spotlight the role of reaction conditions. (Green Chem., 2011, DOI: 10.1039/c1gc15320j)

Recent advances in recycling of homogeneous catalysts using membrane separation. Membrane filtration is now an attractive approach for the recycling of soluble catalysts.  Nanofiltration has shown great potential as a method for process intensification in organo-, anzyme, and homogeneous catalysis.  Vogt and co-workers discuss selected, recent advances in catalyst recovery by membrane filtration in this review and look at implications for future development.  (Green Chem., 2011, DOI: 10.1039/c1gc15264e)
Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

New Impact Factor for Green Chemistry

Green Chemistry received a 5-year impact factor* of 6.056 in the 2010 Journal Citation Reports released by Thomson ISI this week.  This reveals steady growth in the impact of Green Chemistry over the last 5 years, reinforcing the importance and maturity of the Journal. 

Five years ago Green Chemistry had an impact factor of 3.255 and its 2010 impact factor of 5.472 demonstrates the Journal’s increasing quality, putting it in the top 20 of all multidisciplinary chemistry journals.

We would like to thank our Editorial and Advisory Board members and all of our authors and referees for their contributions; this support is vital to the continuing success of Green Chemistry.

The release of the 2010 impact factors also brought good news for RSC Publishing with a rise in the average impact factor across all journals and some great individual performances… read more here.

*A 5-year impact factor is the average number of times articles from a journal published in the past five years have been cited in the JCR year.  It is calculated by taking the number of citations in the JCR year to articles published in the preceding 5 years and dividing by the number of articles published in the previous 5 years.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Controlled lactide polymerisation in supercritical carbon dioxide with organo-catalyst

Researchers from Australia and the UK have developed a truly ‘green’ process for the synthesis of polylactic acid in the absence of toxic solvents and catalysts.

The team led by Idriss Blakely (The University of Queensland, Australia) and Steven Howdle (University of Nottingham, UK) have developed an approach where polylactide can be synthesised in a controlled manner in supercritical CO2 using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as an organo-catalyst.  This new method, unlike others before it, does not require the use of organic solvents or metal catalysts, and is conducted at much lower temperatures than for bulk polymerisation of lactic acid.

To read more, click the link below! FREE until 27 July.

Controlled polymerisation of lactide using an organo-catalyst in supercritical carbon dioxide, Idriss Blakey, Anguang Yu, Steven M. Howdle, Andrew K. Whittaker and Kristofer J. Thurecht, Green Chem., 2011, DOI: 10.1039/C1GC15344G

If you liked this, you may also be interested in this article too!

Direct conversion of polyamides to ω-hydroxyalkanoic acid derivatives by using supercritical MeOH, Akio Kamimura, Kouji Kaiso, Shuzo Suzuki, Yusuke Oishi, Yuki Ohara, Tsunemi Sugimoto, Kohichi Kashiwagi and Makoto Yoshimoto, Green Chem., 2011, DOI: 10.1039/C1GC15172J

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

A free environmental assessment tool for liquid chromatography methods

Scientists from Sweden, Egypt, Denmark and India have collaborated to develop a computational tool to assess the greenness of high performance liquid chromatography (HPLC) methods.

This environmental assessment tool (EAT) takes into account the safety, environmental and health issues for all solvents involved or used in the chromatographic method.  A total score is then calculated that can be used to compare the greenness of various HPLC methods.  Although other tools have been developed to try and evaluate the green aspect of these methods, they often do not provide a sufficiently quantitative result for comparison between various methods and are not always user-friendly or widely accessible.

The HPLC-EAT software can be downloaded free of charge at http://www.biotek.lu.se/hplc-eat/ and can also be combined with another free software eco-solvent tool to perform life cycle assessments of waste disposal options (such as distillation or incineration).

Click the link below to find out more! Read the full text for free until 22 July

Energy & environment: Free environmental assessment for liquid chromatography solvents, Y Gaber, U Tornvall, M A Kumar, M A Amin and R Hatti-Kaul, Green Chem., 2011, DOI: 10.1039/c0gc00667j

You may also be interested in the following article too!

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

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Recycling polyamides to give valuable chemicals

 Polyamides have been decomposed to ω-hydroxyalkanoic acid derivatives – important intermediates in the chemical industry – using supercritical methanol.  This is one of the first methods for economical upgrading of polymers through the depolymerisation process.

Akio Kamimura and colleagues from Yamaguchi University and UIbe Industries Ltd., Japan, have developed a method to convert polyamides to valuable chemicals.  Currently, recycling of plastics commonly involves converting the polymers back to their monomers. However, these methods are not always economically viable because they are often more expensive than other ways of treating waste plastics.  By converting polymers to valuable chemicals, this would make polymer recycling a more attractive route and solve some of the economic problems. 

In this study, by using supercritical methanol, Kamimura converted nylon-6 selectively to two valuable compounds – methyl 6-hydroxycapronate and methyl 5-hexenoate. Given that the average price for these ω-hydroxyalkanoic acid derivatives is about 6-7 times higher (per kg, based on 2008 figures) than the monomer (caprolactam), Kamimura believes that this method will open up new avenues in the development of plastics recycling.

To read more, please click the link below!  Full text Free until 20th July.

Direct conversion of polyamides to ω-hydroxyalkanoic acid derivatives by using supercritical MeOH, Akio Kamimura, Kouji Kaiso, Shuzo Suzuki, Yusuke Oishi, Yuki Ohara, Tsunemi Sugimoto, Kohichi Kashiwagi and Makoto Yoshimoto, Green Chem., 2011, DOI: 10.1039/C1GC15172J

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)