Bidentate N,O-prolinate ruthenium benzylidene catalyst highly active in RCM of disubstituted dienes

The synthesis of a bidentate N,O-prolinate ruthenium benzylidene from commercially available starting materials and its activity in ring-closing metathesis of functionalized disubstituted dienes at 30 °C is disclosed

Consequential life cycle assessment of kraft lignin recovery with chemical recycling

: The recovery of kraft lignin from black liquor allows an increasing of the pulp production of a kraft mill (marginal tonnage) and at the same time provide a valuable material that can be used as energy or chemical feedstock. However, because lignin precipitation is an energy- and material-consuming process, the environmental consequences from a life cycle perspective are under discourse. The aim of this study is to investigate, through the application of consequential life cycle assessment, the potential environmental benefits of kraft lignin recovery and its subsequent use as an energy or chemical feedstock. A newly developed chemical recovery strategy was assessed. The results revealed how the use of lignin as energy feedstock is not environmentally advantageous compared to producing energy directly from the pulp mill's recovery boiler. However, the best results were observed when lignin was used as a chemical feedstock in four applications to replace bitumen, carbon black, phenol, and bisphenol-A

Zeolite-Assisted Lignin-First Fractionation of Lignocellulose: Overcoming Lignin Recondensation through Shape-Selective Catalysis

This is the peer reviewed version of the following article: E. Subbotina, A. Velty, J. S. M. Samec, A. Corma, ChemSusChem 2020, 13, 4528, which has been published in final form at https://doi.org/10.1002/cssc.202000330. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Organosolv pulping releases reactive monomers from both lignin and hemicellulose by the cleavage of weak C-O bonds. These monomers recombine to form undesired polymers through the formation of recalcitrant C-C bonds. Different strategies have been developed to prevent this process by stabilizing the reactive monomers (i.e., lignin-first approaches). To date, all reported approaches rely on the addition of capping agents or metal-catalyzed stabilization reactions, which usually require high pressures of hydrogen gas. Herein, a metal- and additive-free approach is reported that uses zeolites as acid catalysts to convert the reactive monomers into more stable derivatives under organosolv pulping conditions. Experiments with model lignin compounds showed that the recondensation of aldehydes and allylic alcohols produced by the cleavage of beta-O-4 ' bonds was efficiently inhibited by the use of protonic beta zeolite. By applying a zeolite with a preferred pore size, the bimolecular reactions of reactive monomers were effectively inhibited, resulting in stable and valuable monophenolics. The developed methodology was further extended to birch wood to yield monophenolic compounds and value-added products from carbohydrates.This work was supported by the Swedish Energy Agency, Stiftelsen Olle Engkvist Byggm~stare, and the European Union through ERC-AdG-2014-671093-SynCatMatch.Subbotina, E.; Velty, A.; Samec, JSM.; Corma Canós, A. (2020). Zeolite-Assisted Lignin-First Fractionation of Lignocellulose: Overcoming Lignin Recondensation through Shape-Selective Catalysis. ChemSusChem. 13(17):4528-4536. https://doi.org/10.1002/cssc.202000330S452845361317Adler, E. (1977). Lignin chemistry?past, present and future. Wood Science and Technology, 11(3), 169-218. doi:10.1007/bf00365615Galkin, M. V., & Samec, J. S. M. (2016). Lignin Valorization through Catalytic Lignocellulose Fractionation: A Fundamental Platform for the Future Biorefinery. ChemSusChem, 9(13), 1544-1558. doi:10.1002/cssc.201600237Schutyser, W., Renders, T., Van den Bosch, S., Koelewijn, S.-F., Beckham, G. T., & Sels, B. F. (2018). Chemicals from lignin: an interplay of lignocellulose fractionation, depolymerisation, and upgrading. Chemical Society Reviews, 47(3), 852-908. doi:10.1039/c7cs00566kSun, Z., Fridrich, B., de Santi, A., Elangovan, S., & Barta, K. (2018). Bright Side of Lignin Depolymerization: Toward New Platform Chemicals. Chemical Reviews, 118(2), 614-678. doi:10.1021/acs.chemrev.7b00588Sturgeon, M. R., Kim, S., Lawrence, K., Paton, R. S., Chmely, S. C., Nimlos, M., … Beckham, G. T. (2013). A Mechanistic Investigation of Acid-Catalyzed Cleavage of Aryl-Ether Linkages: Implications for Lignin Depolymerization in Acidic Environments. ACS Sustainable Chemistry & Engineering, 2(3), 472-485. doi:10.1021/sc400384wShuai, L., Amiri, M. T., Questell-Santiago, Y. M., Héroguel, F., Li, Y., Kim, H., … Luterbacher, J. S. (2016). Formaldehyde stabilization facilitates lignin monomer production during biomass depolymerization. Science, 354(6310), 329-333. doi:10.1126/science.aaf7810Questell-Santiago, Y. M., Zambrano-Varela, R., Talebi Amiri, M., & Luterbacher, J. S. (2018). Carbohydrate stabilization extends the kinetic limits of chemical polysaccharide depolymerization. Nature Chemistry, 10(12), 1222-1228. doi:10.1038/s41557-018-0134-4Deuss, P. J., Scott, M., Tran, F., Westwood, N. J., de Vries, J. G., & Barta, K. (2015). Aromatic Monomers by in Situ Conversion of Reactive Intermediates in the Acid-Catalyzed Depolymerization of Lignin. Journal of the American Chemical Society, 137(23), 7456-7467. doi:10.1021/jacs.5b03693Lahive, C. W., Deuss, P. J., Lancefield, C. S., Sun, Z., Cordes, D. B., Young, C. M., … Barta, K. (2016). Advanced Model Compounds for Understanding Acid-Catalyzed Lignin Depolymerization: Identification of Renewable Aromatics and a Lignin-Derived Solvent. Journal of the American Chemical Society, 138(28), 8900-8911. doi:10.1021/jacs.6b04144Barta, K., & Ford, P. C. (2014). Catalytic Conversion of Nonfood Woody Biomass Solids to Organic Liquids. Accounts of Chemical Research, 47(5), 1503-1512. doi:10.1021/ar4002894Deuss, P. J., Lahive, C. W., Lancefield, C. S., Westwood, N. J., Kamer, P. C. J., Barta, K., & de Vries, J. G. (2016). Metal Triflates for the Production of Aromatics from Lignin. ChemSusChem, 9(20), 2974-2981. doi:10.1002/cssc.201600831Kaiho, A., Kogo, M., Sakai, R., Saito, K., & Watanabe, T. (2015). In situ trapping of enol intermediates with alcohol during acid-catalysed de-polymerisation of lignin in a nonpolar solvent. Green Chemistry, 17(5), 2780-2783. doi:10.1039/c5gc00130gJastrzebski, R., Constant, S., Lancefield, C. S., Westwood, N. J., Weckhuysen, B. M., & Bruijnincx, P. C. A. (2016). Tandem Catalytic Depolymerization of Lignin by Water-Tolerant Lewis Acids and Rhodium Complexes. ChemSusChem, 9(16), 2074-2079. doi:10.1002/cssc.201600683Zhang, L., Xi, G., Yu, K., Yu, H., & Wang, X. (2017). Furfural production from biomass–derived carbohydrates and lignocellulosic residues via heterogeneous acid catalysts. Industrial Crops and Products, 98, 68-75. doi:10.1016/j.indcrop.2017.01.014Anderson, E. M., Stone, M. L., Katahira, R., Reed, M., Beckham, G. T., & Román-Leshkov, Y. (2017). Flowthrough Reductive Catalytic Fractionation of Biomass. Joule, 1(3), 613-622. doi:10.1016/j.joule.2017.10.004Kumaniaev, I., Subbotina, E., Sävmarker, J., Larhed, M., Galkin, M. V., & Samec, J. S. M. (2017). Lignin depolymerization to monophenolic compounds in a flow-through system. Green Chemistry, 19(24), 5767-5771. doi:10.1039/c7gc02731aVan den Bosch, S., Renders, T., Kennis, S., Koelewijn, S.-F., Van den Bossche, G., Vangeel, T., … Sels, B. F. (2017). Integrating lignin valorization and bio-ethanol production: on the role of Ni-Al2O3catalyst pellets during lignin-first fractionation. Green Chemistry, 19(14), 3313-3326. doi:10.1039/c7gc01324hDusselier, M., Van Wouwe, P., Dewaele, A., Jacobs, P. A., & Sels, B. F. (2015). Shape-selective zeolite catalysis for bioplastics production. Science, 349(6243), 78-80. doi:10.1126/science.aaa7169Zhang, L., Xi, G., Chen, Z., Jiang, D., Yu, H., & Wang, X. (2017). Highly selective conversion of glucose into furfural over modified zeolites. Chemical Engineering Journal, 307, 868-876. doi:10.1016/j.cej.2016.09.001Cui, J., Tan, J., Deng, T., Cui, X., Zhu, Y., & Li, Y. (2016). Conversion of carbohydrates to furfural via selective cleavage of the carbon–carbon bond: the cooperative effects of zeolite and solvent. Green Chemistry, 18(6), 1619-1624. doi:10.1039/c5gc01948

Engineering design of the EURISOL multi-MW spallation target

The European Isotope Separation On-Line Radioactive Ion Beam project (EURISOL) is set to design the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, four target stations are foreseen, three direct targets of approximately 100 kW of beam power and one multi-MW target assembly, all driven by a high-power particle accelerator. In this high power target station, high-intensity RIBs of neutron-rich isotopes will be obtained by inducing fission in several actinide targets surrounding a liquid metal spallation neutron source. This article summarises the work carried out within Task 2 of the EURISOL Design Study, with special attention to the coupled neutronics of the mercury proton-to-neutron converter and the fission targets. The overall performance of the facility, which will sustain fast neutron fluxes of the order of 1014 n/cm2/s, is evaluated, together with the production of radionuclides in the actinide targets, showing that the targeted 1015 fissions/s can be achieved. Some of the greatest challenges in the design of high power spallation sources are the high power densities, entailing large structural stresses, and the heat removal, requiring detailed thermo-hydraulic calculations. The use of a thin martensitic steel beam-window and a well-controlled mercury flow has been shown to reduce the von-Misses stress in the former below the 200 MPa limit, with reasonable maximum flow rates of ~6 m/s. Alternatively, a windowless target configuration has been proposed, based on a liquid mercury transverse film. With this design, higher power densities and fission rates may be achieved, avoiding the technical difficulties related to the beam window. Experimentally, several tests have been performed at IPUL (Riga, Latvia) in order to study the stability of the liquid metal flow and validate the mercury loop design

A Salt Metathesis Route To Ruthenium Carbene Complex Isomers With Pyridine Dicarboxamide-Derived Chelate Pincer Ligands

Reaction of the doubly deprotonated pyridine 2,6-dicarboxamido ligand (1) with (PCy_3)_2Cl_2 Ru=CHPh (3a) in THF gave a mixture of (lig)(PCy_3)Ru=CHPh isomers (4). The pentane soluble N,N,O-4 isomer was isolated by extraction and characterized by X-ray diffraction. The O,N, O-4 isomer was identified in the residue. Single crystals of the closely related complex (lig)(NHC) Ru=CHPh, O,N,O-5, were obtained from the reaction of 1 with (NHC)(PCy_3)Cl_2Ru=CHPh (3b) and used for the X-ray crystal structure analysis of the system

Network models of soil porous structure

Soils sustain life on Earth. In times of increasing anthropogenic demands on soils [1] there is growing need to seek for novel approaches to understand the relationships between the soil porous structure and specific soil functions. Recently [2-4], soil pore structure was described as a complex network of pores using spatially embedded varying fitness network model [2] or heterogeneous preferential attachment scheme [3-4], both approaches revealing the apparent scale-free topology of soils. Here, we show, using a large set of soil images of structures obtained by X-ray computed tomography that both methods predict topological similar networks of soil pore structures. Furthermore, by analyzing the node-node link correlation properties of the obtained networks we suggest an approach to quantify the complexity of soil pore structur

Localization of 102 exons to a 2.5 Mb region involved in Down syndrome

Exon amplification has been applied to a 2.5 Mb region of chromosome 21 that has been associated with some features of Down syndrome (DS). Identification of the majority of genes from this region will facilitate the correlation of the over-expression of particular genes with specific phenotypes of DS. Over 100 gene fragments have been isolated from this 2.5 Mb segment. The exons have been characterized by sequence analysis, comparison with public databases and expansion to cDNA clones. Localization of the exons to chromosome 21 has been determined by hybridization to genomic Southern blots and to YAC and cosmid clones representing the region. This has resulted in a higher resolution physical map with a marker approximately every 25 kb. This integrated physical and transcript map will be valuable for fine mapping of DNA from individuals with partial aneuploidy of chromosome 21 as well as for assessing and ultimately generating a complete gene map of this segment of the genom

Environmental evolution and archaeological record of Barrancas river basin, Jujuy province, Argentina

Since 2012 our research team started the “Barrancas Archaeological Project” which main goal is to study the history of the people that dwelled this locality and neighbouring areas during the last 10000 years and yo put in value the cultural heritage of these societies. This paper have two aims: 1) to characterize the general environmental evolution of the Barrancas river basin since the end of Pleistocene and to discuss its impact on the human groups that used it: and 2) to briefly describe the archaeological record recovered in the upper and mid-section of the Barrancas river, mainly the chronology and general characteristics of the archaeological sites under study and the relative chronology and placement of the currently documented rock art. Barrancas archaeological evidence conjoined with the paleoenvironmental data obtained in this basin shows that substantial changes in local habitats have had a relevant role in the way in what human groups used this spaces through time, allowing to characterize them alternatively as a nodal or inter-nodal area through Holocene.Introducción El área de estudio - Antecedentes paleoambientales suprarregionales y regionales Evolución ambiental de Barrancas - Los registros paleoambientales de Barrancas - Tendencias paleoambientales - Evolución de la capacidad de carga en la cuenca desde los 7300 cal AP Síntesis de los sitios arqueológicos y ocupaciones humanas en Barrancas - Ocupaciones humanas del Holoceno Temprano y Medio (10.000-3750 años cal. AP) - Ocupaciones humanas entre 3500-1550 años cal. AP - Ocupaciones humanas ente 1200 y 200 cal AP - Manifestaciones rupestres Discusión y Conclusió