jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Emiko Koyama | Noriko Ito | Junichi Sugiyama | Joshua P. Barham | Yasuo Norikane | Reiko Azumi | Noriyuki Ohneda | Yoshinobu Ohno | Takeo Yoshimura | Hiromichi Odajima | Tadashi Okamoto
Source: Journal of Flow Chemistry (article, 2018-11-20)
Field: Chemistry — Organic Chemistry

A continuous-flow resonator-type microwave reactor for high-efficiency organic synthesis and Claisen rearrangement as a model reaction We have developed a single-mode microwave reactor for continuous-flow synthesis with various methods of operation. This device measures the resonant frequency and modulates the oscillation frequency accordingly to maintain the maximum electric field intensity in the cavity. It can be operated either using constant applied irradiation power or using new programs which change the electric power (E-GRA) and change the flow rate (Fl-GRA), in order to rapidly screen various reaction conditions. As a model reaction, the Claisen rearrangement reaction of allyl 1-naphthyl ether 1 was rapidly optimized in this device, affording the desired product 2-allylnapthalen-1-ol 2 in high (91%) yield and up to 20 g/h productivity. Claisen rearrangement ; Microwave ; Continuous flow ; Volumetric flow rate ; Materials science ; Yield (engineering) ; Oscillation (cell signaling) ; Analytical Chemistry (journal) ; Electric field ; Continuous reactor ; Chemistry ; Nuclear magnetic resonance ; Organic chemistry ; Thermodynamics ; Catalysis ; Physics ; Mechanics Microwave-Assisted Synthesis and Applications ; Innovative Microfluidic and Catalytic Techniques Innovation ; Gyrotron and Vacuum Electronics Research
Authors: Jaume Rostoll‐Berenguer | Gonzalo Blay | José R. Pedro | Carlos Vila
Source: Catalysts (article, 2018-12-12)
Field: Chemistry — Organic Chemistry

9,10-Phenanthrenedione as Visible-Light Photoredox Catalyst: A Green Methodology for the Functionalization of 3,4-Dihydro-1,4-Benzoxazin-2-Ones through a Friedel-Crafts Reaction A visible-light photoredox functionalization of 3,4-dihydro-1,4-benzoxazin-2-ones through a Friedel-Crafts reaction with indoles using an inexpensive organophotoredox catalyst is described. The reaction uses a dual catalytic system that is formed by a photocatalyst simple and cheap, 9,10-phenanthrenedione, and a Lewis acid, Zn(OTf)2. 5W white LEDs are used as visible-light source and oxygen from air as a terminal oxidant, obtaining the corresponding products with good yields. The reaction can be extended to other electron-rich arenes. Our methodology represents one of the most valuable and sustainable approach for the functionalization of 3,4-dihydro-1,4-benzoxazin-2-ones, as compared to the reported procedures. Furthermore, several transformations were carried out, such as the synthesis of the natural product cephalandole A and a tryptophol derivative. Photoredox catalysis ; Surface modification ; Catalysis ; Chemistry ; Friedel–Crafts reaction ; Combinatorial chemistry ; Photochemistry ; Visible spectrum ; Derivative (finance) ; Lewis acids and bases ; Photocatalysis ; Organic chemistry ; Materials science ; Optoelectronics Radical Photochemical Reactions ; Catalytic C–H Functionalization Methods ; Synthesis of Indole Derivatives
Authors: Xiyan Xu | Gema Pliego | Juan A. Zazo | Shuming Liu | José A. Casas | Juan J. Rodrı́guez
Source: Journal of Chemical Technology & Biotechnology (article, 2018-01-03)
Field: Chemistry — Analytical Chemistry

Two‐step persulfate and Fenton oxidation of naphthenic acids in water Abstract BACKGROUD In the current study, two‐step persulfate and Fenton oxidation has been investigated for the mineralization of naphthenic acids at 80 °C and initial pH ≈ 8. This pH evolves during the persulfate oxidation step towards the optimum for Fenton oxidation (≈ 3). The effects of persulfate and H 2 O 2 doses, iron concentration, duration of the persulfate oxidation step and operating temperature have been assessed. RESULTS The combined treatment allowed up to ≈ 80% mineralization of cyclohexanoic acid using fairly low relative amounts of reagents (20 and 30% of the stoichiometric for persulfate and H 2 O 2 , respectively). For mineralization of cyclohexanoic acid, 115 and 87 kJ mol ‐1 were obtained as representative values of the apparent activation energy for the persulfate and Fenton oxidation steps, respectively. The system was also successfully tested with other naphthenic acids, including cyclohexanebutyric acid, 2‐naphthoic acid and 1,2,3,4‐tetrahydro‐2‐naphthoic acid. Treatment of the naphthenic acids tested by this system gave rise to easily biodegradable effluents consisting mainly of short‐chain organic acids. The biodegradability was confirmed by the BOD 5 /COD ratio and respirometric tests. CONCLUSION The results show the potential application of this approach as a promising cost‐effective solution for the treatment of naphthenic acids‐bearing aqueous wastes. This approach has significant advantage compared with the single thermally‐activated persulfate or Fenton oxidation, since it allows a high mineralization at reduced reagent cost upon replacing part of the persulfate by less expensive H 2 O 2 . © 2018 Society of Chemical Industry Persulfate ; Mineralization (soil science) ; Chemistry ; Naphthenic acid ; Reagent ; Aqueous solution ; Biodegradation ; Nuclear chemistry ; Inorganic chemistry ; Organic chemistry ; Catalysis Petroleum Processing and Analysis ; Advanced oxidation water treatment ; Radioactive element chemistry and processing
Authors: Tukhar Jyoti Konch | Raj Kumar Gogoi | Abhijit Gogoi | Kundan Saha | Jumi Deka | K. Anki Reddy | Kalyan Raidongia
Source: Materials Chemistry Frontiers (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Nanofluidic transport through humic acid modified graphene oxide nanochannels The chemical similarity of graphene oxide (GO) and humic acid has been exploited to fine-tune the ionic and molecular transport properties of a lamellar GO membrane. Graphene ; Oxide ; Humic acid ; Lamellar structure ; Membrane ; Materials science ; Ionic bonding ; Nanotechnology ; Chemical engineering ; Chemistry ; Ion ; Organic chemistry ; Composite material ; Biochemistry Graphene research and applications ; Membrane Separation Technologies ; Nanopore and Nanochannel Transport Studies
Authors: Leonhard H. Urner | Yasmine B. Maier | Rainer Haag | Kevin Pagel
Source: Journal of the American Society for Mass Spectrometry (article, 2018-10-01)
Field: Chemistry — Spectroscopy

Exploring the Potential of Dendritic Oligoglycerol Detergents for Protein Mass Spectrometry The ability to design detergents that are suitable for protein analysis by mass spectrometry (MS) represents an on-going challenge in the field of native MS. Desirable detergent characteristics include charge-reducing properties and low gas-phase stabilities of complexes formed with proteins. In this work, the gas-phase properties of oligoglycerol detergents (OGDs) are optimized by fine tuning of their molecular structure. Furthermore, a tandem mass spectrometry (MS/MS) approach is presented that estimates the gas-phase properties of detergents simply by studying the dissociation behaviour of protein-detergent complexes (PDCs) formed with the soluble protein β-lactoglobulin (BLG). Graphical Abstract ᅟ. Chemistry ; Mass spectrometry ; Tandem mass tag ; Tandem mass spectrometry ; Gas phase ; Isobaric labeling ; Dissociation (chemistry) ; Chromatography ; Protein mass spectrometry ; Top-down proteomics ; Electron-capture dissociation ; Collision-induced dissociation ; Proteomics ; Analytical Chemistry (journal) ; Organic chemistry ; Quantitative proteomics ; Biochemistry Mass Spectrometry Techniques and Applications ; Analytical Chemistry and Chromatography ; Advanced Proteomics Techniques and Applications
Authors: Francesco Ibba | Pietro Capurro | Silvia Garbarino | Manuel Anselmo | Lisa Moni | Andrea Basso
Source: Organic Letters (article, 2018-01-30)
Field: Chemistry — Organic Chemistry

Photoinduced Multicomponent Synthesis of α-Silyloxy Acrylamides, an Unexplored Class of Silyl Enol Ethers The photoinduced, multicomponent reaction of α-diazoketones, silanols, and isocyanides affords α-silyloxy acrylamides, formally derived from α-keto amides. The presence of a secondary amido group makes classic preparative methods for silyl enol ethers unfeasible in this case, while the mild conditions required by this photochemical approach allow their synthesis in good yields; moreover, the general structure can be easily modified by varying each component of the multicomponent reaction. Fine-tuning of the reaction conditions (i.e., solvents, radiation, additives) can be exploited to obtain complete Z selectivity. The reactivity of this overlooked class of silyl enol ethers has been investigated, and features that could pave the way to new applications have been found. Silylation ; Enol ; Chemistry ; Selectivity ; Reactivity (psychology) ; Organic chemistry ; Reaction conditions ; Combinatorial chemistry ; Photochemistry ; Catalysis Cyclopropane Reaction Mechanisms ; Synthetic Organic Chemistry Methods ; Asymmetric Synthesis and Catalysis
Authors: Mehdi Shakourian‐Fard | S. Maryamdokht Taimoory | Volodymyr Semeniuchenko | Ganesh Kamath | John F. Trant
Source: Journal of Molecular Liquids (article, 2018-07-17)
Field: Materials Science — Materials Chemistry

The effect of ionic liquid adsorption on the electronic and optical properties of fluorographene nanosheets Graphene ; Ionic bonding ; Adsorption ; Chemical physics ; HOMO/LUMO ; Binding energy ; Materials science ; Covalent bond ; Molecule ; Work function ; Electronic structure ; Computational chemistry ; Boron nitride ; Density functional theory ; Physical chemistry ; Chemistry ; Nanotechnology ; Organic chemistry ; Ion ; Atomic physics ; Layer (electronics) Graphene research and applications ; Supercapacitor Materials and Fabrication ; Advanced Sensor and Energy Harvesting Materials
Authors: Mitchell D. Nothling | Thomas G. McKenzie | Amin Reyhani | Greg G. Qiao
Source: Macromolecular Rapid Communications (article, 2018-05-10)
Field: Chemistry — Organic Chemistry

Tunable, Quantitative Fenton‐RAFT Polymerization via Metered Reagent Addition A continuous supply of radical species is a key requirement for activating chain growth and accessing quantitative monomer conversions in reversible addition-fragmentation chain transfer (RAFT) polymerization. In Fenton-RAFT, activation is provided by hydroxyl radicals, whose indiscriminate reactivity and short-lived nature poses a challenge to accessing extended polymerization times and quantitative monomer conversions. Here, an alternative Fenton-RAFT procedure is presented, whereby radical generation can be finely controlled via metered dosing of a component of the Fenton redox reaction (H<sub>2</sub> O<sub>2</sub> ) using an external pumping system. By limiting the instantaneous flux of radicals and ensuring sustained radical generation over tunable time periods, metered reagent addition reduces unwanted radical "wasting" reactions and provides access to consistent quantitative monomer conversions with high chain-end fidelity. Fine tuning of radical concentration during polymerization is achieved simply via adjustment of reagent dose rate, offering significant potential for automation. This modular strategy holds promise for extending traditional RAFT initiation toward more tightly regulated radical concentration profiles and affords excellent prospects for the automation of Fenton-RAFT polymerization. Chain transfer ; Raft ; Reversible addition−fragmentation chain-transfer polymerization ; Radical polymerization ; Chemistry ; Polymerization ; Radical ; Reagent ; Monomer ; Photochemistry ; Polymer chemistry ; Combinatorial chemistry ; Organic chemistry ; Polymer Advanced Polymer Synthesis and Characterization ; Radioactive element chemistry and processing ; Synthetic Organic Chemistry Methods
Authors: Simon Drieschner | Maximilian von Seckendorff | Elena del Corro | Jörg Wohlketzetter | Benno M. Blaschke | M. Stutzmann | José A. Garrido
Source: Nanotechnology (article, 2018-03-07)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Uniformly coated highly porous graphene/MnO<sub>2</sub>foams for flexible asymmetric supercapacitors Supercapacitors are called to play a prominent role in the newly emerging markets of electric vehicles, flexible displays and sensors, and wearable electronics. In order to compete with current battery technology, supercapacitors have to be designed with highly conductive current collectors exhibiting high surface area per unit volume and uniformly coated with pseudocapacitive materials, which is crucial to boost the energy density while maintaining a high power density. Here, we present a versatile technique to prepare thickness-controlled thin-film micro graphene foams (μGFs) with pores in the lower micrometer range grown by chemical vapor deposition which can be used as highly conductive current collectors in flexible supercapacitors. To fabricate the μGF, we use porous metallic catalytic substrates consisting of nickel/copper alloy synthesized on nickel foil by electrodeposition in an electrolytic solution. Changing the duration of the electrodeposition allows the control of the thickness of the metal foam, and thus of the μGF, ranging from a few micrometers to the millimeter scale. The resulting μGF with a thickness and pores in the micrometer regime exhibits high structural quality which leads to a very low intrinsic resistance of the devices. Transferred onto flexible substrates, we demonstrate a uniform coating of the μGFs with manganese oxide, a pseudocapacitively active material. Considering the porous structure and the thickness of the μGFs, square wave potential pulses are used to ensure uniform coverage by the oxide material boosting the volumetric and areal capacitance to 14 F cm<sup>-3</sup> and 0.16 F cm<sup>-2</sup>. The μGF with a thickness and pores in the micrometer regime in combination with a coating technique tuned to the porosity of the μGF is of great relevance for the development of supercapacitors based on state-of-the-art graphene foams. Materials science ; Supercapacitor ; Graphene ; Porosity ; Micrometer ; Nanotechnology ; Oxide ; Current density ; Electrical conductor ; Current collector ; Capacitance ; Composite material ; Optoelectronics ; Electrode ; Electrolyte ; Metallurgy Supercapacitor Materials and Fabrication ; Advancements in Battery Materials ; Graphene research and applications
Authors: Tekalign A. Tikish | Ashok Kumar | Jung Yong Kim
Source: Advances in Materials Science and Engineering (article, 2018-01-01)
Field: Materials Science — Polymers and Plastics

Study on the Miscibility of Polypyrrole and Polyaniline Polymer Blends We report on the miscibility and phase behaviour of polypyrrole‐polyaniline (PPy/PANI) as a function of blend composition. The PPy/PANI blends were prepared by solution processing method, using dimethyl sulfoxide (DMSO) solvent. Characterization of the polymer blends was carried out based on the data analysis from Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), and differential scanning calorimetry (DSC). The PPy/PANI system was successfully formed blends in DMSO solvent. The polymer blends showed almost amorphous nature in XRD spectra because of intermolecular interaction between PPy and PANI macromolecules, which was confirmed by FT‐IR data. Specifically, the DSC result for the PPY : PANI = 50 : 50 wt.% blend showed only one glass transition temperature ( T g ), which indicates that the two polymers are well miscible without undergoing any phase separation. Miscibility ; Materials science ; Differential scanning calorimetry ; Polypyrrole ; Polyaniline ; Fourier transform infrared spectroscopy ; Glass transition ; Polymer blend ; Polymer ; Amorphous solid ; Polymer chemistry ; Chemical engineering ; Conductive polymer ; Phase (matter) ; Copolymer ; Composite material ; Organic chemistry ; Polymerization ; Chemistry Conducting polymers and applications ; Organic Electronics and Photovoltaics ; Advanced Sensor and Energy Harvesting Materials
Authors: Sándor B. Ötvös | István Pálinkó | Ferenc Fülöp
Source: Catalysis Science & Technology (article, 2018-11-23)
Field: Materials Science — Materials Chemistry

Catalytic use of layered materials for fine chemical syntheses The present work reviews the catalytic use of layered solid materials for fine chemical syntheses with focus on layered double hydroxides, but including other classes of layered compounds of catalytic relevance. Catalysis ; Layered double hydroxides ; Work (physics) ; Materials science ; Focus (optics) ; Chemical engineering ; Chemistry ; Nanotechnology ; Organic chemistry ; Physics ; Engineering Layered Double Hydroxides Synthesis and Applications ; Nanomaterials for catalytic reactions ; Polyoxometalates: Synthesis and Applications
Authors: Rambabu Dandela | Srinu Tothadi | Udaya Kiran Marelli | Ashwini Nangia
Source: IUCrJ (article, 2018-10-24)
Field: Chemistry — Physical and Theoretical Chemistry

Systematic synthesis of a 6-component organic-salt alloy of naftopidil, and pentanary, quaternary and ternary multicomponent crystals The single-crystal X-ray structure of a 6-component organic-salt alloy (hexanary) of naftopidil (1) (an active pharmaceutical ingredient) with benzoic acid (2) and four different hydroxy-substituted benzoic acids, <i>i.e.</i> salicylic acid (3), 2,3-di-hydroxybenzoic acid (4), 2,4-di-hydroxybenzoic acid (5) and 2,6-di-hydroxybenzoic acid (6), is reported. The hexanary assembly originates from the observation that the binary salts of naftopidil with the above acids are isostructural. In addition to the 6-component solid, we also describe five 5-component, ten 4-component, and ten 3-component organic-salt alloys of naftopidil (1) with carboxylic acids (2)-(6). These alloys were obtained from different combinations of the acids with the drug. The synthetic design of the multicomponent organic alloys is based on the rationale of geometrical factors (shape and size) and chemical interactions (hydrogen bonds). The common supramolecular synthon in all these crystal structures was the cyclic N<sup>+</sup>-H⋯O<sup>-</sup> and O-H⋯O hydrogen-bonded motif of (9) graph set between the 2-hy-droxyammonium group of naftopidil and the carboxyl-ate anion. This ionic synthon is strong and robust, directing the isostructural assembly of naftopidil with up to five different carboxylic acids in the crystal structure together with the lower-level multicomponent adducts. Solution crystallization by slow evaporation provided the multicomponent organic salts and alloys which were characterized by a combination of single-crystal X-ray diffraction, powder X-ray diffraction, NMR and differential scanning calorimetry techniques. Synthon ; Isostructural ; Chemistry ; Benzoic acid ; Crystal engineering ; Differential scanning calorimetry ; Supramolecular chemistry ; Crystallography ; Ternary operation ; Crystal structure ; Crystallization ; Hydrogen bond ; Organic chemistry ; Molecule Crystallography and molecular interactions ; Coordination Chemistry and Organometallics ; Crystal structures of chemical compounds
Authors: Ranran Zhang | Qiuling Zhao | Xia Wang | Wensheng Gao | Jensen Li | Wing Yim Tam
Source: Nanophotonics (article, 2018-06-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Measuring circular phase‐dichroism of chiral metasurface Abstract The ability of chiral media to differentiate circularly polarized light is conventionally characterized by circular dichroism (CD) which is based on the difference in the absorption of the incident light for different polarizations. Thus, CD probes the bulk properties of chiral media. Here, we introduce a new approach termed as circular phase‐dichroism that is based on the surface properties and is defined as the difference of the reflection phase for different circularly polarized incident lights in characterizing chiral media. As a demonstration, we measure the reflection phase from planar chiral sawtooth metasurface for circularly polarized light in the visible range using a simple Fabry Perot interference technique. The measured circular phase‐dichroism is also crosschecked by conventional CD measurement of the transmitted light and by full‐wave simulations. Our results demonstrate the potential applications of circular phase‐dichroism in sensing and metasurface characterizations. Circular dichroism ; Circular polarization ; X-ray magnetic circular dichroism ; Optics ; Phase (matter) ; Reflection (computer programming) ; Vibrational circular dichroism ; Ray ; Materials science ; Linear dichroism ; Dichroism ; Magnetic circular dichroism ; Physics ; Chemistry ; Spectral line ; Crystallography Metamaterials and Metasurfaces Applications ; Electromagnetic Scattering and Analysis ; Advanced Antenna and Metasurface Technologies
Authors: Fredrik Schultheiss | Christina Windmark | Stefan Sjöstrand | Magnus Rasmusson | Jan-Eric Ståhl
Source: The International Journal of Advanced Manufacturing Technology (article, 2018-03-20)
Field: Materials Science — Materials Chemistry

Machinability and manufacturing cost in low-lead brass Today, commercially used brasses commonly contain 2 to 4 wt% lead. As the availability of low-lead and lead-free brass increases, there are environmental incentives for investigating the consequences of replacing the lead-containing brasses with lead-free equivalents. Generally, lead-free brass is expected to have a lower machinability than its lead-alloyed counterpart, implying a higher manufacturing cost. Thus, the aim of this study has been to quantify the added manufacturing cost by replacing a standard brass alloy with a low-lead alternative. This was done through a case study performed at a Swedish SME which replaced CuZn39Pb3 (3.3 wt% Pb) with low-lead CuZn21Si3P (< 0.09 wt% lead) for a select part. Since CuZn21Si3P is almost twice as expensive as CuZn39Pb3, the material cost was found to have a substantial influence on the manufacturing cost. Additionally, the lower machinability implied a longer cycle time and higher losses while machining CuZn21Si3P, resulting in a 77% overall increase in manufacturing cost when using the low-lead material. Arguably, the difference in material cost, and thus manufacturing cost, may decrease over time making production of low-lead and lead-free brass products a viable option, especially when considering the environmental incentive for decreasing the amount of lead in circulation. Machinability ; Brass ; Lead (geology) ; Machining ; Lead time ; Metallurgy ; Manufacturing cost ; Manufacturing engineering ; Materials science ; Engineering ; Operations management ; Mechanical engineering ; Copper Metallurgy and Material Science ; Aluminum Alloy Microstructure Properties ; Bauxite Residue and Utilization