A method for preparation of a new stable Cu(I) catalyst supported on weakly acidic polyacrylate resin without additional stabilizing ligands is described. A simple and efficient methodology for Ullmann Cu(I) catalyzed C-N cross coupling reactions using this original catalyst is reported. Coupling reactions of 4-chloropyridinium chloride with anilines containing electron donating (EDG) or electron withdrawing (EWG) groups, naphthalen-2-amine and piperazine, respectively, are successfully demonstrated.
- MeSH
- 2-Naphthylamine chemistry MeSH
- Acrylic Resins chemistry MeSH
- Aniline Compounds chemistry MeSH
- Electrons * MeSH
- Catalysis MeSH
- Hydrogen-Ion Concentration MeSH
- Copper chemistry MeSH
- Equipment Reuse MeSH
- Piperazines chemistry MeSH
- Pyridinium Compounds chemical synthesis MeSH
- Green Chemistry Technology MeSH
- Publication type
- Journal Article MeSH
- Publication type
- Meeting Abstract MeSH
A click chemistry approach based on the reaction between alkynylflavins and mono(6-azido-6-deoxy)-β-cyclodextrin has proven to be a useful tool for the synthesis of flavin-cyclodextrin conjugates studied as monooxygenase mimics in enantioselective sulfoxidations.
Chemical, physical and mechanical methods of nanomaterial preparation are still regarded as mainstream methods, and the scientific community continues to search for new ways of nanomaterial preparation. The major objective of this review is to highlight the advantages of using green chemistry and bionanotechnology in the preparation of functional low-cost catalysts. Bionanotechnology employs biological principles and processes connected with bio-phase participation in both design and development of nano-structures and nano-materials, and the biosynthesis of metallic nanoparticles is becoming even more popular due to; (i) economic and ecologic effectiveness, (ii) simple one-step nanoparticle formation, stabilisation and biomass support and (iii) the possibility of bio-waste valorisation. Although it is quite difficult to determine the precise mechanisms in particular biosynthesis and research is performed with some risk in all trial and error experiments, there is also the incentive of understanding the exact mechanisms involved. This enables further optimisation of bionanoparticle preparation and increases their application potential. Moreover, it is very important in bionanotechnological procedures to ensure repeatability of the methods related to the recognised reaction mechanisms. This review, therefore, summarises the current state of nanoparticle biosynthesis. It then demonstrates the application of biosynthesised metallic nanoparticles in heterogeneous catalysis by identifying the many examples where bionanocatalysts have been successfully applied in model reactions. These describe the degradation of organic dyes, the reduction of aromatic nitro compounds, dehalogenation of chlorinated aromatic compounds, reduction of Cr(VI) and the synthesis of important commercial chemicals. To ensure sustainability, it is important to focus on nanomaterials that are capable of maintaining the important green chemistry principles directly from design inception to ultimate application.
The efforts have been made to review phyllosilicate derived (clay-based) heterogeneous catalysts for biodiesel production via lignocellulose derived feedstocks. These catalysts have many practical and potential applications in green catalysis. Phyllosilicate derived heterogeneous catalysts (modified via any of these approaches like acid activated clays, ion exchanged clays and layered double hydroxides) exhibits excellent catalytic activity for producing cost effective and high yield biodiesel. The combination of different protocols (intercalated catalysts, ion exchanged catalysts, acidic activated clay catalysts, clay-supported catalysts, composites and hybrids, pillared interlayer clay catalysts, and hierarchically structured catalysts) was implemented so as to achieve the synergetic effects (acidic-basic) in resultant material (catalyst) for efficient conversion of lignocellulose derived feedstock (non-edible oils) to biodiesel. Utilisation of these Phyllosilicate derived catalysts will pave path for future researchers to investigate the cost-effective, accessible and improved approaches in synthesising novel catalysts that could be used for converting lignocellulosic biomass to eco-friendly biodiesel.
- MeSH
- Biomass MeSH
- Biofuels * MeSH
- Esterification MeSH
- Catalysis MeSH
- Lignin MeSH
- Plant Oils * MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Natural biopolymers, polymeric organic molecules produced by living organisms and/or renewable resources, are considered greener, sustainable, and eco-friendly materials. Natural polysaccharides comprising cellulose, chitin/chitosan, starch, gum, alginate, and pectin are sustainable materials owing to their outstanding structural features, abundant availability, and nontoxicity, ease of modification, biocompatibility, and promissing potentials. Plentiful polysaccharides have been utilized for making assorted (nano)catalysts in recent years; fabrication of polysaccharides-supported metal/metal oxide (nano)materials is one of the effective strategies in nanotechnology. Water is one of the world's foremost environmental stress concerns. Nanomaterial-adorned polysaccharides-based entities have functioned as novel and more efficient (nano)catalysts or sorbents in eliminating an array of aqueous pollutants and contaminants, including ionic metals and organic/inorganic pollutants from wastewater. This review encompasses recent advancements, trends and challenges for natural biopolymers assembled from renewable resources for exploitation in the production of starch, cellulose, pectin, gum, alginate, chitin and chitosan-derived (nano)materials.
- MeSH
- Adsorption MeSH
- Alginates MeSH
- Biopolymers * MeSH
- Cellulose MeSH
- Water Pollutants, Chemical chemistry isolation & purification MeSH
- Chitin MeSH
- Chitosan MeSH
- Water Purification methods MeSH
- Catalysis MeSH
- Nanostructures * chemistry MeSH
- Nanotechnology MeSH
- Conservation of Water Resources MeSH
- Wastewater chemistry MeSH
- Pectins MeSH
- Starch MeSH
- Green Chemistry Technology MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Production of enantiopure esomeprazole by biocatalysis is of great demand by pharmaceutical industry. A Gram-positive bacterium oxidizing omeprazole sulfide 1a (5-methoxy-2-[((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)thio]-1H-benzoimidazole) to (S)-sulfoxide esomeprazole 2a (S)-5-methoxy-2-[(4-methoxy-3,5-dimethylpyridin-2-yl) methylsulfinyl]-3H-benzoimidazole was isolated from soil polluted with elemental sulfur. The strain exhibited the highest identity with the genus Lysinibacillus and catalyzed oxidation of 1a into enantiopure esomeprazole with conversion of 77% in a stirred bioreactor, fed-batch culture. No consecutive oxidation of (S)-sulfoxide to sulfone was observed during whole-cell catalysis. The unique characteristics of the catalyst provide a solid basis for further improvement and development of sustainable green bioprocess.
- MeSH
- Bacillus metabolism MeSH
- Bioreactors MeSH
- Biotransformation MeSH
- Chromatography, Thin Layer MeSH
- DNA Primers MeSH
- Hydrogen-Ion Concentration MeSH
- Culture Media MeSH
- Omeprazole analogs & derivatives metabolism MeSH
- Oxidation-Reduction MeSH
- Polymerase Chain Reaction MeSH
- Base Sequence MeSH
- Stereoisomerism MeSH
- Temperature MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Lignins are the most abundant biopolymers that consist of aromatic units. Lignins are obtained by fractionation of lignocellulose in the form of "technical lignins". The depolymerization (conversion) of lignin and the treatment of depolymerized lignin are challenging processes due to the complexity and resistance of lignins. Progress toward mild work-up of lignins has been discussed in numerous reviews. The next step in the valorization of lignin is the conversion of lignin-based monomers, which are limited in number, into a wider range of bulk and fine chemicals. These reactions may need chemicals, catalysts, solvents, or energy from fossil resources. This is counterintuitive to green, sustainable chemistry. Therefore, in this review, we focus on biocatalyzed reactions of lignin monomers, e.g., vanillin, vanillic acid, syringaldehyde, guaiacols, (iso)eugenol, ferulic acid, p-coumaric acid, and alkylphenols. For each monomer, its production from lignin or lignocellulose is summarized, and, mainly, its biotransformations that provide useful chemicals are discussed. The technological maturity of these processes is characterized based on, e.g., scale, volumetric productivities, or isolated yields. The biocatalyzed reactions are compared with their chemically catalyzed counterparts if the latter are available.
In comparison with the rapid progress (and often unpredictable changes) in clinical technologies and models of care, hospital capital planning has remained remarkably conventional and mostly unresponsive over time. Progress in this field has tended to be slow-paced and incremental in nature. Hospital design (with a few distinctive exceptions) has tended not to display the bravura concepts of change commonly associated with contemporary medicine. This is both a paradox and a threat to progress in healthcare. Capital consumes a large amount of healthcare resource and through its fixed nature can sediment services in place given the opportunity cost of change. Capital investment is often justified on the grounds of improving cost and throughput performance targets and can be stultified through the various financing methods adopted. It is rare to see capital business plans describe how the investment will (in measurable terms) contribute to improvement in clinical outcomes or better population health status, yet these two dimensions of healthcare provide its rationale. Recent evidence emerging from a pan-European study of new capital projects demonstrates that green shoots of change in capital thinking are emerging. One of the catalysts is undoubtedly the recognition of care pathways as the new foundation for capital planning and design. Care pathways (within hospital and spanning whole systems) provide a template and a language that can unite clinicians, nurses, managers, planners, architects and financiers in the common purpose of creating a stronger and more effective interface between the service and capital elements of healthcare. There is strong evidence in a number of leading edge examples (case studies) to suggest that a range of critical success factors can now be identified as providing a basis for generic application in the wider field of health capital infrastructure. These include designing in new concepts of functional adaptability, improving the synergies between the workforce and the buildings they occupy, improving patient safety (including reducing the risks associated with new opportunistic diseases) and responding more adequately to patients and citizens needs. The axiom that improved quality leads to improved cost effectiveness in capital provision can now also be demonstrated through the adoption of care pathway principles in the planning and design of new hospitals healthcare infrastructure.
