Author Archive

Iodine catalysis in diarylsulphide synthesis

Diarylsulphides are popular motifs for the basis of drug design and materials, but their synthesis is usually dependant on inherently wasteful cross coupling reactions that require metals such as palladium, copper, and indium. Now iodine has been discovered to be an effective catalyst for the synthesis of diarylsulphides from thiophenols and cyclohexanone derivatives. Researchers from Xiangtan in China have shown that the desired reaction is achievable when an oxygen atmosphere is used to regenerate the catalyst. A large number of pendant functional groups are tolerated, with yields of up to 80% observed.

The use of iodine to replace metal containing catalysts is hugely beneficial in securing the long term sustainability of this synthetic protocol. The vulnerability of scarce metal resources is a vital consideration often overlooked when designing new organic syntheses supposedly within the remit of green chemistry. Unlike C-S cross coupling procedures that result in stoichiometric halide containing wastes, this new protocol produces only water as a by-product, whilst also circumventing the need for an auxiliary base or an expensive metal catalyst. Unfortunately the only satisfactory solvent that could be found was NMP, which will need to be improved upon if this procedure is to be considered as a green process. Otherwise this synthetic method is a welcome advance in the development of sustainable catalytic chemistries.

By James Sherwood

Read the article in full – free to access for 4 weeks!

Iodine-catalyzed efficient 2-arylsulfanylphenol formation from thiols and cyclohexanones, Yunfeng Liao, Pengcheng Jiang, Shanping Chen, Hongrui Qi and Guo-Jun Deng, Green Chem., 2013, DOI: 10.1039/c3gc41671b

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Sustainable Chemicals from Microalgae: Encompassing Biocrude through to Fine Chemicals

The Sustainable Chemicals from Microalgae one day conference will take place on the 19th November 2013 at the Chemistry Centre, Piccadilly, London. The conference will bring together researchers from academia and industry at all levels interested in developing microalgae in industrial biotechnology. This highly interdisciplinary symposium is co-sponsored by the BBSRC  (Biotechnology and Biological Sciences Research Council), a major funder of biotechnology-related research within the UK.

The programme of this meeting will feature both oral, flash poster and conventional poster presentations. Please follow the links to register to attend – registration fee £35: http://rsc.li/microalgae-2013

The list of speakers includes:

Professor Wim Brilman, Sustainable Process Technology, University of Twente, The Netherlands
Professor Mike Burkart, Department of Chemistry and Biochemistry, University of California, San Diego, USA
Professor Chris Dupont, Microbial and Environmental Genomics Group, J. Craig Venter Institute, San Diego, USA
Dr Juan Nogales Enrique, Centre de Investigaciones Biologicas (CSIC), Madrid, Spain
Professor Rene H Wijffels, Bioprocess Engineering, Wageningen University, The Netherlands
Mr Steve Skill, Plymouth Marine Laboratory, UK
Professor Alison Smith, Department of Plant Sciences, University of Cambridge, UK
Professor Rod Scott, Department of Biology and Biochemistry, University of Bath, UK
Professor John Love, College of Life and Environmental Sciences, University of Exeter, UK
Dr Michelle Stanley, The Scottish Association of Marine Science, UK
Dr Saul Purton, Institute of Structural and Molecular Biology, University College London, UK

For more details about this exciting conference and to register, please visit the website!

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Albert Matlack’s top papers for October

Albert Matlack, one of the founding educators of green chemistry and author of the book ‘Introduction to Green Chemistry’, selects his favourite papers in Green Chemistry this month…

Mechanical depolymerisation of acidulated cellulose: understanding the solubility of high molecular weight oligomers, Abhijit Shrotri, Lynette Kay Lambert, Akshat Tanksale and Jorge Beltramini, Green Chem., 2013, 15, 2761–2768, DOI: 10.1039/c3gc40945g

In this work, cellulose was milled with sulfuric acid to produce oligomers which were hydrogenated over a Ni/Pt/aluminium oxide catalyst 200 °C for an hour to produce 90% of sorbitol and mannitol. This yield is better than the efforts of others to do the job. Sorbitol can be converted to isosorbide, then to high melting point biopolymers. Further work is needed to get more than the 34.6% of the starting cellulose to dissolve.

Continuous flow nanocatalysis: reaction pathways in the conversion of levulinic acid to valuable chemicals, Jose M. Bermudez, J. Angel Menéndez, Antonio A. Romero, Elena Serrano, Javier Garcia-Martinez and Rafael Luque, Green Chem., 2013, 15, 2786–2792, DOI: 10.1039/c3gc41022f

This work shows the advantages of a continuous flow system to produce biomass platform chemicals. The authors use a ThalesNano H-Cube of levulinic acid to produce 60% methyltetrohydrofuran and 40% 1,4-pentanediol in one minute at 150 °C, which shows the value of the system over a batch method.

“Release and catch” catalytic systems, Michelangelo Gruttadauria, Francesco Giacalone and Renato Noto, Green Chem., 2013, 15, 2608–2618, DOI: 10.1039/c3gc41132j

This review covers catch and release systems which do not use covalent bonding to a support. The concept is good in the sense that a homogeneous catalyst may have a single active site, whereas a heterogeneous catalyst may have several types of active sites. The systems work with a variety of metal catalysts, but activity decreases on repeating cycles. Metal leaching may be taking place. Further work is needed to make such systems practical for widespread use.

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THF co-solvent enhances hydrocarbon fuel precursor yields from lignocellulosic biomass

Charles Wyman and colleagues have demonstrated a highly effective lignocellulosic bio-refinery model, producing unrivalled quantities of furfural, 5-hydroxymethylfurfural (HMF), and levulinic acid as products. Proposed as a basis for the production of renewable fuels, the furan derivatives generated by this process are also a promising platform onto many other intriguing bio-based molecules. Additionally, more than 90% of the lignin contained within the maple wood feedstock was reclaimed, making the process as a whole exceptionally appealing.

Instead of the typical acidified aqueous media often used, the hydrolysis of the lignocellulose feedstock (and subsequent sugar dehydration) was enhanced with the addition of the potentially renewable solvent tetrahydrofuran. The organic solvent increased yields of HMF by an order of magnitude over what could be obtained otherwise in a one-pot reaction conducted at 170 °C. Under these optimised conditions, 87% of the total pentose (C5) sugar content was accountable in the form of furfural, while the hexose (C6) sugar content was converted from cellulose into HMF (in up to yields of 21% of the theoretical maximum), levulinic acid (up to 40%), and free sugars. The authors believe this represents a key step towards achieving commercial viability for sustainable, sugar derived bio-fuels.

By James Sherwood

This article is free to access for 4 weeks! Click the link below to read more:

THF co-solvent enhances hydrocarbon fuel precursor yields from lignocellulosic biomass, Charles M. Cai, Taiying Zhang, Rajeev Kumar and Charles E. Wyman, Green Chem., 2013, DOI: 10.1039/c3gc41214h

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Green Solvents – Mission Completed or Mission Impossible?

The search for alternatives to volatile organic solvents is one of the continuing major themes in Green Chemistry. “Solvents” are explicitly mentioned in principle 5 of the 12 Green Chemistry Principles, but their use impacts of course also directly on issues such as waste prevention, energy efficiency, and safety. The search for alternative materials and concepts to facilitate solution phase processes towards the goals of sustainability forms a natural link between Green Chemistry and Engineering. Since the year 2000, the biennial conference “Green Solvents” brings together researchers from academia and industry, as well as students, to discuss the progress in science and application in this area. As in previous years, the presenters at the 2012 edition of the conference have been invited to contribute a review or original research paper to the journal and you will find the resulting articles bundled in this issue.

The organization of six editions of this meeting together with Peter Wasserscheid and Ken Seddon has been scientifically most rewarding and personally a real pleasure. The concept to organize the program without parallel sessions, arranging it according to the scientific and technical challenges rather than the materials or methods has led to most fruitful interactions and stimulating discussions. One of the most striking developments reflected across the board is that the advanced fluids such as ionic liquids, supercritical fluids, water, or liquid polymers are often not adequately described as “solvents” when used for molecular transformations or separation techniques. They act as additives, stabilizers, matrices, switchable components, catalysts, etc. Unlike with traditional solvents, only very small amounts of the fluids are often required, for example to combine reactivity and separation in catalyst immobilization. Smart systems change their properties upon external stimuli or directly interact with reactive components to steer a reaction. Reaction engineering concepts for flow chemistry open new approaches with these materials and vice versa. So, are we at the stage “Mission Completed”?

Actually – I don’t really think so: striving for sustainability is an iterative process and if we are doing well, we can always do better! Immobilizing a catalyst today, we are already satisfied if it retains largely its activity and selectivity from solution; very often, we find that the supporting matrix interacts with the catalyst leading to a reduced performance. There is no reason why the interaction should not lead to an activation or increase in selectivity! In fact, there are a – still slowly – increasing number of observations that support this idea. Is it possible to switch not only between solubility properties, but also between reactivities? How can heat exchange be controlled in reactive systems without using solvents? Can we use fluids that stabilize nanoparticles for the control of their reactivity just as we use ligands to control single site catalysts? If we find such seemingly elegant solutions, will they really improve the sustainability of industrial process chains upon implementation? We are far from giving satisfactory answers to these and many more very fundamental questions!

Solution phase synthesis is dominating the fine chemicals and pharmaceuticals industry, and resource and energy efficient production is increasingly making a difference in the business models of these sectors. Material synthesis and processing is also highly depending on the liquid phase. Utilization of biomass requires solution phase processes even in the very early stages of the supply chain, in large scale bio-refineries just as well as for decentralized operations. Chemical transformations lie also at the intersection of the energetic and chemical supply chain. In all these crucial areas of application, novel concepts and materials for solution phase processes can make a difference!

Therefore, I am already today looking forward to the next edition of the “Green Solvents” conference: it will be held in Dresden, Germany, from October 19–22 2014 (for details, see: http://www.dechema.de/gsfs2014). If you enjoy reading the articles in this issue, if you share the enthusiasm for the exciting scientific challenges in this area, or if you see potential connections to your own research, you don’t want to miss this event!

Professor Walter Leitner – Chair of the Green Chemistry Editorial Board

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Green and Sustainable Surface and Materials Chemistry Conference

The Green and Sustainable Surface and Materials Chemistry conference will be held in Stockholm, Sweden, on the 23rd October 2013. The meeting will attract a large audience of surface and materials scientists, chemists and engineers, as well as experts in a wide range of green and sustainable materials. There will be presentations from academia and industry covering the following topics:

– Renewable energy
– New technologies for water purification
– Marine biofouling
– Chemicals from renewable sources
– Green corrosion protection
– Green formulation

**The deadline for poster abstract submission has now been extended to 30th September**

To find out more about this exciting conference and to register, please visit the website.

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Albert Matlack’s top papers for September

Albert Matlack, one of the founding educators of green chemistry and author of the book ‘Introduction to Green Chemistry’, selects his favourite papers in Green Chemistry this month…

Olefin metathesis in aqueous media, Jasmine Tomasek and Jürgen Schatz, Green Chem., 2013, 15, 2317–2338, DOI: 10.1039/C3GC41042K

This should cause one to think about how many discoveries leading to this result were made by chance. Herbert Eleuterio of duPont discovered metathesis when he used a molybdenum catalyst in a Ziegler polymerization of ethylene in 1957. Efforts to get consistent results with tungsten hexachloride were futile until it was found that tungstenoxytetrachloride worked well. Most metathesis catalysts were sensitive to air and moisture. However, a run with a hydrated ruthenium salt worked just as well as the anhydrous compound. This review covers work since then. The field of polymers today arose from accidental discoveries.

Low density polyethylene was found when chemists at ICI tried to react benzaldehyde with ethylene and got a trace of air in the bomb. High density polyethylene was discovered by Karl Ziegler who was studying the oligerimerization of ethylene with triethylaluminum when a trace of nickel from a partially cleaned bomb gave only 1-butene. When he tried titanium tetrachloride HDPE formed. Natta discovered stereoselective polymerization when he extended the reaction to propylene. Metallocene catalysts for the polymerization of olefins by Kaminsky were discovered when a student failed to blanket a polymerization with nitrogen. Plunkett of duPont discovered poly(tetrafluoroethylene) when a cylinder known to be full of the monomer released no monomer. Conducting polymers were found by Shirakawa, MacDiarmid and Heeger when a student put 1000 times too much catalyst in a polymerization of acetylene. An iodine reaction, presumably to determine the content of double bonds, showed how to dope it.

Add to these results of serendipity, H.C. Brown’s discovery of hydroboration while trying to reduce a double bond with diborane. Notice the number of Nobel prizes awarded for the various discoveries.

The message is, if something unusual happens, check to see why.

Organic solvent-free and efficient manufacture of functionalized cellulose nanocrystals via one-pot tandem reactions, Lirong Tang, Biao Huang, Nating Yang, Tao Li, Qilin Lu, Wenyi Lin and Xuerong Chen, Green Chem., 2013, 15, 2369–2373, DOI: 10.1039/C3GC40965A

Functionalized cellulose nanocrystals were formed via ball milling followed by ultrasonication. The reaction was run with a large excess of maleic anhydride in 20% aqueous sulfuric acid. No organic solvent was present. After balling for an hour, ultrasonication for 7 hours gave a 61% yield with 0.34 degree of substitution. It might be good to substitute less maleic acid and to run a final ring closure by heating. Other monomers could be tried as well.

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Albert Matlack’s top papers

Albert Matlack, one of the founding educators of green chemistry and author of the seminal book ‘Introduction to Green Chemistry’, selects his favourite papers in Green Chemistry this month…

Characterization, synthesis and catalysis of hydrotalcite-related materials for highly efficient materials transformations, Shun Nishimura, Atsushi Takagaki and Kohki Ebitani, Green Chem., 2013, 15(8),2026–2042, DOI: 10.1039/C3GC40405F

This is a review of hydrotalcites, which are layered magnesium aluminum hydroxy carbonates. They are the strongest bases known and are easy to recover for reuse by filtration. They are known for improved selectivity and yield when reactions are run in the constrained space between layers. Zeolites, metal organic frameworks and clays also offer such advantages. The review covers the synthesis, reactions alone and when used as a support for transition metals.

*Open Access* A prototype device for evaporation in batch and flow chemical processes, Benjamin J. Deadman, Claudio Battilocchio, Eric Sliwinskia and Steven V. Ley, Green Chem., 2013, 15(8), 2050–2055, DOI: 10.1039/C3GC40967H

In this work, Ley et. al. have developed a device for evaporating, concentrating and switching solvents in continuous flow so that all solvents can be recovered for reuse. Twenty one solvents ranging  from dichloromethane to dimethylformamide were recovered satisfactorily. This enlarges the possibilities for the use of microchanneled reactors in process intensification. They offer higher selectivities and yields, safer reactions, easy heating and cooling, no need to worry about explosive limits, no need for a pilot plant with  smaller cheaper chemical plants. Other methods include spinning disc and tube in tube reactors. With the latter, up to 15 tons per hour can be processed. Oxford Catalysts has developed such systems for steaming reforming plus Fischer-Tropsch conversion of stranded natural gas to liquids. Two research groups have developed microchanneled reactors with inline analysis for five variables that are self-optimizing over a period of two to three. The group of Buchwald did it for a Heck Reaction and Poliakoff‘s group did for the reaction of 1-pentanol with dimethyl carbonate.

Highly efficient production of lactic acid from cellulose using lanthanide triflate catalysts, Fen-Fen Wang, Chun-Ling Liu and Wen-Sheng Dong, Green Chem., 2013, 15(8), 2091–2095, DOI: 10.1039/C3GC40836A

In this work, cellulose was converted to lactic acid with an erbium triflate catalyst in water at 240 degrees C, in 30 minutes in 89.6% yield. The catalyst showed no loss of activity after five runs. This avoids the need to hydrolyze cellulose to sugars as a separate step. Lactic acid is the monomer for the commercial poly(lactic acid) which is biodegradable. The conversion of lactic acid to acrylic acid is being commercialized.

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More HOT papers in Green Chemistry

Here are some more HOT papers published in Green Chemistry, as recommended by the referees:

A waste-minimized protocol for the preparation of 1,2-azido alcohols and 1,2-amino alcohols, Eleonora Ballerini, Paolo Crotti, Ileana Frau, Daniela Lanari, Ferdinando Pizzoa and Luigi Vaccaro, Green Chem., 2013, DOI: 10.1039/c3gc40988k

Palladium on iron oxide nanoparticles: the morphological effect of the support in glycerol hydrogenolysis, Junwei Ge, Ziyan Zeng, Fenglin Liao, Weiran Zheng, Xinlin Hong and Shik Chi Edman Tsang, Green Chem., 2013, DOI: 10.1039/c3gc40712h

One-by-one hydrogenation, cross-coupling reaction, and Knoevenagel condensations catalyzed by PdCl2 and the downstream palladium residue, Hu Wang, Li Li, Xing-Feng Bai, Wen-Hui Deng, Zhan-Jiang Zheng, Ke-Fang Yang and Li-Wen Xu, Green Chem., 2013, DOI: 10.1039/c3gc40991k

These three papers have been made free to access for the next 4 weeks!

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1st International Conference of the Excellence Cluster “Tailor-made Fuels from Biomass”: Conference Report 2013

From June 18th to 20th, 2013, the Cluster of Excellence “Tailor-Made Fuels From Biomass” (TMFB), which is based at RWTH Aachen University organized its 1st International Conference in Aachen. The conference was held in the host city of Aachen, which is located at the Vaalserberg triple point between Germany, the Netherlands and Belgium and was made famous by Charlemagne. The three-day conference covered all subject areas surrounding the synthesis, production and combustion of modern biofuels and addressed an international, interdisciplinary audience from academia and industry. Since 2007, researchers from the fields of chemistry, biology, process engineering, mechanical engineering and associated research fields have been working together on the development of tailored biofuels within the TMFB. In previous years, the Cluster of Excellence used its “International Workshop” as a platform for the exchange of TMFB Members with external researchers. This year the conference’s stage was opened, and for the first time more than half of the 40 speakers visited from external institutions. The program included lectures from invited speakers and researchers from inside and outside the Cluster of Excellence as well as a poster session, where young researchers from different scientific disciplines were able to present and discuss their work.
 
The first day of the conference emphasized the interdisciplinary approach of the TMFB by combining together lectures addressing the interaction of the involved disciplines, namely the transformation of lignocellulose into biofuels, the combustion properties of alternative fuels, the importance of lubrication in combustion engines and the health concerns associated with exhaust gases. Bringing together all of the conference participants for this series of diverse lectures highlighted the importance of examining the development of the next generation of biofuels from all perspectives.

Prof. Tom Welton presenting on Ionic Liquids for Biomass Fractionation

The lecture portion of the conference began, according to the value chain of biofuel production, with the fractionation of lignocellulose. Prof. Tom Welton outlined how the unique environment provided by ionic liquids can solubilize lignocellulosic feedstocks, which generally have low solubilities in aqueous and organic solutions. By applying a novel pretreatment method called Ionosolv, 80% of the lignin can be separated without changing the native structure of the lignin molecules. However, Prof. Welton pointed out that the obtained cellulose fraction has to be washed carefully to avoid the inactivation of cellulases by small amounts of ionic liquid. The dissolution of lignocellulose in ionic liquids allowed for the separation of lignin, cellulose and hemicellulose, such that the cation and anion of the ionic liquid could be tailored to improve the separation of authentic lignocellulose materials. 

The TMFB lego model, explaining the TMFB biofuel production approach

Two members of TMFB, Prof. Jürgen Klankermayer (Technical Chemistry) and Manuel Dahmen (Process Technology, Mechanical Engineering), presented on the collaborative approach being developed within the Cluster of Excellence to define and synthesize biofuel targets. Mr. Dahmen outlined the development of theoretical models to identify potential biofuels based on predicting the combustion fuel properties (i.e. boiling point, heating value, cetane number) of biomass-derived substrates. The insight provided by this predictive property model identifies which molecular structures have suitable fuel properties and helps to direct the synthetic efforts within the TMFB cluster. Prof. Klankermayer highlighted the various catalytic strategies, both homogeneous and heterogeneous, being developed within the TMFB cluster toward the synthesis of the next generation of biofuels including 2-methyltetrahydrofuran and 1-octanol. The combined presentation from two lecturers of two different disciplines at the same time formed a vital example of the successfully implemented interdisciplinary research culture in Aachen’s Cluster of Excellence. 

Prof. Paul Anastas, the father of Green Chemistry, presented the closing seminar on the first day of the conference. Rather than discussing his exceptional research work on such topics as the theoretical prediction of chemical toxicity or the integration of process design into Green Chemistry practices, Prof. Anastas presented his philosophy on the current state of Green Chemistry. His stimulating and motivating presentation illustrated the importance of Green Chemistry by providing numerous examples on the implementation of green technologies and challenged the conference participants to continue to strive in the development of a sustainability chemical industry by creating truly innovative technologies. He addressed several questions regarding the establishment of green chemistry and its impact on today’s society, leading to many excited discussions at the get-together in the evening.

On the second day of the conference, Prof. Charles Westbrook outlined his work on the development of kinetic models to explain the ignition and combustion of alternative fuels. His lecture provided evidence on the relationship between combustion properties and the molecular structure of a biofuel, which again illustrated how combustion models can help to guide synthetic chemists towards optimal molecular structures. Furthermore, his work emphasized how several combustion techniques must be combined to provide a suitable model and as such requires interdisciplinary collaboration to provide answers to this sustainability problem. 

The remainder of the second day of the conference was filled with excellent lectures provided by both internal and external speakers on a variety of chemistry, biology and engineering topics. The afternoon presentations and discussions identified that lignocellulose pretreatment methods and the characterization of the resulting biomass fractions are vital to all downstream processes. Qingqi Yan presented a way to pretreat the biomass mechanically using a screw press. The advantages of this device are the universal usage for all kinds of lignocellulosic biomass, the scalability, the robustness, the low operational costs and the high disruption of lignocellulosic structures. By combining the screw press with the chemical hydrolysis in one step, valuable reducing sugars can be produced in a very early stage of the process chain. Furthermore, Prof. Markus Pauly presented on the use of 2D NMR spectroscopy for the characterization of lignocellulosic materials. The identification of lignocellulose presents a particular problem to chemists due to its complex structure and low solubility. Prof. Pauly outlined a technique to solubilize lignocellulose using deuterated ionic liquids and dimethyl sulfoxide and analyze the various components of this biopolymer using 2D NMR. This technique has provided a method to investigate the influence of various plant feedstocks on the structure of lignocellulose and to evaluate different methods used in the fractionation of lignocellulose. 

The Combustion Kinetics session covered various aspects of biofuel kinetics and emphasized the paramount importance of international collaboration in this field. John Dec started the session by giving detailed insight into the differences of the reaction chemistry of bio-ketones as compared to conventional fuels and also discussed the implications of these differences to novel combustion concepts. His talk covered the development of the reaction mechanism for di-n-butylether (DNBE) as a TMFB example. Further, his talk emphasized the statement made by Prof. Westbrook during the morning’s invited lecture, that such mechanism development is the work of a complete “gang” of scientists, bringing together the enormous experimental and brain power needed worldwide.

The Fuels Spray, Flow and Mixing session covered physicochemical effects on the combustion system as well as experimental visualizations of biofuel injection compared to and complemented by high-fidelity simulations. The session closed with a study on injector deposits resulting from the applications ofbiofuels presented by Dr. Christian Fink from Rostock University. In the Combustion Systems Session, a strong focus was on Diesel engine application of various alternative fuels and fuel blends. Prof. Eilts from the Technical University Braunschweig, pointed at the potential of higher alcohols to reduce soot when blended with Diesel fuel. Unfortunately, adverse effects on the number of very small particles were also reported. A more detailed study on fuel effects in Diesel engine combustion was reported for a comparison of DNBE, octanol and Diesel. Combined examinations on single cylinder diesel engine test bench, high pressure spray chamber and CFD simulations of both experiments reveal that to reach clean combustion, the mixing behavior may be more important than the cetane rating. The very good mixture preparation obtained with DNBE enables soot-free low-NOx combustion for the entire engine load range, despite the high cetane rating (about 100) of DNBE.

Discussions during the Poster Session at the 1st TMFB International Conference

Another session in the afternoon covered the pathways from biofuels to propulsion. Well to wheel balances of blends confirming to EN 590 surveyed sustainability aspects of already usable fuels. The closing talk, presented by Prof. Claus Felby from the University of Copenhagen, dealt with the question of bringing bio-refineries to large scale, which will be a key factor with regards to cost and also energy efficiency of biofuel processes. 

To analyze the biomass composition with respect to its glucose, xylose and cellulose content, Helene Wulfhorst from the University of Kaiserslautern showed the potential and challenges of applying near- and mid-infrared spectroscopy. To exploit the possibilities of this technique, choosing the optimal calibration strategy is absolutely essential. For this reason different calibration strategies were compared with each other, to demonstrate the best way of analyzing biomass composition. An essential step to convert biomass into a biofuel or platform chemical is fermentation. Irina Borodina, a researcher from the Danish Chalmers University of Technology, made a short digression to the biological corner of the conference by presenting the potential of yeast cells in general as cell factories for biorefinery processes. The fact that yeasts are not the only opportunities to convert biomass was shown by the three presentations of Jasmine Roth from the University of Kaiserslautern, Sandra Wewetzer/Frederike Carstensen from the RWTH Aachen University and Simon Curvers from Direvo Industrial Biotechnology GmbH. Jasmine Roth presented experimental and modeled data of acetone-butanol-ethanol (ABE) fermentations based on Clostridium acetobutylicum and complex liquid hydrolysates combined with an in situ product removal by particle-based extraction. Sandra Wewetzer and Frederike Carstensen introduced a process concept for the conversion of glucose into itaconic acid using the fungus Ustilago maydis. To increase the efficiency of the process a membrane module is integrated into the bioreactor to enable an in situ product recovery. On the last conference day Simon Curvers presented the BlueCon® concept of the company Direvo which allows for the direct conversion of a broad range of substrates into ethanol and / or lactic acid. The fermentations were performed with the extremely thermophilic Caldicellulosiruptor strains without any additionally added enzymes. 

Prof. Julie Zimmerman was invited to present her work towards the development of algae for the production of biofuels. Her presentation outlined how this important biological resource can be grown, separated into its different components and catalytically transformed into biofuels. Her work illustrated how process integration employing supercritical carbon dioxide can permit the fractionation of algae and transesterification within a single reactor to reduce the energy costs of harvesting this resource for fuels and chemicals. Her work combines together biochemistry and engineering to provide another excellent example of the interdisciplinary approach required to tackle sustainability issues.  

Apart from the interesting scientific lectures and discussions at day, there was also a supporting program in the evenings. On the first evening, a get-together with Bavarian-style food and drinks was organized to create the opportunity to network with new acquaintances and catch up with established ones. On the second evening, all lecturers, professors, principal investigators, external guests and selected additional TMFB members were invited to the Conference Dinner in the Lenné-pavillon at the Casino Aachen, which is made of glass and offers a beautiful view of the fountain in the Kurpark. With the sunny weather, the terrace of the pavillon was the place where the great part of the dinner guests came together to eat, drink and enjoy the pleasant and inspiring conversations.

In conclusion, the 1st International Conference of the Cluster of Excellence TMFB has set the bar high for the second TMFB conference, which will take place again in Aachen, June 16th to 18th, 2014. Researchers interested in interdisciplinary perspectives on new biofuels are most likely to benefit once more from the valuable input, animated discussions and great networking opportunities.

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