A GAS-CHROMATOGRAPHIC APPARATUS FOR THE STUDY OF THE HOT-ATOM CHEMISTRY OF ORGANIC HALIDES

1961 ◽  
Vol 39 (3) ◽  
pp. 706-710 ◽  
Author(s):  
M. D. Silbert ◽  
R. H. Tomlinson
Keyword(s):  
Active Materials ◽  
Temperature Program ◽  
Organic Halides ◽  
Wide Range ◽  
Atom Chemistry

The construction of an easily assembled and inexpensive gas-chromatographic apparatus is described. This system has been designed to determine β-active materials. The operation of this instrument involves the use of a temperature program in order to resolve materials boiling over a wide range of temperature.

Facile and practical hydrodehalogenations of organic halides enabled by calcium hydride and palladium chloride

2021 ◽  
Author(s):  
Jingjing Gui ◽  
Xin Cai ◽  
Lingyun Chen ◽  
Yuxin Zhou ◽  
Wenjing Zhu ◽  
...  
Keyword(s):  
Palladium Chloride ◽  
Calcium Hydride ◽  
Organic Halides ◽  
Wide Range

Herein, a convenient hydrodehalogenation method was described by employing less-explored calcium hydride as the reductant. A wide range of organic halides such as aromatic bromides, aromatic chlorides, aromatic triflates, aliphatic...

scholarly journals Simultaneous Monitoring of Crystalline Active Materials and Resistance Evolution in Lithium-Sulfur Batteries

2019 ◽  
Author(s):  
Yu-Chuan Chien ◽  
Ashok Menon ◽  
William Brant ◽  
Daniel Brandell ◽  
Matthew Lacey
Keyword(s):  
Energy Storage ◽  
Structural Changes ◽  
Dissolution Kinetics ◽  
Carbon Composite ◽  
Diffusion Resistance ◽  
Active Materials ◽  
Host Matrix ◽  
Current Interruption ◽  
Wide Range ◽  
Lithium Sulfur

Operando X-ray diffraction (XRD) is a valuable tool for studying secondary battery materials as it allows for the direct correlation of electrochemical behavior with structural changes of crystalline active materials. This is especially true for the lithium-sulfur chemistry, in which energy storage capability depends on the complex growth and dissolution kinetics of lithium sulfide (Li2S) and sulfur (S8) during discharge and charge, respectively. In this work, we present a novel development of this method through combining operando XRD with simultaneous and continuous resistance measurement using an Intermittent Current Interruption (ICI) method. We show that a coefficient of diffusion resistance, which reflects the transport properties in the sulfur/carbon composite electrode, can be determined from analysis of each current interruption. Its relationship to the established Warburg impedance model is validated theoretically and experimentally. We also demonstrate for an optimized electrode formulation and cell construction that the diffusion resistance increases sharply at the discharge end point, which is consistent with the blocking of pores in the carbon host matrix. The combination of XRD with ICI allows for a direct correlation of structural changes with not only electrochemical properties but also energy loss processes at a non-equilibrium state, and therefore is a valuable technique for the study of a wide range of energy storage chemistries.<br>

Tight binding models accurately predict band structures for copolymer semiconductors

2020 ◽  
Vol 22 (35) ◽  
pp. 19659-19671 ◽  
Author(s):  
Prithvi Tipirneni ◽  
Vishal Jindal ◽  
Michael J. Janik ◽  
Scott T. Milner
Keyword(s):  
Conjugated Polymers ◽  
Organic Photovoltaics ◽  
Tight Binding ◽  
Band Gaps ◽  
Active Materials ◽  
Band Structures ◽  
Wide Range ◽  
Binding Models

Conjugated polymers possess a wide range of desirable properties including accessible band gaps, plasticity, tunability, mechanical flexibility and synthetic versatility, making them attractive as active materials in organic photovoltaics (OPVs).

scholarly journals Origami-inspired active graphene-based paper for programmable instant self-folding walking devices

2015 ◽  
Vol 1 (10) ◽  
pp. e1500533 ◽  
Author(s):  
Jiuke Mu ◽  
Chengyi Hou ◽  
Hongzhi Wang ◽  
Yaogang Li ◽  
Qinghong Zhang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Building Blocks ◽  
Artificial Muscles ◽  
Gradient Structure ◽  
Slow Response ◽  
Active Materials ◽  
Wide Range ◽  
Folding Paper ◽  
Graphene Paper ◽  
And Robotics

Origami-inspired active graphene-based paper with programmed gradients in vertical and lateral directions is developed to address many of the limitations of polymer active materials including slow response and violent operation methods. Specifically, we used function-designed graphene oxide as nanoscale building blocks to fabricate an all-graphene self-folding paper that has a single-component gradient structure. A functional device composed of this graphene paper can (i) adopt predesigned shapes, (ii) walk, and (iii) turn a corner. These processes can be remote-controlled by gentle light or heating. We believe that this self-folding material holds potential for a wide range of applications such as sensing, artificial muscles, and robotics.

scholarly journals Aminoalkyl radicals as halogen-atom transfer agents for activation of alkyl and aryl halides

Science ◽  
2020 ◽  
Vol 367 (6481) ◽  
pp. 1021-1026 ◽  
Author(s):  
Timothée Constantin ◽  
Margherita Zanini ◽  
Alessio Regni ◽  
Nadeem S. Sheikh ◽  
Fabio Juliá ◽  
...  
Keyword(s):  
Halogen Atom ◽  
Building Blocks ◽  
Aryl Halides ◽  
Atom Transfer ◽  
Reduction Potentials ◽  
Tributyltin Hydride ◽  
Organic Halides ◽  
Wide Range ◽  
Carbon Carbon Bonds ◽  
Radical Processes

Organic halides are important building blocks in synthesis, but their use in (photo)redox chemistry is limited by their low reduction potentials. Halogen-atom transfer remains the most reliable approach to exploit these substrates in radical processes despite its requirement for hazardous reagents and initiators such as tributyltin hydride. In this study, we demonstrate that α-aminoalkyl radicals, easily accessible from simple amines, promote the homolytic activation of carbon-halogen bonds with a reactivity profile mirroring that of classical tin radicals. This strategy conveniently engages alkyl and aryl halides in a wide range of redox transformations to construct sp3-sp3, sp3-sp2, and sp2-sp2 carbon-carbon bonds under mild conditions with high chemoselectivity.

scholarly journals Sensors and sensor arrays based on conjugated polymers and carbon nanotubes

2002 ◽  
Vol 74 (9) ◽  
pp. 1753-1772 ◽  
Author(s):  
Liming Dai ◽  
Prabhu Soundarrajan ◽  
Taehyung Kim
Keyword(s):  
Carbon Nanotubes ◽  
Conjugated Polymers ◽  
Excited States ◽  
Sensor Arrays ◽  
Glucose Sensors ◽  
Mechanical And Thermal Properties ◽  
Active Materials ◽  
Wide Range ◽  
Pros And Cons ◽  
Potential Use

The need for cheaper, faster, and more accurate measurements has been a driving force for the development of new sensing devices. As is well known, the electrical conductivity of conjugated polymers can be reliably regulated over a wide range through interactions with electron acceptors and donors. This, together with the fast optical dynamics (either in the ground or excited states) of most conjugated polymers, has made conjugated polymers very attractive as transducer-active materials. On the other hand, the unusual electronic, mechanical, and thermal properties of carbon nanotubes have also led to their potential use in a wide range of devices, including sensors. In particular, the ability of carbon nanotubes and their derivatives to operate as gas and glucose sensors has been recently demonstrated. This article provides a status review on the research and development of sensors and sensor arrays based on conjugated polymers and carbon nanotubes. The unique features characteristic of most reported sensing transduction modes related to conjugated polymers and carbon nanotubes are discussed, along with their pros and cons.

High-Throughput Analysis of Materials for Chemical Looping Processes

2020 ◽  
Author(s):  
Nicholas Singstock ◽  
Christopher Bartel ◽  
Aaron M. Holder ◽  
Charles B. Musgrave
Keyword(s):  
High Throughput ◽  
Process Design ◽  
Experimental Studies ◽  
Chemical Processes ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Active Materials ◽  
High Throughput Analysis ◽  
Wide Range ◽  
Modern Chemical

Chemical looping is a promising approach for improving the energy efficiency of many industrial chemical processes. However, a major limitation of modern chemical looping technologies is the lack of suitable active materials to mediate the involved subreactions. Identification of suitable materials has been historically limited by the scarcity of high-temperature (> 600 °C) thermochemical data to evaluate candidate materials. An accurate thermodynamic approach is demonstrated here to rapidly identify active materials which is applicable to a wide variety of chemical looping chemistries. Application of this analysis to chemical looping combustion correctly classifies 17/17 experimentally studied redox materials by their viability and identifies over 1,300 promising yet previously unstudied active materials. This approach is further demonstrated by analyzing redox pairs for mediating a novel chemical looping process for producing pure SO2 from raw sulfur and air which could provide a more efficient and lower emission route to sulfuric acid. 12 promising redox materials for this process are identified, two of which are supported by previous experimental studies of their individual oxidation and reduction reactions. This approach provides the necessary foundation for connecting process design with high-throughput materials discovery to accelerate the innovation and development of a wide-range of chemical looping technologies.

High-Throughput Analysis of Materials for Chemical Looping Processes

2020 ◽  
Author(s):  
Nicholas Singstock ◽  
Christopher Bartel ◽  
Aaron M. Holder ◽  
Charles B. Musgrave
Keyword(s):  
High Throughput ◽  
Process Design ◽  
Experimental Studies ◽  
Chemical Processes ◽  
Chemical Looping Combustion ◽  
Chemical Looping ◽  
Active Materials ◽  
High Throughput Analysis ◽  
Wide Range ◽  
Modern Chemical

Chemical looping is a promising approach for improving the energy efficiency of many industrial chemical processes. However, a major limitation of modern chemical looping technologies is the lack of suitable active materials to mediate the involved subreactions. Identification of suitable materials has been historically limited by the scarcity of high-temperature (> 600 °C) thermochemical data to evaluate candidate materials. An accurate thermodynamic approach is demonstrated here to rapidly identify active materials which is applicable to a wide variety of chemical looping chemistries. Application of this analysis to chemical looping combustion correctly classifies 17/17 experimentally studied redox materials by their viability and identifies over 1,300 promising yet previously unstudied active materials. This approach is further demonstrated by analyzing redox pairs for mediating a novel chemical looping process for producing pure SO2 from raw sulfur and air which could provide a more efficient and lower emission route to sulfuric acid. 12 promising redox materials for this process are identified, two of which are supported by previous experimental studies of their individual oxidation and reduction reactions. This approach provides the necessary foundation for connecting process design with high-throughput materials discovery to accelerate the innovation and development of a wide-range of chemical looping technologies.

scholarly journals Recent Advances in Perylene Diimide-Based Active Materials in Electrical Mode Gas Sensing

Chemosensors ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 30
Author(s):  
Salman Ali ◽  
Akhil Gupta ◽  
Mahnaz Shafiei ◽  
Steven J. Langford
Keyword(s):  
Organic Solar Cells ◽  
Gas Sensing ◽  
Field Effect Transistors ◽  
Molecular Engineering ◽  
Future Research ◽  
Active Materials ◽  
Research Perspectives ◽  
Wide Range ◽  
Sensing Performance ◽  
Electrical Mode

This review provides an update on advances in the area of electrical mode sensors using organic small molecule n-type semiconductors based on perylene. Among small organic molecules, perylene diimides (PDIs) are an important class of materials due to their outstanding thermal, chemical, electronic, and optical properties, all of which make them promising candidates for a wide range of organic electronic devices including sensors, organic solar cells, organic field-effect transistors, and organic light-emitting diodes. This is mainly due to their electron-withdrawing nature and significant charge transfer properties. Perylene-based sensors of this type show high sensing performance towards various analytes, particularly reducing gases like ammonia and hydrazine, but there are several issues that need to be addressed including the selectivity towards a specific gas, the effect of relative humidity, and operating temperature. In this review, we focus on the strategies and design principles applied to the gas-sensing performance of PDI-based devices, including resistive sensors, amperometric sensors, and operating at room temperature. The device properties and sensing mechanisms for different analytes, focusing on hydrazine and ammonia, are studied in detail, and some future research perspectives are discussed for this promising field. We hope the discussed results and examples inspire new forms of molecular engineering and begin to open opportunities for other rylene diimide classes to be applied as active materials.

scholarly journals Filament Rigidity and Connectivity Tune the Deformation Modes of Active Biopolymer Networks

2017 ◽  
Author(s):  
Samantha Stam ◽  
Simon L. Freedman ◽  
Shiladitya Banerjee ◽  
Kimberly L. Weirich ◽  
Aaron R. Dinner ◽  
...  
Keyword(s):  
Molecular Motors ◽  
The Self ◽  
Self Organization ◽  
Cross Linking ◽  
Physical Parameters ◽  
Active Materials ◽  
Wide Range ◽  
Filament Bundles ◽  
Deformation Modes ◽  
Insight Into

ABSTRACTMolecular motors embedded within collections of actin and microtubule filaments underlie the dynamic behaviors of cytoskeletal assemblies. Understanding the physics of such motor-filament materials is critical to developing a physical model of the cytoskeleton and the design of biomimetic active materials. Here, we demonstrate through experiments and simulations that the rigidity and connectivity of filaments in active biopolymer networks regulates the anisotropy and the length scale of the underlying deformations, yielding materials with varying contractility. Semi-flexible filaments that can be compressed and bent by motor stresses undergo deformations that are predominantly biaxial. By contrast, rigid filament bundles contract via actomyosin sliding deformations that are predominantly uniaxial. Networks dominated by filament buckling are robustly contractile under a wide range of connectivities, while networks dominated by actomyosin sliding can be tuned from contractile to extensile through reduced connectivity via cross-linking. These results identify physical parameters that control the forces generated within motor-filament arrays, and provide insight into the self-organization and mechanics of cytoskeletal assemblies.

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