O conceito de biorrefinaria pode ser entendido como a evolução de tecnologias a partir de biomassa, as quais compreendem processos químicos, biológicos e térmicos. Tal conceito tira vantagem do sinergismo entre distintas tecnologias, resultando em grande variedade de produtos. Recentemente, um novo conceito foi criado, a biorrefinaria integrada, a qual deve ser capaz de converter eficientemente uma gama de biomassa em biocombustíveis, bioprodutos e energia. Nesse sentido, a biorrefinaria integrada é similar a uma refinaria tradicional, que busca otimizar as fontes de matérias primas e a economicidade global da produção. Além disso, biorrefinarias integradas implicam o uso de inovações, ou seja, novas rotas químicas devem ser desenvolvidas a fim de reduzir custos, aumentar competitividade e, sobretudo, explorer o potencial dos resíduos. O conceito de biorrefinaria integrada pode ser aplicado a diversos tipos de matérias primas. Unidades produtoras de etanol parecem ser um excelente exemplo de como diferentes produtos secundários e resíduos podem sofrer transformações químicas, gerando novos derivados de maior valor agregado, aumentando dessa forma a rentabilidade global do negócio. Para tal, faz-se necessário inovar, ou seja, introduzir novas rotas catalíticas de transformação química, as quais, por sua vez, demandam o desenvolvimento de novos catalisadores. O objetivo de nosso trabalho é o de apresentar os principais desafios em termos de Catálise quando o conceito de biorrefinaria integrada é aplicado a uma unidade produtora de etanol. O problema dos resíduos lignocelulósicos será discutido, apresentando-se para eles diversas soluções. Igualmente, as emissões de CO2 serão abordadas, e seu uso como matéria prima para a produção de gás de síntese será destacado.”

Falabella Sousa-Aguiar, um 'embaixador' da catálise brasileira confirma conferência na 39ª. RASBQ. » Leia mais...

The development of efficient and cost-effective means of deconstructing lignocellulosic biomass to produce biofuels and other valuable chemicals requires multiple strategies and involves different areas of expertise. Our understanding of linocellulosic materials and the numerous carbohydrate modifying proteins that can be used in the depolymerization process is just beginning to be unveiled. Among the different strategies, molecular modeling techniques emerge as a valuable tool capable of providing accurate molecular views of complex biomolecular systems, including enzymes structure and dynamics, substrate recognition and binding, reaction mechanisms, and functions. Advanced modeling techniques also play key roles in understanding the nanoarchitecture of polysaccharide and lignin assembling in plant cell walls. Our work has been focused on molecular dynamics simulations of glycosyl hydrolases of different families, the interactions of expansins with cellulose, and on the statistical mechanics modeling of the thermodynamic cohesion forces that maintain the nanoarchitecture of plant cell walls. Here, I will report on our recent studies in this area, highlighting the synergy between molecular modeling and experiments in the field of lignocellulosic biofuels. 

Skaf fala sobre o papel da química teórica na área de biocombustíveis na 39ª RASBQ.   » Leia mais...

Peptides have suffered a remarkable renaissance as therapeutic agents.  They can be situated between the small-molecules (<500 Da) and biologics (>5000 Da), the two most extensive classes of well-established therapeutic agents.  Peptides provide both the specificity and potency of larger protein biologics but with minimal immunogenicity. Furthermore, they are smaller, more accessible and cheaper to manufacture using chemical methods, thus presumably combining the advantages of the two therapeutic approaches. 

While nature has been fine-tuning the bioactive chemical structure of these structures for thousands of years, peptide chemists and protein engineers have the exciting challenge to improve the intrinsically unfavorable pharmacokinetic properties of the majority of native peptides. The drawbacks of peptides as therapeutic agents are associated with their generally high conformational instability.  Nature, first, and then scientists have been encountered into the cyclization the best way to prepare constrained peptides with higher activities and improved pharmacokinetic properties.

In this presentation, we will review our current research devoted to the synthesis of natural cyclic peptides as well as the design and synthesis of cyclic peptides with improved properties. 

Traditionally, R&D in all companies was an area with little contact with the external world, for the projects in the area developed were considered top secret. The environment has changes today, and big companies now understand that it is impossible to innovate on their own. The success of innovation, translated into new products, new applications, new businesses is directly related to how people connects – both inside and outside the company.

Inside the company, there is a constant look for diverse teams that reflect the diversity that exists in the outside world. We look for diversity of thoughts, of backgrounds, of cultures, to increase the chance that any given challenge is being looked at from as many different viewpoints as possible. This is why there are many opportunities for chemists and chemistry-related professionals that go beyond the lab.

Outside the company, we need to connect with customers, with suppliers but also with universities, with startup companies, with research centers and make sure the best of all worlds can be put together for everyone to benefit.

There are many challenges for R&D. This talk will approach the main ones and also the opportunities for people and for business, and also show success stories of innovation in Brazil.

Diretor de Pesquisa da Dow fará conferência na 39ª RA.   » Leia mais...

The Drug Discovery Unit (DDU) was set up at the University of Dundee in 2006. It is a fully integrated drug discovery unit, combining hit discovery, medicinal and computational chemistry, drug metabolism and pharmacokinetics. The key aims of the unit are to tackle unmet medical need. We have two main therapeutic focuses: neglected tropical diseases such as malaria, tuberculosis and kinetoplastid infections; and novel drug targets emerging from the academic sector. In this presentation, I will summarise the capabilities of the DDU and outline some of the work that we have carried out on drug discovery for neglected diseases.

Ian Gilbert, um descobridor de fármacos, confirma vinda para a 39ª Reunião Anual.   » Leia mais...

Lignocellulosic fibers are renewable and abundant materials, and play an important role in the development of the bio-economy as generators of biofuels, chemicals and materials. Lignocellulosic fibers obtained from plants with short growth cycles, and largely available in Brazil (such as sisal, coconut, curaua) have been preferentially considered in our research, as well as their major constituents, namely, cellulose and lignin, and respective derivatives. The presence of phenolic aromatic rings in lignins and lignosulfonates (both byproducts of biorefineries) enables their use in the preparation of phenolic polymers (that can be used as matrix in lignophenolic composites), and the presence of alcoholic hydroxyl groups allows their use in the preparation of polyurethanes (that can be used as matrix in lignopolyurethanes composites). Lignocellulosic fibers have been used as reinforcements of these matrices. The polar groups present in the components of lignocellulosic fibers, mainly hydroxyl groups, can positively interact with polymeric matrices having polar groups in their respective chemical stucture, as it is the case of polyphenolic and polyurethane- matrices type. The introduction of structures typical of lignin into the matrix through chemical reactions may further improve the compatibility between the matrix and lignin-containing fibers. In this context, bio-based composites, with diversified and useful properties,  have been prepared from a high content of raw materials derived from renewable sources. The experience that has been acquired on investigations on materials, such as composites, has benefited the transition from macro- to  nanoscale. Ultrafine fibers (submicron scale) and nanofibers possess attractive characteristics, such as a very large surface area against the volume ratio and flexibility to functionalize their surfaces, which are direct consequences of their diameter dimensions. Among the available methods to prepare such fibers, electrospinning should be highlighted since, for example, once the appropriate conditions are established the processing time is relatively short. In this context, appropriate conditions for the electrospinning of solutions prepared from lignocellulosic fibers and/or their main constituents (cellulose and lignin) have been searched, as well as for the electrospinning of solutions prepared by mixing fibers and/or lignin, cellulose, nanocrystalline cellulose with a polymer. These are  ongoing studies and the set of results obtained already are promising.

Saccharomyces cerevisiae and many other microorganisms have the remarkable ability to accumulate vast amounts of metallic elements. This ability has been exploited for the production of yeast based mineral supplements which have been used for decades. However, the efficacy/toxicity of trace element is depends on its chemical form (i.e. speciation). The primary form of Se supplementation is selenium enriched yeast which is able to convert inorganic Se to organoselnium species. Using high resolution molecular and atomic  spectrometry approaches the key components of the selenium metabolic pathway have been identified. An ion mobility FT MS protocol enabled the simultaneous monitoring of all S and Se metabolites. Employing the developed analytical methods the stress response of Saccharomyces cerevisiae to H₂O₂, and various toxic metals were studied. Apart from conventional molecular species of selenium such us selenometionine, selenocysteine or selenoglutathione here we report the presence of nanometer sized metallic deposits in yeast cells grown in the presence of selenium. Using a combination of synchrotron based micro X-ray fluorescence and hard x-ray microscopy and nano secondary ion-, electrospray- and inductively coupled plasma-mass spectrometry 3D imaging and localization of these intracellular selenium deposits was carried out. 

Life is connected to light in several ways.  From photosynthesis to the health of humans and being present in countless applications, light have revolutionized our society. During biological evolution living organisms learn how to use light in  organized ways in order to accomplish complex reactions such as vision and photosynthesis. However, part of these reactions can become uncontrolled, generating reactive species that damage cells and tissues by a process called photosenstization, in which chromophors absorb light and transfer its energy to neighboring molecules. Photosensitization reactions affect the yield of photosynthesis as well as are the main responsibles for the damage in skin, which is caused by UVA and visible light. We will exploit the mechanisms by which the natural chromophors (chlorophils, flavins, melanins, lypofuscin) absorb light and act as photosensitizers, damaging surrounding tissues. These reactions provide a mechanistic explanation for skin photoaging activated by visible light. Man has learned to use these same reactions to actively induce cell death of diseased tissues and consequently to treat several diseases with light, in a process called Photodynamic Therapy (PDT). In PDT synthetic photosensitizers are used to efficiently induce photosensitized reactions and we aim to use the photosensitization reactions to specifically trigger controlled mechanisms of cell death. We will show that by causing small damages in mitochondria, apoptotic cell death is efficiently induced, while if there is parallel damage in mitochondia and in lysosome autophagic cell death is induced. With this knowledge we hope to develop more efficient photosensitizers based both in new organic molecules or in hybrid organic/inorganic nanoparticles, which have more specific biological.

(Despite numerous important methodological advancements in all areas of chemistry, still most organic synthesis as well as the industrial production of chemicals can be improved. Currently, more than 80% of all products of the chemical industry are made via catalysis. In this regard, the development of new and more efficient catalysts constitutes a key factor for achieving a sustainable production of all kinds of chemicals today and in the future. Here, several major challenges will be presented in the talk; e.g. the benign reduction of carboxylic acid derivatives. Furthermore, it will be shown that recently developed molecular-defined as well as nano-structured base metal catalysts enable us to perform catalytic hydrogenation and dehydrogenation processes in high yields and with unprecedented selectivity. Specific examples which demonstrate the potential of sustainable catalytic processes will also include examples from energy technology. 

 Selected references

[1]  S. Das, B. Wendt, K. Möller, K. Junge, M. Beller, Angew. Chem. Int. Ed. 2012, 51, 1662.

[2] F. Westerhaus, R. Jagadeesh, G. Wienhöfer, M.-M. Pohl, J. Radnik, A.-E. Surkus, K. Junge, H. Junge, M. Beller, Nature Chem. 2013, 5, 607-612.

[3] M. Nielsen, E. Alberico, W. Baumann, H.-J. Drexler, H. Junge, S. Gladiali, M. Beller, Nature 2013, 494, 85-89.

[4] S. Fleischer, S. Zhou, K. Junge, M. Beller, Angew. Chem. Int. Ed. 2013, 52, 5120-5124.

[5] A. Boddien, D. Mellmann, F. Gärtner, R. Jackstell, H. Junge, P. J. Dyson, G. Laurenczy, R. Ludwig, M. Beller, Science 2011, 333, 1733-1736.

Sodium magadiite is a lamellar sodium silicate discovered in the 1960´s, in the alkaline Lake Magadi, Kenya. Despite its old age, its crystalline structure has never been described. The reason is that the crystals are always very small and full of defects.

Even in that case, magadiite continues to be of interest, along with the other members of the hydrated sodium silicate family, in several areas of the Chemistry.

Magadiite entered our laboratories in disguise, together with other solids. With time, it made its presence known to all of us and demanded our full understanding of its formation before it could be completely of use. Today it is studied and used as support for several systems, catalyst on itself, adsorbent of gases and other applications in challenging aspects of present life.

The conference will show all the aspects of magadiite chemistry studied within the Micro and Mesoporous Molecular Sieves Group, starting with the solid itself and following towards its transformations into materials with ever-increasing applications even without full knowledge of its crystalline structure.

The usual way to design the curriculum for the teaching of science (chemistry) is based on the conceptual and procedural contents of the discipline, inspired by what is taught at university level. At present this course of action has failed.

Current knowledge of cognitive science have provided new insights into the teaching of science. The theoretical terms that currently uses scientific cannot be  translated to everyday language; for it is necessary  generate a similar activity to that has generated these terms  in their day and . The needs of students are to understand how the world in which they live works.

Research in science education is paving the way for another way to organize knowledge in basic education, which requires, first, identify the main contribution science has made to Western culture and setting patterns of explanation that should be safeguarded to structure them for all the sciences.

Our goals are not 'disciplinar knowledge; this will come later, when students have explicitly opted to study science.

We advance that school science must meet the following objectives: knowing conditions for the life of the species that live in our planet and for a good management of resources and have care for their own (and other people) health. 

In this talk, advanced applications of electrochemical processes for mass deployment of sustainable and cost-effective photovoltaic (PV) technologies will be reviewed. Electrochemistry has shown to be the most promising technology for the development of low cost thin film PV modules with high throughput capabilities. The dissertation will be focused in the presentation of fundamental electrochemical processes developed and adapted to the deposition of metallic stacks and metal-chalcogenides compounds. As illustrative examples, the development of electrodeposited based CuIn_1-xGa_xSe₂ (CIGS) solar cells and modules, and new Cu₂ZnSn(S_1-ySe_y)₄ (CZTSSe) absorbers  based on earth abundant elements will be presented. The main challenges of these technologies will be reviewed, exemplifying the importance of electrochemistry for the future sustainable development of cost-efficient PV modules.

In particular, a deep electrochemical analysis of these complex systems will be presented and discussed. The optimization of these processes allows achieving a 17.5% CIGS world record solar cell by electrodeposition, and 14.6% world record of 60x120 cm² module in the frame of the Scalenano European Project. Complementary, first development of CZTSSe by electrochemical route has allowed achieving a 9.1% efficiency world record solar cell. Using these two examples, the advantages and challenges of electrodeposition techniques will be discussed, to be at the forefront of the development of advanced PV technologies.

Notwithstanding the apparent advantages of light energy, implementation of this energy source in organic synthetic methodologies and in the large scale production of fine chemicals has been largely neglected. Two main reasons have restrained substantial progress in photochemistry. The first reason concerns the photophysical aspects of organic molecules. Due to the absence of efficient chromophores in its core structure, most organic compounds are unable to efficiently absorb light energy to induce photochemical transformations. The second reason involves the limited scale-up potential of photochemistry. Large scale applications are hampered by the limited penetration depth of light irradiation due to absorption (Bouguer-Lambert-Beer law).

Photoredox catalysis is emerging as a new and powerful tool in synthetic organic chemistry to facilitate such photochemical reactions by means of visible light.^[1] Notable examples involve the use of ruthenium(II)polypyridine complexes which upon irradiation produce a photoexcited state. This photoexcited state gives rise to a single electron transfer process (SET) with organic substrates which can undergo subsequently a synthetic transformation. Whereas a myriad of different reactions have recently succumbed to this mode of catalysis, it is important to note that several challenges still remain with respect to high catalyst loadings, extended reaction times, scalability, quantum yield and generality of the catalyst system.

In this oral communication, we will report on the acceleration of photocatalytic reactions in continuous photomicroreactors. We will go into detail on both engineering and chemical/catalytic aspects of continuous-flow photochemistry. Relevant examples from our group, such as the Stadler-Ziegler reaction, trifluoromethylation reactions and disulfide formation will be detailed on during the presentation. Moreover, insight information will be provided about the discovery process and the different parameters that led to success.

Dr. T. e as reações em fluxo na 39ª RASBQ.   » Leia mais...