scholarly journals Propane to olefins tandem catalysis: a selective route towards light olefins production

2021 ◽  
Author(s):  
Matteo Monai ◽  
Marianna Gambino ◽  
Sippakorn Wannakao ◽  
Bert M. Weckhuysen
Keyword(s):  
Chemical Industry ◽  
Building Blocks ◽  
Single Step ◽  
Propane Dehydrogenation ◽  
Light Olefins ◽  
Tandem Catalysis ◽  
Challenges And Opportunities ◽  
Propylene Metathesis

Combining propane dehydrogenation with propylene metathesis in a single step yields mixtures of propylene, ethylene and butenes, important building blocks for the chemical industry. The open challenges and opportunities in the field are highlighted.

scholarly journals Synthetically Accessible Virtual Inventory (SAVI)

2020 ◽  
Author(s):  
Hitesh Patel ◽  
Wolf Ihlenfeldt ◽  
Philip Judson ◽  
Yurii S. Moroz ◽  
Yuri Pevzner ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Chemical Synthesis ◽  
Programming Languages ◽  
Expert Knowledge ◽  
Scoring Systems ◽  
Building Blocks ◽  
Single Step

We have made available a database of over 1 billion compounds predicted to be easily synthesizable. They have been created by a set of transforms based on an adaptation and extension of the CHMTRN/PATRAN programming languages describing chemical synthesis expert knowledge, which originally stem from the LHASA project. The chemoinformatics toolkit CACTVS was used to apply a total of 53 transforms to about 150,000 readily available building blocks (enamine.net). Only single-step, two-reactant syntheses were calculated for this database even though the technology can execute multi-step reactions. The possibility to incorporate scoring systems in CHMTRN allowed us to subdivide the database of 1.75 billion compounds in sets according to their predicted synthesizability, with the most-synthesizable class comprising 1.09 billion synthetic products. Properties calculated for all SAVI products show that the database should be well-suited for drug discovery. It is being made publicly available for free download from https://cactus.nci.nih.gov/download/savi_download/.

scholarly journals Design, synthesis, and characterization of novel nanowire structures for photovoltaics and intracellular probes

2011 ◽  
Vol 83 (12) ◽  
pp. 2153-2169 ◽  
Author(s):  
Bozhi Tian ◽  
Charles M. Lieber
Keyword(s):  
Critical Role ◽  
Physical Property ◽  
Building Blocks ◽  
Materials Synthesis ◽  
Design Synthesis ◽  
Unique System ◽  
Challenges And Opportunities ◽  
Iterative Control ◽  
Novel Applications

Semiconductor nanowires (NWs) represent a unique system for exploring phenomena at the nanoscale and are expected to play a critical role in future electronic, optoelectronic, and miniaturized biomedical devices. Modulation of the composition and geometry of nanostructures during growth could encode information or function, and realize novel applications beyond the conventional lithographical limits. This review focuses on the fundamental science aspects of the bottom-up paradigm, which are synthesis and physical property characterization of semiconductor NWs and NW heterostructures, as well as proof-of-concept device concept demonstrations, including solar energy conversion and intracellular probes. A new NW materials synthesis is discussed and, in particular, a new “nano-tectonic” approach is introduced that provides iterative control over the NW nucleation and growth for constructing 2D kinked NW superstructures. The use of radial and axial p-type/intrinsic/n-type (p-i-n) silicon NW (Si-NW) building blocks for solar cells and nanoscale power source applications is then discussed. The critical benefits of such structures and recent results are described and critically analyzed, together with some of the diverse challenges and opportunities in the near future. Finally, results are presented on several new directions, which have recently been exploited in interfacing biological systems with NW devices.

Mechanochemistry for sustainable, efficient dehydrogenation/hydrogenation

2020 ◽  
Author(s):  
Blaine G. Fiss ◽  
Austin James Richard ◽  
Tomislav Friscic ◽  
Audrey Moores
Keyword(s):  
Ball Milling ◽  
Chemical Industry ◽  
Organic Molecules ◽  
Solvent Free ◽  
Chemical Transformations ◽  
Triple Bonds ◽  
Bulk Chemicals ◽  
Challenges And Opportunities ◽  
Hydrogenation Reactions ◽  
Solution Routes

Hydrogenation reactions are one of the pillars of the chemical industry, with applications from bulk chemicals to pharmaceuticals manufacturing. The ability to selectively add hydrogen across double and/or triple bonds is key in the chemist’s toolbox, and the enabling component in the development of sustainable processes. Traditional solution-based approaches to hydrogenation reactions are tainted by significant consumption of energy and production of solvent waste. This review highlights the development and applications of recently emerged solvent-free approaches to conduct the hydrogenation of organic molecules using mechanochemistry, i.e. chemical transformations induced or sustained by mechanical force. In particular, we will show how mechanochemical techniques such as ball-milling enable catalytic or stoichiometric metal-mediated hydrogenation reactions that are simple, fast, and are conducted under significantly milder conditions compared to traditional solution routes. Importantly, we highlight the current challenges and opportunities in this field, while also identifying exciting cases in which mechanochemical hydrogenation strategies lead to new, unique targets and reactivity.

scholarly journals Emergent mechanics of biological structures

2014 ◽  
Vol 25 (22) ◽  
pp. 3461-3465 ◽  
Author(s):  
Sophie Dumont ◽  
Manu Prakash
Keyword(s):  
Temporal Patterns ◽  
Building Blocks ◽  
Mechanical Force ◽  
Active Force ◽  
Conceptual Frameworks ◽  
Spatial And Temporal Patterns ◽  
Biological Structures ◽  
Challenges And Opportunities ◽  
Remarkable Progress ◽  
The Way

Mechanical force organizes life at all scales, from molecules to cells and tissues. Although we have made remarkable progress unraveling the mechanics of life's individual building blocks, our understanding of how they give rise to the mechanics of larger-scale biological structures is still poor. Unlike the engineered macroscopic structures that we commonly build, biological structures are dynamic and self-organize: they sculpt themselves and change their own architecture, and they have structural building blocks that generate force and constantly come on and off. A description of such structures defies current traditional mechanical frameworks. It requires approaches that account for active force-generating parts and for the formation of spatial and temporal patterns utilizing a diverse array of building blocks. In this Perspective, we term this framework “emergent mechanics.” Through examples at molecular, cellular, and tissue scales, we highlight challenges and opportunities in quantitatively understanding the emergent mechanics of biological structures and the need for new conceptual frameworks and experimental tools on the way ahead.

Bifunctional hybrid catalysts derived from Cu/Zn-based nanoparticles for single-step dimethyl ether synthesis

2016 ◽  
Vol 6 (4) ◽  
pp. 1054-1063 ◽  
Author(s):  
M. Gentzen ◽  
W. Habicht ◽  
D. E. Doronkin ◽  
J.-D. Grunwaldt ◽  
J. Sauer ◽  
...  
Keyword(s):  
Dimethyl Ether ◽  
Building Blocks ◽  
Single Step ◽  
Bifunctional Catalysts ◽  
Hybrid Catalysts ◽  
Dimethyl Ether Synthesis ◽  
Ether Synthesis

Model kit for bifunctional catalysts: colloidal Cu/Zn-based nanoparticles were synthesized and used as building blocks in syngas to dimethyl ether (STD) catalysts.

scholarly journals Challenges and opportunities for fossil fuels in a carbon - constrained world – an Australian perspective

2014 ◽  
Vol 126 (2) ◽  
pp. 13
Author(s):  
William Rowlands
Keyword(s):  
Climate Change ◽  
Greenhouse Gases ◽  
Crude Oil ◽  
Chemical Industry ◽  
Fossil Fuels ◽  
Refining Industry ◽  
Oil Supply ◽  
Challenges And Opportunities ◽  
Value Add

With climate change undeniable, what are Australia’s opportunities for achieving more controlled greenhouse gases releases, while still using fossil fuels? How does this interplay with the reduction of fossil crude oil supply and the increasing shift in Australia towards importing finished products, declining refinery infrastructure and consequently reduction in the availability of chemical feed stocks for the local chemical industry? In fact, will there be an Australian chemicals and refining industry 30 years from now? The talk discussed these questions and aimed to outline a vision for Australia that might successfully deal with some of their aspects. Furthermore, this vision will be partially translated and exemplified with our lignite value add project in Victoria.

scholarly journals Cobalt Hydride Oxidase Catalysis Enabled Hydroamination of Unactivated Olefins

2021 ◽  
Author(s):  
Wei-Ting Ye ◽  
Rong Zhu
Keyword(s):  
Building Blocks ◽  
Single Step ◽  
Tertiary Amines ◽  
Mechanistic Studies ◽  
Organic Transformations ◽  
Design Elements ◽  
Alkyl Radicals ◽  
Solvent Free Conditions ◽  
Oxidative Processes ◽  
Nitrogen Nucleophiles

Dioxygen is an abundant, selective, and sustainable oxidant that is considered ideal for organic transformations. Oxidative processes using dioxygen as the electron acceptor without oxygen atom incorporation into the substrate are often referred to as oxidase reactions. However, the ground state triplet nature of dioxygen makes such a synthetically valuable pathway incompatible with simple free alkyl radicals, a ubiquitous class of reactive intermediates in the daily synthesis of pharmaceuticals, agrochemicals, and complex natural products. Here we report that a combination of strong cage effect and bimetallic radical-polar crossover successfully addresses this problem, and opens up an oxidase pathway in cobalt hydride catalysis. This leads to a general and chemoselective method that tackles several key challenges in catalytic hydroamination, a fundamental transformation for amine synthesis. Under balloon pressure of dioxygen at ambient temperature, we demonstrate single-step intra- and intermolecular formal addition of a variety of nitrogen nucleophiles, including free amines, sulfonamides, amides, and carbamates, to unactivated alkenes in the presence of a silane, under solvent-free conditions. Important medicinal chemistry building blocks such as a-branched tertiary amines can be easily accessed, which are often difficult targets otherwise due to their steric hindrance and reducing nature. Mechanistic studies including stoichiometric experiments with well-defined organocobalt complexes provide support for the key hypothesis, which points the way to the development of sustainable processes involving other nucleophiles based on the same design elements.

scholarly journals Engineered Biosynthesis of β-Alkyl Tryptophan Analogs

2018 ◽  
Author(s):  
Christina E. Boville ◽  
Remkes A. Scheele ◽  
Philipp Koch ◽  
Sabine Brinkmann-Chen ◽  
Andrew R. Buller ◽  
...  
Keyword(s):  
Pyrococcus Furiosus ◽  
Building Blocks ◽  
Single Step ◽  
Environmentally Benign ◽  
Tryptophan Synthase ◽  
X Ray Crystallography ◽  
Potential Applications ◽  
Uv Visible ◽  
Substrate Tolerance ◽  
Multi Step Methods

<a>Non-canonical amino acids (ncAAs) with dual stereocenters at the α and β positions are valuable precursors to natural products and therapeutics. Despite the potential applications of such bioactive β-branched ncAAs, their availability is limited due to the inefficiency of the multi-step methods used to prepare them. Here we report a stereoselective biocatalytic synthesis of β-branched tryptophan analogs using an engineered variant of <i>Pyrococcus furiosus</i> tryptophan synthase (<i>Pf</i>TrpB), <i>Pf</i>TrpB<sup>7E6</sup>. <i>Pf</i>TrpB<sup>7E6</sup> is the first biocatalyst to synthesize bulky β-branched tryptophan analogs in a single step, with demonstrated access to 27 ncAAs. The molecular basis for the efficient catalysis and broad substrate tolerance of <i>Pf</i>TrpB<sup>7E6</sup> was explored through X-ray crystallography and UV-visible light spectroscopy, which revealed that a combination of active-site and remote mutations increase the abundance and persistence of a key reactive intermediate. <i>Pf</i>TrpB<sup>7E6</sup> provides an operationally simple and environmentally benign platform for preparation of β-branched tryptophan building blocks.</a>

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