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417 results on '"Rode, A. V."'

21. ZrO2 Supported Cu Nanoparticles for Sonogashira and Ullmann Coupling Reactions Under Palladium-Free Conditions.

Author

Patil, Seema P., Rajmane, Archana S., Jadhav, Sanjay N., Rajmane, Vijaya S., Rode, Chandrashekhar V., and Kumbhar, Arjun S.

Subjects
SONOGASHIRA reaction, COUPLING reactions (Chemistry), COPPER, COPPER catalysts, ARYL bromides, NANOPARTICLES, ARYL halides
Abstract

Cu nanoparticles supported on ZrO2 (CuNPs@ZrO2) were synthesized using a one‐step co-precipitation process, and their application in C–C coupling reactions was investigated. The catalyst was characterized using XRD, XPS, SEM, TEM, and TGA techniques. The prepared catalyst was used for the Sonogashira cross-coupling reactions of aryl bromides with phenyl-acetylene in the presence of K2CO3 in DMF at 110 °C, which resulted in substituted alkynes with good to excellent yields. The protocol was also extended for the Ullmann coupling reactions of aryl iodides under similar reaction conditions, yielding the desired products with good to excellent yields without homo-coupling. Interestingly, unlike other copper catalysts, the present catalyst worked under air and did not require an inert atmosphere to prevent alkyne. This catalytic system is versatile, tolerant, and significantly cheaper than the "traditional" Pd-catalyzed Sonogashira cross-coupling of terminal alkynes with aryl halides. The catalyst could be reused for five catalytic cycles with no significant change in the product yield. All of these characteristics make our prepared CuNPs@ZrO2 catalyst quite suitable for the gram-scale synthesis of biaryls and alkynes, with a simple workup. [ABSTRACT FROM AUTHOR]

Published
2024
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29. Megahertz single-particle imaging at the European XFEL

Author

Sobolev, Egor, Zolotarev, Sergei, Giewekemeyer, Klaus, Bielecki, Johan, Okamoto, Kenta, Reddy, Hemanth K. N., Andreasson, Jakob, Ayyer, Kartik, Barak, Imrich, Bari, Sadia, Barty, Anton, Bean, Richard, Bobkov, Sergey, Chapman, Henry N., Chojnowski, Grzegorz, Daurer, Benedikt J., Dörner, Katerina, Ekeberg, Tomas, Flückiger, Leonie, Galzitskaya, Oxana, Gelisio, Luca, Hauf, Steffen, Hogue, Brenda G., Horke, Daniel A., Hosseinizadeh, Ahmad, Ilyin, Vyacheslav, Jung, Chulho, Kim, Chan, Kim, Yoonhee, Kirian, Richard A., Kirkwood, Henry, Kulyk, Olena, Küpper, Jochen, Letrun, Romain, Loh, N. Duane, Lorenzen, Kristina, Messerschmidt, Marc, Mühlig, Kerstin, Ourmazd, Abbas, Raab, Natascha, Rode, Andrei V., Rose, Max, Round, Adam, Sato, Takushi, Schubert, Robin, Schwander, Peter, Sellberg, Jonas A., Sikorski, Marcin, Silenzi, Alessandro, Song, Changyong, Spence, John C. H., Stern, Stephan, Sztuk-Dambietz, Jolanta, Teslyuk, Anthon, Timneanu, Nicusor, Trebbin, Martin, Uetrecht, Charlotte, Weinhausen, Britta, Williams, Garth J., Xavier, P. Lourdu, Xu, Chen, Vartanyants, Ivan A., Lamzin, Victor S., Mancuso, Adrian, and Maia, Filipe R. N. C.

Published
2020
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32. Conversion of benzyl phenyl ether to monoaromatics in high-temperature aqueous ethanol solution under high-pressure carbon dioxide conditions.

Author

Taniguchi, Kenkichi, Kusumawati, Etty N., Nanao, Hidetaka, Rode, Chandrashekhar V., Sato, Osamu, Yamaguchi, Aritomo, and Shirai, Masayuki

Subjects
PHENYL ethers, BENZYL ethers, CARBON dioxide, AQUEOUS solutions, ETHANOL, BENZYL alcohol, LIGNIN structure, LIGNANS
Abstract

Solvolysis of benzyl phenyl ether (BPE), which is a model compound of lignin ether linkage, was studied in an aqueous ethanol solution, which can be obtained from bioethanol, under high-pressure carbon dioxide conditions. A batch study revealed that BPE solvolysis to monoaromatics (benzyl ethyl ether (BEE), benzyl alcohol (BA), and phenol (Ph)) proceeded in aqueous ethanol solution over 523 K and the addition of high-pressure carbon dioxide enhanced the initial solvolysis rate and suppressed the side reaction (hydrogenolysis to toluene (TL)). The ethanol molar fraction (ethanol–water volume ratio) is the key factor for the solvolysis reaction, and the highest monoaromatic yield of 72.9% (BEE 10.7%, BA 19.3%, Ph 37.9%, and TL 5.1%) was obtained in aqueous ethanol solution (2 cm3 : 1 cm3 = water:ethanol) at 598 K for 3 h under a pressure of 18 MPa of carbon dioxide. The solvolysis reaction proceeded continuously to produce monoaromatics with a flow system. A monoaromatic yield of 76.7% (BEE 8.6%, BA 19.7%, Ph 39.6%, and TL 8.9%) was obtained, and the formation rates were 2.7 × 10−4 mmol min−1 for BEE, 6.2 × 10−4 mmol min−1 for BA, and 12.4 × 10−4 mmol min−1 for Ph at 598 K under flowing water (26 mmol min−1), ethanol solution (4.1 mmol min−1), carbon dioxide (1.2 mmol min−1), and BPE (15.6 × 10−4 mmol min−1) under a total pressure of 40 MPa. [ABSTRACT FROM AUTHOR]

Published
2023
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35. Activity performance and kinetics for glycerol carbonylation with urea over Zn‐Co mixed metal oxide catalyst.

Author

Kondawar, Sharda E., Kasar, Gaytri B., Khatua, Angshuman S., and Rode, Chandrashekhar V.

Subjects
GLYCERIN, CARBONYLATION, METAL catalysts, METALLIC oxides, X-ray photoelectron spectroscopy, UREA, RAMAN spectroscopy
Abstract

Efficient carbonylation of glycerol using urea with Zn‐Co mixed metal oxide (MMO) catalyst has been achieved. Various methods of catalyst preparation were explored for glycerol carbonate (GC) synthesis. The optimized method of catalyst preparation was found to be co‐precipitation (CP) with a Zn:Co ratio of 70:30, achieving 81% glycerol conversion with 97% GC selectivity. X‐ray diffraction (XRD) studies revealed the formation of ZnO, Co3 O4, and spinel ZnCo2O4 phases. Thermal treatment given to the catalyst allows insertion of Zn cations into Co3O4 lattice forming ZnCo2O4 phase which was also evidenced in X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Herein, for the first time, reaction kinetics was studied to propose the rate equation, based on which a plausible reaction pathway is proposed involving two‐site adsorption of glycerol (basic site) and urea (acidic site), which undergo carbonylation followed by cyclization into GC. A recycle study and hot filtration test have proven the reusability of the catalyst. [ABSTRACT FROM AUTHOR]

Published
2023
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50. Optical funnel to guide and focus virus particles for X-ray laser imaging

Author

Awel, Salah, Lavin-Varela, Sebastian, Roth, Nils, Horke, Daniel A., Rode, Andrei V., Kirian, Richard A., K��pper, Jochen, and Chapman, Henry N.

Subjects
Physics - Atmospheric and Oceanic Physics, Atmospheric and Oceanic Physics (physics.ao-ph), Fluid Dynamics (physics.flu-dyn), FOS: Physical sciences, Physics::Optics, Physics - Fluid Dynamics, Computational Physics (physics.comp-ph), Physics - Computational Physics, Optics (physics.optics), Physics - Optics
Abstract

The need for precise manipulation of nanoparticles in gaseous or near-vacuum environments is encountered in many studies that include aerosol morphology, nanodroplet physics, nanoscale optomechanics, and biomolecular physics. Photophoretic forces, whereby momentum exchange between a particle and surrounding gas is induced with optical light, were recently shown to be a robust means of trapping and manipulating nanoparticles in air. We previously proposed a photophoretic "optical funnel" concept for the delivery of bioparticles to the focus of an x-ray free-electron laser (XFEL) beam for femtosecond x-ray diffractive imaging. Here, we describe the formation of a high-aspect-ratio optical funnel and provide a first experimental demonstration of this concept by transversely compressing and concentrating a high-speed beam of aerosolized viruses by a factor of three in a low-pressure environment. These results pave the way toward improved sample delivery efficiency for XFEL imaging experiments as well as other forms of imaging and spectroscopy.

Published
2021

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