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Sample records for fmt efficient synthesis

  1. Dual Roles of FmtA in Staphylococcus aureus Cell Wall Biosynthesis and Autolysis

    Science.gov (United States)

    Qamar, Aneela

    2012-01-01

    The fmtA gene is a member of the Staphylococcus aureus core cell wall stimulon. The FmtA protein interacts with β-lactams through formation of covalent species. Here, we show that FmtA has weak d-Ala-d-Ala-carboxypeptidase activity and is capable of covalently incorporating C14-Gly into cell walls. The fluorescence microscopy study showed that the protein is localized to the cell division septum. Furthermore, we show that wall teichoic acids interact specifically with FmtA and mediate recruitment of FmtA to the S. aureus cell wall. Subjection of S. aureus to FmtA concentrations of 0.1 μM or less induces autolysis and biofilm production. This effect requires the presence of wall teichoic acids. At FmtA concentrations greater than 0.2 μM, autolysis and biofilm formation in S. aureus are repressed and growth is enhanced. Our findings indicate dual roles of FmtA in S. aureus growth, whereby at low concentrations, FmtA may modulate the activity of the major autolysin (AtlA) of S. aureus and, at high concentrations, may participate in synthesis of cell wall peptidoglycan. These two roles of FmtA may reflect dual functions of FmtA in the absence and presence of cell wall stress, respectively. PMID:22564846

  2. Fatigue Monitoring Tool for Airline Operators (FMT

    Directory of Open Access Journals (Sweden)

    Gislason Sigurdur Hrafn

    2017-12-01

    Full Text Available A Fatigue Monitoring Tool (FMT model was constructed for an operational airline in order to manage the fatigue levels of their crews in accordance with Fatigue Risk Management System (FRMS practices. This article describes the implementation of the Fatigue Monitoring Tool model and the airline’s aims to put the recent scientific findings on aviation fatigue into practical use. The model consists of proxy points allotted to various duties and rest periods.

  3. Step-up fecal microbiota transplantation (FMT) strategy

    Science.gov (United States)

    Cui, Bota; Li, Pan; Xu, Lijuan; Peng, Zhaoyuan; Xiang, Jie; He, Zhi; Zhang, Ting; Ji, Guozhong; Nie, Yongzhan; Wu, Kaichun; Fan, Daiming; Zhang, Faming

    2016-01-01

    ABSTRACT Gut dysbiosis is a characteristic of inflammatory bowel disease (IBD) and is believed to play a role in the pathogenesis of IBD. Fecal microbiota transplantation (FMT) is an effective strategy to restore intestinal microbial diversity and has been reported to have a potential therapeutic value in IBD. Our recent study reported a holistic integrative therapy called “step-up FMT strategy,” which was beneficial in treating steroid-dependent IBD patients. This strategy consists of scheduled FMTs combined with steroids, anti-TNF-α antibody treatment or enteral nutrition. Herein, we will elaborate the strategy thoroughly, introducing the concept, potential indication, methodology, and safety of “step-up FMT strategy” in detail. PMID:26939622

  4. Efficient synthesis of substituted dihydrotetraazapentacenes.

    Science.gov (United States)

    Seillan, Claire; Brisset, Hugues; Siri, Olivier

    2008-09-18

    We describe a versatile and very efficient synthesis of previously unknown substituted 5,14-dihydro-5,7,12,14-tetraazapentacenes (DHTAPs). A structural study by NMR spectroscopy showed that the conjugated pi-system of the pentacyclic skeleton rearranges depending on the electronic effect of the substituent(s).

  5. FMT (Flight Software Memory Tracker) For Cassini Spacecraft-Software Engineering Using JAVA

    Science.gov (United States)

    Kan, Edwin P.; Uffelman, Hal; Wax, Allan H.

    1997-01-01

    The software engineering design of the Flight Software Memory Tracker (FMT) Tool is discussed in this paper. FMT is a ground analysis software set, consisting of utilities and procedures, designed to track the flight software, i.e., images of memory load and updatable parameters of the computers on-board Cassini spacecraft. FMT is implemented in Java.

  6. Zeolite membranes for efficient synthesis of biofuels

    OpenAIRE

    Sandström, Linda

    2009-01-01

    The greenhouse effect and the limited fossil oil resources have increased the demand of renewable fuels. Zeolite membranes have potential applications in numerous separation processes, and could be useful in the development of efficient processes for renewable fuel production. Methanol synthesis from synthesis gas is equilibrium limited, and continuous removal of products in a zeolite membrane reactor could improve the productivity of a conventional methanol synthesis process. In this work, m...

  7. Efficient microwave irradiation enhanced stereoselective synthesis ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 122; Issue 4. Efficient microwave irradiation enhanced stereoselective synthesis and antitumor activity of indolylchalcones and their pyrazoline analogs. Magdy A H Zahran Hanan F Salama Yasmin G Abdin Amira M Gamal-Eldeen. Full Papers Volume 122 Issue 4 ...

  8. Efficient and convenient synthesis of symmetrical carboxylic ...

    African Journals Online (AJOL)

    An efficient and convenient procedure for the synthesis of symmetrical carboxylic anhydrides from carboxylic acids with sulfated zirconia by PEG-1000 phase transfer catalysis has been developed. The reactions proceeded under mild and solvent-free conditions to provide the carboxylic anhydrides in good to excellent ...

  9. CT/FMT dual-model imaging of breast cancer based on peptide-lipid nanoparticles

    Science.gov (United States)

    Xu, Guoqiang; Lin, Qiaoya; Lian, Lichao; Qian, Yuan; Lu, Lisen; Zhang, Zhihong

    2016-03-01

    Breast cancer is one of the most harmful cancers in human. Its early diagnosis is expected to improve the patients' survival rate. X-ray computed tomography (CT) has been widely used in tumor detection for obtaining three-dimentional information. Fluorescence Molecular Tomography (FMT) imaging combined with near-infrared fluorescent dyes provides a powerful tool for the acquisition of molecular biodistribution information in deep tissues. Thus, the combination of CT and FMT imaging modalities allows us to better differentiate diseased tissues from normal tissues. Here we developed a tumor-targeting nanoparticle for dual-modality imaging based on a biocompatible HDL-mimicking peptide-phospholipid scaffold (HPPS) nanocarrier. By incorporation of CT contrast agents (iodinated oil) and far-infrared fluorescent dyes (DiR-BOA) into the hydrophobic core of HPPS, we obtained the FMT and CT signals simultaneously. Increased accumulation of the nanoparticles in the tumor lesions was achieved through the effect of the tumor-targeting peptide on the surface of nanoparticle. It resulted in excellent contrast between lesions and normal tissues. Together, the abilities to sensitively separate the lesions from adjacent normal tissues with the aid of a FMT/CT dual-model imaging approach make the targeting nanoparticles a useful tool for the diagnostics of breast cancer.

  10. Effect of Aging on the Composition of Fecal Microbiota in Donors for FMT and Its Impact on Clinical Outcomes.

    Science.gov (United States)

    Anand, Rohit; Song, Yang; Garg, Shashank; Girotra, Mohit; Sinha, Amitasha; Sivaraman, Anita; Phillips, Laila; Dutta, Sudhir K

    2017-04-01

    Fecal microbiota transplantation (FMT) is emerging as an effective therapy for the treatment of recurrent Clostridium difficile infection (RCDI). Selecting an appropriate donor is vital to the success of FMT. However, the relationship between age of donors and the efficacy of FMT has not been examined to date. The aim of this study was to examine the effect of age of healthy donors on their fecal microbiota and assess the impact of these changes on the clinical efficacy of FMT. This IRB-approved prospective study enrolled donors who were deemed healthy for FMT after careful detailed screening for infectious diseases per institutional protocol. The study was conducted between January 2011 and October 2014. Fecal samples were processed and analyzed using 16S rRNA gene amplicon sequencing. Differences in relative abundance and diversity of the donor fecal microbiota were analyzed in donors above and below 60 years of age. Effect of fecal microbiota from donors of different age groups on the efficacy of FMT was also evaluated. Twenty-eight healthy human subjects from ages 20-82 years were enrolled as donors for FMT. All patients receiving FMT from their respective donors had resolution of RCDI symptoms and had a negative C. difficile toxin test 4-12 weeks after FMT. Genomic analysis showed that the relative abundance of phylum Actinobacteria and family Bifidobacteriaceae was reduced in the donors ≥60 years of age (p < 0.05). However, Bacteroidetes-to-Fermicutes ratio did not demonstrate a significant change between the two groups. Furthermore, microbial diversity did not change significantly with advancing age. These observations suggest that aging in healthy donors is associated with compositional alterations in the fecal microbiome without change in the overall microbial diversity. These changes do not seem to affect the clinical efficacy of FMT in RCDI patients over 12 months.

  11. Within the International Collaboration CHAIN: a Summary of Events Observed with Flare Monitoring Telescope (FMT) in Peru

    Science.gov (United States)

    Ishitsuka, J.; Asai, A.; Morita, S.; Terrazas, R.; Cabezas, D.; Gutierrez, V.; Martinez, L.; Buleje, Y.; Loayza, R.; Nakamura, N.; Takasao, S.; Yoshinaga, Y.; Hillier, A.; Otsuji, K.; Shibata, K.; Ishitsuka, M.; Ueno, S.; Kitai, R.; Ishii, T.; Ichimoto, K.; Nagata, S.; Narukage, N.

    2014-02-01

    In 2008 we inaugurated the new Solar Observatory in collaboration with Faculty of Sciences of San Luis Gonzaga de Ica National University, 300 km south of Lima. In March of 2010 a Flare Monitoring Telescope of Hida Observatory of Kyoto University arrived to Ica, part of CHAIN Project (Continuous H-alpha Imaging Network). In October of the same year we hosted the First FMT Workshop in Ica, then in July of 2011 the Second FMT Workshop was opened. Since that we are focused on two events registered by FMT in Peru to publish results. FMT is a good tool to introduce young people from universities into scientific knowledge; it is good also for education in Solar Physics and outreach. Details of this successful collaboration will be explained in this presentation.

  12. Alum an Efficient Catalyst for Erlenmeyer Synthesis

    African Journals Online (AJOL)

    NICO

    found to be useful precursors for the synthesis of amino acids,2 peptides,3 and ... tuted imidazoles,21h etc. However, there are no examples of the use of alum as a catalyst for the synthesis of azlactone deriva- tives. 2. Result and Discussion .... 12 P.S. Rao and R.V. Venkataratnam, Indian J. Chem, 1994, 33B, 984–985.

  13. Nickel nanoparticles: A highly efficient catalyst for one pot synthesis ...

    Indian Academy of Sciences (India)

    J. Chem. Sci. Vol. 124, No. 4, July 2012, pp. 907–912. c Indian Academy of Sciences. Nickel nanoparticles: A highly efficient catalyst for one pot synthesis of tetraketones and biscoumarins ... Department of Chemistry, University of Delhi, Delhi 110 007, India e-mail: ... and for the synthesis of various heterocyclic com-.

  14. An Efficient, Green Chemical Synthesis of the Malaria Drug ...

    African Journals Online (AJOL)

    Purpose: To provide a robust, efficient synthesis of the malaria drug piperaquine for potential use in resource-poor settings. Methods: We used in-process analytical technologies (IPAT; HPLC) and a program of experiments to develop a synthesis of piperaquine that avoids the presence of a toxic impurity in the API and is ...

  15. An efficient chemical synthesis of nicotinamide riboside (NAR) and analogues.

    Science.gov (United States)

    Tanimori, Shinji; Ohta, Takeshi; Kirihata, Mitsunori

    2002-04-22

    A simple and efficient synthesis of nicotinamide riboside (NAR) 1 and derivatives 4 and 5 via trimethylsilyl trifluoromethanesulfonate (TMSOTf)-mediated N-glycosilation followed by spontaneous deacetylation by treating with methanol is reported.

  16. An Improved, Highly Efficient Method for the Synthesis of Bisphenols

    Directory of Open Access Journals (Sweden)

    L. S. Patil

    2011-01-01

    Full Text Available An efficient synthesis of bisphenols is described by condensation of substituted phenols with corresponding cyclic ketones in presence of cetyltrimethylammonium chloride and 3-mercaptopropionic acid as a catalyst in extremely high purity and yields.

  17. An efficient synthesis of loline alkaloids

    Science.gov (United States)

    Cakmak, Mesut; Mayer, Peter; Trauner, Dirk

    2011-07-01

    Loline (1) is a small alkaloid that, in spite of its simple-looking structure, has posed surprising challenges to synthetic chemists. It has been known for more than a century and has been the subject of extensive biological investigations, but only two total syntheses have been achieved to date. Here, we report an asymmetric total synthesis of loline that, with less then ten steps, is remarkably short. Our synthesis incorporates a Sharpless epoxidation, a Grubbs olefin metathesis and an unprecedented transannular aminobromination, which converts an eight-membered cyclic carbamate into a bromopyrrolizidine. The synthesis is marked by a high degree of chemo- and stereoselectivity and gives access to several members of the loline alkaloid family. It delivers sufficient material to support a programme aimed at studying the complex interactions between plants, fungi, insects and bacteria brokered by loline alkaloids.

  18. Cooperative catalysis designing efficient catalysts for synthesis

    CERN Document Server

    Peters, René

    2015-01-01

    Written by experts in the field, this is a much-needed overview of the rapidly emerging field of cooperative catalysis. The authors focus on the design and development of novel high-performance catalysts for applications in organic synthesis (particularly asymmetric synthesis), covering a broad range of topics, from the latest progress in Lewis acid / Br?nsted base catalysis to e.g. metal-assisted organocatalysis, cooperative metal/enzyme catalysis, and cooperative catalysis in polymerization reactions and on solid surfaces. The chapters are classified according to the type of cooperating acti

  19. Efficient synthesis of phosphonodepsipeptides derived from norleucine

    Czech Academy of Sciences Publication Activity Database

    Pícha, Jan; Buděšínský, Miloš; Hančlová, Ivona; Šanda, Miloslav; Fiedler, Pavel; Vaněk, Václav; Jiráček, Jiří

    2009-01-01

    Roč. 65, č. 31 (2009), s. 6090-6103 ISSN 0040-4020 R&D Projects: GA ČR GA203/06/1405; GA MŠk(CZ) LC06077 Institutional research plan: CEZ:AV0Z40550506 Keywords : phosphonate * pseudopeptide * inhibitor * synthesis * norleucine Subject RIV: CC - Organic Chemistry Impact factor: 3.219, year: 2009

  20. Mg2FeH6 Synthesis Efficiency Map

    Directory of Open Access Journals (Sweden)

    Katarzyna Witek

    2018-02-01

    Full Text Available The influences of the processing parameters on the Mg2FeH6 synthesis yield were studied. Mixtures of magnesium hydride (MgH2 and iron (Fe were mechanically milled in a planetary ball mill under argon for 0.5-, 1-, 2- and 3-h periods and subsequently sintered at temperatures from 300–500 ∘ C under hydrogen. The reaction yield, phase content and hydrogen storage properties of the received materials were investigated. The morphologies of the powders after synthesis were studied by SEM. The synthesis effectiveness map was presented. The obtained results prove that synthesis parameters, such as the milling time and synthesis temperature, greatly influence the reaction yield and material properties and show that extended mechanical milling may not be beneficial to the reaction efficiency.

  1. An Efficient Microscale Procedure for the Synthesis of Aspirin

    Science.gov (United States)

    Pandita, Sangeeta; Goyal, Samta

    1998-06-01

    The synthesis of aspirin is a part of many undergraduate organic synthesis labs and is frequently used in qualitative organic analysis laboratory for the identification of salicylic acid. We have found that aspirin can be synthesized on microscale by a simple and efficient procedure that eliminates the heating step employed in literature procedures and gives a pure, ferric-negative product (no purple color with alcoholic ferric chloride solution).

  2. efficient and convenient synthesis of symmetrical carboxylic

    African Journals Online (AJOL)

    Preferred Customer

    strong acidity and high activity in light alkane conversions at relatively mild temperatures [36,. 37]. In this paper, we wish to report an efficient and convenient method for the preparation of symmetrical carboxylic anhydrides from the corresponding carboxylic acids with sulfated zirconia by phase transfer catalysis without any ...

  3. Efficient synthesis of benzothiazine and acrylamide compounds

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Ana Maria Alves; Walfrido, Simone Torres Padua; Leite, Lucia Fernanda Costa; Lima, Maria Carmo Alves; Galdino, Suely Lins; Pitta, Ivan Rocha [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Antibioticos; Barbosa Filho, Jose Maria [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Simone, Carlos Alberto de; Ellena, Javier Alcides, E-mail: irpitta@gmail.co [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Fisica

    2010-07-01

    This article describes the synthesis of the new (2Z)-2-(4-methoxybenzylidene)-6-nitro-4H -benzo[1,4]thiazine-3-one, (2Z)-2-(4-methoxybenzylidene)-4-methyl-6-nitro-4H-benzo[1,4]thiazine-3-one, (2Z)-6-amino-2-(4-methoxybenzylidene)-4H -benzo[1,4]thiazine-3-one, (2Z)-6-butylamino-2-(4-methoxybenzylidene)-4-methyl-4H-benzo[1,4] -thiazine-3-one and (2E)-N-alkyl-N-(2-hydroxy-5-nitrophenyl) -3-phenylacrylamides and the spectroscopic data. The arylidenebenzothiazine compounds were prepared using the Knoevenagel condensation with substituted benzaldehydes in the presence of sodium methoxide in DMF. The presence of a nitro substituent in the 4-position, water and a slightly acid reaction medium in this condensation caused the rupture of the benzothiazine ring and subsequent formation of the phenylacrylamide compounds. A crystallographic data was presented for (2E)-3-(4-bromophenyl)-N-dodecyl-N -(2-hydroxy-5-nitrophenyl) acrylamide. (author)

  4. Efficient synthesis of metallated thioporphyrazines in task specific ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 128; Issue 9. Efficient synthesis of metallated thioporphyrazines in task specific ionic liquids and their spectroscopic investigation of binding with selected transition metal ions. POONAM RITIKA NAGPAL SMRITI ARORA SHIVE M S CHAUHAN. Regular Article Volume ...

  5. Novel efficient process for methanol synthesis by CO2 hydrogenation

    NARCIS (Netherlands)

    Kiss, Anton Alexandru; Pragt, J.J.; Vos, H.J.; Bargeman, Gerrald; de Groot, M.T.

    2016-01-01

    Methanol is an alternative fuel that offers a convenient solution for efficient energy storage. Complementary to carbon capture activities, significant effort is devoted to the development of technologies for methanol synthesis by hydrogenation of carbon dioxide. While CO2 is available from plenty

  6. Efficient Synthesis of 1-Sulfonyl-1,2,3-triazoles

    Science.gov (United States)

    Raushel, Jessica; Fokin, Valery V.

    2010-01-01

    An efficient room temperature method for the synthesis of 1-sulfonyl-1,2,3-triazoles from in situ generated copper(I) acetylides and sulfonyl azides is described. Copper(I) thiophene-2-carboxylate (CuTC) catalyst produces the title compounds under both non-basic anhydrous and aqueous conditions in good yields. PMID:20931987

  7. An efficient synthesis, X-ray and spectral characterization of ...

    Indian Academy of Sciences (India)

    An efficient synthesis, X-ray and spectral characterization of biphenyl derivatives. Ravindra R Kamble Dharesh B Biradar Gangadhar Y Meti Tasneem Taj Tegginamath Gireesh Imthiyaz Ahmed M Khazi Sundar T Vaidyanathan Raju Mohandoss Balasubramanian Sridhar Viraraghav Parthasarathi. Volume 123 Issue 4 July ...

  8. Sulfated polyborate: A mild, efficient catalyst for synthesis of N ...

    Indian Academy of Sciences (India)

    Rapid, efficient and inexpensive method for synthesis of N-tert-butyl/N-trityl protected amides via Ritter reaction of nitriles with tertiary alcohols in the presence of a sulfated polyborate catalyst under solvent-free conditions is described. The catalyst has the advantage of Lewis as well as Bronsted acidity and recyclability ...

  9. Efficient Synthesis of the Plant Growth Regulator Ancymidol

    Directory of Open Access Journals (Sweden)

    Heiko Patzelt

    2003-06-01

    Full Text Available The important cytochrome P450 inhibitor ancymidol is used as a plant growth retardant and has potential for various medicinal applications. However its high price sets economic limits to large-scale applications. Here a short and high-yielding synthesis is reported, providing ancymidol in substantial amounts in a cost- and time-efficient way.

  10. An efficient and sustainable synthesis of NHC gold complexes.

    Science.gov (United States)

    Johnson, Alice; Gimeno, M Concepción

    2016-08-11

    A simple, efficient and sustainable method for the general synthesis of NHC gold(i) complexes is described. The reaction of imidazolium salts, of different electronic and steric requirements, with [AuX(tht)] (tht = tetrahydrothiophene) derivatives, in the presence of NBu4(acac), in air and at room temperature leads to the NHC gold species in good yields and with very short reaction times.

  11. The thermodynamic efficiency of ATP synthesis in oxidative phosphorylation.

    Science.gov (United States)

    Nath, Sunil

    2016-12-01

    As the chief energy source of eukaryotic cells, it is important to determine the thermodynamic efficiency of ATP synthesis in oxidative phosphorylation (OX PHOS). Previous estimates of the thermodynamic efficiency of this vital process have ranged from Lehninger's original back-of-the-envelope calculation of 38% to the often quoted value of 55-60% in current textbooks of biochemistry, to high values of 90% from recent information theoretic considerations, and reports of realizations of close to ideal 100% efficiencies by single molecule experiments. Hence this problem has been reinvestigated from first principles. The overall thermodynamic efficiency of ATP synthesis in the mitochondrial energy transduction OX PHOS process has been found to lie between 40 and 41% from four different approaches based on a) estimation using structural and biochemical data, b) fundamental nonequilibrium thermodynamic analysis, c) novel insights arising from Nath's torsional mechanism of energy transduction and ATP synthesis, and d) the overall balance of cellular energetics. The torsional mechanism also offers an explanation for the observation of a thermodynamic efficiency approaching 100% in some experiments. Applications of the unique, molecular machine mode of functioning of F 1 F O -ATP synthase involving direct inter-conversion of chemical and mechanical energies in the design and fabrication of novel, man-made mechanochemical devices have been envisaged, and some new ways to exorcise Maxwell's demon have been proposed. It is hoped that analysis of the fundamental problem of energy transduction in OX PHOS from a fresh perspective will catalyze new avenues of research in this interdisciplinary field. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Detection of breast cancer microcalcification using 99mTc-MDP SPECT or Osteosense 750EX FMT imaging

    International Nuclear Information System (INIS)

    Felix, Dayo D.; Gore, John C.; Yankeelov, Thomas E.

    2015-01-01

    Background: In previous work, we demonstrated the presence of hydroxyapetite (type II microcalcification), HAP, in triple negative MDA-MB-231 breast cancer cells. We used 18 F-NaF to detect these types of cancers in mouse models as the free fluorine, 18 F − , binds to HAP similar to bone uptake. In this work, we investigate other bone targeting agents and techniques including 99m Tc-MDP SPECT and Osteosense 750EX FMT imaging as alternatives for breast cancer diagnosis via targeting HAP within the tumor microenvironment. Methods: Thirteen mice were injected subcutaneously in the right flank with 10 6 MDA-MB-231 cells. When the tumor size reached ~ 0.6 cm 3 , mice (n = 9) were injected with ~ 37 MBq of 99m Tc-MDP intravenously and then imaged one hour later in a NanoSPECT/CT or injected intravenously with 4 nmol/g of Osetosense 750EX and imaged 24 hours later in an FMT (n = 4). The imaging probe concentration in the tumor was compared to that of muscle. Following SPECT imaging, the tumors were harvested, sectioned into 10 μm slices, and underwent autoradiography or von Kossa staining to correlate 99m Tc-MDP binding with HAP distribution within the tumor. The SPECT images were normalized to the injected dose and regions-of-interest (ROIs) were drawn around bone, tumor, and muscle to obtain the radiotracer concentration in these regions in units of percent injected dose per unit volume. ROIs were drawn around bone and tumor in the FMT images as no FMT signal was observed in normal muscle. Results: Uptake of 99m Tc-MDP was observed in the bone and tumor with little or no uptake in the muscle with concentrations of 11.34 ± 1.46 (mean ± SD), 2.22 ± 0.95, and 0.05 ± 0.04 %ID/cc, respectively. Uptake of Osteosense 750EX was also observed in the bone and tumor with concentrations of 0.35 ± 0.07 (mean ± SD) and 0.04 ± 0.01 picomoles, respectively. No FMT signal was observed in the normal muscle. There was no significant difference in the bone-to-tumor ratio between

  13. Detection of breast cancer microcalcification using 99mTc-MDP SPECT or Osteosense 750EX FMT imaging

    Science.gov (United States)

    Felix, Dayo D.; Gore, John C.; Yankeelov, Thomas E.; Peterson, Todd E.; Barnes, Stephanie; Whisenant, Jennifer; Weis, Jared; Shoukouhi, Sepideh; Virostko, John; Nickels, Michael; McIntyre, J. Oliver; Sanders, Melinda; Abramson, Vandana; Tantawy, Mohammed N.

    2015-01-01

    Background In previous work, we demonstrated the presence of hydroxyapetite (type II microcalcification), HAP, in triple negative MDA-MB-231 breast cancer cells. We used 18F-NaF to detect these types of cancers in mouse models as the free fluorine, 18F−, binds to HAP similar to bone uptake. In this work, we investigate other bone targeting agents and techniques including 99mTc-MDP SPECT and Osteosense 750EX FMT imaging as alternatives for breast cancer diagnosis via targeting HAP within the tumor microenvironment. Methods Thirteen mice were injected subcutaneously in the right flank with 106 MDA-MB-231 cells. When the tumor size reached ~0.6 cm3, mice (n = 9) were injected with ~37 MBq of 99mTc-MDP intravenously and then imaged one hour later in a NanoSPECT/CT or injected intravenously with 4 nmol/g of Osetosense 750EX and imaged 24 hours later in an FMT (n = 4). The imaging probe concentration in the tumor was compared to that of muscle. Following SPECT imaging, the tumors were harvested, sectioned into 10 µm slices, and underwent autoradiography or von Kossa staining to correlate 99mTc-MDP binding with HAP distribution within the tumor. The SPECT images were normalized to the injected dose and regions-of-interest (ROIs) were drawn around bone, tumor, and muscle to obtain the radiotracer concentration in these regions in units of percent injected dose per unit volume. ROIs were drawn around bone and tumor in the FMT images as no FMT signal was observed in normal muscle. Results Uptake of 99mTc-MDP was observed in the bone and tumor with little or no uptake in the muscle with concentrations of 11.34 ± 1.46 (mean ± SD), 2.22 ± 0.95, and 0.05 ± 0.04 %ID/cc, respectively. Uptake of Osteosense 750EX was also observed in the bone and tumor with concentrations of 0.35 ± 0.07 (mean ± SD) and 0.04 ± 0.01 picomoles, respectively. No FMT signal was observed in the normal muscle. There was no significant difference in the bone-to-tumor ratio between the two

  14. Detection of breast cancer microcalcification using (99m)Tc-MDP SPECT or Osteosense 750EX FMT imaging.

    Science.gov (United States)

    Felix, Dayo D; Gore, John C; Yankeelov, Thomas E; Peterson, Todd E; Barnes, Stephanie; Whisenant, Jennifer; Weis, Jared; Shoukouhi, Sepideh; Virostko, John; Nickels, Michael; McIntyre, J Oliver; Sanders, Melinda; Abramson, Vandana; Tantawy, Mohammed N

    2015-03-01

    In previous work, we demonstrated the presence of hydroxyapetite (type II microcalcification), HAP, in triple negative MDA-MB-231 breast cancer cells. We used (18)F-NaF to detect these types of cancers in mouse models as the free fluorine, (18)F(-), binds to HAP similar to bone uptake. In this work, we investigate other bone targeting agents and techniques including (99m)Tc-MDP SPECT and Osteosense 750EX FMT imaging as alternatives for breast cancer diagnosis via targeting HAP within the tumor microenvironment. Thirteen mice were injected subcutaneously in the right flank with 10(6) MDA-MB-231 cells. When the tumor size reached ~0.6 cm(3), mice (n=9) were injected with ~37 MBq of (99m)Tc-MDP intravenously and then imaged one hour later in a NanoSPECT/CT or injected intravenously with 4 nmol/g of Osetosense 750EX and imaged 24 hours later in an FMT (n=4). The imaging probe concentration in the tumor was compared to that of muscle. Following SPECT imaging, the tumors were harvested, sectioned into 10 μm slices, and underwent autoradiography or von Kossa staining to correlate (99m)Tc-MDP binding with HAP distribution within the tumor. The SPECT images were normalized to the injected dose and regions-of-interest (ROIs) were drawn around bone, tumor, and muscle to obtain the radiotracer concentration in these regions in units of percent injected dose per unit volume. ROIs were drawn around bone and tumor in the FMT images as no FMT signal was observed in normal muscle. Uptake of (99m)Tc-MDP was observed in the bone and tumor with little or no uptake in the muscle with concentrations of 11.34±1.46 (mean±SD), 2.22±0.95, and 0.05±0.04%ID/cc, respectively. Uptake of Osteosense 750EX was also observed in the bone and tumor with concentrations of 0.35±0.07 (mean±SD) and 0.04±0.01picomoles, respectively. No FMT signal was observed in the normal muscle. There was no significant difference in the bone-to-tumor ratio between the two modalities (5.1±2.3 for SPECT and 8.8

  15. Catalogue of Energy Efficiency Measures for France - Synthesis report

    International Nuclear Information System (INIS)

    2013-10-01

    ADEME wished to learn about existing effective energy efficiency measures implemented outside of France, whether cross-sectoral or targeted at a specific sector (industry, transport, buildings or agriculture). The objective of this survey was to determine whether any of these measures could be applied in France, with the goal of holding down the growth of energy consumption. This survey has led to the writing of a catalog of 53 two-page fact sheets describing the measures identified as interesting for France. These measures were analysed via classic criteria of evaluation such as cost-efficiency or impact, allowing to highlight the most successful measures for the French territory. ADEME presents you a synthesis of this survey in this document

  16. Synthesis of energy-efficient FSMs implemented in PLD circuits

    Science.gov (United States)

    Nawrot, Radosław; Kulisz, Józef; Kania, Dariusz

    2017-11-01

    The paper presents an outline of a simple synthesis method of energy-efficient FSMs. The idea consists in using local clock gating to selectively block the clock signal, if no transition of a state of a memory element is required. The research was dedicated to logic circuits using Programmable Logic Devices as the implementation platform, but the conclusions can be applied to any synchronous circuit. The experimental section reports a comparison of three methods of implementing sequential circuits in PLDs with respect to clock distribution: the classical fully synchronous structure, the structure exploiting the Enable Clock inputs of memory elements, and the structure using clock gating. The results show that the approach based on clock gating is the most efficient one, and it leads to significant reduction of dynamic power consumed by the FSM.

  17. An efficient synthesis of D-galactose-based multivalent neoglycoconjugates

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, S.F. de; Souza Filho, J.D. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Quimica; Alves, Ricardo J., E-mail: ricardodylan@farmacia.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Fac. de Farmacia; Figueiredo, Rute C. [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2012-11-15

    In this work, the synthesis of dimeric, trimeric and tetrameric D-galactose-based neoglycoconjugates is reported. The monosaccharide ligand was prepared in 5 straightforward steps from D-galactose using the Doebner modification of the Knoevenagel reaction for chain elongation. The ligand was coupled to 1,4-butanediamine, tris-(2-ethylamino)amine, pentaerythrityltetramine and PAMAM dendrimers (1,4-butanodiamine core G0 and 1,12-dodecanediamine core G0). The unprotected glycodendrimers were purified by size-exclusion chromatography (SEC). This was the only step in which a chromatographic method was employed throughout the synthetic route. This is a new and efficient strategy for the preparation of neoglycoconjugates. (author)

  18. Nickel nanoparticles: A highly efficient catalyst for one pot synthesis ...

    Indian Academy of Sciences (India)

    synthesis of tetraketones and biscoumarins. JITENDER M KHURANA. ∗ ... designed wherein, polyvinyl pyrrolidone (PVP) stabilized nickel nanoparticles have been used as a catalyst for promoting the synthesis of 2,2 -aryl-methylene ..... synthesis of tetraketones (3) and bis- coumarins (4) using air stable PVP coated nickel.

  19. Efficient synthesis and sulfonation of ordered mesoporous carbon materials.

    Science.gov (United States)

    Hou, Keke; Zhang, Anfeng; Gu, Lin; Liu, Min; Guo, Xinwen

    2012-07-01

    Ordered mesoporous carbons (OMCs) with hexagonal structure were efficiently synthesized via cooperative self-assembly of phenol/formaldehyde resol and surfactant F127 under acidic aqueous conditions. Induced by HCl, a gel phase mainly containing phenol/formaldehyde resol and F127 was obtained within several hours. X-ray diffraction (XRD), transmission electron microscope (TEM) and nitrogen adsorption isotherms indicated that the synthesized samples possess 2-D hexagonal mesostructure. The influence of the synthesis conditions, including acid concentration and mass ratio of resol to F127, was investigated. When the acid concentration was fixed in the range of 0.6-2.0 M and the mass ratio of resol to F127 in the range of 3.5-4.0, highly ordered mesoporous carbon could be synthesized. The synthesized OMCs could be easily sulfonated in concentrated sulfuric acid at elevated temperature. The results indicate that the mesostructural stability and the content of the surface sulfonic acid (SO(3)H) groups depend mainly on the pyrolysis temperature of the OMCs and the sulfonation temperature, suggesting that the combination of pyrolysis and sulfonation temperature is essential for developing OMCs with high densities of SO(3)H groups. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Highly efficient solvent-free synthesis of pyranopyrazoles by a ...

    Indian Academy of Sciences (India)

    organic synthesis and medicinal chemistry because they are one-pot processes bringing together three or more components and show high atom economy and high selectivity.1,2 MCRs have great contribution in con- vergent synthesis of complex and important organic molecules from simple and readily available starting.

  1. An efficient domino one-pot synthesis of novel spirofuran ...

    Indian Academy of Sciences (India)

    AFSHIN YAZDANI-ELAH-ABADI

    using sulfated polyborate as a recyclable catalyst J. Chem. Sci. 129 141. 29. Seitz L E, Suling W J and Reynolds R C 2002 Synthesis and antimycobacterial activity of pyrazine and quinoxa- line derivatives J. Med. Chem. 45 5604. 30. Badran M M, Moneer A A, Refaat H M and El-Malah. A A 2007 Synthesis and antimicrobial ...

  2. Efficient, green and solvent-free synthesis of tetrasubstituted ...

    Indian Academy of Sciences (India)

    optical materials, and photographic materials.7 In addi- tion, these compounds are employed in agriculture e.g., herbicides, pesticides, fungicides,8 and plant growth regulators.9 Therefore, the synthesis of these imidazole derivatives has attracted much attention in organic synthesis. Different methods have been developed.

  3. On synthesis and optimization of steam system networks. 1. Sustained boiler efficiency

    CSIR Research Space (South Africa)

    Majozi, T

    2010-08-01

    Full Text Available situations. This paper presents a process integration technique for network synthesis using conceptual and mathematical analysis without compromising boiler efficiency. It was found that the steam flow rate to the HEN could be reduced while maintaining boiler...

  4. A new and efficient procedure for the synthesis of hexahydropyrimidine-fused 1,4-naphthoquinones

    Directory of Open Access Journals (Sweden)

    Marcelo Isidoro P. Reis

    2015-07-01

    Full Text Available A new and efficient method for the synthesis of hexahydropyrimidine-fused 1,4-naphthoquinones in one step with high yields from the reaction of lawsone with 1,3,5-triazinanes was developed.

  5. PbO as an efficient and reusable catalyst for one-pot synthesis of ...

    Indian Academy of Sciences (India)

    free synthesis of tetrahydrobenzo pyrans (yields 81-91%) and benzylidene malonitriles (yields 90-96%) at room temperature using green chemistry approach. PbO nanoparticles were found to be highly efficient, eco-friendly and recyclable ...

  6. Multiphase flow processing in microreactors combined with heterogeneous catalysis for efficient and sustainable chemical synthesis

    NARCIS (Netherlands)

    Yue, Jun

    2017-01-01

    The convergence of continuous flow chemistry and microreactor technology creates numerous possibilities towards the development of an efficient and sustainable chemical synthesis. In this field, the combination of heterogeneous catalysis and multiphase flow processing in microreactors represents an

  7. An efficient synthesis of 8-substituted Odoratine derivatives by the ...

    Indian Academy of Sciences (India)

    methylenedioxyphenyl)-5,6,7-trimethoxyisoflavone] derivatives, structurally similar to glaziovianin A, a known cytotoxic substance, has been described. The key steps in the synthesis are site selective bromination reaction followed by Suzuki ...

  8. Efficient example of cross-linked polymeric catalysed synthesis of ...

    Indian Academy of Sciences (India)

    quinolin-8-one and 8H- ... and suitable for parallel synthesis. Utility of polymer- supported catalysts is now well-recognized because of their ease of workup and separation of products ..... and 4-nitrobenzaldehyde (1mmol) in ethanol (10ml).

  9. An efficient synthesis of 8-substituted Odoratine derivatives by the ...

    Indian Academy of Sciences (India)

    ′, 4′-methylenedioxyphenyl)-. 5,6,7-trimethoxyisoflavone] derivatives, structurally similar to glaziovianin A, a known cytotoxic substance, has been described. The key steps in the synthesis are site selective bromination reaction followed by ...

  10. An efficient one-pot synthesis of novel pyrazolophthalazinyl ...

    Indian Academy of Sciences (India)

    Administrator

    are still being made to find and develop new MCRs. 2. The indole template is generally recognized as an important structure in medicinal chemistry, and in particular, oxindoles that incorporate a quaternary stereogenic centre at C3 are attractive targets in or- ganic synthesis because of their significant biologi- cal activities.

  11. Simple, Efficient and Green Synthesis of Oximes under Ultrasound ...

    African Journals Online (AJOL)

    NICO

    Introduction. The chemical applications of ultrasound, 'Sonochemistry', have become an exciting new field of research during the past decade and increasingly used in organic synthesis in recent years. This is because a large number of organic reactions can be carried out in higher yields, shorter reaction times and milder.

  12. The Efficient Synthesis of 2-Arylamino-2-imidazolines, 2-Heteroaryl ...

    African Journals Online (AJOL)

    collected by filtration and recrystallized from ethanol. Charac- teristic data for the products 3a–e are listed in Table 1. Synthesis of dimethyl aryldithioimidocarbonates 5a-c. General procedure. To a well-stirred cold solution of aromatic amines (0.05 mol) in. DMF (20 ml) were added aqueous NaOH (20M, 4 ml), carbon.

  13. Highly efficient solvent-free synthesis of pyranopyrazoles by a ...

    Indian Academy of Sciences (India)

    phate [(CH2)4SO3HMIM][HSO4], an acidic ionic liquid and as a catalyst, under solvent-free conditions. The ... cyano ethylene. In addition, weak bases can also be used for this Michael-type cyclization.7 Other recent methods for the synthesis of pyranopyrazoles ... absolute ethanol,8 a two-component reaction involv-.

  14. Efficient synthesis of metallated thioporphyrazines in task specific ...

    Indian Academy of Sciences (India)

    In this paper, we are reporting the novel methodology for the synthesis of thiaporphyrazines-based receptors ... standard and the chemical shifts (δ) are expressed in ppm. IR spectra were recorded on a Perkin–Elmer ..... sity Grants Commission (UGC) of India, for financial assistance. References. 1. Fuchter M J, Zhong C, ...

  15. A Novel Implementation of Efficient Algorithms for Quantum Circuit Synthesis

    Science.gov (United States)

    Zeller, Luke

    In this project, we design and develop a computer program to effectively approximate arbitrary quantum gates using the discrete set of Clifford Gates together with the T gate (π/8 gate). Employing recent results from Mosca et. al. and Giles and Selinger, we implement a decomposition scheme that outputs a sequence of Clifford, T, and Tt gates that approximate the input to within a specified error range ɛ. Specifically, the given gate is first rounded to an element of Z[1/2, i] with a precision determined by ɛ, and then exact synthesis is employed to produce the resulting gate. It is known that this procedure is optimal in approximating an arbitrary single qubit gate. Our program, written in Matlab and Python, can complete both approximate and exact synthesis of qubits. It can be used to assist in the experimental implementation of an arbitrary fault-tolerant single qubit gate, for which direct implementation isn't feasible.

  16. Novel and Efficient Synthesis of the Promising Drug Candidate Discodermolide

    Science.gov (United States)

    2010-02-01

    intermediate for polypropionate synthesis, gave known building blocks for discodermolide. The biosynthetic cascades controlled by the type I polyketide...Longley, R. E.; Schulte, G. K. J. Org. Chem. 1990, 55, 4912. Additions and corrections: J. Org. Chem. 1991, 56, 1346. (5) (a) ter Haar , E.; Kowalski, R...tether between the initiating terminal olefin and the site of desired reactivity was to be three carbons long, setting up a cascade in which the first

  17. Biotransformation: a green and efficient way of antioxidant synthesis.

    Science.gov (United States)

    Zafar, Salman; Ahmed, Rida; Khan, Rasool

    2016-09-01

    Antioxidant compounds play a vital role in human physiology. They prevent the oxidation of biomolecules by scavenging free radicals produced during physiochemical processes and/or as a result of several pathological states. A balance between the reactive oxygen species (free radicals) and antioxidants is essential for proper physiological conditions. Excessive free radicals cause oxidative stress which can lead to several human diseases. Therefore, synthesis of the effective antioxidants is crucial in managing the oxidative stress. Biotransformation has evolved as an effective technique for the production of structurally diverse molecules with a wide range of biological activities. This methodology surpasses the conventional chemical synthesis due to the fact that enzymes, being specific in nature, catalyze reactions affording products with excellent regio- and stereoselectivities. Structural transformation of various classes of compounds such as alkaloids, steroids, flavonoids, and terpenes has been carried out through this technique. Several bioactive molecules, especially those having antioxidant potential have also been synthesized by using different biotransformation techniques and enzymes. Hydroxylated, glycosylated, and acylated derivatives of phenols, flavonoids, cinnamates, and other molecules have proven abilities as potential antioxidants. A critical review of the biotransformation of these compounds into potent antioxidant metabolites is presented here.

  18. An efficient one-pot four-segment condensation method for protein chemical synthesis.

    Science.gov (United States)

    Tang, Shan; Si, Yan-Yan; Wang, Zhi-Peng; Mei, Kun-Rong; Chen, Xin; Cheng, Jing-Yuan; Zheng, Ji-Shen; Liu, Lei

    2015-05-04

    Successive peptide ligation using a one-pot method can improve the efficiency of protein chemical synthesis. Although one-pot three-segment ligation has enjoyed widespread application, a robust method for one-pot four-segment ligation had to date remained undeveloped. Herein we report a new one-pot multisegment peptide ligation method that can be used to condense up to four segments with operational simplicity and high efficiency. Its practicality is demonstrated by the one-pot four-segment synthesis of a plant protein, crambin, and a human chemokine, hCCL21. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. EFFICIENT SODIUM SELENATE-CATALYZED SYNTHESIS OF 3,4 ...

    African Journals Online (AJOL)

    Sodium selenate efficiently catalyzes the three-component Biginelli reaction of an aldehyde, a,β-keto ester and urea or thiourea under solvent-free conditions to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones or –thiones in excellent yields. KEY WORDS: Dihydropyrimidinones, Sodium selenate, Biginelli reaction, ...

  20. Use of theoretical efficiencies of protein and fat synthesis to ...

    African Journals Online (AJOL)

    The main objection against conventional net energy systems is that owing to variation in gain composition and the different energy contents of protein and fat, the efficiency of energy gain cannot be regarded as a growth constant. The present approach shows that the separate accommodation of protein and fat in predicting ...

  1. catalysed indolylation and pyrrolylation of isatins: Efficient synthesis ...

    Indian Academy of Sciences (India)

    Abstract. An efficient and cheap synthetic approach to 3,3-di(indolyl)oxindoles and 3,3-di(pyrrolyl) oxindoles has been developed via Zn(OTf)2 catalysed indolylation and pyrrolylation of isatins. A preliminary biochemical assay of the synthesized molecules in rodent models were performed to estimate the serum glutamate ...

  2. Bimetallic Nanoparticles as Efficient Catalysts: Facile and Green Microwave Synthesis

    Science.gov (United States)

    Blosi, Magda; Ortelli, Simona; Costa, Anna Luisa; Dondi, Michele; Lolli, Alice; Andreoli, Sara; Benito, Patricia; Albonetti, Stefania

    2016-01-01

    This work deals with the development of a green and versatile synthesis of stable mono- and bi-metallic colloids by means of microwave heating and exploiting ecofriendly reagents: water as the solvent, glucose as a mild and non-toxic reducer and polyvinylpirrolidone (PVP) as the chelating agent. Particle size-control, total reaction yield and long-term stability of colloids were achieved with this method of preparation. All of the materials were tested as effective catalysts in the reduction of p-nitrophenol in the presence of NaBH4 as the probe reaction. A synergistic positive effect of the bimetallic phase was assessed for Au/Cu and Pd/Au alloy nanoparticles, the latter showing the highest catalytic performance. Moreover, monoand bi-metallic colloids were used to prepare TiO2- and CeO2-supported catalysts for the liquid phase oxidation of 5-hydroxymethylfufural (HMF) to 2,5-furandicarboxylic acid (FDCA). The use of Au/Cu and Au/Pd bimetallic catalysts led to an increase in FDCA selectivity. Finally, preformed Pd/Cu nanoparticles were incorporated into the structure of MCM-41-silica. The resulting Pd/Cu MCM-41 catalysts were tested in the hydrodechlorination of CF3OCFClCF2Cl to CF3OCF=CF2. The effect of Cu on the hydrogenating properties of Pd was demonstrated. PMID:28773672

  3. Bimetallic Nanoparticles as Efficient Catalysts: Facile and Green Microwave Synthesis

    Directory of Open Access Journals (Sweden)

    Magda Blosi

    2016-07-01

    Full Text Available This work deals with the development of a green and versatile synthesis of stable mono- and bi-metallic colloids by means of microwave heating and exploiting ecofriendly reagents: water as the solvent, glucose as a mild and non-toxic reducer and polyvinylpirrolidone (PVP as the chelating agent. Particle size-control, total reaction yield and long-term stability of colloids were achieved with this method of preparation. All of the materials were tested as effective catalysts in the reduction of p-nitrophenol in the presence of NaBH4 as the probe reaction. A synergistic positive effect of the bimetallic phase was assessed for Au/Cu and Pd/Au alloy nanoparticles, the latter showing the highest catalytic performance. Moreover, monoand bi-metallic colloids were used to prepare TiO2- and CeO2-supported catalysts for the liquid phase oxidation of 5-hydroxymethylfufural (HMF to 2,5-furandicarboxylic acid (FDCA. The use of Au/Cu and Au/Pd bimetallic catalysts led to an increase in FDCA selectivity. Finally, preformed Pd/Cu nanoparticles were incorporated into the structure of MCM-41-silica. The resulting Pd/Cu MCM-41 catalysts were tested in the hydrodechlorination of CF3OCFClCF2Cl to CF3OCF=CF2. The effect of Cu on the hydrogenating properties of Pd was demonstrated.

  4. Rapid, efficient and eco-friendly procedure for the synthesis of ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 129; Issue 2. Rapid, efficient and eco-friendly procedure for the synthesis of quinoxalines under solvent-free conditions using sulfated polyborate as a recyclable catalyst. KRISHNA S INDALKAR CHETAN K KHATRI GANESH U CHATURBHUJ. Rapid Communication ...

  5. An efficient synthesis of pyrazolo[1,5-a]pyrimidines and evaluation of ...

    Indian Academy of Sciences (India)

    An efficient synthesis of pyrazolo[1,5-a]pyrimidines and evaluation of their antimicrobial activity. SOMESHWAR DESHMUKH, KUNAL DINGORE, VISHWAS GAIKWAD and. MADHUKAR JACHAK. ∗. Organic Chemistry Research Center, Department of Chemistry, K T H M College, Affiliated to Savitribai. Phule Pune University ...

  6. Efficient Synthesis of 4,7-Diamino Substituted 1,10-Phenanthroline-2,9-dicarboxamides

    DEFF Research Database (Denmark)

    Larsen, Anders Foller; Ulven, Trond

    2011-01-01

    A convenient and high-yielding multigram synthesis of the versatile intermediate 4,7-dichloro-1,10-phenanthroline-2,9-dicarboxylic acid is described. The intermediate is further efficiently derivatized to 4,7-diamino-1,10-phenanthroline-2,9-dicarboxamides with potential G-quadruplex stabilizing...

  7. An Efficient Green Synthesis of 3-Amino-1 H -chromenes Catalyzed ...

    African Journals Online (AJOL)

    An Efficient Green Synthesis of 3-Amino-1 H -chromenes Catalyzed by ZnO Nanoparticles Thin-film. ... South African Journal of Chemistry ... The mild reaction conditions, reusability of the catalyst, easy work-up and high yields of products make the present protocol sustainable and advantageous compared to conventional ...

  8. Boric acid as a mild and efficient catalyst for one-pot synthesis of 1 ...

    Indian Academy of Sciences (India)

    Abstract. An efficient green chemistry method has been developed for the synthesis of 1-amidoalkyl-2-naphthol derivatives via a one-pot three-component condensation of 2-naphthol, aldehydes and amide in the presence of boric acid as a mild catalyst.

  9. Boric acid as a mild and efficient catalyst for one-pot synthesis of 1

    Indian Academy of Sciences (India)

    Abstract. An efficient green chemistry method has been developed for the synthesis of 1-amidoalkyl-2-naphthol derivatives via a one-pot three-component condensation of 2-naphthol, aldehydes and amide in the presence of boric acid as a mild catalyst.

  10. A simple and efficient approach for synthesis of 1,4-dihydro ...

    African Journals Online (AJOL)

    A simple highly versatile and efficient synthesis of various 1,4-dihydropyridines in the condensation of aromatic aldehydes with β-dicarbonyl compounds and ammonium acetate in the presence of nano-sulfated zirconia, nano-structured ZnO, nano-γ-alumina and nano-ZSM-5 zeolites, as catalyst in the ethanol at moderate ...

  11. Simple and efficient synthesis of [MCI(NHC)] (M = Au, Ag) complexes.

    Science.gov (United States)

    Visbal, Renso; Laguna, Antonio; Gimeno, M Concepción

    2013-06-25

    A facile and efficient synthetic route leading to catalytically relevant N-heterocyclic carbene (NHC) gold complexes is described. The method consists of one pot synthesis starting from readily available imidazolium salts and [AuCl(tht)], in the presence of K2CO3. Using the same protocol NHC silver complexes have been synthesised starting from AgNO3.

  12. An efficient, optimized synthesis of fentanyl and related analogs.

    Directory of Open Access Journals (Sweden)

    Carlos A Valdez

    Full Text Available The alternate and optimized syntheses of the parent opioid fentanyl and its analogs are described. The routes presented exhibit high-yielding transformations leading to these powerful analgesics after optimization studies were carried out for each synthetic step. The general three-step strategy produced a panel of four fentanyls in excellent yields (73-78% along with their more commonly encountered hydrochloride and citric acid salts. The following strategy offers the opportunity for the gram-scale, efficient production of this interesting class of opioid alkaloids.

  13. Highly Efficient Procedure for the Synthesis of Fructone Fragrance Using a Novel Carbon based Acid

    Directory of Open Access Journals (Sweden)

    Xuezheng Liang

    2010-08-01

    Full Text Available The novel carbon based acid has been synthesized via one-step hydrothermal carbonization of furaldehyde and hydroxyethylsulfonic acid. A highly efficient procedure for the synthesis of fructone has been developed using the novel carbon based acid. The results showed that the catalyst possessed high activity for the reaction, giving a yield of over 95%. The advantages of high activity, stability, reusability and low cost for a simple synthesis procedure and wide applicability to various diols and β-keto esters make this novel carbon based acid one of the best choices for the reaction.

  14. An efficient synthesis and spectroscopic characterization of Schiff bases containing 9,10-anthracenedione moiety

    Directory of Open Access Journals (Sweden)

    Fareed Ghulam

    2013-01-01

    Full Text Available A new method has been developed for the synthesis of novel Schiff bases containg anthraquinone moiety using dodeca-Tungstosilicic acid/P2O5 under solvent free conditions at room temperature. The reaction was completed in 1-3 minutes with excellent yields. This method was found to be more efficient, easy and hazardous free for the synthesis of azomethines. The development of these type of methadologies in synthetic chemistry may contribute to green chemistry. The structures of synthesized novel Schiff bases was elucidated using 1H-NMR, 13C-NMR, LCMS, FTIR and CHN analysis.

  15. Simple and Efficient Procedure for Synthesis of N'-Arylamidines Using Trimethylaluminum

    Energy Technology Data Exchange (ETDEWEB)

    Korbad, Balaji L.; Lee, Sanghyeup [Catholic Univ., of Daegu, Daegu (Korea, Republic of)

    2013-04-15

    In conclusion, we have developed simple and efficient procedure for the synthesis of N'-arylamidines using tri-methylaluminum, nitriles and aryl amines under mild condition. Aliphatic, aromatic nitriles were reacted well with a variety of aromatic amine to afford corresponding amidines in good to high yields. Amidines are an important class of compounds that have wide range of application in the fields of catalyst design, material science, medicinal chemistry and also shown the promising anti-inflammatory and analgesic activity. They are valuable synthons for synthesis of various heterocyclic compounds. In addition, recent studies have demonstrated their capacity to fix carbon dioxide.

  16. Stereoselective synthesis of hydroxy stilbenoids and styrenes by atom-efficient olefination with thiophthalides.

    Science.gov (United States)

    Mitra, Prithiba; Shome, Brateen; De, Saroj Ranjan; Sarkar, Anindya; Mal, Dipakranjan

    2012-04-14

    The synthesis of stilbenoids and styryl carboxylic acids is accomplished with high E-stereoselectivity by olefination of aldehydes with thiophthalides under basic conditions. The olefination is highly atom-efficient as it only loses elemental sulfur during the reaction. This olefination, in conjunction with retro Kolbe-Schmitt reaction, allows facile synthesis of E-hydroxystilbenoids with minimal employment of protecting groups. This study also discloses two important findings: formation of i) 4-methylsulfanyl isocoumarins and ii) an 2-arylindenone. This journal is © The Royal Society of Chemistry 2012

  17. Efficient Synthesis and Bioactivity of Novel Triazole Derivatives.

    Science.gov (United States)

    Hu, Boyang; Zhao, Hanqing; Chen, Zili; Xu, Chen; Zhao, Jianzhuang; Zhao, Wenting

    2018-03-21

    Triazole pesticides are organic nitrogen-containing heterocyclic compounds, which contain 1,2,3-triazole ring. In order to develop potential glucosamine-6-phosphate synthase (GlmS) inhibitor fungicides, forty compounds of triazole derivatives were synthesized in an efficient way, thirty nine of them were new compounds. The structures of all the compounds were confirmed by high resolution mass spectrometer (HRMS), ¹H-NMR and 13 C-NMR. The fungicidal activities results based on means of mycelium growth rate method indicated that some of the compounds exhibited good fungicidal activities against P. CapasiciLeonian , Sclerotinia sclerotiorum (Lib.) de Bary, Pyricularia oryzae Cav. and Fusarium oxysporum Schl. F.sp. vasinfectum (Atk.) Snyd. & Hans. at the concentration of 50 µg/mL, especially the inhibitory rates of compounds 1-d and 1-f were over 80%. At the same time, the preliminary studies based on the Elson-Morgan method indicated that the compounds exhibited some inhibitory activity toward glucosamine-6-phosphate synthase (GlmS). These compounds will be further studied as potential antifungal lead compounds. The structure-activity relationships (SAR) were discussed in terms of the effects of the substituents on both the benzene and the sugar ring.

  18. Information and efficiency in the nervous system--a synthesis.

    Directory of Open Access Journals (Sweden)

    Biswa Sengupta

    Full Text Available In systems biology, questions concerning the molecular and cellular makeup of an organism are of utmost importance, especially when trying to understand how unreliable components--like genetic circuits, biochemical cascades, and ion channels, among others--enable reliable and adaptive behaviour. The repertoire and speed of biological computations are limited by thermodynamic or metabolic constraints: an example can be found in neurons, where fluctuations in biophysical states limit the information they can encode--with almost 20-60% of the total energy allocated for the brain used for signalling purposes, either via action potentials or by synaptic transmission. Here, we consider the imperatives for neurons to optimise computational and metabolic efficiency, wherein benefits and costs trade-off against each other in the context of self-organised and adaptive behaviour. In particular, we try to link information theoretic (variational and thermodynamic (Helmholtz free-energy formulations of neuronal processing and show how they are related in a fundamental way through a complexity minimisation lemma.

  19. Diastereoselective synthesis of {beta}-piperonyl-{gamma}-butyrolactones from morita-baylis-hillman adducts. highly efficient synthesis of ({+-})-yatein, ({+-})-podorhizol and ({+-})-epi-podorhizol

    Energy Technology Data Exchange (ETDEWEB)

    Trazzi, Giordano; Andre, Marcelo Fabiano; Coelho, Fernando, E-mail: coelho@iqm.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica

    2010-07-01

    Starting from a Morita-Baylis-Hillman adduct we describe a simple and very efficient method for the diastereoselective preparation of hydroxylated beta-piperonyl-g-butyrolactones. To exemplify the efficiency of this approach we also describe a highly efficient synthesis for the biologically active lignans ({+-})-yatein, ({+-})-podorhizol and ({+-})-epi-podorhizol. (author)

  20. One-pot synthesis of 2H-pyrans by indium(III) chloride-catalyzed reactions. efficient synthesis of pyranocoumarins, pyranophenalenones, and pyranoquinolinones

    International Nuclear Information System (INIS)

    Lee, Yong Rok; Kim, Do Hoon; Shim, Jae Jin; Kim, Seog K.; Park, Jung Hag; Cha, Jin Soon; Lee, Chong Soon

    2002-01-01

    An efficient synthesis of 2H-pyrans is achieved by indium (III) chloride-catalyzed reactions of 1,3-dicarbonyl compounds with a variety of α.β-unsaturated aldehydes in moderates yields. This method has been applied to the synthesis of pyranocoumarins, pyranophenaleneones, and pyranoquinolinone alkaloids

  1. Efficient synthesis of α,β-unsaturated alkylimines performed with allyl cations and azides: application to the synthesis of an ant venom alkaloid.

    Science.gov (United States)

    Hayashi, Kyohei; Tanimoto, Hiroki; Zhang, Huan; Morimoto, Tsumoru; Nishiyama, Yasuhiro; Kakiuchi, Kiyomi

    2012-11-16

    An efficient synthesis of α,β-unsaturated alkylimines at low temperature using azides has been developed. Carbocations generated from allyl alcohols helped achieve a rapid conversion under mild conditions with azides to afford reactive α,β-unsaturated imines. Hydroxy or alkoxy groups are essential for these transformations, and utilizing readily accessible allyl alcohols gave a wide extension of substrates. The efficiency of this novel method is demonstrated in the total synthesis of an iminium ant venom alkaloid.

  2. Highly Efficient Synthesis of Clean Biofuels from Biomass Using FeCuZnAlK Catalyst

    Science.gov (United States)

    Qiu, Song-bai; Xu, Yong; Ye, Tong-qi; Gong, Fei-yan; Yang, Zhi; Yamamoto, Mitsuo; Liu, Yong; Li, Quan-xin

    2011-12-01

    Highly efficient synthesis of clean biofuels using the bio-syngas obtained from biomass gasification was performed over Fe1.5Cu1Zn1Al1K0.117 catalyst. The maximum biofuel yield from the bio-syngas reaches about 1.59 kg biofuels/(kgcatal·h) with a contribution of 0.57 kg alcohols/(kgcatal·h) and 1.02 kg liquid hydrocarbons/(kgcatal·h). The alcohol products in the resulting biofuels were dominated by the C2+ alcohols (mainly C2—C6 alcohols) with a content of 73.55%-89.98%. The selectivity of the liquid hydrocarbons (C5+) in the hydrocarbon products ranges from 60.37% to 70.94%. The synthesis biofuels also possess a higher heat value of 40.53-41.49 MJ/kg. The effects of the synthesis conditions, including temperature, pressure, and gas hourly space velocity, on the biofuel synthesis were investigated in detail. The catalyst features were characterized by inductively coupled plasma and atomic emission spectroscopy, X-ray diffraction, temperature programmed reduction, and the N2 adsorption-desorption isotherms measurements. The present biofuel synthesis with a higher biofuel yield and a higher selectivity of liquid hydrocarbons and C2+ alcohols may be a potentially useful route to produce clean biofuels and chemicals from biomass.

  3. An Efficient Method for the N-Bromosuccinimide Catalyzed Synthesis of Indolyl-Nitroalkanes

    Directory of Open Access Journals (Sweden)

    Ching-Fa Yao

    2009-10-01

    Full Text Available An efficient and practical method for the synthesis of indolyl-nitroalkane derivatives catalyzed by N-bromosuccinimide is described. The generality of this method was demonstrated by synthesizing an array of diverse 3-substituted indole derivatives by the reaction of different β-nitrostyrenes with various substituted indoles. Simple reaction conditions accompanied by good yields of indolyl-nitroalkanes are the merits of this methodology.

  4. An Efficient One-Pot Multicomponent Synthesis of 4-Aza-Podophyllotoxin Derivatives in Ionic Liquid

    Directory of Open Access Journals (Sweden)

    Hossein Naeimi

    2013-01-01

    Full Text Available A simple, green, and efficient procedure for the synthesis of 4-aza-podophyllotoxin derivatives by using a one-pot three-component reaction of benzaldehydes, 1,3-cyclohexanediones, and anilinolactones in the presence of catalytic amount of alum in 1-butyl-3-methylimidazolium triflate as green media is described. This reaction proceeded under mild conditions with the use of an inexpensive and readily available catalyst, high to excellent yields, and simple workup procedure.

  5. Synthesis of (R-Dihydropyridones as Key Intermediates for an Efficient Access to Piperidine Alkaloids

    Directory of Open Access Journals (Sweden)

    Serkos A Haroutounian

    2007-04-01

    Full Text Available The efficient transformation of D-glucal to (2R-hydroxymethyldihydro-pyridinone 5 in seven steps and 35 % overall yield is reported. Dihydropyridone 5 constitutes a versatile chiral building block for the synthesis of various piperidine alkaloids. In this regard, 5 was converted to piperidinol 13 and piperidinone 15, that may be further elaborated for the syntheses of (+-desoxoprosophylline (1 and deoxymannojirimycin (3 or D-mannolactam (4, respectively.

  6. Efficient three-component one-pot synthesis of steroidal polysubstituted anilines.

    Science.gov (United States)

    Zhang, Yan-Ling; Li, Ya-Fei; Shi, Yun-Kai; Yu, Bin; Zhang, Guo-Chen; Qi, Ping-Ping; Fu, Dong-Jun; Shan, Li-Hong; Liu, Hong-Min

    2015-12-01

    An efficient and practical base-promoted cascade reaction has been developed to access steroidal polysubstituted anilines from simple precursors. The protocol reported herein achieved the formation of a benzene ring as well as three continuous C-C bonds in a single operation. The reaction mechanism was proposed on the basis of the key intermediate obtained. Besides, this method could be potentially employed for the synthesis of biphenyl compounds. The adjacent amine and nitrile groups existed in the final products have the potential for late stage functionalization, which would provide efficient access to steroidal compound collections with structural diversity and complexity. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. A mild and efficient procedure for the synthesis of ethers from various alkyl halides

    Directory of Open Access Journals (Sweden)

    Mosstafa Kazemi

    2013-10-01

    Full Text Available A simple, mild and practical procedure has been developed for the synthesis of symmetrical and unsymmetrical ethers by using DMSO, TBAI in the presence of K2CO3. We extended the utility of Potassium carbonate as an efficient base for the preparation of ethers. A wide range of alkyl aryl and dialkyl ethers are synthezied from treatment of aliphatic alcohols and phenols with various alkyl halides in the prescence of efficient base Potassium carbonate. Secondary alkyl halides were easily converted to corresponding ethers in releatively good yields . This is a mild, simple and practical procedure for the preparation of ethers in high yields and suitable times under mild condition.

  8. Highly efficient and eco-friendly gold-catalyzed synthesis of homoallylic ketones

    KAUST Repository

    Gómez-Suárez, Adrián

    2014-08-01

    We report a new catalytic protocol for the synthesis of γ,δ-unsaturated carbonyl units from simple starting materials, allylic alcohols and alkynes, via a hydroxalkoxylation/Claisen rearrangement sequence. This new process is more efficient (higher TON and TOF) and more eco-friendly (increased mass efficiency) than the previous state-of-the-art technique. In addition, this method tolerates both terminal and internal alkynes. Moreover, computational studies have been carried out in order to shed light on how the Claisen rearrangement is initiated. © 2014 American Chemical Society.

  9. Simplified Application of Material Efficiency Green Metrics to Synthesis Plans: Pedagogical Case Studies Selected from "Organic Syntheses"

    Science.gov (United States)

    Andraos, John

    2015-01-01

    This paper presents a simplified approach for the application of material efficiency metrics to linear and convergent synthesis plans encountered in organic synthesis courses. Computations are facilitated and automated using intuitively designed Microsoft Excel spreadsheets without invoking abstract mathematical formulas. The merits of this…

  10. Rapid and Efficient Synthesis of Hydroxytriarylmethanes under Ultra Sonic Irradiation Using Keggin Heteropolyacids and Preyssler Catalysts in Green Conditions

    Directory of Open Access Journals (Sweden)

    Hooshang Hamidian

    2013-01-01

    Full Text Available A new synthesis of hydroxytriarylmethane derived from the reaction of 2-sulfobenzoic anhydride and phenols in the presence of heteropolyacids as green, reusable, and efficient catalyst (using catalytic amount under ultrasonic irradiation is reported in this paper.

  11. An Efficient Synthesis of 1-Alkyl-2-phenyl-4-quinolones from 2-Halobenzoic Acids

    International Nuclear Information System (INIS)

    Song, Yoon Ju; Choi, Jin Sun; Lee, Jae In

    2013-01-01

    The present method offers an efficient synthesis of 1-alkyl-2-phenyl-4-quinolones from 2-haloben-zoic acids. It has the advantages with respect to (i) synthesis of 2 equiv of alkynones 5 from 1 equiv of 4,6-pyrimidyl di(2-halobenzoates) 3, (ii) synthesis of versatile 1-alkyl-2-phenyl-4-quinolones in high overall yields, and (iii) use of readily available and cheap starting materials. Therefore, this method could be utilized as a practical synthesis of 1-alkyl-2-phenyl-4-quinolones. Several methods have been developed to synthesize 1-alkyl-2-phenyl-4-quinolones from 2'-substituted acetophenones, anilines, and 2-halobenzoyl chlorides as starting materials. The reaction of N-methylisatoic anhydride with the lithium enolate of an 4'-methoxyacetophenone afforded the 1-methyl-2-phenyl-4-quinolone in a short sequence, but the yield was low. N-(2-Acetylphenyl)benzamides, prepared by Friedel-Crafts acylation of N-phenyl benzamides with acetyl chloride or benzoylation of 2'-aminoacetophenones with benzoyl chlorides,8 were cyclized with potassium t-butoxide to yield 2-aryl-4-quinolones, which were further alkylated with alkyl iodides to give 1-alkyl-2-aryl-4-quinolones

  12. An efficient synthesis of tetramic acid derivatives with extended conjugation from L-Ascorbic Acid

    Directory of Open Access Journals (Sweden)

    Bisht Surendra S

    2006-12-01

    Full Text Available Abstract Background Tetramic acids with polyenyl substituents are an important class of compounds in medicinal chemistry. Both solid and solution phase syntheses of such molecules have been reported recently. Thiolactomycin, a clinical candidate for treatment of tuberculosis has led to further explorations in this class. We have recently developed an efficient synthesis of tetramic acids derivatives from L- ascorbic acid. In continuation of this work, we have synthesised dienyl tetramic acid derivatives. Results 5,6-O-Isopropylidene-ascorbic acid on reaction with DBU led to the formation of tetronolactonyl allyl alcohol, which on oxidation with pyridinium chlorochromate gave the respective tetranolactonyl allylic aldehydes. Wittig olefination followed by reaction of the resulting tetranolactonyl dienyl esters with different amines resulted in the respective 5-hydroxy lactams. Subsequent dehydration of the hydroxy lactams with p-toluene sulphonic acid afforded the dienyl tetramic acid derivatives. All reactions were performed at ambient temperature and the yields are good. Conclusion An efficient and practical method for the synthesis of dienyl tetramic acid derivatives from inexpensive and easily accessible ascorbic acid has been developed. The compounds bear structural similarities to the tetramic acid based polyenic antibiotics and thus this method offers a new and short route for the synthesis of tetramic acid derivatives of biological significance.

  13. Guided synthesis of accumulative solutions for the conceptual design of an efficient stove working with biomass

    International Nuclear Information System (INIS)

    Álvarez Cabrales, Alexis; Gaskins Espinosa, Benjamín Gabriel; Pérez Rodríguez, Roberto; Simeón Monet, Rolando Esteban

    2014-01-01

    The conceptual design is closely related to a product functional structure and the search of solution principles for its definition. This work exposes an accumulative method for the traceability of the functional structure that implements the guided conceptual synthesis of solutions in the preliminary analysis of this designing process stage. The method constitutes a contribution to Pahls and Beitzs classic design model. In it, the functional information system is manipulated, providing the designer with a help so that he can examine the different solutions that are obtained, giving him the possibility of selecting the most convenient one. The guided analysis of the accumulative solutions synthesis is illustrated by means of the conceptual design of an efficient stove working with biomass. (author)

  14. Efficient retrograde transport of pseudorabies virus within neurons requires local protein synthesis in axons.

    Science.gov (United States)

    Koyuncu, Orkide O; Perlman, David H; Enquist, Lynn W

    2013-01-16

    After replicating in epithelial cells, alphaherpesviruses such as pseudorabies virus (PRV) invade axons of peripheral nervous system neurons and undergo retrograde transport toward the distant cell bodies. Although several viral proteins engage molecular motors to facilitate transport, the initial steps and neuronal responses to infection are poorly understood. Using compartmented neuron cultures to physically separate axon infection from cell bodies, we found that PRV infection induces local protein synthesis in axons, including proteins involved in cytoskeletal remodeling, intracellular trafficking, signaling, and metabolism. This rapid translation of axonal mRNAs is required for efficient PRV retrograde transport and infection of cell bodies. Furthermore, induction of axonal damage, which also induces local protein synthesis, prior to infection reduces virion trafficking, suggesting that host damage signals and virus particles compete for retrograde transport. Thus, similar to axonal damage, virus infection induces local protein translation in axons, and viruses likely exploit this response for invasion. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. 1,5-Anhydro-D-Fructose – Efficient Synthesis and Chemical Uses

    DEFF Research Database (Denmark)

    Lundt, Inge; Dekany, Gyula; Stütz, Arnold E.

    1,5-Anhydro-D-fructose (AF) is a valuable chiral building block for organic synthesis.[1] However, the antioxidant and antimicrobial properties of AF are equally important.[1] Due to these interesting properties AF is heavily patented for the use in pharmaceuticals, foods and cosmetics. However...... methods available despite the fact that the first low-yielding procedure by Lichtenthaler et al. was already described in 1980.[3] In this presentation we will show new and efficient chemical methods employing easily available and cheap starting materials for the synthesis of 1,5- and 1,4-anhydroketoses...... as well as for derivatives and analogues thereof. The potential of AF will be highlighted as will be the use of AF as a chiral building block for the preparation of other interesting compounds with biological activities such as, for example, Deoxymannojirimycin (DMJ). [1] S.M. Andersen, I. Lundt, J...

  16. Green Synthesis of Hierarchically Porous Carbon Nanotubes as Advanced Materials for High-Efficient Energy Storage.

    Science.gov (United States)

    Wang, Jian-Gan; Liu, Hongzhen; Zhang, Xingyuan; Li, Xu; Liu, Xingrui; Kang, Feiyu

    2018-02-05

    Hierarchically porous carbon nanomaterials with well-defined architecture can afford a promising platform for effectively addressing energy and environmental concerns. Herein, a totally green and straightforward synthesis strategy for the fabrication of hierarchically porous carbon nanotubes (HPCNTs) by a simple carbonization treatment without any assistance of soft/hard templates and activation procedures is demonstrated. A high specific surface area of 1419 m 2 g -1 and hierarchical micro-/meso-/macroporosity can be achieved for the HPCNTs. The unique porous architecture enables the HPCNTs serving as excellent electrode/host materials for high-performance supercapacitors and Li-sulfur batteries. The design strategy may pave a new avenue for the rational synthesis of hierarchically porous carbon nanostructures for high-efficient energy storage applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Knowledge Based Synthesis of Efficient Structures for Concurrent Computation Using Fat-Trees and Pipelining.

    Science.gov (United States)

    1986-12-31

    based on the proof is feasible. KES.U.86.11 AFO -Th, 87-0 791 Kestrel Institute Knowledge Based Synthesis of Efficient Structures for Concurrent...its own index and those of its children . lAn unbalanced tree can be described by specifying a connection between the root of some subtrees and chosen...node T.internal-, it is assumed that t" = (concat j", k), where 7 and are the subscripts of the children . No other information can be supplied for the

  18. Highly stereoselective and efficient synthesis of functionalized cyclohexanes with multiple stereocenters.

    Science.gov (United States)

    Schneider, Christoph; Reese, Oliver

    2002-06-03

    Chiral 7-oxo-2-enimides 2, which were readily obtained through a silyloxy-Cope rearrangement of syn-aldol products 1, have proved to be versatile substrates for a one-step, highly efficient and stereoselective synthesis of functionalized cyclohexanes. Organocopper and organoaluminum reagents have been employed as nucleophiles that underwent a conjugate addition to the enimide structure of the Cope products. The enolates formed in situ attacked the aldehyde or iminium ion in an intramolecular aldol or Mannich reaction, respectively, to directly yield cyclohexanols 3 and 4 and cyclohexylamines 5, respectively, in moderate to good yields and with excellent stereocontrol.

  19. Energy efficient room temperature synthesis of cardanol-based novolac resin using acoustic cavitation.

    Science.gov (United States)

    Jadhav, Nilesh L; Sastry, Sai Krishna C; Pinjari, Dipak V

    2018-04-01

    The present study deals with synthesis of cardanol-cased novolac (CBN) resin by the condensation reaction between cardanol and formaldehyde using acoustic cavitation. It is a step-growth polymerization which occurs in the presence of an acid catalyst such as adipic acid, citric acid, oxalic acid, sulphuric acid and hydrochloric acid. CBN was also synthesised by a conventional method for the sake of comparison of techniques. The effect of molar ratio, effect of catalyst, effect of different catalyst and effect of power on the conversion to CBN has been studied. The synthesised CBN was characterized using the Fourier Transform Infra Red Spectroscopy (FTIR), Gel Permeation Chromatography (GPC), Nuclear Magnetic Resonance (NMR) Spectroscopy and Thermogravimetric Analysis (TGA). The reaction was monitored by the Acid value, free formaldehyde content and viscosity of the synthesised product. The reaction time required for the conventionally synthesised CBN was 5 h (300 min) with 120 °C as an operating temperature while sonochemically the time reduced to 30 min at room temperature. The amount of time and energy saved can be quantified. Ultrasound facilitated synthesis was found to be an energy efficient and time-saving method for the synthesis of novolac resin. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. A coenzyme-independent decarboxylase/oxygenase cascade for the efficient synthesis of vanillin.

    Science.gov (United States)

    Furuya, Toshiki; Miura, Misa; Kino, Kuniki

    2014-10-13

    Vanillin is one of the most widely used flavor compounds in the world as well as a promising versatile building block. The biotechnological production of vanillin from plant-derived ferulic acid has attracted much attention as a new alternative to chemical synthesis. One limitation of the known metabolic pathway to vanillin is its requirement for expensive coenzymes. Here, we developed a novel route to vanillin from ferulic acid that does not require any coenzymes. This artificial pathway consists of a coenzyme-independent decarboxylase and a coenzyme-independent oxygenase. When Escherichia coli cells harboring the decarboxylase/oxygenase cascade were incubated with ferulic acid, the cells efficiently synthesized vanillin (8.0 mM, 1.2 g L(-1) ) via 4-vinylguaiacol in one pot, without the generation of any detectable aromatic by-products. The efficient method described here might be applicable to the synthesis of other high-value chemicals from plant-derived aromatics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Synthesis and Evaluation of Tetramethylguanidinium-Polyethylenimine Polymers as Efficient Gene Delivery Vectors

    Directory of Open Access Journals (Sweden)

    Manohar Mahato

    2014-01-01

    Full Text Available Previously, we demonstrated that 6-(N,N,N′,N′-tetramethylguanidinium chloride-hexanoyl-polyethylenimine (THP polymers exhibited significantly enhanced transfection efficiency and cell viability. Here, in the present study, we have synthesized a series of N,N,N′,N′-tetramethylguanidinium-polyethylenimine (TP1-TP5 polymers via a single-step reaction involving peripheral primary amines of bPEI and varying amounts of 2-(1H-benzotriazol-1-yl-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU. These polymers were found to interact efficiently with negatively charged pDNA and formed stable complexes in the size range of ~240–450 nm. Acid-base titration profiles revealed improved buffering capacity of TP polymers as compared to bPEI. Transfection and cytotoxicity assays performed with TP/pDNA complexes on HEK293, CHO, and HeLa cells showed significantly higher transfection efficiency and cell viability with one of the complexes, TP2/pDNA complex, exhibited the highest transfection efficiency (~1.4–2.3-fold outcompeting native bPEI and the commercially available transfection reagent, Lipofectamine 2000. Compared to previously reported THP polymers, the transfection efficiency of TP/pDNA complexes was found to be lower, as examined by flow cytometry. These results highlight the importance of the hydrophobic C-6 linker in THP polymers in forming compact nanostructures with pDNA, which might lead to efficient uptake and internalization of the complexes; however, the projected TP polymers offer an advantage of their rapid and economical one-step synthesis.

  2. Synthesis and evaluation of tetramethylguanidinium-polyethylenimine polymers as efficient gene delivery vectors.

    Science.gov (United States)

    Mahato, Manohar; Yadav, Santosh; Kumar, Pradeep; Sharma, Ashwani Kumar

    2014-01-01

    Previously, we demonstrated that 6-(N,N,N',N'-tetramethylguanidinium chloride)-hexanoyl-polyethylenimine (THP) polymers exhibited significantly enhanced transfection efficiency and cell viability. Here, in the present study, we have synthesized a series of N,N,N',N'-tetramethylguanidinium-polyethylenimine (TP1-TP5) polymers via a single-step reaction involving peripheral primary amines of bPEI and varying amounts of 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU). These polymers were found to interact efficiently with negatively charged pDNA and formed stable complexes in the size range of ~240-450 nm. Acid-base titration profiles revealed improved buffering capacity of TP polymers as compared to bPEI. Transfection and cytotoxicity assays performed with TP/pDNA complexes on HEK293, CHO, and HeLa cells showed significantly higher transfection efficiency and cell viability with one of the complexes, TP2/pDNA complex, exhibited the highest transfection efficiency (~1.4-2.3-fold) outcompeting native bPEI and the commercially available transfection reagent, Lipofectamine 2000. Compared to previously reported THP polymers, the transfection efficiency of TP/pDNA complexes was found to be lower, as examined by flow cytometry. These results highlight the importance of the hydrophobic C-6 linker in THP polymers in forming compact nanostructures with pDNA, which might lead to efficient uptake and internalization of the complexes; however, the projected TP polymers offer an advantage of their rapid and economical one-step synthesis.

  3. Synthesis of β-Nicotinamide Riboside Using an Efficient Two-Step Methodology.

    Science.gov (United States)

    Zhang, Ning; Sauve, Anthony A

    2017-12-24

    A two-step chemical method for the synthesis of β-nicotinamide riboside (NR) is described. NR has achieved wide use as an NAD + precursor (vitamin B3) and can significantly increase central metabolite NAD + concentrations in mammalian cells. β-NR can be prepared with an efficient two-step procedure. The synthesis is initiated via coupling of commercially available 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose with ethyl nicotinate in the presence of trimethylsilyl trifluoromethanesulfonate (TMSOTf). 1 H NMR showed that the product was formed with complete stereoselectivity to produce only the β-isomer in high yield (>90% versus starting sugar). The clean stereochemical result suggests that the coupling proceeds via a cationic cis-1,2-acyloxonium-sugar intermediate, which controls addition by nucleophiles to generate predominantly β-stereochemistry. The subsequent deprotection of esters in methanolic ammonia generates the desired product in 85% overall yield versus sugar. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

  4. Highly Efficient Synthesis of an Emerging Lipophilic Antioxidant: 2-Ethylhexyl Ferulate

    Directory of Open Access Journals (Sweden)

    Kuo-Chuan Huang

    2016-04-01

    Full Text Available Ferulic acid in ester form has shown a stronger ability in ameliorating certain pathological conditions and inhibiting lipid oxidation. In present study, a solvent-free and reduced pressure evaporation system was developed for lipase-catalyzed synthesis of 2-ethylhexyl ferulate (2-EF from ferulic acid and 2-ethylhexanol. A Box-Behnken design with response surface methodology (RSM and artificial neural network (ANN was selected to model and optimize the process. Based on the yields of 2-EF, reaction temperature was shown to be the most important process factor on the molar conversion among all variables. The residual values and the coefficient of determination (R2 calculated from the design data indicated that ANN was better than RSM in data fitting. Overall, the present lipase-catalyzed approach for 2-EF synthesis at low reaction temperature in a reduced pressure evaporation system shows high 2-EF production efficiency. Notably, this approach can reduce the enzyme denaturation and ferulic acid oxidation that usually occur during long-term biosynthetic operations at high temperature.

  5. Improving the time efficiency of the Fourier synthesis method for slice selection in magnetic resonance imaging.

    Science.gov (United States)

    Tahayori, B; Khaneja, N; Johnston, L A; Farrell, P M; Mareels, I M Y

    2016-01-01

    The design of slice selective pulses for magnetic resonance imaging can be cast as an optimal control problem. The Fourier synthesis method is an existing approach to solve these optimal control problems. In this method the gradient field as well as the excitation field are switched rapidly and their amplitudes are calculated based on a Fourier series expansion. Here, we provide a novel insight into the Fourier synthesis method via representing the Bloch equation in spherical coordinates. Based on the spherical Bloch equation, we propose an alternative sequence of pulses that can be used for slice selection which is more time efficient compared to the original method. Simulation results demonstrate that while the performance of both methods is approximately the same, the required time for the proposed sequence of pulses is half of the original sequence of pulses. Furthermore, the slice selectivity of both sequences of pulses changes with radio frequency field inhomogeneities in a similar way. We also introduce a measure, referred to as gradient complexity, to compare the performance of both sequences of pulses. This measure indicates that for a desired level of uniformity in the excited slice, the gradient complexity for the proposed sequence of pulses is less than the original sequence. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  6. Highly efficient isocyanate-free microwave-assisted synthesis of [6]-oligourea

    KAUST Repository

    Qaroush, Abdussalam K.

    2013-01-01

    A new eco-friendly, isocyanate-free, energy-saving method for the production of [6]-oligourea, utilizing a green carbonylating agent, viz. propylene carbonate, is reported. It comprises an organocatalyzed, microwave-assisted, solvent-free synthesis. Two modes of microwave-assisted synthesis, viz. dynamic and fixed energy modes, were applied. Upon optimization, the dynamic mode gave 79% yields of [6]-oligourea. On the other hand, almost quantitative yields were obtained using the fixed mode, within 20 min, at 10 W and with the same catalyst loading. Combination of both organocatalysis and microwave energy input appears to be a key issue for the efficiency of the reaction, with the fixed energy mode being best suited. It should be noted that all data reported are reproducible (due to the homogeneous microwave technology used by CEM Discover S-Class of microwave reactors). To the best of our knowledge, this is the best eco-friendly synthetic approach for the preparation of the title oligomers. It paves the way for using more of the biorenewable and sustainable chemicals as a feedstock for the production of polyureas. The oligomer produced was analyzed by EA, ATR-FTIR, XRD, 1H and 13CNMR. Furthermore, thermal properties of the resulting [6]-oligourea were analyzed using TGA and DSC. © The Royal Society of Chemistry 2013.

  7. An efficient synthesis of 1α,25-dihydroxyvitamin D3 LC-biotin.

    Science.gov (United States)

    Kattner, Lars; Bernardi, Dan

    2017-10-01

    In recent years the apparent impact of vitamin D deficiency on human health has gained increased awareness. Consequently, the development of appropriate assays to measure the status of medicinally most relevant vitamin D metabolites in human blood, serum or relevant tissue is continuously being improved. Particularly, assaying of 1α,25-dihydroxyvitamin D 3 , in turn considered as the most active metabolite, is mainly indicated in disorders leading to calcaemia or those resulting from an impaired 1α-hydroxylation of 25-hydroxyvitamin D 3 . Thus, in some competitive protein binding and ELISA assays, biotin-linked 1α,25-dihydroxyvitamin D 3 (1α,25-dihydroxyvitamin D 3 LC-biotin) is employed for measurement of actual calicitriol concentration. A new efficient synthesis of 1α,25-dihydroxyvitamin D 3 LC-biotin is described, starting with readily available vitamin D 2 , and combining a classical approach to access 1α,25-dihydroxyvitamin D 3 , appropriate OH-protective group transformations, and a C-3-O-alkylation, suitable to connect the biotin-linker in a reliable, selective and high yielding strategy. The developed methodology is applicable to the synthesis of a wide variety of C-3-OH-linked vitamin D 3 and D 2 derivatives. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Design of Orthogonal Filtered Multitone Modulation Systems and Comparison among Efficient Realizations

    Directory of Open Access Journals (Sweden)

    Moret Nicola

    2010-01-01

    Full Text Available Abstract We address the efficient realization of a filtered multitone (FMT modulation system and its orthogonal design. FMT modulation can be viewed as a Discrete Fourier Transform (DFT modulated filter bank (FB. It generalizes the popular orthogonal frequency division multiplexing (OFDM scheme by deploying frequency confined subchannel pulses. We compare three realizations that have been described by Cvetković and Vetterli (1998, and Weiss and Stewart (2000, and Tonello (2006. A detailed derivation of them is performed in the time-domain via the exploitation of different FB polyphase decompositions. We then consider the design of an orthogonal FMT system and we exploit the third realization which allows simplifying the orthogonal FB design and obtaining a block diagonal system matrix with independent subblocks. A numerical method is then presented to obtain an orthogonal FB with well frequency confined subchannel pulses for arbitrarily large number of subchannels. Several examples of pulses with minimal length are reported and their performance is evaluated in typical multipath fading channels. Finally, we compare the orthogonal FMT system with a cyclically prefixed OFDM system in the IEEE 802.11 wireless LAN channel. In this scenario, FMT with minimal length pulses and single tap subchannel equalization outperforms the OFDM system in achievable rate.

  9. Design of Orthogonal Filtered Multitone Modulation Systems and Comparison among Efficient Realizations

    Directory of Open Access Journals (Sweden)

    Andrea M. Tonello

    2010-01-01

    Full Text Available We address the efficient realization of a filtered multitone (FMT modulation system and its orthogonal design. FMT modulation can be viewed as a Discrete Fourier Transform (DFT modulated filter bank (FB. It generalizes the popular orthogonal frequency division multiplexing (OFDM scheme by deploying frequency confined subchannel pulses. We compare three realizations that have been described by Cvetković and Vetterli (1998, and Weiss and Stewart (2000, and Tonello (2006. A detailed derivation of them is performed in the time-domain via the exploitation of different FB polyphase decompositions. We then consider the design of an orthogonal FMT system and we exploit the third realization which allows simplifying the orthogonal FB design and obtaining a block diagonal system matrix with independent subblocks. A numerical method is then presented to obtain an orthogonal FB with well frequency confined subchannel pulses for arbitrarily large number of subchannels. Several examples of pulses with minimal length are reported and their performance is evaluated in typical multipath fading channels. Finally, we compare the orthogonal FMT system with a cyclically prefixed OFDM system in the IEEE 802.11 wireless LAN channel. In this scenario, FMT with minimal length pulses and single tap subchannel equalization outperforms the OFDM system in achievable rate.

  10. Design of Orthogonal Filtered Multitone Modulation Systems and Comparison among Efficient Realizations

    Science.gov (United States)

    Moret, Nicola; Tonello, Andrea M.

    2010-12-01

    We address the efficient realization of a filtered multitone (FMT) modulation system and its orthogonal design. FMT modulation can be viewed as a Discrete Fourier Transform (DFT) modulated filter bank (FB). It generalizes the popular orthogonal frequency division multiplexing (OFDM) scheme by deploying frequency confined subchannel pulses. We compare three realizations that have been described by Cvetković and Vetterli (1998), and Weiss and Stewart (2000), and Tonello (2006). A detailed derivation of them is performed in the time-domain via the exploitation of different FB polyphase decompositions. We then consider the design of an orthogonal FMT system and we exploit the third realization which allows simplifying the orthogonal FB design and obtaining a block diagonal system matrix with independent subblocks. A numerical method is then presented to obtain an orthogonal FB with well frequency confined subchannel pulses for arbitrarily large number of subchannels. Several examples of pulses with minimal length are reported and their performance is evaluated in typical multipath fading channels. Finally, we compare the orthogonal FMT system with a cyclically prefixed OFDM system in the IEEE 802.11 wireless LAN channel. In this scenario, FMT with minimal length pulses and single tap subchannel equalization outperforms the OFDM system in achievable rate.

  11. An efficient synthesis and antifungal evaluation of natural product streptochlorin and its analogues.

    Science.gov (United States)

    Jia, Chen-Yang; Xu, Li-Yong; Yu, Xiang; Ding, Yu-Bing; Jin, Bing; Zhang, Ming-Zhi; Zhang, Wei-Hua; Yang, Guang-Fu

    2018-03-01

    Streptochlorin, a small indole alkaloid isolated from marine Streptomyces sp., exhibits a wide range of potent biological activities. An efficient and economic synthetic protocol for streptochlorin has been developed and validated, 4 steps from indole in a total yield of 45%, and further applied for the synthesis of its analogues. Biological testing showed that most of the target compounds exhibited potential antifungal activity in the primary assays, especially compounds 6, 7 and 9c were the most active ones, representing effective activity against the phytopathogenic fungi screened in preliminary test and might be explored for the study of mode of action in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Efficient Synthesis of Single-Chain Polymer Nanoparticles via Amide Formation

    Directory of Open Access Journals (Sweden)

    Ana Sanchez-Sanchez

    2015-01-01

    Full Text Available Single-chain technology (SCT allows the transformation of individual polymer chains to folded/collapsed unimolecular soft nanoparticles. In this work we contribute to the enlargement of the SCT toolbox by demonstrating the efficient synthesis of single-chain polymer nanoparticles (SCNPs via intrachain amide formation. In particular, we exploit cross-linking between active methylene groups and isocyanate moieties as powerful “click” chemistry driving force for SCNP construction. By employing poly(methyl methacrylate- (PMMA- based copolymers bearing β-ketoester units distributed randomly along the copolymer chains and bifunctional isocyanate cross-linkers, SCNPs were successfully synthesized at r.t. under appropriate reaction conditions. Characterization of the resulting SCNPs was carried out by means of a combination of techniques including size exclusion chromatography (SEC, infrared (IR spectroscopy, proton nuclear magnetic resonance (1H NMR spectroscopy, dynamic light scattering (DLS, and elemental analysis (EA.

  13. One-Step Facile Synthesis of a Simple Hole Transport Material for Efficient Perovskite Solar Cells

    KAUST Repository

    Chen, Hu

    2016-04-04

    A hole transporting material was designed for use in perovskite solar cells, with a facile one-step synthesis from inexpensive, com-mercially available reagents. The molecule comprises a central fluorinated phenyl core with pendant aryl amines, namely, 3,6-difluoro-N1,N1,N2,N2,N4,N4,N5,N5-octakis(4-methoxyphenyl)benzene-1,2,4,5-tetraamine (DFTAB). A power conversion efficiency of up to 10.4% was achieved in a mesoporous perovskite device architecture. The merits of a simple and potentially low cost syn-thetic route as well as promising performance in perovskite devices, encourages further development of this materials class as new low-cost hole transporting materials for the scale up of perovskite solar cells.

  14. Sulfated Titania Nanoparticles: an Efficient Catalyst for the Synthesis of Polyhydroquinoline Derivatives through Hantzsch Multicomponent Reaction

    Directory of Open Access Journals (Sweden)

    A. Tadjarodi

    2015-10-01

    Full Text Available Sulfated titania nanoparticles (SO42-/TiO2 NPs were synthesized using titanium tetraisopropoxide (TTIP by the sol-gel method. The structure and morphology of the prepared nanocatalyst was characterized using X-ray diffraction (XRD, scanning electron microscopy (SEM and Brunauer–Emmett–Teller (BET methods as well as Fourier transform infrared (FT-IR and energy dispersive X-ray (EDX spectroscopy. The obtained nanoparticles were used as an efficient, reusable and environmentally friendly catalyst for the synthesis of polyhydroquinoline (PHQ derivatives via a one-pot multicomponent reaction of various aldehydes, ammonium acetate and 1,3-dicarbonyl compounds under reflux conditions. The desired Hantzsch esters were obtained in good to excellent yields and short reaction times. The SO42- /TiO2 NPs could be recycled at least three times without significant loss of their catalytic activity.

  15. Rearrangement of 5-trimethylsilylthebaine on treatment with L-selectride: an efficient synthesis of (+)-bractazonine.

    Science.gov (United States)

    Chen, Weibin; Wu, Huifang; Bernard, Denzil; Metcalf, Matthew D; Deschamps, Jeffrey R; Flippen-Anderson, Judith L; MacKerell, Alexander D; Coop, Andrew

    2003-03-07

    Treatment of 5-trimethylsilylthebaine with L-Selectride gave rise to a rearrangement to 10-trimethylsilylbractazonine through migration of the phenyl group, whereas treatment of thebaine with strong Lewis acids is known to lead to a similar rearrangement through migration of the alkyl bridge to give, after reduction, (+)-neodihydrothebaine. It is suggested that the rearrangement of the alkyl group of thebaine is favored due to the formation of a tertiary benzylic cation. However, for 5-trimethylsilylthebaine, the lithium ion of L-Selectride acts as the Lewis acid and the beta-silyl effect dominates in the stabilization of any positive charge. This rearrangement provides a clear example of the greater relative migratory aptitude of phenyl groups over alkyl groups, and provides an efficient synthesis of (+)-bractazonine from thebaine.

  16. Efficient Synthesis and Antibacterial Evaluation of (±-Yanglingmycin and Its Analogues

    Directory of Open Access Journals (Sweden)

    Wenjia Dan

    2016-01-01

    Full Text Available An efficient synthetic route was developed for the large-scale preparation of (±-Yanglingmycin and its analogues. Three series of derivatives of (±-Yanglingmycin were synthesized and the structures of all compounds were elucidated by analyses of NMR and ESI-MS spectra data. Moreover, their antibacterial activities against seven species of bacteria were systematically evaluated by the micro-broth dilution method, most of which displayed considerable activity. It was worth noting that compounds 5b, 5c, 5d, 6g, and 7 were found to be the most promising leading candidates, with peak MIC values of 0.98 μg·mL−1 for Bacillus subtilis, which is superior to positive controls (MIC = 3.91 μg·mL−1. The above results might lay the firm foundation for the design and synthesis of novel antibacterial drugs based on (±-Yanglingmycin.

  17. PEG-400 as an efficient and recyclable reaction medium for the synthesis of polyhydroquinolines via Hantzsch reaction

    Directory of Open Access Journals (Sweden)

    Shitole Nana Vikram

    2013-01-01

    Full Text Available Polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using PEG-400 as reaction medium. The present method does not involve any hazardous organic solvents or toxic catalysts. The present methodology offers several advantages such as simple procedure, excellent yields with shorter reaction times and purification of products by non-chromatographic methods.

  18. I 2/K 2 CO 3: An efficient catalyst for the synthesis of 5-aryl-2, 6 ...

    Indian Academy of Sciences (India)

    Molecular iodine in the presence of potassium carbonate has been found to be an efficient and ecofriendly catalyst for the synthesis of polysubstituted dicyanoanilines from aldehydes, acetone and malononitrile under solvent-free thermal condition. The experimental procedure is simple, includes shorter reaction times (less ...

  19. Efficient Friedel-Crafts benzoylation of aniline derivatives with 4-fluorobenzoyl chloride using copper triflate in the synthesis of aminobenzophenones

    DEFF Research Database (Denmark)

    Tran, Phuong Hoang; Phung, Huy Quang; Hansen, Poul Erik

    2016-01-01

    An efficient pathway for the synthesis of the aminobenzophenone derivatives via Friedel–Crafts benzoylation using copper triflate as catalyst is proposed. New derivatives are synthesized. The copper triflate could be easily recovered and reused without loss of catalytic activity. Both the use...... of ionic liquids and microwave heating turned out to be fruitful....

  20. Poly(4-vinylpyridine efficiently catalyzed one-pot four-component synthesis of pyrano[2,3-c]pyrazoles

    Directory of Open Access Journals (Sweden)

    Jalal Albadi

    2014-10-01

    Full Text Available An efficient one-pot synthesis of pyrano[2,3-c]pyrazoles via four-component reaction of phenyl hydrazine, ethyl acetoacetate, malononitrile and aromatic aldehydes, catalyzed by poly(4-vinylpyridine is reported. This method provides many advantages such as, atom-economy, easy work up, clean procedure, short reaction times and high yields of products.

  1. Highly efficient one-pot three-component synthesis of naphthopyran derivatives in water catalyzed by hydroxyapatite

    Science.gov (United States)

    An expeditious and efficient protocol for the synthesis of naphthopyrans has been developed that proceeds via one-pot three-component sequential reaction in water catalyzed by hydroxyapatite or sodium-modified-hydroxyapatite. The title compounds have been obtained in high yield a...

  2. Fused Tetrazoles as Azide Surrogates in Click Reaction: Efficient Synthesis of N-Heterocycle-substituted 1,2,3-Triazoles

    Science.gov (United States)

    Chattopadhyay, Buddhadeb; Rivera Vera, Claudia I.; Chuprakov, Stepan; Gevorgyan, Vladimir

    2010-01-01

    It has been shown that various pyrido-, quinolino-, pyrazino- and qunoxalinotetrazoles can efficienly be used as azide components in the Cu-catalyzed click reaction with alkynes. This method allows for efficient synthesis of a wide variety of N-heterocyclic derivatives of 1,2,3-triazoles. PMID:20380424

  3. I2/K2CO3: An efficient catalyst for the synthesis of 5-aryl-2,6-dicyano ...

    Indian Academy of Sciences (India)

    Abstract. Molecular iodine in the presence of potassium carbonate has been found to be an efficient and eco- friendly catalyst for the synthesis of polysubstituted dicyanoanilines from aldehydes, acetone and malononitrile under solvent-free thermal condition. The experimental procedure is simple, includes shorter reaction ...

  4. A Facile Synthesis of Nitrogen-Doped Highly Porous Carbon Nanoplatelets: Efficient Catalysts for Oxygen Electroreduction

    Science.gov (United States)

    Zhang, Yaqing; Zhang, Xianlei; Ma, Xiuxiu; Guo, Wenhui; Wang, Chunchi; Asefa, Tewodros; He, Xingquan

    2017-02-01

    The oxygen reduction reaction (ORR) is of great importance for various renewable energy conversion technologies such as fuel cells and metal-air batteries. Heteroatom-doped carbon nanomaterials have proven to be robust metal-free electrocatalysts for ORR in the above-mentioned energy devices. Herein, we demonstrate the synthesis of novel highly porous N-doped carbon nanoplatelets (N-HPCNPs) derived from oatmeal (or a biological material) and we show the materials’ high-efficiency as electrocatalyst for ORR. The obtained N-HPCNPs hybrid materials exhibit superior electrocatalytic activities towards ORR, besides excellent stability and good methanol tolerance in both basic and acidic electrolytes. The unique nanoarchitectures with rich micropores and mesopores, as well as the high surface area-to-volume ratios, present in the materials significantly increase the density of accessible catalytically active sites in them and facilitate the transport of electrons and electrolyte within the materials. Consequently, the N-HPCNPs catalysts hold a great potential to serve as low-cost and highly efficient cathode materials in direct methanol fuel cells (DMFCs).

  5. Efficient synthesis and evaluation of bis-pyridinium/bis-quinolinium metallosalophens as antibiotic and antitumor candidates

    Science.gov (United States)

    Elshaarawy, Reda F. M.; Eldeen, Ibrahim M.; Hassan, Eman M.

    2017-01-01

    Inspired with the pharmacological diversity of salophens and in our endeavor to explore a new strategy which may conflict the invasion of drug resistance, we report herein efficient synthetic routes for the synthesis of new RO-salophen(Cl), pyridinium/quinolinium-based salophens (3a-e) and metallosalophens (4a-j). These new architectures have been structurally characterized by elemental and spectral analysis as well pharmacologically evaluated for their in vitro antimicrobial, against a common panel of pathogenic bacterial and fungal strains, and anticancer activities against human colon carcinoma (HCT-116) cell lines. Antimicrobial assay results revealed that all tested compounds exhibited moderate to superb broad-spectrum efficacy in comparison to the standard antibiotic with a preferential ability to perform as a fungicides than to act as bactericides. Noteworthy, VO(II)-salophens are more effective in reduction HCT-116 cell viability than Cu(II)-salophens. For example, VO(II)-salophen3 (4f) (IC50 = 2.13 μg/mL) was ca. 10-fold more efficient than Cu(II)-salophen3 (4e) (IC50 = 20.30 μg/mL).

  6. Evaluation of an automated double-synthesis module: efficiency and reliability of subsequent radiosyntheses of FHBG and FLT

    International Nuclear Information System (INIS)

    Niedermoser, Sabrina; Pape, Manuela; Gildehaus, Franz Josef; Wängler, Carmen; Hartenbach, Markus; Schirrmacher, Ralf; Bartenstein, Peter; Wängler, Björn

    2012-01-01

    We optimized the synthesis methods for 3′-deoxy-3′-[ 18 F]fluorothymidine ([ 18 F]FLT) and 9-(4-[ 18 F]fluoro-3-[hydroxymethyl]butyl)guanine) ([ 18 F]FHBG) and automated them on an Explora General Nucleophilic double-synthesis module. Furthermore, the synthesis efficiency and reliability and the formation of cross-contaminations of the products when preparing two consecutive batches were evaluated. Whereas the preinstalled FLT synthesis conditions required substantial modification in reaction and neutralization conditions to achieve radiochemical yields of up to 60% within 70±10 min including high-performance liquid chromatography purification, the synthesis of FHBG had to be implemented to the module to obtain competitive radiochemical yields of up to 40% in an overall synthesis time of 60±10 min. The radiochemical purities obtained were ≥99% and ≥96% for the synthesis of [ 18 F]FLT and [ 18 F]FHBG, respectively. No significant changes in yield or purity could be observed between both batch productions. We found that the yields and purities also did not change when performing FLT after FHBG syntheses and vice versa. Hence, we developed a synthesis setup that offers the opportunity to perform two subsequent syntheses of either [ 18 F]FLT, [ 18 F]FHBG or [ 18 F]FLT after [ 18 F]FHBG without decrease in radiochemical yields and purities. Also, no cross-contaminations were observed, which can be attributed to the use of separate product delivery tubes, purification columns and an automated intermediate cleaning program. These results open up the possibility of producing consecutively either two equal 18 F-fluorinated tracers or two different ones in high yields on the same synthesis module.

  7. Efficient reductive amination process for enantioselective synthesis of L-phosphinothricin applying engineered glutamate dehydrogenase.

    Science.gov (United States)

    Yin, Xinjian; Wu, Jianping; Yang, Lirong

    2018-03-16

    The objective of this study was to identify and exploit a robust biocatalyst that can be applied in reductive amination for enantioselective synthesis of the competitive herbicide L-phosphinothricin. Applying a genome mining-based library construction strategy, eight NADPH-specific glutamate dehydrogenases (GluDHs) were identified for reductively aminating 2-oxo-4-[(hydroxy)(methyl)phosphinoyl]butyric acid (PPO) to L-phosphinothricin. Among them, the glutamate dehydrogenase cloned from Pseudomonas putida (PpGluDH) exhibited relatively high catalytic activity and favorable soluble expression. This enzyme was purified to homogeneity for further characterization. The specific activity of PpGluDH was 296.1 U/g-protein, which is significantly higher than the reported value for a GluDH. To the best of our knowledge, there has not been any report on protein engineering of GluDH for PPO-oriented activity. Taking full advantage of the available information and the diverse characteristics of the enzymes in the enzyme library, PpGluDH was engineered by site-directed mutation based on multiple sequence alignment. The mutant I170M, which had 2.1-fold enhanced activity, was successfully produced. When the I170M mutant was applied in the batch production of L-phosphinothricin, it showed markedly improved catalytic efficiency compared with the wild type enzyme. The conversion reached 99% (0.1 M PPO) with an L-phosphinothricin productivity of 1.35 g/h·L, which far surpassed the previously reported level. These results show that PpGluDH I170M is a promising biocatalyst for highly enantioselective synthesis of L-phosphinothricin by reductive amination.

  8. Tuning the Synthesis of Manganese Oxides Nanoparticles for Efficient Oxidation of Benzyl Alcohol

    Science.gov (United States)

    Fei, Jingyuan; Sun, Lixian; Zhou, Cuifeng; Ling, Huajuan; Yan, Feng; Zhong, Xia; Lu, Yuxiang; Shi, Jeffrey; Huang, Jun; Liu, Zongwen

    2017-01-01

    The liquid phase oxidation of benzyl alcohol is an important reaction for generating benzaldehyde and benzoic acid that are largely required in the perfumery and pharmaceutical industries. The current production systems suffer from either low conversion or over oxidation. From the viewpoint of economy efficiency and environmental demand, we are aiming to develop new high-performance and cost-effective catalysts based on manganese oxides that can allow the green aerobic oxidation of benzyl alcohol under mild conditions. It was found that the composition of the precursors has significant influence on the structure formation and surface property of the manganese oxide nanoparticles. In addition, the crystallinity of the resulting manganese nanoparticles was gradually improved upon increasing the calcination temperature; however, the specific surface area decreased obviously due to pore structure damage at higher calcination temperature. The sample calcined at the optimal temperature of 600 °C from the precursors without porogen was a Mn3O4-rich material with a small amount of Mn2O3, which could generate a significant amount of {O}_2- species on the surface that contributed to the high catalytic activity in the oxidation. Adding porogen with precursors during the synthesis, the obtained catalysts were mainly Mn2O3 crystalline, which showed relatively low activity in the oxidation. All prepared samples showed high selectivity for benzaldehyde and benzoic acid. The obtained catalysts are comparable to the commercial OMS-2 catalyst. The synthesis-structure-catalysis interaction has been addressed, which will help for the design of new high-performance selective oxidation catalysts.

  9. Efficient synthesis and physicochemical characterization of natural danshensu, its S isomer and intermediates thereof

    Science.gov (United States)

    Sidoryk, Katarzyna; Filip, Katarzyna; Cmoch, Piotr; Łaszcz, Marta; Cybulski, Marcin

    2018-02-01

    The synthesis and molecular structure details of R- 3,4-dihydroxyphenyl lactic acid (danshensu) and related compounds, i.e. S isomer and the key intermediates have been described. Danshensu is an important water soluble phenolic acid of Salvia miltiorrhiza herb (danshen or red sag) with numerous applications in traditional Chinese medicine (TCM). Our synthetic approach was based on the Knoevenagel condensation of the protected 3,4-dihydroxybenzaldehyd and Meldrum acid derivative, followed by asymmetric Sharples dihydroxylation, reductive mono dehydroxylation and final deprotection. All compounds were characterized by various spectroscopic techniques: 1H-, 13C- magnetic resonance (NMR); Fourier-transformed infrared (FTIR); Raman, HR mass spectroscopy. For the determination of compound optical purities original HPLC methods were developed which allowed for the efficient resolution of danshensu R and S enantiomers as well as its intermediate enantiomers, using commercially available chiral stationary phases. Furthermore, in order to better understand danshensu specificity as a potential API in drug formulation, the physicochemical properties of the compounds were studied by thermal analysis, including differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).

  10. Efficient synthesis of tension modulation in strings and membranes based on energy estimation.

    Science.gov (United States)

    Avanzini, Federico; Marogna, Riccardo; Bank, Balázs

    2012-01-01

    String and membrane vibrations cannot be considered as linear above a certain amplitude due to the variation in string or membrane tension. A relevant special case is when the tension is spatially constant and varies in time only in dependence of the overall string length or membrane surface. The most apparent perceptual effect of this tension modulation phenomenon is the exponential decay of pitch in time. Pitch glides due to tension modulation are an important timbral characteristic of several musical instruments, including the electric guitar and tom-tom drum, and many ethnic instruments. This paper presents a unified formulation to the tension modulation problem for one-dimensional (1-D) (string) and two-dimensional (2-D) (membrane) cases. In addition, it shows that the short-time average of the tension variation, which is responsible for pitch glides, is approximately proportional to the system energy. This proportionality allows the efficient physics-based sound synthesis of pitch glides. The proposed models require only slightly more computational resources than linear models as opposed to earlier tension-modulated models of higher complexity. © 2012 Acoustical Society of America.

  11. Green synthesis of copper nanoparticles for the efficient removal (degradation) of dye from aqueous phase.

    Science.gov (United States)

    Sinha, Tanur; Ahmaruzzaman, M

    2015-12-01

    The present work reports the utilization of a common household waste material (fish scales of Labeo rohita) for the synthesis of copper nanoparticles. The method so developed was found to be green, environment-friendly, and economic. The fish scale extracts were acting as a stabilizing and reducing agents. This method avoids the use of external reducing and stabilizing agents, templates, and solvents. The compositional abundance of gelatin may be envisaged for the effective reductive as well as stabilizing potency. The mechanisms for the formation of nanoparticles have also been presented. The synthesized copper nanoparticles formed were predominantly spherical in nature with an average size of nanoparticles in the range of 25-37 nm. The copper nanoparticles showed characteristic Bragg's reflection planes of fcc which was supported by both selected area electron diffraction and X-ray diffraction pattern and showed surface plasmon resonance at 580 nm. Moreover, the energy dispersive spectroscopy pattern also revealed the presence of only elemental copper in the copper nanoparticles. The prepared nanoparticles were used for the remediation of a carcinogenic and noxious textile dye, Methylene blue, from aqueous solution. Approximately, 96 % degradation of Methylene blue dye was observed within 135 min using copper nanoparticles. The probable mechanism for the degradation of the dye has been presented, and the degraded intermediates have been identified using the liquid chromatography-mass spectroscopy technique. The high efficiency of nanoparticles as photocatalysts has opened a promising application for the removal of hazardous dye from industrial effluents contributing indirectly to environmental cleanup process.

  12. Synthesis of core-shell Y2O3 nanoparticles for enhanced luminescence efficiency

    Science.gov (United States)

    Choi, Ju H.; Hyun, Jae Y.; Kim, Ki H.; Kim, Jae P.

    2013-09-01

    In this works, rare earth ion doped core and core-shell Y2O3 phosphors have been extensively studied for many applications due to the high stability and emission range and intensity. The core-shell Y2O3: (RE= Eu, Dy, Tb) nanoparticles are synthesized using a two-step process in which 100-150 nm Y2O3 core particles are synthesized using a molten salt synthesis and the shell is deposited using a sol-gel process The core-shell architecture was designed for enhanced luminescence efficiency with long emission lifetimes. Specifically, a multi-shell architecture was necessary to spatially separate Dy3+, Eu3+ and Tb3+ within the phosphor to circumvent the energy transfer to the surface quenching sites. First, the crystallinity of Y2O3nanophosphors was characterized using X-ray analysis. RE-doped Y2O3 core nanoparticles have a good compositional homogeneity. We have also recorded emission spectra and measured fluorescence lifetime. After coating passive shell layer, emission spectra and measured emission lifetimes were compared with those form Y2O3 nanophosphor core system and the effectiveness of these core-shell phosphors were successfully assessed.

  13. An Efficient Synthesis of Nitriles from Aldoximes Using Diethyl Phosphorocyanidate under Mild Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kieseung; An, Hyeonseong; Hwang, Chanyeon [Woosuk Univ.,Wanju (Korea, Republic of)

    2012-10-15

    Nitriles are valuable intermediates in organic synthesis not only because they serve as the appropriate precursors to various functional groups, but also because they are widely used as the key intermediates for pharmaceuticals, agrochemicals and various N-heterocyclic compounds. The cyano group itself is also frequently found in many biologically important molecules. Therefore, a variety of synthetic routes to nitriles from diverse chemical precursors have been developed. Among these routes, nitrile synthesis from aldoximes using an appropriate dehydrating agent has been a general and clean method. For this purpose, numerous reagents such as chlorosulfonyl isocyanate, di-2-pyridyl sulfite, Burgess reagent, [RuCl{sub 2}(p-cymene)]{sub 2}/MS, 4A, BOP, Pd(OAc){sub 2}/PPh{sub 3}, Cu(OAc){sub 2}/ultrasound have been developed. These reagents, however, may have limitations in some respects such as harsh reaction conditions, use of expensive or less readily available reagents, low yields, and lack of generality. Therefore, there is still a need to develop mild and general method for this conversion. Diethyl phosphorocyanidate (DEPC) was initially introduced as an efficient peptide coupling reagent, and has been utilized for useful organic reactions. Previously, we reported that 2-chloro-1-methylpyridinium iodide is an efficient and mild reagent for the dehydration of aldoximes to nitriles under mild conditions. In continuation of our interest in developing mild method for the conversion of aldoximes to nitriles, we herein wish to report the first application of DEPC to the efficient synthesis of nitriles from aldoximes under mild conditions (Scheme 1). In order to obtain the information regarding the optimum reaction conditions, 4-pyridine aldoxime (1a) was reacted with DEPC without base, and in presence of various base in CH{sub 2}Cl{sub 2} at rt for a prolonged reaction time (20 h) (Table 1). CH{sub 2}CI{sub 2} was chosen as reaction medium in this reaction due to the

  14. An efficient solid-phase synthesis of peptidyl-N-acetylguanidines for use in native chemical ligation.

    Science.gov (United States)

    Okamoto, Ryo; Isoe, Madoka; Izumi, Masayuki; Kajihara, Yasuhiro

    2016-05-01

    In the modern protocols of chemical protein syntheses, peptide-α-thioesters have been used as key components for the assembly of full-length polypeptides through chemoselective peptide coupling reactions. A variety of thioester precursors have been developed for the synthesis of the peptide-α-thioesters by Fmoc solid phase peptide synthesis (Fmoc-SPPS). Recently our group found a peptidyl-N-acetylguanidine as a new peptide-α-thioester precursor. This peptide derivative can be converted into a corresponding peptide-α-thioester only by treatment with an excess amount of a thiol in aqueous buffers at around neutral pH. This unique property allowed us to envision the practical use of the peptidyl-N-acetylguanidines for the chemical syntheses of proteins; however, an efficient synthetic method has been lacking. Herein, we report an efficient solid-phase synthesis of peptidyl-N-acetylguanidines. This new synthetic method employing selective activation and cleavage of a peptide bond successfully provided peptidyl-N-acetylguanidines from the on-resin protected peptides prepared by standard Fmoc-SPPS. We also evaluated the reactivity of a peptidyl-N-acetylguanidine in native chemical ligation through the synthesis of glucose-dependent insulinotropic polypeptide analogue. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  15. Synthesis of Substituted 1,4-Diazepines and 1,5-Benzodiazepines Using an Efficient Heteropolyacid-Catalyzed Procedure

    Directory of Open Access Journals (Sweden)

    Sihame Benadji

    2010-12-01

    Full Text Available An efficient and improved procedure for the synthesis of 1,4-diazepine and 1,5-benzodiazepine derivatives via the reaction of ketimine intermediates with aldehydes in the presence of Keggin-type heteropolyacids (HPAs was developed. High yields and short reaction times were obtained for both electron-releasing and electron-withdrawing substituted 1,4-diazepine  and 1,5-benzodiazepines derivatives.

  16. Amberlyst-15: An Efficient and reusable heterogeneous catalyst for the synthesis of β-amino carbonyl compounds

    Directory of Open Access Journals (Sweden)

    Pathakota Venkata Ramana

    2015-12-01

    Full Text Available A simple and efficient method has been developed for the synthesis of β-amino carbonyl compounds from aromatic ketones, aldehydes and amines by Mannich reaction in the presence of amberlyst-15 as a reusable heterogeneous catalyst at room temperature under solvent-free conditions. The noteworthy advantages of the present method are short reaction times, good product yields, simple procedures and use of non-toxic catalyst.

  17. A facile, green and efficient surfactant-free method for synthesis of aluminum nanooxides with an extraordinary high surface area.

    Science.gov (United States)

    Mohammadnezhad, Gholamhossein; Akintola, Oluseun; Plass, Winfried; Steiniger, Frank; Westermann, Martin

    2016-04-21

    Nano boehmite with unprecedented high surface area and pore volume (802 m(2) g(-1), 2.35 cm(3) g(-1)) was prepared using a facile, green and efficient surfactant-free synthesis method. The structure of the material is characterized by the presence of plates with varying thicknesses and morphologies. The calcined samples show curved and rolled plates with a nanotube-like appearance.

  18. Synthesis of substituted 1,4-diazepines and 1,5-benzodiazepines using an efficient heteropolyacid-catalyzed procedure.

    Science.gov (United States)

    Kaoua, Rachedine; Bennamane, Norah; Bakhta, Saliha; Benadji, Sihame; Rabia, Cherifa; Nedjar-Kolli, Bellara

    2010-12-28

    An efficient and improved procedure for the synthesis of 1,4-diazepine and 1,5-benzodiazepine derivatives via the reaction of ketimine intermediates with aldehydes in the presence of Keggin-type heteropolyacids (HPAs) was developed. High yields and short reaction times were obtained for both electron-releasing and electron-withdrawing substituted 1,4-diazepine  and 1,5-benzodiazepines derivatives.

  19. An efficient PEG-400 mediated catalyst free green synthesis of 2 ...

    Indian Academy of Sciences (India)

    This green protocol can be utilized for fast synthesis of various 2-aminothiazoles in good yields. Keywords. 2-amino thiazole; α-diazoketone; PEG-400; green synthesis. 1. Introduction. Heterocyclic amines such as 2-amino thiazoles are very interesting compounds as they are found to be useful in the treatment of allergies,1 ...

  20. An efficient and facile synthesis of divergent C-3/C-5 bis ...

    Indian Academy of Sciences (India)

    extensive attention in organic synthesis and also serve as potential synthons for the synthesis of alkaloids, ... recent years, MBH adduct of oxindole has attracted attention due to its significance of multi-functionalized ...... scope, rate acceleration and selective formation of bis-. MBH adduct with cyclic enones with DABCO as ...

  1. Efficient synthesis of fluorophosphonylated alkyles by ring-opening reaction of cyclic sulfates.

    Science.gov (United States)

    Diab, Sonia Amel; Sene, Aboubacary; Pfund, Emmanuel; Lequeux, Thierry

    2008-09-04

    Ring-opening reactions of functionalized 1,2-cyclic sulfates and oxetanes with the phosphonodifluoromethyl carbanion are reported. This approach allows an easy access to fluorinated beta-hydroxyphosphonates that are building blocks in the synthesis of acyclic nucleosides. Synthesis of precursors of nucleoside phosphorylase inhibitors from these alcohols is described.

  2. New efficient catalyst for ammonia synthesis: barium-promoted cobalt on carbon

    DEFF Research Database (Denmark)

    Hagen, Stefan; Barfod, Rasmus; Fehrmann, Rasmus

    2002-01-01

    Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia......Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia...

  3. Direct formation of small Cu2O nanocubes, octahedra, and octapods for efficient synthesis of triazoles

    Science.gov (United States)

    Tsai, Ya-Huei; Chanda, Kaushik; Chu, Yi-Ting; Chiu, Chun-Ya; Huang, Michael H.

    2014-07-01

    In most studies describing the preparation of Cu2O crystals of various morphologies, the particle sizes are normally hundreds of nanometers to micrometers due to rapid particle growth, so they are not exactly nanocrystals. Here we report surfactant-free formation of sub-100 nm Cu2O nanocrystals with systematic shape evolution from cubic to octahedral structures by preparing an aqueous mixture of Cu(OAc)2, NaOH, and N2H4 solution. Adjustment of the hydrazine volume enables the particle shape control. Uniform nanocubes and octahedra were synthesized with edge lengths of 37 and 67 nm, respectively. Novel Cu2O octapods with an edge length of 135 nm were also produced by mixing CuCl2 solution, SDS surfactant, NaOH solution, and NH2OH.HCl reductant solution. All of them are nearly the smallest Cu2O nanocrystals of the same shapes ever reported. These small cubes, octahedra, and octapods were employed as catalysts in the direct synthesis of 1,2,3-triazoles from the reaction of alkynes, organic halides, and NaN3 at 55 °C. All of them displayed high product yields in short reaction times. The octahedra enclosed by the {111} facets are the best catalysts, and can catalyze this cycloaddition reaction with high yields in just 2 h when different alkynes were used to make diverse triazole products. Hence, the small Cu2O particles provide time-saving, energy-efficient, and high product yield benefits to organocatalysis.In most studies describing the preparation of Cu2O crystals of various morphologies, the particle sizes are normally hundreds of nanometers to micrometers due to rapid particle growth, so they are not exactly nanocrystals. Here we report surfactant-free formation of sub-100 nm Cu2O nanocrystals with systematic shape evolution from cubic to octahedral structures by preparing an aqueous mixture of Cu(OAc)2, NaOH, and N2H4 solution. Adjustment of the hydrazine volume enables the particle shape control. Uniform nanocubes and octahedra were synthesized with edge

  4. Efficient synthesis of superparamagnetic magnetite nanoparticles under air for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, Namita, E-mail: saxenanamita@yahoo.com [School of Nano Sciences, Central University of Gujarat, Gandhinagar 382030 (India); Singh, Man, E-mail: mansingh50@hotmail.com [School of Chemical Sciences, Central University of Gujarat, Gandhinagar 382030 (India)

    2017-05-01

    The facile co-precipitation process of synthesising Superparamagnetic Iron Oxide Nanoparticles (SPIONs) especially magnetite was investigated and simplified, to develop a reproducible and scaled up synthesis process under air, for producing particles with enhanced percentage of magnetite, thus eliminating the crucial and complicated need of using the inert atmosphere. Presence of magnetite was confirmed by XRD, TEM, and Raman spectroscopy. Efficiency of synthesising magnetite was increased up to approx. ∼58 wt%, under air with no other phases but maghemite present. Alkali concentration was optimised, and particles with better magnetisation values were synthesised. The approximate weight percentage of magnetite was calculated using the simple and rapid XRD peak deconvolution method. Higher pH values from 13 to14 were investigated in the study while alkali concentration was varied from 0.5 to 4 M. 1Molar NaOH with a final pH of 13.4 was found to be optimum. Well crystallised particles with approx. 6–12 nm size, narrow size distribution and cubo-spheroidal shape were synthesised. Particles were Superparamagnetic with high values of saturation magnetisation of up to 68 emu/g and negligible values of remanence and coercivity. A reaction yield of up to 62% was obtained. Hydrophilic coated particles were produced in a single, one step facile process for biomedical applications, using optimised parameters of pH and alkali concentration obtained in the study. Single domain particles with good magnetisation formed stable aqueous dispersions. FTIR, UV-Visible and DLS were used to confirm the coating and dispersion stabilities of the particles. These particles have the requisite properties required for application in different biomedical fields.

  5. Facile and controlled synthesis of aligned WO3 nanorods and nanosheets as an efficient photocatalyst material

    Science.gov (United States)

    Ahmed, Bilal; Kumar, Sumeet; Ojha, Animesh K.; Donfack, P.; Materny, A.

    2017-03-01

    In this work, we have performed a facile and controlled synthesis of WO3 nanorods and sheets in different crystal phases (triclinic, orthorhombic and monoclinic) of WO3 using the sol-gel method. The detailed structures of the synthesized materials were examined by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy measurements. The shapes and crystal phases of the WO3 nanostructures were found to be highly dependent on the calcination temperature. The variation in crystalline phases and shapes is modified the electronic structure of the samples, which causes a variation in the value of optical band gap. The value of the Raman line intensity ratio I264/I320 has been successfully used to identify the structural transition from the triclinic to the orthorhombic phase of WO3. The PL spectra of the synthesized products excited at wavelengths 380, 400, and 420 nm exhibit intense emission peaks that cover the complete visible range (blue-green-red). The emission peaks at 460 and 486 nm were caused by the near band-edge and band to band transition, respectively. The peaks in spectral range 500-600 nm might be originated from the presence of oxygen vacancies lying within the energy band gap. The synthesized WO3 nanostructures showed improved photocatalytic activity for the photodegradation of MB dye. The enhanced photocatalytic activity of WO3 nanosheets compared to WO3 nanorods for photodegradation of methylene blue (MB) dye could be due to the shape of the nanostructured WO3. The sheet type of structure provides more active surface for the interaction of dye molecules compared to the rods, which results in a more efficient degradation of the dye molecules.

  6. Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan

    Directory of Open Access Journals (Sweden)

    Wafa Gati

    2012-12-01

    Full Text Available We have developed a general synthesis of polysubstituted 1,4-dihydropyridines and pyridines based on a highly regioselective lithiation/6-endo-dig intramolecular carbolithiation from readily available N-allyl-ynamides. This reaction, which has been successfully applied to the formal synthesis of the anti-dyskinesia agent sarizotan, further extends the use of ynamides in organic synthesis and further demonstrates the synthetic efficiency of carbometallation reactions.

  7. Thermodynamic efficiency of synthesis, storage and breakdown of the high-energy metabolites by photosynthetic microalgae

    International Nuclear Information System (INIS)

    Sorgüven, Esra; Özilgen, Mustafa

    2013-01-01

    Lipids and carbohydrates are employed in the nature to store internal energy due to the large number of the high energy atomic bonds in their structure. Internal energy stored in the bonds is used to fuel work producing engines or metabolic activity of living organisms. This paper investigates the thermodynamic efficiency of the glucose and lipid synthesis and breakdown by photosynthetic microalgae. Photosynthetic microalgae are able to convert 3.8% of the solar exergy into the chemical exergy of algal lipid. As the microalgae convert the first product of the photosynthesis, i.e. glucose, into lipid, 47–49% of the chemical exergy is lost. If the microalgal cell consumes the photosynthetically produced glucose for its own energy demand, then about 30% of the glucose exergy can be converted into work potential in case of immediate and short-term energy demands. Organism can convert about 22% of the glucose exergy into work potential after a long-term storage. If the algal lipid is harvested for biodiesel production and the produced biodiesel is combusted in a Diesel engine, then about 17% of the exergy of the photosynthetically produced glucose can be converted into useful work. Biodiesel is among the most popular renewable fuels. The lipids are harvested from their storage in the cells to produce biodiesel before following the lipid breakdown path of the cellular metabolism. Our analysis indicates that, extracting the first product of photosynthesis, i.e. glucose or glucose polymers instead of lipids may be more efficient thermodynamically, if new motors capable to extract their bond energy is developed. - Highlights: • Photosynthetic microalgae convert 3.8% of the solar exergy into the chemical exergy of algal lipid. • Converting the first product of the photosynthesis (glucose) into lipid causes 47–49% of exergy loss. • Organism can convert 30% of the glucose exergy into work potential for its own immediate or short-term energy demand. • Organism can

  8. Simple and an efficient method for the synthesis of 1-[2-dimethylamino-1-(4-methoxy-phenyl)-ethyl]-cyclohexanol hydrochloride: (+/-) venlafaxine racemic mixtures.

    Science.gov (United States)

    Basappa; Kavitha, C V; Rangappa, K S

    2004-06-21

    A novel synthetic method was developed for the synthesis of venlafaxine using inexpensive reagents. An improvement in the method, in the yield was achieved for the conversion of the venlafaxine. This is an improved version, simple and efficient method for the large-scale synthesis of venlafaxine.

  9. Efficient synthesis of functionalized 1,2,3-triazoles by catalyst-free 1,3-dipolar cycloaddition of nitroalkenes with sodium azide

    International Nuclear Information System (INIS)

    Wang, Ting; Hu, Xiao-Chun; Huang, Xu-Jiao; Li, Xin-Sheng; Xie, Jian-Wu

    2012-01-01

    A simple and efficient protocol has been developed for the synthesis of 1,2,3-triazole derivatives by catalyst-free 1,3-dipolar cycloaddition of nitroalkenes with sodium azide under mild conditions (author)

  10. An efficient catalyst-free synthesis of novel chromeno[4,3-b ...

    Indian Academy of Sciences (India)

    Sudesh Kumari

    . Introduction. The Michael Initiated Ring Closure ... as eco-friendly reaction media in catalyst free organic synthesis.7 Ethylene glycol has promising ... The multiscan absorption correction was applied. The crystal structure of 8a was solved by ...

  11. Safe and efficient Boc-SPPS for the synthesis of glycopeptide-α-thioesters.

    Science.gov (United States)

    Izumi, Masayuki; Murakami, Masumi; Okamoto, Ryo; Kajihara, Yasuhiro

    2014-02-01

    Boc-solid phase peptide synthesis is useful for the preparation of peptide-α-thioesters. However, this strategy usually employs hydrogen fluoride for the final deprotection step. These strongly acidic conditions cannot be applied for the synthesis of acid-labile glycopeptide-α-thioesters. The protocol presented here is a modified in situ neutralization Boc-solid phase peptide synthesis employing 10% sulfuric acid/dioxane conditions for intermediate Boc removal and TfOH for the final side-chain deprotection step. These conditions were found to be applicable for the synthesis of acid-labile glycopeptide-α-thioesters. In this protocol, a glycopeptide is synthesized as α- thioester on a thiol linker, and the product glycopeptide-α-thioester is released from the resin by thiolysis after side-chain deprotection step with an acid cocktail containing TfOH instead of hydrogen fluoride. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.

  12. A green and efficient protocol for the synthesis of quinoxaline, benzoxazole and benzimidazole derivatives using heteropolyanion-based ionic liquids: as a recyclable solid catalyst.

    Science.gov (United States)

    Vahdat, Seyed Mohammad; Baghery, Saeed

    2013-09-01

    In this paper, we introduce two nonconventional ionic liquid compounds which are composed of propane sulfonate functionalized organic cations and heteropolyanions as green solid acid catalysts for the highly efficient and green synthesis of 2,3-disubstitutedquinoxaline derivatives. These ionic liquids are in the solid state at room temperature and the synthesis is carried out via the one-pot condensation reaction of various o-phenylenediamine with 1,2-diketone derivatives. Benzoxazole and benzimidazole derivatives were also synthesized by these novel catalysts via the one-pot condensation from reaction orthoester with o-aminophenol (synthesis of benzoxazole derivatives) and ophenylenediamine (synthesis of benzimidazole derivatives). All experiments successfully resulted in the desired products. The described novel synthesis method has several advantages of safety, mild condition, high yields, short reaction times, simplicity and easy workup compared to the traditional method of synthesis.

  13. Hydrothermal Synthesis of VO2 Polymorphs: Advantages, Challenges and Prospects for the Application of Energy Efficient Smart Windows.

    Science.gov (United States)

    Li, Ming; Magdassi, Shlomo; Gao, Yanfeng; Long, Yi

    2017-09-01

    Vanadium dioxide (VO 2 ) is a widely studied inorganic phase change material, which has a reversible phase transition from semiconducting monoclinic to metallic rutile phase at a critical temperature of τ c ≈ 68 °C. The abrupt decrease of infrared transmittance in the metallic phase makes VO 2 a potential candidate for thermochromic energy efficient windows to cut down building energy consumption. However, there are three long-standing issues that hindered its application in energy efficient windows: high τ c , low luminous transmittance (T lum ), and undesirable solar modulation ability (ΔT sol ). Many approaches, including nano-thermochromism, porous films, biomimetic surface reconstruction, gridded structures, antireflective overcoatings, etc, have been proposed to tackle these issues. The first approach-nano-thermochromism-which is to integrate VO 2 nanoparticles in a transparent matrix, outperforms the rest; while the thermochromic performance is determined by particle size, stoichiometry, and crystallinity. A hydrothermal method is the most common method to fabricate high-quality VO 2 nanoparticles, and has its own advantages of large-scale synthesis and precise phase control of VO 2 . This Review focuses on hydrothermal synthesis, physical properties of VO 2 polymorphs, and their transformation to thermochromic VO 2 (M), and discusses the advantages, challenges, and prospects of VO 2 (M) in energy-efficient smart windows application. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Efficient 2-step biocatalytic strategies for the synthesis of all nor(pseudo) ephedrine isomers

    OpenAIRE

    Sehl, T.; Hailes, H. C.; Ward, J. M.; Menyes, U.; Pohl, M.; Rother, D.

    2014-01-01

    Chiral 1,2-amino alcohols are important building blocks for chemistry and pharmacy. Here, we developed two different biocatalytic 2-step cascades for the synthesis of all four nor(pseudo)ephedrine (N(P)E) stereoisomers. In the first one, the combination of an (R)-selective thiamine diphosphate (ThDP)-dependent carboligase with an (S)- or (R)-selective ω-transaminase resulted in the formation of (1R,2S)-NE or (1R,2R)-NPE in excellent optical purities (ee >99% and de >98%). For the synthesis of...

  15. Sound Synthesis of the Harpsichord Using a Computationally Efficient Physical Model

    OpenAIRE

    Vesa Välimäki; Henri Penttinen; Mikael Laurson; Jonte Knif; Cumhur Erkut

    2004-01-01

    A sound synthesis algorithm for the harpsichord has been developed by applying the principles of digital waveguide modeling. A modification to the loss filter of the string model is introduced that allows more flexible control of decay rates of partials than is possible with a one-pole digital filter, which is a usual choice for the loss filter. A version of the commuted waveguide synthesis approach is used, where each tone is generated with a parallel combination of the string model and a s...

  16. Synthesis and simulation of efficient divided wall column sequences for bioethanol recovery and purification from an actual lignocellulosic fermentation broth

    DEFF Research Database (Denmark)

    Torres-Ortega, Carlo Edgar; Rong, Ben-Guang

    2016-01-01

    and evaluation of the intensified recovery and purification systems. A three-level methodology intensified the recovery, the purification, and both sections simultaneously. We proposed replacement of flashes by column sections, hybridizing unit operations by reformulating column sections, and relocation......, the intensified system with lowest TAC, and a multieffect distillation column scheme. The intensified system obtained cost savings of 15–20% higher than the multieffect scheme. We concluded that the novel synthesis procedure generated systems that efficiently reduced the energy and capital costs...

  17. An efficient Hantzsch synthesis of 1,4-dihydropyridines using p-toluenesulfonic acid under solvent-free condition

    Directory of Open Access Journals (Sweden)

    Masoud Nasr-Esfahani

    2014-03-01

    Full Text Available An efficient Hantzsch synthesis of various substituted 1,4-dihydropyridines from an aldehyde, a β-dicarbonyl compound and ammonium acetate using p-toluenesulfonic acid in a solvent-free condition in the absence of any other co-catalyst is described. The process is simple and environmentally benign and the catalyst is commercially available and inexpensive. This method has the advantages of excellent yield (80–96% and short reaction time (5-20 min.. Irradiation of a typical 1,4-dihydropyridine leads to the corresponding pyridine.

  18. Fast and efficient green synthesis of thiosulfonate S-esters by microwave-supported permanganate oxidation of symmetrical disulfides

    DEFF Research Database (Denmark)

    Thi, Luu Thi Xuan; Thi Nguyen, Thao-Tran; Le, Thach Ngoc

    2015-01-01

    Potassium permanganate absorbed on copper(II) sulfate pentahydrate has been found to be an efficient, inexpensive, and green oxidation agent for the synthesis of “symmetrical” thiosulfonate S-esters by oxidation of the corresponding symmetrical disulfides. The oxidation reactions were carried out...... under solvent-free reaction conditions within 15 min under the influence of microwave irradiation, as well as (for comparison) supported by conventional heating, to afford yields of the thiosulfonate S-esters in the range of 60–83%. The oxidation reaction appears to proceed (at least partly) via...

  19. An Efficient Solvent-Free Protocol for the Synthesis of 1-Amidoalkyl-2-naphthols using Silica-Supported Molybdatophosphoric Acid

    Directory of Open Access Journals (Sweden)

    Abdolkarim Zare

    2010-01-01

    Full Text Available A highly efficient, green and simple solvent-free method for the synthesis of 1-amidoalkyl-2-naphthols via one-pot multi-components condensation of 2-naphthol, aromatic aldehydes and amides in the presence of catalytic amount of silica-supported molybdatophosphoric acid (H3PMo12O40.xH2O/SiO2, 3.17 mol% is described. The reactions proceed rapidly and the title compounds are produced in high to excellent yields.

  20. Efficient and 'green' microwave-assisted synthesis of haloalkylphosphonates via the Michaelis-Arbuzov reaction

    Czech Academy of Sciences Publication Activity Database

    Jansa, Petr; Holý, Antonín; Dračínský, Martin; Baszczyňski, Ondřej; Česnek, Michal; Janeba, Zlatko

    2011-01-01

    Roč. 13, č. 4 (2011), s. 882-888 ISSN 1463-9262 R&D Projects: GA AV ČR KJB400550903; GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : microwave-assisted synthesis * haloalkylphosphonates * Michaelis-Arbuzov reaction Subject RIV: CC - Organic Chemistry Impact factor: 6.320, year: 2011

  1. Efficient synthesis of large-scale thinned arrays using a density-taper initialised genetic algorithm

    CSIR Research Space (South Africa)

    Du Plessis, WP

    2011-09-01

    Full Text Available The use of the density-taper approach to initialise a genetic algorithm is shown to give excellent results in the synthesis of thinned arrays. This approach is shown to give better SLL values more consistently than using random values and difference...

  2. LaCl 3. 7H 2 O: An efficient catalyst for the synthesis of phosphinates ...

    Indian Academy of Sciences (India)

    An expeditious neat procedure was developed for the synthesis of a series of new methyl phenyl heterocyclic phosphinates (3a-l) through Michaelis-Arbuzov reaction by the reaction of various heterocyclic halides (Cl or Br) (1a-l) with dimethyl phenylphosphonite (2) under N2 atmosphere using a heterogeneous catalyst, ...

  3. A facile and efficient synthesis of (+)- and (-)-allo-muscarine and analogs

    DEFF Research Database (Denmark)

    Norrild, Jens Chr.; Pedersen, Christian

    1997-01-01

    Treatment of easily obtainable 1-alkylamino-1,3,6-trideoxyhexitols with hydrogen fluoride in the presence of formic acid gives the corresponding C-5 inverted 2,5-anhydrides in high yields. The synthesis of allo-muscarine and its N-benzyl analog from galactono-1,4-lactone is reported in 30 and 41...

  4. Synthesis and characterization of a new efficient blue-light- emitting copolymer

    NARCIS (Netherlands)

    Hilberer, A; Brouwer, H.J; van der Scheer, B.J.; Wildeman, J.; Hadziioannou, G

    1995-01-01

    In this paper we present the synthesis, the characterization, and the use in light-emitting diodes of a new blue-light-emitting copolymer, poly[2,5,2'',5''-tetraoctyl-p-terphenyl-4,4''-ylenevinylene-p-phenylenevinylene]. This copolymer, obtained by a poly-Heck reaction, has a fully unsaturated

  5. A convenient and efficient one-step method for the synthesis of ...

    African Journals Online (AJOL)

    hydroxy-5-methyl benzaldehyde with a mole of N,N'-bis(2-pyridyl)dopamine in THF at ambient conditions in high yield (75-80%). KEY WORDS: Dicompartmental ligand, Synthesis, Phenol-based ligand, Acyclic ligand. Bull. Chem. Soc. Ethiop. 2010 ...

  6. A Simple and Efficient Synthesis of 12-Aryl-8,9,10,12 ...

    African Journals Online (AJOL)

    Highly effective zinc oxide nanoparticles catalyzed solvent-free synthesis of some tetrahydrobenzo[a]xanthen-11-one derivatives via one-pot multi-component reaction of aldehydes, 2-naphthol and dimedone. The present approach creates a variety of biologically active heterocyclic compounds in excellent yields and short ...

  7. LaCl 3. 7H 2 O: An efficient catalyst for the synthesis of phosphinates ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 126; Issue 1 ... Abstract. An expeditious neat procedure was developed for the synthesis of a series of new methyl phenyl heterocyclic phosphinates (3a-l) through Michaelis-Arbuzov reaction by the reaction of various heterocyclic halides (Cl or Br) (1a-l) with dimethyl ...

  8. ZnO nanoparticle as catalyst for efficient green one-pot synthesis of ...

    Indian Academy of Sciences (India)

    Green chemistry protocols with the reusability of the nano particle as catalyst in the synthesis of coumarins is described. The zinc oxide (ZnO) nanoparticles functions as highly effective catalyst for the reactions of various -hydroxy benzaldehydes with 1,3-dicarbonyl compounds under microwave and thermal conditions to ...

  9. Boric acid as a mild and efficient catalyst for one-pot synthesis of 1 ...

    Indian Academy of Sciences (India)

    Multicomponent reaction; amidoalkyl naphthol; boric acid; catalyst; solvent-free synthesis. 1. Introduction. Multicomponent reactions (MCRs), in ... silica-sodium hydrogen sul- phate,14 molybdophosphoric acid (H3[P(Mo3O10)4]),15 ... The solid obtained was collected by filtration and purified by recrystallization from ethanol.

  10. A Simple and Efficient Synthesis of 12-Aryl-8,9,10,12 ...

    African Journals Online (AJOL)

    NICO

    Highly effective zinc oxide nanoparticles catalyzed solvent-free synthesis of some tetrahydrobenzo[a]xanthen-11-one derivatives via one-pot multi-component reaction of aldehydes, 2-naphthol and dimedone. The present approach creates a variety of biologi- cally active heterocyclic compounds in excellent yields and short ...

  11. An efficient and rapid synthesis of 3-hydroxy-3-alkyl-2-oxindoles via ...

    Indian Academy of Sciences (India)

    L Raju Chowhan

    Abstract. A robust and rapid synthesis of 3-hydroxy-3-alkyl-2-oxindoles from isatins is described. This method introduces an ecofriendly, un-activated Zn dust, solid NH4Cl and substrates under aqueous conditions, which has produced the product in moderate to good yields. Without using column chromatography, majority ...

  12. A green and efficient method for the synthesis of homodimeric (β ...

    African Journals Online (AJOL)

    ... derivatives by intramolecular cyclization in various yields. Of particular interest is the use of the water as solvent of reaction and in absence of catalyst. Also these operating conditions protect the environment and economic points of view. Keywords: aqueous synthesis; bioactivity; dihydropyridine; dimedone; green method; ...

  13. Lipopolycationic Telomers for Gene Transfer: Synthesis and Evaluation of Their in Vitro Transfection Efficiency

    NARCIS (Netherlands)

    Verderone, G.; van Craynest, N.; Boussif, O.; Santaella, C.; Bischoff, Rainer; Kolbe, H.V.; Vierling, P.

    2000-01-01

    We report on the synthesis of a series of lipopolyamine telomers I-14,n, I-18,n, and II-18,n and on their in vitro gene-transfer capability. Their structure consists of a polyamine polar moiety, including n primary amine functions (from 1 to 70), connected to a hydrophobic moiety, including two

  14. Stereochemically rich pentaketides from bis(isoxazolines): a general strategy for efficient polyketide synthesis.

    Science.gov (United States)

    Fader, Lee D; Carreira, Erick M

    2004-07-08

    [reaction: see text] A strategy based on diastereoselective dipolar cycloaddition reaction of nitrile oxides and allylic alcoholates has been applied to the synthesis of bis(isoxazolines) that are precursors to polyketide fragments. These intermediates can be elaborated into protected polyols by chemoselective reductive opening of each isoxazoline sequentially or, alternatively, both simultaneously, potentially providing access to all stereoisomers of this carbon skeleton.

  15. ZnO nanoparticle as catalyst for efficient green one-pot synthesis of ...

    Indian Academy of Sciences (India)

    Department of Studies and Research in Industrial Chemistry, School of Chemical Sciences,. Kuvempu University, Shankaraghatta 577 ... materials and modern techniques of creating and inves- tigating specific active sites on catalyst .... Optimization of the ZnO nanoparticles catalysed model reaction for synthesis of ethyl ...

  16. A Combination of Modal Synthesis and Subspace Iteration for an Efficient Algorithm for Modal Analysis within a FE-Code

    Directory of Open Access Journals (Sweden)

    M.W. Zehn

    2003-01-01

    Full Text Available Various well-known modal synthesis methods exist in the literature, which are all based upon certain assumptions for the relation of generalised modal co-ordinates with internal modal co-ordinates. If employed in a dynamical FE substructure/superelement technique the generalised modal co-ordinates are represented by the master degrees of freedom (DOF of the master nodes of the substructure. To conduct FE modal analysis the modal synthesis method can be integrated to reduce the number of necessary master nodes or to ease the process of defining additional master points within the structure. The paper presents such a combined method, which can be integrated very efficiently and seamless into a special subspace eigenvalue problem solver with no need to alter the FE system matrices within the FE code. Accordingly, the merits of using the new algorithm are the easy implementation into a FE code, the less effort to carry out modal synthesis, and the versatility in dealing with superelements. The paper presents examples to illustrate the proper work of the algorithm proposed.

  17. Rapid and efficient synthesis of soluble graphene nanosheets using N-methyl-p-aminophenol sulfate as a reducing agent

    International Nuclear Information System (INIS)

    Wang Xialie; Wen Xiaohong; Liu Zhanpeng; Tan Yi; Yuan Ye; Zhang Ping

    2012-01-01

    Mass production of soluble graphene still remains a challenge, although several methodologies have been proposed. Here we report a rapid and efficient method for the synthesis of soluble graphene nanosheets (GNSs) with long-term dispersion stability in both aqueous and common organic solvents. Within only 12 min at 95 °C, exfoliated graphite oxide in ammonia solution (pH 10) was reduced to soluble GNSs using N-methyl-p-aminophenol sulfate (metol) as a reducing agent without external stabilizers. The prepared GNSs were characterized by different techniques and a comparison of metol and hydrazine hydrate as reducing agents was made. The results indicated that, with the advantages of being rapid, efficient, inexpensive and relatively environmentally friendly, the reduction of graphite oxide into soluble GNSs by metol is a promising substitute for hydrazine hydrate in the mass production of soluble GNSs. (paper)

  18. Atomically thin Pt shells on Au nanoparticle cores: facile synthesis and efficient synergetic catalysis

    DEFF Research Database (Denmark)

    Engelbrekt, Christian; Seselj, Nedjeljko; Poreddy, Raju

    2016-01-01

    We present a facile synthesis protocol for atomically thin platinum (Pt) shells on top of gold (Au) nanoparticles (NPs) (Au@PtNPs) in one pot under mild conditions. The Au@PtNPs exhibited remarkable stability (> 2 years) at room temperature. The synthesis, bimetallic nanostructures and catalytic ...... activity for the direct production of γ-valerolactone, an alternative biofuel/fuel additive, from levulinic acid and methyl levulinate was finally demonstrated....... in electrooxidation of sustainable fuels (i.e. formic acid, methanol and ethanol), and selective hydrogenation of benzene derivatives. Especially high activity was achieved for formic acid oxidation, 549 mA (mgPt)−1 (at 0.6 V vs. SCE), which is 3.5 fold higher than a commercial

  19. A Tractable and Efficient One-Pot Synthesis of 5'-Azido-5'-deoxyribonucleosides

    Directory of Open Access Journals (Sweden)

    Theodore V. Peterson

    2014-02-01

    Full Text Available Synthetic routes to 5'-azidoribonucleosides are reported for adenosine, cytidine, guanosine, and uridine, resulting in a widely applicable one-pot methodology for the synthesis of these and related compounds. The target compounds are appropriate as precursors in a variety of purposive syntheses, as the synthetic and therapeutic relevance of azido- and amino-modified nucleosides is expansive. Furthermore, in the conversion of alcohols to azides, these methods offer a tractable alternative to the Mitsunobu and other more difficult reactions.

  20. An Efficient, Mild and Solvent-Free Synthesis of Benzene Ring Acylated Harmalines

    Directory of Open Access Journals (Sweden)

    Sabira Begum

    2009-12-01

    Full Text Available A facile synthesis of a series of benzene ring acylated analogues of harmaline has been achieved by Friedel-Crafts acylation under solvent-free conditions at room temperature using acyl halides/acid anhydrides and AlCl3. The reaction afforded 10- and 12-acyl analogues of harmaline in good yield, along with minor quantities of N-acyl-tryptamines and 8-acyl analogues of N-acyltryptamines.

  1. Synthesis of highly efficient azure-to-blue-emitting Zn-Cu-Ga-S quantum dots.

    Science.gov (United States)

    Kim, Bu-Yong; Kim, Jong-Hoon; Lee, Ki-Heon; Jang, Eun-Pyo; Han, Chang-Yeol; Jo, Jung-Ho; Jang, Ho Seong; Yang, Heesun

    2017-04-06

    To realize blue emission-capable non-Cd I-III-VI quantum dots (QDs), we explore the synthesis of ternary Cu-Ga-S (CGS) QDs and subsequent quaternary Zn-Cu-Ga-S (ZCGS) via Zn alloying into a CGS host. The resulting ZCGS/ZnS core/shell QDs possess not only Zn content-dependent tunable emissions in the azure-to-blue range but also exceptional quantum yields of 78-83%.

  2. Efficient synthesis of 2'-deoxynucleoside 3'-C-phosphonates: reactivity of geminal hydroxyphosphonate moiety.

    Science.gov (United States)

    Králíková, S; Budĕsínský, M; Masojidková, M; Rosenberg, I

    2000-07-01

    In this report we present a novel, simple way for the synthesis of 3'-C-phosphonate derivatives of all four basic 2'-deoxynucleosides in both fully protected and deprotected forms. The reactivity of the geminal hydroxy phosphonate moiety located at the 3'-carbon atom of the nucleoside was studied with respect to the use of this type of nucleoside phosphonic acid for the preparation of short oligonucleotides, namely, dinucleoside monophosphate analogues.

  3. Simple enzymatic procedure for l‐carnosine synthesis: whole‐cell biocatalysis and efficient biocatalyst recycling

    Science.gov (United States)

    Heyland, Jan; Antweiler, Nicolai; Lutz, Jochen; Heck, Tobias; Geueke, Birgit; Kohler, Hans‐Peter E.; Blank, Lars M.; Schmid, Andreas

    2010-01-01

    Summary β‐Peptides and their derivates are usually stable to proteolysis and have an increased half‐life compared with α‐peptides. Recently, β‐aminopeptidases were described as a new enzyme class that enabled the enzymatic degradation and formation of β‐peptides. As an alternative to the existing chemical synthesis routes, the aim of the present work was to develop a whole‐cell biocatalyst for the synthesis and production of β‐peptides using this enzymatic activity. For the optimization of the reaction system we chose the commercially relevant β,α‐dipeptide l‐carnosine (β‐alanine‐l‐histidine) as model product. We were able to show that different recombinant yeast and bacteria strains, which overexpress a β‐peptidase, could be used directly as whole‐cell biocatalysts for the synthesis of l‐carnosine. By optimizing relevant reaction conditions for the best‐performing recombinant Escherichia coli strain, such as pH and substrate concentrations, we obtained high l‐carnosine yields of up to 71%. Long‐time as well as biocatalyst recycling experiments indicated a high stability of the developed biocatalyst for at least five repeated batches. Application of the recombinant E. coli in a fed‐batch process enabled the accumulation of l‐carnosine to a concentration of 3.7 g l−1. PMID:21255308

  4. Templated synthesis of nickel nanoparticles: Toward heterostructured nanocomposites for efficient hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Nicholas Cole [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    The world is currently facing an energy and environmental crisis for which new technologies are needed. Development of cost-competitive materials for catalysis and hydrogen storage on-board motor vehicles is crucial to lead subsequent generations into a more sustainable and energy independent future. This thesis presents work toward the scalable synthesis of bimetallic heterostructures that can enable hydrogen to compete with carbonaceous fuels by meeting the necessary gravimetric and volumetric energy densities and by enhancing hydrogen sorption/desorption kinetics near ambient temperatures and pressures. Utilizing the well-known phenomenon of hydrogen spillover, these bimetallic heterostructures could work by lowering the activation energy for hydrogenation and dehydrogenation of metals. Herein, we report a novel method for the scalable synthesis of silica templated zero-valent nickel particles (Ni$\\subset$ SiO2) that hold promise for the synthesis of nickel nanorods for use in bimetallic heterostructures for hydrogen storage. Our synthesis proceeds by chemical reduction of a nickel-hydrazine complex with sodium borohydride followed by calcination under hydrogen gas to yield silica encapsulated nickel particles. Transmission electron microscopy and powder X-ray diffraction were used to characterize the general morphology of the resultant nanocapsules as well as the crystalline phases of the incorporated Ni0 nanocrystals. The structures display strong magnetic behavior at room temperature and preliminary data suggests nickel particle size can be controlled by varying the amount of nickel precursor used in the synthesis. Calcination under different environments and TEM analysis provides evidence for an atomic migration mechanism of particle formation. Ni$\\subset$SiO2 nanocapsules were used as seeds to induce heterogeneous nucleation and subsequent growth within the nanocapsule via electroless nickel plating. Nickel nanoparticle

  5. A Simple and efficient protocol for the synthesis of 1,4-dihydro pyridines (Hantzsch pyridines catalyzed by Germanium (IV iodide

    Directory of Open Access Journals (Sweden)

    Chandramouleswararao Jillepalli

    2014-12-01

    Full Text Available A simple and efficient protocol has been developed for the synthesis of Hantzsch pyridines. In the reported synthesis, a variety of aldehydes undergo smooth condensation reaction with ethyl acetoacetate and ammonium acetate in presence of Germanium (IV iodide in acetonitrile. This method is applicable to a variety of substrates to afford the corresponding 1,4-dihydropyridines in one-pot reaction in excellent yields.

  6. One-pot synthesis of well-defined polyether/polyester block copolymers and terpolymers by a highly efficient catalyst switch approach

    KAUST Repository

    Alamri, Haleema

    2016-04-20

    A highly efficient methodology, based on a novel catalyst switch approach with rapid crossover characteristics, was developed for the one-pot synthesis of block co/terpolymers of cyclic ethers and esters. This new approach, which takes advantage of one of the best catalysts for epoxide (t-BuP4) and cyclic ester (t-BuP2) polymerization, opens new horizons toward the synthesis of cyclic ether/ester complex macromolecular architectures. © The Royal Society of Chemistry 2016.

  7. Financing of energy-efficient productive industrial projects. Situation and first ideas for the future. Synthesis

    International Nuclear Information System (INIS)

    Billard, Yannael; Julien, Emmanuel; Blaisonneau, Laurent; Streiff, Frederic; Padilla, Sylvie; Benazzi, Eric; Domergue, Bruno; Fraysse, Sebastien; Gaussens, Jean-Pierre; Packeu, Paris; Bodino, Didier; Randimbivololona, Prisca; Verbbrughe, Gregory; Bissonnier, Alain; Dantec, Caroline

    2016-11-01

    Based on in-depth interviews with decision makers and experts belonging to energy consuming industrial groups, or involved in technological offer or in financing, this study addressed the issue of energy efficiency in the industrial sector, and of its financing. Interviewed persons represented 11 large companies, 5 medium-sized companies, and 14 industrial sectors, and 3 main professional profiles (from technical to financial). The authors thus explored current financing models implemented to finance energy efficiency, by analysing existing decision-making processes, brakes on energy efficiency in industry, levers favourable to energy efficiency in industry, operational and functional organisations addressing issues related to energy efficiency, the risk management policy implemented for the assessment and follow-up of investments in energy efficiency, and existing and envisaged financial packages to make these investments possible. As far as financing is concerned, the authors analyse present practices, difficulties faced, good and repeatable practices, and discuss some lines of thought to mobilise actors in order to structure and promote energy efficiency in industrial projects, to reduce the risk for an easier financing of such projects, to structure financing tools, to promote incentive taxes and aids

  8. Facile and efficient synthesis of [{sup 18}F]fluoromisonidazole using novel 2-nitroimidazole derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Young-Do; Lim, Seok Tae; Sohn, Myung-Hee; Kim, Hee-Kwon, E-mail: hkkim717@jbnu.ac.kr [Department of Nuclear Medicine, Chonbuk National University Medical School and Hospital, Jeonju (Korea, Republic of); Jung, Yongju [Department of Chemical Engineering, Korea University of Technology and Education, Cheonan (Korea, Republic of)

    2016-07-01

    [{sup 18}F]Fluoromisonidazole ([{sup 18}F]FMISO) is a hypoxia imaging marker utilized in positron emission tomography. Novel FMISO precursors were prepared from a commercially available material, and several reaction factors that affect synthesis of [{sup 18}F]FMISO were examined to achieve a higher fluorination yield. [{sup 18}F]FMISO was obtained from radiosynthesis, followed by the hydrolysis of protecting groups with HCl. New 2-nitroimidazole precursor showed a higher [{sup 18}F]fluorination and a higher synthetic yield. This result provided alternative guidelines for the preparation of hypoxia imaging marker. (author)

  9. Simple, mild, and highly efficient synthesis of 2-substituted benzimidazoles and bis-benzimidazoles

    Energy Technology Data Exchange (ETDEWEB)

    Eren, Bilge, E-mail: bilge.eren@bilecik.edu.tr [Faculty of Science and Arts, Department of Chemistry, Bilecik Seyh Edebali University, (Turkey); Bekdemir, Yunus [Faculty of Science and Arts, Canik Basari University, Samsun (Turkey)

    2014-07-01

    A new convenient method for preparation of 2-substituted benzimidazoles and bis-benzimidazoles is presented. In this method, o-phenylenediamines were condensed with bisulfite adducts of various aldehydes and di-aldehydes under neat conditions by microwave heating. The results were also compared with results of synthesis by conventional heating under reflux. Structures of the products were confirmed by infrared, {sup 1}H- and {sup 13}C-NMR spectroscopy. Short reaction times, good yields, easy purification of products, and mild reaction conditions are the main advantages of this method. (author)

  10. Selective and efficient synthesis of ethanol from dimethyl ether and syngas

    DEFF Research Database (Denmark)

    Rasmussen, Dominik Bjørn

    an important role as a gasoline additive or substitute and a catalytic process has been demonstrated, in which dimethyl ether (DME) produced from synthesis gas is converted to methyl acetate (MA), which is subsequently converted to EtOH and methanol (MeOH). MeOH can afterwards be easily converted to DME, using...... well-established processes. Syngas can be produced from biomass, making the entire process sustainable and environmentally friendly. The main benefit of this method is its unprecedented selectivity towards EtOH, while MeOH, the primary by-product, and the unreacted syngas are easily recycled...

  11. An Efficient, Clean, and Catalyst-Free Synthesis of Fused Pyrimidines Using Sonochemistry

    Directory of Open Access Journals (Sweden)

    M. Mamaghani

    2014-01-01

    Full Text Available In this report, synthesis of indenopyrido[2,3-d]pyrimidine and pyrimido[4,5-b]quinoline derivatives was investigated via one-pot three-component reaction between 6-amino-2-(alkylthio-pyrimidin-4(3Hone, 1,3-indanedione, or 1,3-cyclohexadione and arylaldehyde under ultrasonic irradiation in ethylene glycol as solvent at 65°C. In these reactions fused pyrimidine derivatives were synthesized with high to excellent yields (82–97% and short reaction times (10–33 min.

  12. Substrate Encapsulation: An Efficient Strategy for the RCM-Synthesis of Unsaturated ε-Lactones

    Science.gov (United States)

    Pentzer, Emily B.; Gadzikwa, Tendai; Nguyen, SonBinh T.

    2009-01-01

    A facile substrate-encapsulated RCM-based synthesis of 7-membered lactones is reported. Coordination of the α,ω–dienyl ester precursor to the bulky Lewis acid (LA) aluminum tris(2,6-diphenylphenoxide) (ATPH) provides a protective extended steric pocket to the olefin moieties, thereby favoring intramolecular RCM over intermolecular ADMET oligomerization. The LA-encapsulated esters undergo ring-closure in the presence of Ru-based olefin metathesis catalysts to give previously difficult-to-access 7-membered β,γ– and γ,δ–unsaturated lactones in good yields. PMID:19053741

  13. Substrate encapsulation: an efficient strategy for the RCM synthesis of unsaturated epsilon-lactones.

    Science.gov (United States)

    Pentzer, Emily B; Gadzikwa, Tendai; Nguyen, SonBinh T

    2008-12-18

    A facile substrate-encapsulated RCM-based synthesis of 7-membered lactones is reported. Coordination of the alpha,omega-dienyl ester precursor to the bulky Lewis acid (LA) aluminum tris(2,6-diphenylphenoxide) (ATPH) provides a protective extended steric pocket to the olefin moieties, thereby favoring intramolecular RCM over intermolecular ADMET oligomerization. The LA-encapsulated esters undergo ring-closure in the presence of Ru-based olefin metathesis catalysts to give previously difficult-to-access 7-membered beta,gamma- and gamma,delta-unsaturated lactones in good yields.

  14. KF/Clinoptilolite: an efficient promoter for the synthesis of thioethers.

    Science.gov (United States)

    Salmanpour, Sadegh; Khalilzadeh, Mohammad A; Hosseini, Abolfazl

    2013-06-01

    Potassium fluoride impregnated on natural zeolite as a new solid base system effectively catalyzes the coupling of thiophenols with electron-deficient fluoro-, chloro- and bromo-arenes in DMSO. This versatile and efficient solid base has been demonstrated to afford the corresponding desired products in good to excellent yields. This procedure provides a convenient, efficient and practical method for the preparation of diaryl thioethers.

  15. Efficient seed-mediated method for the large-scale synthesis of Au nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Waqqar; Bhatti, Arshad Saleem [COMSATS Institute of Information Technology, Department of Physics (Pakistan); Ruitenbeek, Jan M. van, E-mail: Ruitenbeek@physics.leidenuniv.nl [Leiden University, Huygens-Kamerlingh Onnes Laboratory (Netherlands)

    2017-03-15

    Seed-mediated methods are widely followed for the synthesis of Au nanorods (NRs). However, mostly dilute concentrations of the Au precursor (HAuCl{sub 4}) are used in the growth solution, which leads to a low final concentration of NRs. Attempts of increasing the concentration of NRs by simply increasing the concentration of HAuCl{sub 4}, other reagents in the growth solution and seeds lead to a faster growth kinetics which is not favourable for NR growth. Herein, we demonstrate that the increase in growth kinetics for high concentrations of reagents in growth solution can be neutralised by decreasing the pH of the solution. The synthesis of the NRs can be scaled up by using higher concentrations of reagents and adding an optimum concentration of HCl in the growth solution. The concentration of HAuCl{sub 4} in the growth solution can be increased up to 5 mM, and 10–20 times more NRs can be synthesised for the same reaction volume compared to that of the conventional seed-mediated method. We have also noticed that a cetyltrimethylammonium bromide (CTAB)-to-HAuCl{sub 4} molar ratio of 50 is sufficient for obtaining high yield of NRs.

  16. Efficient scrambling-free synthesis of heteroleptic terbium triple-decker (porphyrinato)(crown-phthalocyaninates).

    Science.gov (United States)

    Birin, Kirill P; Gorbunova, Yulia G; Tsivadze, Aslan Yu

    2012-08-28

    New heteroleptic triple-decker terbium complexes of general structure [Br(4)TPP]Tb[(15C5)(4)Pc]Tb[Br(4)TPP] (Tb-TD) and [Br(4)TPP]Tb[(15C5)(4)Pc]Tb[(15C5)(4)Pc] (Tb-TD*) (Br(4)TPP = tetrakis-meso-(4-bromophenyl)-porphyrin, (15C5)(4)Pc = tetra-(15-crown-5)-phthalocyanine) are synthesized with 48% and 57% yields, respectively. The triple-decker complexes were prepared by interaction of generated in situ terbium monoporphyrinate [Br(4)TPP]Tb(acac) and corresponding double-decker precursors. The heteroleptic double-decker precursor [Br(4)TPP]Tb[(15C5)(4)Pc] was prepared for the first time in a two step one-pot synthesis. No ligand scrambling was observed in the synthesis of Tb-TD, while 4% scrambling was determined in the case of Tb-TD*. High yields of target triple-decker complexes were achieved despite the presence of electron-donating crown-ether fragments with low thermal stability at the phthalocyanine deck. Analysis of lanthanide-induced paramagnetic shifts of protons of Tb-TD together with data of previously reported La, Pr, Nd and Eu analogues allowed precise separation of contributions of contact and dipolar lanthanide terms as well as verification of isostructurality of complexes within the series.

  17. Spray-combustion synthesis: efficient solution route to high-performance oxide transistors.

    Science.gov (United States)

    Yu, Xinge; Smith, Jeremy; Zhou, Nanjia; Zeng, Li; Guo, Peijun; Xia, Yu; Alvarez, Ana; Aghion, Stefano; Lin, Hui; Yu, Junsheng; Chang, Robert P H; Bedzyk, Michael J; Ferragut, Rafael; Marks, Tobin J; Facchetti, Antonio

    2015-03-17

    Metal-oxide (MO) semiconductors have emerged as enabling materials for next generation thin-film electronics owing to their high carrier mobilities, even in the amorphous state, large-area uniformity, low cost, and optical transparency, which are applicable to flat-panel displays, flexible circuitry, and photovoltaic cells. Impressive progress in solution-processed MO electronics has been achieved using methodologies such as sol gel, deep-UV irradiation, preformed nanostructures, and combustion synthesis. Nevertheless, because of incomplete lattice condensation and film densification, high-quality solution-processed MO films having technologically relevant thicknesses achievable in a single step have yet to be shown. Here, we report a low-temperature, thickness-controlled coating process to create high-performance, solution-processed MO electronics: spray-combustion synthesis (SCS). We also report for the first time, to our knowledge, indium-gallium-zinc-oxide (IGZO) transistors having densification, nanoporosity, electron mobility, trap densities, bias stability, and film transport approaching those of sputtered films and compatible with conventional fabrication (FAB) operations.

  18. Sound Synthesis of the Harpsichord Using a Computationally Efficient Physical Model

    Science.gov (United States)

    Välimäki, Vesa; Penttinen, Henri; Knif, Jonte; Laurson, Mikael; Erkut, Cumhur

    2004-12-01

    A sound synthesis algorithm for the harpsichord has been developed by applying the principles of digital waveguide modeling. A modification to the loss filter of the string model is introduced that allows more flexible control of decay rates of partials than is possible with a one-pole digital filter, which is a usual choice for the loss filter. A version of the commuted waveguide synthesis approach is used, where each tone is generated with a parallel combination of the string model and a second-order resonator that are excited with a common excitation signal. The second-order resonator, previously proposed for this purpose, approximately simulates the beating effect appearing in many harpsichord tones. The characteristic key-release thump terminating harpsichord tones is reproduced by triggering a sample that has been extracted from a recording. A digital filter model for the soundboard has been designed based on recorded bridge impulse responses of the harpsichord. The output of the string models is injected in the soundboard filter that imitates the reverberant nature of the soundbox and, particularly, the ringing of the short parts of the strings behind the bridge.

  19. Sound Synthesis of the Harpsichord Using a Computationally Efficient Physical Model

    Directory of Open Access Journals (Sweden)

    Knif Jonte

    2004-01-01

    Full Text Available A sound synthesis algorithm for the harpsichord has been developed by applying the principles of digital waveguide modeling. A modification to the loss filter of the string model is introduced that allows more flexible control of decay rates of partials than is possible with a one-pole digital filter, which is a usual choice for the loss filter. A version of the commuted waveguide synthesis approach is used, where each tone is generated with a parallel combination of the string model and a second-order resonator that are excited with a common excitation signal. The second-order resonator, previously proposed for this purpose, approximately simulates the beating effect appearing in many harpsichord tones. The characteristic key-release thump terminating harpsichord tones is reproduced by triggering a sample that has been extracted from a recording. A digital filter model for the soundboard has been designed based on recorded bridge impulse responses of the harpsichord. The output of the string models is injected in the soundboard filter that imitates the reverberant nature of the soundbox and, particularly, the ringing of the short parts of the strings behind the bridge.

  20. An efficient method based on the uniformity principle for synthesis of large-scale heat exchanger networks

    International Nuclear Information System (INIS)

    Zhang, Chunwei; Cui, Guomin; Chen, Shang

    2016-01-01

    Highlights: • Two dimensionless uniformity factors are presented to heat exchange network. • The grouping of process streams reduces the computational complexity of large-scale HENS problems. • The optimal sub-network can be obtained by Powell particle swarm optimization algorithm. • The method is illustrated by a case study involving 39 process streams, with a better solution. - Abstract: The optimal design of large-scale heat exchanger networks is a difficult task due to the inherent non-linear characteristics and the combinatorial nature of heat exchangers. To solve large-scale heat exchanger network synthesis (HENS) problems, two dimensionless uniformity factors to describe the heat exchanger network (HEN) uniformity in terms of the temperature difference and the accuracy of process stream grouping are deduced. Additionally, a novel algorithm that combines deterministic and stochastic optimizations to obtain an optimal sub-network with a suitable heat load for a given group of streams is proposed, and is named the Powell particle swarm optimization (PPSO). As a result, the synthesis of large-scale heat exchanger networks is divided into two corresponding sub-parts, namely, the grouping of process streams and the optimization of sub-networks. This approach reduces the computational complexity and increases the efficiency of the proposed method. The robustness and effectiveness of the proposed method are demonstrated by solving a large-scale HENS problem involving 39 process streams, and the results obtained are better than those previously published in the literature.

  1. Synthesis route to supported gold nanoparticle layered double hydroxides as efficient catalysts in the electrooxidation of methanol.

    Science.gov (United States)

    Ballarin, Barbara; Mignani, Adriana; Scavetta, Erika; Giorgetti, Marco; Tonelli, Domenica; Boanini, Elisa; Mousty, Christine; Prevot, Vanessa

    2012-10-23

    This work describes a new one-step method for the preparation of AuNP/LDH nanocomposites via the polyol route. The novelty of this facile, simple synthesis is the absence of additional reactants such as reductive agents or stabilizer, which gives the possibility to obtain phase-pure systems free of undesiderable effect. The AuNP formation is confirmed by SEM, TEM, PXRD, and XAS; moreover, the electrochemical characterization is also reported. The electrocatalytic behavior of AuNP/LDH nanocomposites has been investigated with respect to the oxidation of methanol in basic media and compared with that of pristine NiAl-Ac. The 4-fold highest catalytic efficiency observed with AuNP/LDH nanocomposites suggests the presence of a synergic effect between Ni and AuNP sites. The combination of these experimental findings with the low-cost synthesis procedure paves the way for the exploitation of the presented nanocomposites materials as catalysts for methanol fuel cells.

  2. Synthesis of NiO:V2O5 nanocomposite and its photocatalytic efficiency for methyl orange degradation

    Directory of Open Access Journals (Sweden)

    Salam A. Mohammed

    2018-03-01

    Full Text Available Vanadium oxide has been largely exploited as a catalyst in many industrial applications. In this article, we show the synthesis of vanadium oxide (V2O5: Nickel Oxide (NiO composite using sol-gel method at optimum conditions. The composite nanomaterials were used to remove methyl orange from waste water via harnessing the photocatalytic activity of it which showed an excellent efficiency of removal at 88%, and 93% after the exposure to the light, and light with heating respectively. This will pave the way into further implementation of these nanomaterials in the removal of some other dyes and contaminants from wastewater. Keywords: Materials chemistry, Physical chemistry, Chemical engineering, Inorganic chemistry

  3. An efficient synthesis of linear β-(1→6)-galactan oligosaccharides related to plant cell wall glycans

    DEFF Research Database (Denmark)

    Andersen, Mathias Christian Franch; Arentoft, Camilla Anna Søholt; Boos, Irene

    2017-01-01

    Galactans are linear structures mainly found in arabinogalactan glycans and RG-I side chains. As a follow-up to our work on both β-(1→3)-linked and β-(1→4)-linked galactans, we herein report a convergent synthesis of β-(1→6)-galactan using our previously synthesized 4,6-benzylidene protected...... disaccharide as a key building block. However, the regioselective reductive opening of the 4,6-benzylidene protected disaccharide turned out to become more challenging as the length of the oligosaccharide increased and a second differential protected disaccharide building block carrying a chloroacetyl group...... on the 6-position was used to elongate the chain in a more efficient way....

  4. Synthesis of Various Ferrite (MFe₂O₄) Nanoparticles and Their Application as Efficient and Magnetically Separable Catalyst for Biginelli Reaction.

    Science.gov (United States)

    Chandel, Madhurya; Ghosh, Barun Kumar; Moitra, Debabrata; Patra, Manoj Kumar; Vadera, Sampat Raj; Ghosh, Narendra Nath

    2018-04-01

    Herein, we reports the application of various spinel ferrite nanoparticles, MFe2O4 (M = Co, Ni, Cu, Zn), as efficient catalyst for Biginelli reaction. All ferrite nanoparticles were synthesized using a novel aqueous solution based method. It was observed that, the catalytic activity of the ferrite nanoparticles followed the decreasing order of CoFe2O4 > CuFe2O4 > NiFe2O4 > ZnFe2O4. The most important feature of these ferrite nanocatalysts is that, these nanoparticles can directly be used as catalyst and no surface modification or functionalization is required. These ferrite nanoparticles are easily separable from reaction mixture after reaction by using a magnet externally. Easy synthesis methodology, high catalytic activity, easy magnetic separation and good reusability make these ferrite nanoparticles attractive catalysts for Biginelli reaction.

  5. Emeraldine Base Form of Polyaniline Nanofibers as New, Economical, Green, and Efficient Catalyst for Synthesis of Z-Aldoximes

    Directory of Open Access Journals (Sweden)

    Rajender Boddula

    2014-01-01

    Full Text Available A facile, clean, economical, efficient, and green process was developed for the preparation of Z-aldoximes at room temperature under solvent-free condition using emeraldine base form of polyaniline as novel catalyst. In this methodology, PANI base absorbed the by-product of HCl (polluting chemical from hydroxylamine hydrochloride and converted to polyaniline-hydrochloride salt (PANI-HCl salt. This PANI-HCl salt could be easily recovered and used in new attempts without any purification in many areas such as catalyst, electrical and electronics applications meant for conducting polymers. As far as our knowledge is concerned, emeraldine base as catalyst in organic synthesis for the first time.

  6. Synthesis of dye-sensitized solar cells. Efficiency cells as a thickness of titanium dioxide

    Directory of Open Access Journals (Sweden)

    Szura Dominika

    2017-01-01

    Full Text Available Defying the influence of the thickness of TiO2 efficiency of dye-sensitized solar cell. It was confirmed that the compatibility of printed layers with the parameters closely related with the DSSC. It was found that the increase in thickness of the titanium dioxide layer, increases the distance between the electrodes, determined by the thickness of the Surlyn foil. With the rise of thickness of dyed layer of TiO2 established decrease in the value of its transmittance. Greatest transparency and aesthetic value obtained for photovoltaic modules with a single layer of titanium dioxide. The improved performance efficiency and preferred yields maximum power were noticed and exhibited by the cells covered with three layers of TiO2. It was established that the behaviour of economic efficiency in the production process, provides a range of cells with two layers of oxide, showing a similar performance and greater transparency.

  7. A straightforward and efficient synthesis of 3-(pyrimidinyl)propanoates from levulinic acid

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Alex F.C.; Malavolta, Juliana L.; Souto, Alynne A.; Goularte, Rayane B.; Flores, Darlene C., E-mail: alex.fcf@ufsm.br [Universidade Federal de Santa Maria (UFSM/NUQUIMHE), RS (Brazil). Departamento de Quimica. Nucleo de Quimica de Heterociclos

    2013-04-15

    The cyclocondensation of methyl 7,7,7-trifluoro-4-methoxy-6-oxo-4-heptenoate and methyl 7,7,7-trichloro-4-methoxy-6-oxo-4-heptenoate, derived from levulinic acid with amidines [NH{sub 2}CONH{sub 2}, NH{sub 2}CR(NH) (R = H, Me, Ph, NH{sub 2}, SMe and 1H-pyrazol-1-yl), 5-amino-3-methyl-1H-pyrazol and 2-aminothiazole] into pyrimidine and pyrimidine-like derivatives as a new type of glutamate-like 3-(trihalomethylatedpyrimidinyl)propanoate is reported. Preparation of 3-(trihalomethylatedpyrimidinyl) propanohydrazides is also described. The synthetic potential of this straightforward protocol was established by the synthesis of fourteen new 3-(pyrimidinyl) propanoates in regular to good yields (38-92%). The structural assignments were based on the analysis of their {sup 1}H and {sup 13}C nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS) data. (author)

  8. Synthesis of PtRu/Ru heterostructure for efficient methanol electrooxidation: The role of extra Ru

    Science.gov (United States)

    Bai, Lei

    2018-03-01

    Platinum-ruthenium (PtRu) nanocubes and PtRu/Ru heterostructure via epitaxial growth were synthesized by varying the amount of Ru precursor. As model catalysts, the PtRu/Ru heterostructure demonstrated the highest catalytic performance in electrooxidation of methanol, which was possibly due to the more hydroxyl species produced from the extra Ru nanoparticles as well as enhanced adsorption of methanol of PtRu alloys in the PtRu/Ru heterostructure. The catalytic performance of the catalysts was closely related with the structure, which was well characterized by a series of methods. It was expected that the present work could provide a new insight for the synthesis of PtRu based nanocatalysts.

  9. Synthesis of taurine–fluorescein conjugate and evaluation of its retina-targeted efficiency in vitro

    Directory of Open Access Journals (Sweden)

    Meihong Huang

    2014-12-01

    Full Text Available In this work, retinal penetration of fluorescein was achieved in vitro by covalent attachment of taurine to fluorescein, yielding the F–Tau conjugate. Nuclear magnetic resonance (NMR and high resolution mass spectrometry (HRMS were used to confirm the successful synthesis of F–Tau. The cellular uptake of F–Tau in adult retinal pigment epithelial cells (ARPE-19 and human retinal microvascular endothelial cells (hRMECs was visualized via confocal scanning microscopy. The results indicated an improvement of solubility and a reduction of logP of F–Tau compared with fluorescein. As compared with fluorescein, F–Tau showed little toxicity, and was retained longer by cells in uptake experiments. F–Tau also displayed higher transepithelial permeabilities than fluorescein in ARPE-19 and hRMECs monolayer cells (P<0.05. These results showed that taurine may be a useful ligand for targeting small-molecule hydrophobic pharmaceuticals into the retina.

  10. Efficient Synthesis of a Conformationally Rigid Polymer Based on myo-Inositol Carbonate

    International Nuclear Information System (INIS)

    Lee, Hye Jin; Kim, Tae Hyun

    2006-01-01

    We have successfully synthesized the polystyrene carrying a conformationally rigid myo-inositol substituent as a possible metal-chelating ligand. We are further investigating the metal binding properties of this polymer and its applicability to the practical use such as molecular imprinting. Compounds having three syn-axial hydroxyl groups on a six membered ring draw an interest due to their ability to form complexes with many cations. The steric requirements of the cyclohexane polyols to form complexes with cations are, however, rather strict and only a few such compounds with three syn-axial hydroxyls, including cis-inositol, were known. Moreover, none of these compounds is readily available, especially in large scales. Recently, synthesis of the readily available myo-inositol 4,6-carbonate with three hydroxyl groups at the axial position on a cyclohexane was reported. To our knowledge, this was the first example of the conformationally rigid cyclohexane polyols using the readily available myo-inositol

  11. Climate and energy efficiency policies: synthesis of France commitments and results

    International Nuclear Information System (INIS)

    2011-01-01

    After a brief recall of the definitions of energy efficiency, of direct and indirect emissions, of total emissions, and of the main French commitments (first climate plan, energy policy orientations in the POPE law, Grenelle de l'Environnement, national action plan for energy efficiency, Grenelle laws), this document briefly presents the current situation and predictions in terms of energy consumption and greenhouse gas emissions. For different sectors, it presents key measures and evokes actual or expected results. These sectors are: energy production, housing and office building, transports, industry, State and local communities, agriculture and forest, information and education, wastes

  12. Simple and efficient Knoevenagel synthesis of ()-2-((1H-indol-3-yl ...

    Indian Academy of Sciences (India)

    Triphenylphosphine (TPP) is found to be an efficient catalyst for the Knoevenagel condensation of indole-3-carboxyaldehydes 1(a-e) and their -substituted derivatives 4(a-e) with the active methylene compound, i.e., 3-cyanoacetylindole (2), affording novel substituted olefins 3(a-e) and 5(a-e) respectively. The latter ...

  13. An efficient catalyst-free synthesis of novel chromeno [4, 3-b ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 129; Issue 8. An efficient catalyst-free ... Keywords. Ethylene glycol; 4-hydroxycoumarin; multicomponent reaction; green chemistry ... Catalyst-free conditions along with green solvent system make the process eco-friendly as well aseconomical. High yields of the ...

  14. Strategies and instruments to promote energy efficiency in developing countries. Synthesis report

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, J.C.; Diepstraten, F.M.J.A.; Kant, A. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands). Unit ECN Policy Studies; De Araujo, L. [Instituta de Economia Industrial. Universidade Federal Rural do Rio de Janeiro, RJ (Brazil); Barathan, S. [Tata Energy Research Inst., Bombay (India); Diallo, S. [ENDA Programme Energie, Dakar (Senegal)

    1995-10-01

    Chapter 2 provides a conceptual framework for the study, starting with a discussion of essential concepts such as primary energy, end-use energy, and energy efficiency. Next, some main issues are addressed related to the measurement of energy intensity for homogeneous end-use applications. Finally, some methods to analyse changes in energy demand and energy intensity at high aggregation level are outlined. Chapter 3 puts industrial energy use in the developing world in a global perspective. Also the significance of industrial energy use in developing countries to global CO{sub 2} emissions is outlined. A more detailed account of the energy efficiency situation in the developing world for four specific industrial sub-sectors (cement, iron and steel, aluminium, and pulp and paper). For each of these sub-sectors, possibilities as well as the scope for improvement of energy efficiency in the developing world, are presented, based on `best practice` plant performance in OECD countries. Chapter 5 provides an overview of policy measures taken and instruments applied globally to bring down levels of industrial energy intensity. After reviewing general policy approaches pursued in the developing world, these are put in perspective of policy interventions in OECD countries. Furthermore, consideration is given to major implementation issues in developing countries. Chapter 6, 7 and 8 present a broad assessment of a great number of specific policy initiatives on industrial energy efficiency improvement in Africa, Asia, and Latin America. Moreover, an analysis is made of inherent barriers and stimulating factors to the improvement of energy efficiency levels. An attempt is made to answer the question as to how these factors can be positively affected by policy interventions and the most effective policy instruments are assessed. The report concludes with observations and recommendations on promising possibilities for cooperation between North and South. (Abstract Truncated)

  15. Synthesis of ZnO/CdSe hierarchical heterostructure with improved visible photocatalytic efficiency

    International Nuclear Information System (INIS)

    Wu, Yao; Xu, Fang; Guo, Defu; Gao, Zhiyong; Wu, Dapeng; Jiang, Kai

    2013-01-01

    ZnO/CdSe hierarchical heterostructure was prepared using pompon-like ZnO as substrate materials, and hexagonal CdSe nanoparticles were dispersed on the ZnO plates. The hybrid ZnO/CdSe samples were intensively investigated by XRD, SEM, TEM, HRTEM, PL and UV–vis absorption spectrum. The photocatalytic experiments confirm that ZnO/CdSe heterostructure exhibits improved photocatalytic efficiency compared to pure ZnO under visible light irradiation. CdSe nanoparticles are believed to serve as photosensitizers to extend the absorption spectrum to visible light region. In addition, the incorporation of CdSe can suppress the recombination of photogenerated electron-hole pairs, which contributes to the enhancement of photocatalytic efficiency.

  16. Synthesis and Characterization of Zinc Oxide Nano fibers for High Efficiency Optoelectronic Applications

    International Nuclear Information System (INIS)

    Mohd Zainizan Sahdan; Mohd Firdaus Malek; Mohamad Rusop

    2011-01-01

    Recently wide band gap materials have been researched extensively for high efficiency optoelectronic applications such as light emitting devices, laser diodes and solar cells [1]. Zinc Oxide (ZnO) is the most promising candidate for its band gap energy approaching 3.37 eV and excitonic binding energy as high as 60 meV . It is also very sensitive at UV wavelength and potentially used for UV sensing applications. In high efficiency optoelectronic devices, two main factors need to be considered are the surface-to-volume ratio and carrier transit time. In thin films fabrication, annealing would improve the structural and crystal properties. We have reported the effects of annealing time on the ZnO nano structures [2]. Therefore, we move forward by varying the annealing time to study the effects on the structural and optical properties of ZnO nano fibers. (author)

  17. An efficient method for synthesis of bis(indolylmethane and di-bis(indolylmethane derivatives in environmentally benign conditions using TBAHS

    Directory of Open Access Journals (Sweden)

    Seyed Hossein Siyadatifard

    2016-05-01

    Full Text Available An efficient procedure for the synthesis of bisindolylmethanes (BIMs from condensation of indole and aromatic aldehydes or ketones is described. The aromatic electrophilic substitution reactions of indole with aromatic aldehydes and ketones are achieved in the presence of tetrabutylammonium hydrogen sulfate (TBAHS as a mild and efficient solid acid catalyst. This methodology offers several advantages such as good yields, simple procedure, mild and environmentally benign conditions.

  18. Synthesis and characterization of core-shell metal oxide nanoparticles for efficient electrochemical water splitting

    OpenAIRE

    Nong, Hong Nhan

    2016-01-01

    Electrocatalytic water splitting is expected to emerge as a key technology for the storage of excess electricity from renewable sources in form of hydrogen or for production of sustainable hydrogen fuel as part of a solar refinery. In particular, polymer electrolyte membrane (PEM) electrolyzers, owing to their high voltage efficiency, high current density, good partial loading range, compact system design, high gas purity and rapid system response, will likely play a critically important role...

  19. Solvothermal Synthesis of Well-Disperse ZnS Nanorods with Efficient Photocatalytic Properties

    OpenAIRE

    Chen, Yun; Yin, Rong-hui; Wu, Qing-sheng

    2012-01-01

    Well-disperse short-range-ordered ZnS nanorods with efficient photocatalytic property for photodegradation of Rhodamin B have been successfully synthesized through a solvothermal method. Solvent used can be recovered and reused, which makes the route environment-friendly. Dodecylamine was found effective in organizing nanorods to ordered monolayer. Characterization showed that these nanorods were uniform with the diameter of about 3 nm and length of nearly 30 nm. And it is expected that these...

  20. Rapid and Efficient Synthesis of Silver Nanofluid Using Electrical Discharge Machining

    OpenAIRE

    Kuo-Hsiung Tseng; Heng-Lin Lee; Chih-Yu Liao; Kuan-Chih Chen; Hong-Shiou Lin

    2013-01-01

    The electrical discharge machining (EDM) system has been proven feasible as a rapid and efficient method for silver nanofluid preparation. This study prepared the silver nano-fluid via EDM and investigated the relationship between its process parameters and product characteristics. The prior study had found that the silver nano-fluid prepared by EDM contained both silver nanoparticles and silver ions. Silver ions had revealed the cause of the high suspension of the silver nanoparticles. To ex...

  1. Nano-Ticl 4 .SiO 2 : a Versatile and Efficient Catalyst for Synthesis of ...

    African Journals Online (AJOL)

    Nano-TiCl4.SiO2 has been found to be an extremely efficient catalyst for the preparation of 3,4-dihydropyrimidinones/thiones via three-component reactions of an aldehyde, β-ketoester or β-diketone and urea or thiourea under mild conditions. Nano-TiCl4.SiO2 as a solid Lewis acid has been synthesized by reaction of ...

  2. Microwave: An Important and Efficient Tool for the Synthesis of Biological Potent Organic Compounds.

    Science.gov (United States)

    Kumari, Kamlesh; Vishvakarma, Vijay K; Singh, Prashant; Patel, Rajan; Chandra, Ramesh

    2017-01-01

    Green Chemistry is an interdisciplinary science or it can also be explained as a branch of chemistry. It is generally described as the chemistry to aim to synthesize chemical compounds to trim down the utilization of harmful chemicals proposed by the Environmental Protection Agency (EPA). Recently, the plan of academicians, researchers, industrialists is to generate greener and more efficient methodologies to carry out various organic syntheses. In the present scenario, green chemistry utilizes the raw materials economically, minimizes the waste and prevents the uses of harmful or hazardous chemicals to make the organic reactions simple and efficient. Microwave technique is a new, simple and efficient technology which opens new prospects to the chemists to carry out various organic and inorganic reactions, which are difficult via conventional methodology. It is used to decrease the duration of time to carry various organic transformation along with maximum yield, minimum by-products, minimum energy utilization, less manpower etc. e.g. various famous organic reactions have been carried out by various research groups like Aldol condensation, Knoevenagel condensation, Beckmann rearrangement, Vilsmeier reaction, Perkin reaction, Benzil-Benzilic acid rearrangement, Fischer cyclization, Mannich reaction, Claisen-Schmidt condensation, etc. Further, reduction, oxidation, coupling, condensation reaction were also performed using microwave technology. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Exploiting the Temporal Logic Hierarchy and the Non-Confluence Property for Efficient LTL Synthesis

    Directory of Open Access Journals (Sweden)

    Andreas Morgenstern

    2010-06-01

    Full Text Available The classic approaches to synthesize a reactive system from a linear temporal logic (LTL specification first translate the given LTL formula to an equivalent omega-automaton and then compute a winning strategy for the corresponding omega-regular game. To this end, the obtained omega-automata have to be (pseudo-determinized where typically a variant of Safra's determinization procedure is used. In this paper, we show that this determinization step can be significantly improved for tool implementations by replacing Safra's determinization by simpler determinization procedures. In particular, we exploit (1 the temporal logic hierarchy that corresponds to the well-known automata hierarchy consisting of safety, liveness, Buechi, and co-Buechi automata as well as their boolean closures, (2 the non-confluence property of omega-automata that result from certain translations of LTL formulas, and (3 symbolic implementations of determinization procedures for the Rabin-Scott and the Miyano-Hayashi breakpoint construction. In particular, we present convincing experimental results that demonstrate the practical applicability of our new synthesis procedure.

  4. An Efficient and Versatile Synthesis of Isoflavones from 2-Methoxybenzoic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae In [Duksung Women' s University, Seoul (Korea, Republic of)

    2016-07-15

    Isoflavones (3-aryl-4H-1-benzopyran-4-ones) are found naturally in soybeans and many plants of the Leguminosae family. They have attracted much attention due to their biological activities, such as their anti-cancer, anti-inflammatory, and antifungal properties. Isoflavones intake through foods is important to human health, because they potentially regulate fatty acid metabolism and methoxy-substituted isoflavones in particular increase cell permeability. Isoflavones have also been synthesized by the coupling of 3-iodochromones with arylboronic acids. The condensation of 2'-hydroxyacetophenones with DMF dimethyl acetal formed 3-(dimethylamino)-2'-hydroxyphenylpropenones, which were cyclized using iodine to form 3-iodochromones. This process was followed by Suzuki coupling with arylboronic acids or aryl boronates to obtain isoflavones. The synthesis of isoflavones (6) from 5 was based on the formylation of the methylene group of 5 using DMF-POCl{sub 3}. Previously, the reaction of the DMF-POCl{sub 3} complex on benzyl 2-hydroxyphenyl ketones led to isoflavones, for which DMF was used as the reagent and solvent for 18 h at gentle reflux.

  5. Efficient catalysis by MgCl2 in hydrogen generation via hydrolysis of Mg-based hydride prepared by hydriding combustion synthesis.

    Science.gov (United States)

    Zhao, Zelun; Zhu, Yunfeng; Li, Liquan

    2012-06-04

    Magnesium chloride efficiently catalyzed the hydrolysis of Mg-based hydride prepared by hydriding combustion synthesis. Hydrogen yield of 1635 mL g(-1) was obtained (MgH(2)), i.e. with 96% conversion in 30 min at 303 K.

  6. An Efficient Synthesis of Substituted Furans by Cupric Halide-Mediated Intramolecular Halocyclization of 2-(1-Alkynyl)-2-alken-1-ones

    International Nuclear Information System (INIS)

    Fu, Weijun; Guo, Wenbo; Zhu, Mei; Xu, Chen; Xu, Fengjuan

    2013-01-01

    An efficient synthesis of 3-halofurans by the intramolecular cyclization of 2-(1-alkynyl)-2-alken-1-ones with cupric halide has been developed. A broad range of 3-chloro- and 3-bromofuran derivatives could be obtained in the present method in moderate to good yields. The 3-halofuran derivatives are potential synthetic intermediates for amplification of molecular complexity

  7. Instantaneous one-pot synthesis of Fe-N-modified graphene as an efficient electrocatalyst for the oxygen reduction reaction in acidic solutions.

    Science.gov (United States)

    Kamiya, Kazuhide; Hashimoto, Kazuhito; Nakanishi, Shuji

    2012-10-21

    We successfully developed a one-pot synthesis method of graphenes modified with iron and nitrogen. The modified graphenes functioned as an efficient electrocatalyst for the oxygen reduction reaction in acidic solutions with an onset-potential of 850 mV vs. RHE in acidic solutions.

  8. Zr(HSO44: An Efficient Catalyst for the Synthesis of 3-(2'- Benzothiazolyl-2,3-dihydroquinazolin- 4(1H-ones

    Directory of Open Access Journals (Sweden)

    Liqiang Wu

    2012-01-01

    Full Text Available A simple and efficient synthesis of 3-(2'-benzothiazolyl-2,3-dihydro quinazolin-4(1H- ones has been accomplished by the one-pot condensation of isatoic anhydride, aldehyde and 2-aminobenzothiazole under solvent-free conditions in the presence of Zr(HSO44.

  9. Efficient Lewis Acid Ionic Liquid-Catalyzed Synthesis of the Key Intermediate of Coenzyme Q10 under Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    Thomas Efferth

    2010-12-01

    Full Text Available An efficient synthesis of a valuable intermediate of coenzyme Q10 by microwave-assisted Lewis acidic ionic liquid (IL-catalyzed Friedel-Crafts alkylation is reported. The acidity of six [Etpy]BF4-based ionic liquids was characterized by means of the FT-IR technique using acetonitrile as a molecular probe. The catalytic activities of these ionic liquids were correlated with their Lewis acidity. With increasing Lewis acid strength of the ionic liquids, their catalytic activity in the Friedel-Crafts reaction increased, except for [Etpy]BF4-AlCl3. The effects of the reaction system, the molar fraction of Lewis acid in the Lewis acid ILs and heating techniques were also investigated. Among the six Lewis acid ionic liquids tested [Etpy]BF4-ZnCl2 showed the best catalytic activity, with a yield of 89% after a very short reaction time (150 seconds. This procedure has the advantages of higher efficiency, better reusability of ILs, energy conservation and eco-friendliness. The method has practical value for preparation of CoQ10 on an industrial scale.

  10. A High Performance Platform Based on cDNA Display for Efficient Synthesis of Protein Fusions and Accelerated Directed Evolution.

    Science.gov (United States)

    Naimuddin, Mohammed; Kubo, Tai

    2016-02-08

    We describe a high performance platform based on cDNA display technology by developing a new modified puromycin linker-oligonucleotide. The linker consists of four major characteristics: a "ligation site" for hybridization and ligation of mRNA by T4 RNA ligase, a "puromycin arm" for covalent linkage of the protein, a "polyadenosine site" for a longer puromycin arm and purification of protein fusions (optional) using oligo-dT matrices, and a "reverse transcription site" for the formation of stable cDNA protein fusions whose cDNA is covalently linked to its encoded protein. The linker was synthesized by a novel branching strategy and provided >8-fold higher yield than previous linkers. This linker enables rapid and highly efficient ligation of mRNA (>90%) and synthesis of protein fusions (∼ 50-95%) in various cell-free expression systems. Overall, this new cDNA display method provides 10-200 fold higher end-usage fusions than previous methods and benefits higher diversity libraries crucial for directed protein/peptide evolution. With the increased efficiency, this system was able to reduce the time for one selection cycle to cDNA display method. A three-finger protein library was evolved to isolate superior nanomolar range binding candidates for vascular endothelial growth factor. This method is expected to provide a beneficial impact to accelerated drug discovery and proteome analysis.

  11. Shape-Controlled Synthesis of High-Quality Cu7 S4 Nanocrystals for Efficient Light-Induced Water Evaporation.

    Science.gov (United States)

    Zhang, Changbo; Yan, Cong; Xue, Zhenjie; Yu, Wei; Xie, Yinde; Wang, Tie

    2016-10-01

    Copper sulfides (Cu 2-x S), are a novel kind of photothermal material exhibiting significant photothermal conversion efficiency, making them very attractive in various energy conversion related devices. Preparing high quality uniform Cu 2-x S nanocrystals (NCs) is a top priority for further energy-and sustainability relevant nanodevices. Here, a shape-controlled high quality Cu 7 S 4 NCs synthesis strategy is reported using sulfur in 1-octadecene as precursor by varying the heating temperature, as well as its forming mechanism. The performance of the Cu 7 S 4 NCs is further explored for light-driven water evaporation without the need of heating the bulk liquid to the boiling point, and the results suggest that as-synthesized highly monodisperse NCs perform higher evaporation rate than polydisperse NCs under the identical morphology. Furthermore, disk-like NCs exhibit higher water evaporation rate than spherical NCs. The water evaporation rate can be further enhanced by assembling the organic phase Cu 7 S 4 NCs into a dense film on the aqueous solution surface. The maximum photothermal conversion efficiency is as high as 77.1%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Efficient synthesis of graphene oxide and the mechanisms of oxidation and exfoliation

    Science.gov (United States)

    Yuan, Rui; Yuan, Jing; Wu, Yanping; Chen, Lei; Zhou, Huidi; Chen, Jianmin

    2017-09-01

    An efficient method for the preparation of graphene oxide (GO) was descried through inducing the ultrasonic in the rate-determining step of oxidation processes. Both the transformation procedures and the detailed molecular behavior of parent graphene (PG), partially oxidized graphene (PGO) and GO in H2SO4 and aqueous solution were investigated by molecular dynamic simulation (MD) combining with experiments. The results obtained from MD simulation show that the addition of KMnO4 truly marked the beginning of the reaction which carried out from the border of PG flakes to the centre. This oxidation procedure was the rate-determining step and mainly contained three steps: the boundary carbon atoms oxidized, the distance of the corresponding interlayer enlarged and the oxidizing agent diffused into the unoxidized region, the processes was repeated until oxidized completely. So, the introducing ultrasonic in this section can accelerate not only the exfoliation of layers but also the diffusion of oxidizer and finally raises the oxidation efficiency dramatically. To further clarify these simulation results, the GO was prepared by the method mentioned above. The analyses results for the X-ray diffraction (XRD), Raman spectra and X-ray photoelectron spectroscopy (XPS) of the resulting GO show that the ultrasonic method could perfectly shortens the oxidation time from 12 h to 3 h and forms the higher degree of oxidation products with more carboxylic acid groups on its edges. Thus, this study provides a better understanding of the transformation procedures of graphite and proposes an efficient way to produce GOs suitable for various chemical modifications.

  13. Plasma-Assisted Synthesis of NiCoP for Efficient Overall Water Splitting

    KAUST Repository

    Liang, Hanfeng

    2016-11-09

    Efficient water splitting requires highly active, earth-abundant, and robust catalysts. Monometallic phosphides such as NiP have been shown to be active toward water splitting. Our theoretical analysis has suggested that their performance can be further enhanced by substitution with extrinsic metals, though very little work has been conducted in this area. Here we present for the first time a novel PH plasma-assisted approach to convert NiCo hydroxides into ternary NiCoP. The obtained NiCoP nanostructure supported on Ni foam shows superior catalytic activity toward the hydrogen evolution reaction (HER) with a low overpotential of 32 mV at 10 mA cm in alkaline media. Moreover, it is also capable of catalyzing the oxygen evolution reaction (OER) with high efficiency though the real active sites are surface oxides in situ formed during the catalysis. Specifically, a current density of 10 mA cm is achieved at overpotential of 280 mV. These overpotentials are among the best reported values for non-noble metal catalysts. Most importantly, when used as both the cathode and anode for overall water splitting, a current density of 10 mA cm is achieved at a cell voltage as low as 1.58 V, making NiCoP among the most efficient earth-abundant catalysts for water splitting. Moreover, our new synthetic approach can serve as a versatile route to synthesize various bimetallic or even more complex phosphides for various applications.

  14. Plasma-Assisted Synthesis of NiCoP for Efficient Overall Water Splitting.

    Science.gov (United States)

    Liang, Hanfeng; Gandi, Appala N; Anjum, Dalaver H; Wang, Xianbin; Schwingenschlögl, Udo; Alshareef, Husam N

    2016-12-14

    Efficient water splitting requires highly active, earth-abundant, and robust catalysts. Monometallic phosphides such as Ni 2 P have been shown to be active toward water splitting. Our theoretical analysis has suggested that their performance can be further enhanced by substitution with extrinsic metals, though very little work has been conducted in this area. Here we present for the first time a novel PH 3 plasma-assisted approach to convert NiCo hydroxides into ternary NiCoP. The obtained NiCoP nanostructure supported on Ni foam shows superior catalytic activity toward the hydrogen evolution reaction (HER) with a low overpotential of 32 mV at -10 mA cm -2 in alkaline media. Moreover, it is also capable of catalyzing the oxygen evolution reaction (OER) with high efficiency though the real active sites are surface oxides in situ formed during the catalysis. Specifically, a current density of 10 mA cm -2 is achieved at overpotential of 280 mV. These overpotentials are among the best reported values for non-noble metal catalysts. Most importantly, when used as both the cathode and anode for overall water splitting, a current density of 10 mA cm -2 is achieved at a cell voltage as low as 1.58 V, making NiCoP among the most efficient earth-abundant catalysts for water splitting. Moreover, our new synthetic approach can serve as a versatile route to synthesize various bimetallic or even more complex phosphides for various applications.

  15. Comparison of the energy efficiency to produce agroethanol between various industries and processes: Synthesis

    International Nuclear Information System (INIS)

    Chavanne, Xavier; Frangi, Jean-Pierre

    2011-01-01

    The article assesses the energy R required by a system to transform a cereal or sugar plant into ethanol. From the specific consumption r j of each process j and its weight w j in the system, process consumption share R j is deduced and hence R, sum of R j . Depending on w j definition, R j and R are relative to either 100 J of ethanol produced or 100 J of plant harvested. Depending on the nature of r j , R j and R represent either only primary external energies, or all fuel and electricity consumed directly, or external and internal energies. From one definition to another R for average sugar cane based industries is the best or the worst relative to other plants. This results also from the use of cane residues as fuels while operating outdated processes. Through r j the process based analysis allows to examine for each system the impact of modern processes or different use of residues. All systems benefit except sugar beet based industry close to its best efficiency. This flexibility permits even to build a self-sufficient system where existing processes produce from system resources substitutes to external energies. R becomes an unambiguous definition of a system efficiency. It shows that all agroethanol systems are more consuming than petroleum industry. The system can be expanded to the vehicle stage to compare with alternatives to ethanol such as electricity and biogas. Wheat straw burnt to produce electricity used in an electrical vehicle will present R close to that of petroleum industry. -- Highlights: → Study of the energy consumptions of agroethanol industries with a process based analysis. → Different definitions of energy efficiency with potential opposite conclusions. → Previous highlight is overcome using self sufficient systems with existing processes. → Consumptions of average and improved agroethanol industries larger than for petroleum industries. → Electricity from wheat straw combustion can compete with gasoline from crude oil.

  16. Solvothermal Synthesis of Well-Disperse ZnS Nanorods with Efficient Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    Yun Chen

    2012-01-01

    Full Text Available Well-disperse short-range-ordered ZnS nanorods with efficient photocatalytic property for photodegradation of Rhodamin B have been successfully synthesized through a solvothermal method. Solvent used can be recovered and reused, which makes the route environment-friendly. Dodecylamine was found effective in organizing nanorods to ordered monolayer. Characterization showed that these nanorods were uniform with the diameter of about 3 nm and length of nearly 30 nm. And it is expected that these monodisperse ZnS nanorods have potential applications in electroluminescence materials.

  17. Efficient Synthesis of Kinsenoside and Goodyeroside A by a Chemo-Enzymatic Approach

    OpenAIRE

    Yang Zhang; Yihong Xia; Yongji Lai; Fang Tang; Zengwei Luo; Yongbo Xue; Guangmin Yao; Yonghui Zhang; Jinwen Zhang

    2014-01-01

    Kinsenoside (1) and goodyeroside A (2), two naturally occurring stereoisomers with diverse biological activities, have been synthesized efficiently by a chemo-enzymatic approach with a total yield of 12.7%. The aglycones, (R)- and (S)-3-hydroxy-γ-butyrolactone, were prepared from D- and L-malic acid by a four-step chemical approach with a yield of 75%, respectively. These butyrolactones were then successfully glycosidated using β-D-glucosidase as a catalyst in a homogeneous organic-water sys...

  18. Efficient Synthesis of Kinsenoside and Goodyeroside A by a Chemo-Enzymatic Approach

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2014-10-01

    Full Text Available Kinsenoside (1 and goodyeroside A (2, two naturally occurring stereoisomers with diverse biological activities, have been synthesized efficiently by a chemo-enzymatic approach with a total yield of 12.7%. The aglycones, (R- and (S-3-hydroxy-γ-butyrolactone, were prepared from D- and L-malic acid by a four-step chemical approach with a yield of 75%, respectively. These butyrolactones were then successfully glycosidated using β-D-glucosidase as a catalyst in a homogeneous organic-water system. Under the optimized enzymatic conditions, the yields of kinsenoside and goodyeroside A in the enzymatic steps both reached 16.8%.

  19. A concise, efficient synthesis of sugar-based benzothiazoles through chemoselective intramolecular C-S coupling

    KAUST Repository

    Shen, Chao

    2012-01-01

    Sugar-based benzothiazoles are a new class of molecules promising for many biological applications. Here, we have synthesized a wide range of sugar-based benzothiazoles from readily accessible glycosyl thioureas by chemoselective, palladium-catalyzed C-S coupling reactions. Corroborated by theoretical calculations, a mechanistic investigation indicates that the coordination to the palladium by a pivaloyl carbonyl group and the presence of intramolecular hydrogen bonding play important roles in the efficiency and chemoselectivity of reaction. These fluorescent glycoconjugates can be observed to readily enter mammalian tumor cells and exhibit potential in vitro antitumor activity. This journal is © The Royal Society of Chemistry 2012.

  20. An efficient protocol for the synthesis of highly sensitive indole imines utilizing green chemistry: optimization of reaction conditions.

    Science.gov (United States)

    Nisar, Bushra; Rubab, Syeda Laila; Raza, Abdul Rauf; Tariq, Sobia; Sultan, Ayesha; Tahir, Muhammad Nawaz

    2018-04-11

    Novel and highly sensitive indole-based imines have been synthesized. Their synthesis has been compared employing a variety of protocols. Ultimately, a convenient, economical and high yielding set of conditions employing green chemistry have been designed for their synthesis.

  1. Synthesis, characterization and corrosion inhibition efficiency of N-(4-(Morpholinomethyl Carbamoyl Phenyl Furan-2-Carboxamide

    Directory of Open Access Journals (Sweden)

    N. Zulfareen

    2016-01-01

    Full Text Available A mannich base namely N-(4-(Morpholinomethyl Carbamoyl Phenyl Furan-2-Carboxamide (MFC was synthesized and characterized by FT-IR, 1H NMR, and 13C NMR. The molecular weight of MFC was confirmed by LC-MS. The inhibition effect of MFC on brass in 1 M HCl medium has been investigated by weight loss measurement, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS and cyclic voltametry (CV. Thermodynamic parameters such as free energy, entropy and enthalpy were calculated to describe the mechanism of corrosion inhibitor. The inhibition efficiency of MFC increases with increase in concentration and temperature ranges from 30 °C to 60 °C. Polarization measurements indicated that MFC acts as a mixed type corrosion inhibitor. AC impedance indicates that Rct value increases with increase in the concentration of inhibitor. CV reveals that the oxidation of the copper is controlled by the addition of inhibitor on the brass metal. Surface analysis using scanning electron microscope (SEM shows a significant morphological improvement on the brass surface with the addition of the inhibitor. The adsorption of MFC on brass obeys Langmuir adsorption isotherm. The molecular structure of MFC was distorted to quantum chemical indices using density functional theory (DFT which indicates that the inhibition efficiency of MFC is closely related to quantum parameters.

  2. Scalable Synthesis of Efficient Water Oxidation Catalysts: Insights into the Activity of Flame-Made Manganese Oxide Nanocrystals.

    Science.gov (United States)

    Liu, Guanyu; Hall, Jeremy; Nasiri, Noushin; Gengenbach, Thomas; Spiccia, Leone; Cheah, Mun Hon; Tricoli, Antonio

    2015-12-21

    Chemical energy storage by water splitting is a promising solution for the utilization of renewable energy in numerous currently impracticable needs, such as transportation and high temperature processing. Here, the synthesis of efficient ultra-fine Mn3O4 water oxidation catalysts with tunable specific surface area is demonstrated by a scalable one-step flame-synthesis process. The water oxidation performance of these flame-made structures is compared with pure Mn2O3 and Mn5O8, obtained by post-calcination of as-prepared Mn3O4 (115 m(2)  g(-1)), and commercial iso-structural polymorphs, probing the effect of the manganese oxidation state and synthetic route. The structural properties of the manganese oxide nanoparticles were investigated by XRD, FTIR, high-resolution TEM, and XPS. It is found that these flame-made nanostructures have substantially higher activity, reaching up to 350 % higher surface-specific turnover frequency (0.07 μmolO2  m(-2)  s(-1)) than commercial nanocrystals (0.02 μmolO2  m(-2)  s(-1)), and production of up to 0.33 mmolO2  molMn (-1)  s(-1). Electrochemical characterization confirmed the high water oxidation activity of these catalysts with an initial current density of 10 mA cm(-2) achieved with overpotentials between 0.35 and 0.50 V in 1 m NaOH electrolyte. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Immobilization of the acylase from Escherichia coli on glyoxyl-agarose gives efficient catalyst for the synthesis of cephalosporins.

    Science.gov (United States)

    Estruch, Ilona; Tagliani, Auro R; Guisán, José Manuel; Fernández-Lafuente, Roberto; Alcántara, Andrés R; Toma, Lucio; Terreni, Marco

    2008-01-01

    The catalytic properties of penicillin G acylase (PGA) from Escherichia coli, when used in kinetically controlled N-acylation (kcNa) of cephalosporanic nuclei, can be strongly influenced by the moiety in 3-position of the cephem structure. In the synthesis of Cefonicid (1c), the adsorption of the cephalosporanic nucleus (7-SACA) in the PGA active site appeared sensitively increased by a positive ionic interaction between an arginine (ArgA145) in the enzyme active site and the sulphonic group of the β-lactam structure. Interestingly, when PGA was immobilized on solid supports, any effect depending on the substrate structure resulted minimized; the catalytic properties of this enzyme were affected with different outcomes depending on the type of matrix and binding chemistry. The PGA immobilized on glyoxyl-agarose (hydrophilic support activated with aldehyde groups) resulted in a good catalyst when used in kinetically controlled N-acylation of different cephalosporanic nuclei. This derivatives allow much better Vs/Vh(1) (defined as the ratio between the rate of synthesis and the rate of hydrolysis of the acylating agent) than the same enzyme immobilized on Eupergit C, an acrylic hydrophobic supports activated with epoxy groups. The synthetic performances of the Eupergit derivative versus different nuclei were always much poorer if compared with glyoxyl-agarose or the soluble protein. The use of PGA immobilized on glyoxyl-agarose allowed the development of efficient processes for the preparation of Cefazolin in high yield and purity. The results obtained in the optimization of this process are presented.

  4. Efficient utilization of waste date pits for the synthesis of green diesel and jet fuel fractions

    International Nuclear Information System (INIS)

    Al-Muhtaseb, Ala’a H.; Jamil, Farrukh; Al-Haj, Lamya; Al-Hinai, Mohab A.; Baawain, Mahad; Myint, Myo Tay Zar; Rooney, David

    2016-01-01

    Highlights: • Active catalysts Pt/C and Pd/C were developed from waste date pits. • Catalysts showed good activity in hydrodeoxygenation of date pit oil to alkane fuels. • The liquid product fractions lay within the range of the jet fuel and green diesel. • Green diesel fraction obtained by Pd/C was 72.03% and jet fuel was 30.39%. • Date pits can be a promising platform for the production of catalysts and biofuels. - Abstract: Date pits are considered one of the major agricultural wastes in Oman. The present work involves the synthesis of active catalysts from waste date pits carbon produced by carbonization and impregnation with Pt and Pd metals. Synthesized catalysts Pt/C and Pd/C were characterized by XRD, SEM, TEM, EDX, BET and XPS. The activity of the catalysts’ performance was evaluated by the hydrodeoxygenation of date pits oil for the production of second-generation biofuels, which includes jet fuel and green diesel fractions. Results indicate that the synthesized catalysts were highly active for the hydrodeoxygenation of date pits oil. Based on the elemental analysis, the degree of deoxygenation (DOD) of product oil was 97.5% and 89.4% for the Pd/C and Pt/C catalysts respectively. The high DOD was also confirmed by product analyses that mainly consist of paraffinic hydrocarbons. Results also showed that between the two catalysts, Pd/C showed a higher activity towards hydrodeoxygenation, a conclusion that was based on the high DOD of the product oil due to hydrocarbons formation. Based on the type of components in the product oil, the maximum fraction of hydrocarbons formed lay within the range of 72.03% and 72.78% green diesel, and 30.39% and 28.25% jet fuel using Pd/C and Pt/C catalysts respectively. It can be concluded that waste date pits can be a promising platform for the production of catalysts and biofuels.

  5. Rational Design and Synthesis of Efficient Sunscreens To Boost the Solar Protection Factor.

    Science.gov (United States)

    Losantos, Raúl; Funes-Ardoiz, Ignacio; Aguilera, José; Herrera-Ceballos, Enrique; García-Iriepa, Cristina; Campos, Pedro J; Sampedro, Diego

    2017-03-01

    Skin cancer incidence has been increasing in the last decades, but most of the commercial formulations used as sunscreens are designed to protect only against solar erythema. Many of the active components present in sunscreens show critical weaknesses, such as low stability and toxicity. Thus, the development of more efficient components is an urgent health necessity and an attractive industrial target. We have rationally designed core moieties with increased photoprotective capacities and a new energy dissipation mechanism. Using these scaffolds, we have synthesized a series of compounds with tunable properties suitable for their use in sunscreens, and enhanced properties in terms of stability, light energy dissipation, and toxicity. Moreover, some representative compounds were included in final sunscreen formulations and a relevant solar protection factor boost was measured. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Electrodeposited synthesis of self-supported Ni-P cathode for efficient electrocatalytic hydrogen generation

    Directory of Open Access Journals (Sweden)

    Ruixian Wu

    2016-06-01

    Full Text Available One of the key challenges for electrochemical water splitting is the development of low-cost and efficient hydrogen evolution cathode. In this work, a self-supported Ni-P cathode was synthesized by a facile electrodeposition method. The composition and morphology were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The Ni-P cathode performed low onset over-potential, good catalytic activity and long-term stability under neutral and alkaline conditions. The mechanism of Ni-P electrode for hydrogen production was discussed by electrochemical impedance spectroscopy. The excellent performance of Ni-P cathode was mainly attributed to the synergistic effect of phosphate anions and the self-supported feature.

  7. Evidence synthesis as the key to more coherent and efficient research

    Directory of Open Access Journals (Sweden)

    Cooper Nicola J

    2009-04-01

    Full Text Available Abstract Background Systematic review and meta-analysis currently underpin much of evidence-based medicine. Such methodologies bring order to previous research, but future research planning remains relatively incoherent and inefficient. Methods To outline a framework for evaluation of health interventions, aimed at increasing coherence and efficiency through i making better use of information contained within the existing evidence-base when designing future studies; and ii maximising the information available and thus potentially reducing the need for future studies. Results The framework presented insists that an up-to-date meta-analysis of existing randomised controlled trials (RCTs should always be considered before future trials are conducted. Such a meta-analysis should inform critical design issues such as sample size determination. The contexts in which the use of individual patient data meta-analysis and mixed treatment comparisons modelling may be beneficial before further RCTs are conducted are considered. Consideration should also be given to how any newly planned RCTs would contribute to the totality of evidence through its incorporation into an updated meta-analysis. We illustrate how new RCTs can have very low power to change inferences of an existing meta-analysis, particularly when between study heterogeneity is taken into consideration. Conclusion While the collation of existing evidence as the basis for clinical practice is now routine, a more coherent and efficient approach to planning future RCTs to strengthen the evidence base needs to be developed. The framework presented is a proposal for how this situation can be improved.

  8. A convenient and highly efficient synthesis of one kind of peptide nucleic acid monomer

    Directory of Open Access Journals (Sweden)

    Xuemei Tang

    2012-12-01

    Full Text Available S-Thyminyl-L-cysteine methyl ester hydrochloride (compound 1, a non-classical peptide nucleic acid monomer, was synthesized through the key intermediate, N-tert- butoxycarbonyl-S-thyminyl-L-cysteine (compound 3, which afforded from the reaction of S-thyminyl-L-cysteine hydrochloride (compound 2 with di-tert-butyl dicarbonate (Boc2O. This was followed by the esterification and deprotection of compound 3 at an overall yield of 82%. The mixture of thionyl chloride and methanol was found as an efficient reagent for simultaneous deprotection of tert-butoxycarbonyl (Boc group and esterification of carboxy group of compound 3. This high-yield two-step method was also applied to other analogues of compound 1 successfully. The chemical structures of four new compounds (5a-5d were confirmed by 1H NMR and 13C NMR.DOI: http://dx.doi.org/10.4314/bcse.v26i3.10

  9. SYNTHESIS OF MAGNETITE NANOPARTICLES AND EVALUATION OF ITS EFFICIENCY FOR ARSENIC REMOVAL FROM SIMULATED INDUSTRIAL WASTEWATER

    Directory of Open Access Journals (Sweden)

    A. Khodabakhshi

    2011-09-01

    Full Text Available In this study the efficiency of magnetic nanoparticles for removal of trivalent arsenic from synthetic industrial wastewater was evaluated. The nanoparticles was prepared by sol-gel method and characterized by X-ray methods including XRD, XRF, and SEM, and vibrating sample magnetometer (VSM. The results showed that synthesized nanoparticles were in the size range of 40-300 nm, purity of about 90%, and magnetization of nanoparticles was 36.5emu/g. In initial conditions including: pH=7, As(III concentration of 10 mg/L, nanomagnetite concentration of 1g/L, shaking speed of 250 rpm and 20 minute retention time, 82% of As (III was removed. Competition from common coexisting ions such as Na+, Ni2+, Cu2+, SO42-, and Cl- was ignorable but for NO3- was significant. The adsorption data of magnetite nanoparticles fit well with Freundlich isotherm equations. The adsorption capacity of the Fe3O4 for As (III at pH=7 was obtained as 23.8 mg/g. It was concluded that magnetite nanoparticles have considerable potential in removal of As(III from synthetic industrial wastewaters.

  10. Synthesis of Efficiently Green Luminescent CdSe/ZnS Nanocrystals Via Microfluidic Reaction

    Directory of Open Access Journals (Sweden)

    Luan Weiling

    2008-01-01

    Full Text Available AbstractQuantum dots with emission in the spectral region from 525 to 535 nm are of special interest for their application in green LEDs and white-light generation, where CdSe/ZnS core-shell structured nanocrystals (NCs are among promising candidates. In this study, triple-ligand system (trioctylphosphine oxide–oleic acid–oleylamine was designed to improve the stability of CdSe NCs during the early reaction stage. With the precisely controlled reaction temperature (285 °C and residence time (10 s by the recently introduced microfluidic reaction technology, green luminescent CdSe NCs (λ = 522 nm exhibiting narrow FWHM of PL (30 nm was reproducibly obtained. After that, CdSe/ZnS core-shell NCs were achieved with efficient luminescence in the pure green spectral region, which demonstrated high PL QY up to 70% and narrow PL FWHM as 30 nm. The strengthened mass and heat transfer in the microchannel allowed the formation of highly luminescent CdSe/ZnS NCs under low reaction temperature and short residence time (T = 120 °C,t = 10 s. The successful formation of ZnS layer was evidence of the substantial improvement of PL intensity, being further confirmed by XRD, HRTEM, and EDS study.

  11. Rapid and Efficient Synthesis of Silver Nanofluid Using Electrical Discharge Machining

    Directory of Open Access Journals (Sweden)

    Kuo-Hsiung Tseng

    2013-01-01

    Full Text Available The electrical discharge machining (EDM system has been proven feasible as a rapid and efficient method for silver nanofluid preparation. This study prepared the silver nano-fluid via EDM and investigated the relationship between its process parameters and product characteristics. The prior study had found that the silver nano-fluid prepared by EDM contained both silver nanoparticles and silver ions. Silver ions had revealed the cause of the high suspension of the silver nanoparticles. To examine the relationship between the stability of silver nanofluid and the process parameters, this study quantified the relationship of process parameters to the material removal rate (MRR of silver electrode and silver ion output rate (IOR in the fluid, in order to achieve the most effective process parameter condition. Furthermore, the stability of silver nano-fluid was analyzed by various devices, including UV-Vis spectroscopy, size-distribution, and Zeta-potential analyzer. The effects of MRR, IOR, particle size, Zeta-potential, and optical properties of silver nanofluid under different process parameters are also discussed.

  12. Synthesis of Highly Uniform and Compact Lithium Zinc Ferrite Ceramics via an Efficient Low Temperature Approach.

    Science.gov (United States)

    Xu, Fang; Liao, Yulong; Zhang, Dainan; Zhou, Tingchuan; Li, Jie; Gan, Gongwen; Zhang, Huaiwu

    2017-04-17

    LiZn ferrite ceramics with high saturation magnetization (4πM s ) and low ferromagnetic resonance line widths (ΔH) represent a very critical class of material for microwave ferrite devices. Many existing approaches emphasize promotion of the grain growth (average size is 10-50 μm) of ferrite ceramics to improve the gyromagnetic properties at relatively low sintering temperatures. This paper describes a new strategy for obtaining uniform and compact LiZn ferrite ceramics (average grains size is ∼2 μm) with enhanced magnetic performance by suppressing grain growth in great detail. The LiZn ferrites with a formula of Li 0.415 Zn 0.27 Mn 0.06 Ti 0.1 Fe 2.155 O 4 were prepared by solid reaction routes with two new sintering strategies. Interestingly, results show that uniform, compact, and pure spinel ferrite ceramics were synthesized at a low temperature (∼850 °C) without obvious grain growth. We also find that a fast second sintering treatment (FSST) can further improve their gyromagnetic properties, such as higher 4πM s and lower ΔH. The two new strategies are facile and efficient for densification of LiZn ferrite ceramics via suppressing grain growth at low temperatures. The sintering strategy reported in this study also provides a referential experience for other ceramics, such as soft magnetism ferrite ceramics or dielectric ceramics.

  13. Synthesis of carbon black/carbon nitride intercalation compound composite for efficient hydrogen production.

    Science.gov (United States)

    Wu, Zhaochun; Gao, Honglin; Yan, Shicheng; Zou, Zhigang

    2014-08-21

    The photoactivity of g-C3N4 is greatly limited by its high recombination rate of photogenerated carriers. Coupling g-C3N4 with other materials has been demonstrated to be an effective way to facilitate the separation and transport of charge carriers. Herein we report a composite of conductive carbon black and carbon nitride intercalation compound synthesized through facile one-step molten salt method. The as-prepared carbon black/carbon nitride intercalation compound composite was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), UV-vis absorption spectrum and photoluminescence spectroscopy (PL). The carbon black nanoparticles, homogeneously dispersed on the surface of carbon nitride intercalation compound, efficiently enhanced separation and transport of photogenerated carriers, thus improving the visible-light photocatalytic activity. The composite of 0.5 wt% carbon black and carbon nitride intercalation compound exhibited a H2 production rate of 68.9 μmol h(-1), which is about 3.2 times higher than hydrogen production on pristine carbon nitride intercalation compound.

  14. Hydrophobic Nanosized All-Silica Beta Zeolite: Efficient Synthesis and Adsorption Application.

    Science.gov (United States)

    Zhu, Zhiguo; Xu, Hao; Jiang, Jingang; Wu, Haihong; Wu, Peng

    2017-08-16

    All-silica beta zeolite, synthesized by conventional hydroxide route, usually possesses small crystal size of a few hundred nanometers but poor hydrophobicity, whereas the fluoride-mediated one exhibits to be highly hydrophobic but microsized. To obtain nanosized all-silica beta zeolite with excellent hydrophobicity, an innovative and efficient hydrothermal route via interzeolite transformation for synthesizing all-silica beta zeolite is proposed in present study. With the assistance of beta seeds and tetraethylammonium hydroxide as the structure-directing agent, siliceous beta zeolite is well-crystallized at a high solid yield via dissolution-recrystallization of all-silica ITQ-1 crystals at an extremely low water content (H 2 O/SiO 2 molar ratio of 1). The obtained all-silica beta crystals are composed of 30-70 nm nanoparticles and highly hydrophobic just next to siliceous beta-F zeolite synthesized by environmentally unfriendly fluoride route, which is derived from relatively small amounts of internal defect sites. Thus, this beta zeolite is superior to other pure silica beta zeolites in the adsorption of large-sized volatile organic compounds (VOCs), which is mainly attributed to its high total pore volume and specific surface area as well as excellent hydrophobicity.

  15. Y(IO₃)₃ as a novel photocatalyst: synthesis, characterization, and highly efficient photocatalytic activity.

    Science.gov (United States)

    Huang, Hongwei; He, Ying; He, Ran; Lin, Zheshuai; Zhang, Yihe; Wang, Shichao

    2014-08-04

    Nonbonding layer-structured Y(IO3)3 was successfully prepared by a simple hydrothermal route and investigated as a novel photocatalyst for the first time. Its crystal structure was characterized by X-ray diffraction, high-resolution transmission electron microscopy, and scanning electron microscopy. The optical absorption edge and band gap of Y(IO3)3 have been determined by UV-vis diffuse reflectance spectra. Theoretical calculations of the electronic structure of Y(IO3)3 confirmed its direct optical transition property near the absorption edge region, and the orbital components of the conduction band and valence band (VB) were also analyzed. The photocatalytic performance of Y(IO3)3 was evaluated by photooxidative decomposition of rhodamine B under ultraviolet light irradiation. It demonstrated that Y(IO3)3 exhibits highly efficient photocatalytic activity, which is much better than those of commercial TiO2 (P25) and important UV photocatalysts BiOCl and BiIO4. The origin of the excellent photocatalytic performance of Y(IO3)3 was investigated by electron spin resonance and terephthalic acid photoluminescence techniques. The results revealed that the highly strong photooxidation ability that resulted from its very positive VB position should be responsible for the excellent photocatalytic performance.

  16. Protein Engineering and Homologous Expression of Serratia marcescens Lipase for Efficient Synthesis of a Pharmaceutically Relevant Chiral Epoxyester.

    Science.gov (United States)

    Chen, Ke-Cai; Zheng, Ming-Min; Pan, Jiang; Li, Chun-Xiu; Xu, Jian-He

    2017-10-01

    The lipase isolated from Serratia marcescens (LipA) is a useful biocatalyst for kinetic resolution of a pharmaceutically relevant epoxyester, (±)-3-(4'-methoxyphenyl) glycidic acid methyl ester [(±)-MPGM], to afford optically pure (-)-MPGM, a key intermediate for the synthesis of diltiazem hydrochloride. Two mutants, LipA L315S and LipA S271F , were identified from the combinatorial saturation mutation library of 14 amino acid residues lining the substrate-binding pocket. LipA L315S , LipA S271F , and their combination LipA L315S/S271F showed 2.6-, 2.2-, and 4.6-fold improvements in their specific activities towards para-nitrophenyl butyrate (pNPB), respectively. Among these positive mutants, LipA S271F displayed a 3.5-fold higher specific activity towards the pharmaco substrate (±)-MPGM. Kinetic study showed that the improvement in catalytic efficiency of LipA S271F against (±)-MPGM was mainly resulted from the enhanced affinity between substrate and enzyme, as indicated by the decrease of K m . Furthermore, to address the insoluble expression issue in Escherichia coli, the homologous expression of LipA gene in S. marcescens was achieved by introducing it into an expression vector pUC18, resulting in ca. 20-fold higher lipase production. The significantly improved volumeric production and specific activity of S. marcescens lipase make it very attractive as a new-generation biocatalyst for more efficient and economical manufacturing of (-)-MPGM.

  17. Multifunctional Fe3O4/Au core/satellite nanocubes: an efficient chemical synthesis, characterization and functionalization of streptavidin protein.

    Science.gov (United States)

    Abbas, Mohamed; RamuluTorati, Sri; Kim, CheolGi

    2017-02-14

    A novel and efficient chemical approach for the synthesis of Fe 3 O 4 /Au core/satellite nanocubes is reported. In a one-pot reaction, metallic Au nanodots were successfully deposited on the polyvinylpyrrolidone (PVP) functionalized Fe 3 O 4 nanocube surface for the fabrication of a core/satellite structure (Fe 3 O 4 /Au) by the reduction of HAuCl 4 using ammonia. Transmission electron microscopy and energy dispersive spectroscopy mapping revealed that small Au nanodots of about 2 nm average size decorated the surface of Fe 3 O 4 nanocubes. X-ray diffraction data was used to confirm the formation of both the phases of a cubic inverse spinel structure for Fe 3 O 4 and a bcc structure for Au in the core/satellite structure of Fe 3 O 4 /Au nanocubes. The magnetic properties of the seed Fe 3 O 4 nanocubes and Fe 3 O 4 /Au core/satellite nanocubes were measured by using a superconducting quantum interference device at 300 K. For biological application purposes, the as-synthesized Fe 3 O 4 /Au core/satellite nanocubes were functionalized by cysteamine followed by successful immobilization of streptavidin protein as confirmed through the fluorescence confocal microscopy images.

  18. Controllable Electrochemical Synthesis of Reduced Graphene Oxide Thin-Film Constructed as Efficient Photoanode in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Soon Weng Chong

    2016-01-01

    Full Text Available A controllable electrochemical synthesis to convert reduced graphene oxide (rGO from graphite flakes was introduced and investigated in detail. Electrochemical reduction was used to prepare rGO because of its cost effectiveness, environmental friendliness, and ability to produce rGO thin films in industrial scale. This study aimed to determine the optimum applied potential for the electrochemical reduction. An applied voltage of 15 V successfully formed a uniformly coated rGO thin film, which significantly promoted effective electron transfer within dye-sensitized solar cells (DSSCs. Thus, DSSC performance improved. However, rGO thin films formed in voltages below or exceeding 15 V resulted in poor DSSC performance. This behavior was due to poor electron transfer within the rGO thin films caused by poor uniformity. These results revealed that DSSC constructed using 15 V rGO thin film exhibited high efficiency (η = 1.5211% attributed to its higher surface uniformity than other samples. The addition of natural lemon juice (pH ~ 2.3 to the electrolyte accelerated the deposition and strengthened the adhesion of rGO thin film onto fluorine-doped tin oxide (FTO glasses.

  19. Photoprompted Hot Electrons from Bulk Cross-Linked Graphene Materials and Their Efficient Catalysis for Atmospheric Ammonia Synthesis.

    Science.gov (United States)

    Lu, Yanhong; Yang, Yang; Zhang, Tengfei; Ge, Zhen; Chang, Huicong; Xiao, Peishuang; Xie, Yuanyuan; Hua, Lei; Li, Qingyun; Li, Haiyang; Ma, Bo; Guan, Naijia; Ma, Yanfeng; Chen, Yongsheng

    2016-11-22

    Ammonia synthesis is the single most important chemical process in industry and has used the successful heterogeneous Haber-Bosch catalyst for over 100 years and requires processing under both high temperature (300-500 °C) and pressure (200-300 atm); thus, it has huge energy costs accounting for about 1-3% of human's energy consumption. Therefore, there has been a long and vigorous exploration to find a milder alternative process. Here, we demonstrate that by using an iron- and graphene-based catalyst, Fe@3DGraphene, hot (ejected) electrons from this composite catalyst induced by visible light in a wide range of wavelength up to red could efficiently facilitate the activation of N 2 and generate ammonia with H 2 directly at ambient pressure using light (including simulated sun light) illumination directly. No external voltage or electrochemical or any other agent is needed. The production rate increases with increasing light frequency under the same power and with increasing power under the same frequency. The mechanism is confirmed by the detection of the intermediate N 2 H 4 and also with a measured apparent activation energy only ∼1/4 of the iron based Haber-Bosch catalyst. Combined with the morphology control using alumina as the structural promoter, the catalyst retains its activity in a 50 h test.

  20. Efficient Synthesis of Molecular Precursors for Para-Hydrogen-Induced Polarization of Ethyl Acetate-1-(13) C and Beyond.

    Science.gov (United States)

    Shchepin, Roman V; Barskiy, Danila A; Coffey, Aaron M; Manzanera Esteve, Isaac V; Chekmenev, Eduard Y

    2016-05-10

    A scalable and versatile methodology for production of vinylated carboxylic compounds with (13) C isotopic label in C1 position is described. It allowed synthesis of vinyl acetate-1-(13) C, which is a precursor for preparation of (13) C hyperpolarized ethyl acetate-1-(13) C, which provides a convenient vehicle for potential in vivo delivery of hyperpolarized acetate to probe metabolism in living organisms. Kinetics of vinyl acetate molecular hydrogenation and polarization transfer from para-hydrogen to (13) C via magnetic field cycling were investigated. Nascent proton nuclear spin polarization (%PH ) of ca. 3.3 % and carbon-13 polarization (%P13C ) of ca. 1.8 % were achieved in ethyl acetate utilizing 50 % para-hydrogen corresponding to ca. 50 % polarization transfer efficiency. The use of nearly 100% para-hydrogen and the improvements of %PH of para-hydrogen-nascent protons may enable production of (13) C hyperpolarized contrast agents with %P13C of 20-50 % in seconds using this chemistry. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Amine-Free Synthesis of Cesium Lead Halide Perovskite Quantum Dots for Efficient Light-Emitting Diodes

    KAUST Repository

    Yassitepe, Emre

    2016-10-31

    Cesium lead halide perovskite quantum dots (PQDs) have attracted significant interest for optoelectronic applications in view of their high brightness and narrow emission linewidth at visible wavelengths. A remaining challenge is the degradation of PQDs during purification from the synthesis solution. This is attributed to proton transfer between oleic acid and oleylamine surface capping agents that leads to facile ligand loss. Here, a new synthetic method is reported that enhances the colloidal stability of PQDs by capping them solely using oleic acid (OA). Quaternary alkylammonium halides are used as precursors, eliminating the need for oleylamine. This strategy enhances the colloidal stability of OA capped PQDs during purification, allowing us to remove excess organic content in thin films. Inverted red, green, and blue PQD light-emitting diodes (LED) are fabricated for the first time with solution-processed polymer-based hole transport layers due to higher robustness of OA capped PQDs to solution processing. The blue and green LEDs exhibit threefold and tenfold improved external quantum efficiency (EQE), respectively, compared to prior related reports for amine/ammonium capped cross-linked PQDs. The brightest blue LED based on all inorganic CsPb(Br1- xClx)3 PQDs is also reported. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Efficient synthesis of 16 aromatic Morita-Baylis-Hillman adducts: Biological evaluation on Leishmania amazonensis and Leishmania chagasi.

    Science.gov (United States)

    Junior, Cláudio G L; de Assis, Priscila A C; Silva, Fábio P L; Sousa, Suervy C O; de Andrade, Natália G; Barbosa, Ticiano P; Nerís, Patrícia L N; Segundo, Luiz V G; Anjos, Italo C; Carvalho, Gabriel A U; Rocha, Gerd B; Oliveira, Márcia R; Vasconcellos, Mário L A A

    2010-12-01

    Sixteen aromatic Morita-Baylis-Hillman adducts (MBHA) 1-16 were efficiently synthesized in a one step Morita-Baylis-Hillman reaction (MBHR) involving commercial aldehydes with methyl acrylate or acrylonitrile (81-100% yields) without the formation of side products on DABCO catalysis and at low temperature (0°C). The toxicities of these compounds were assessed against promastigote form of Leishmania amazonensis and Leishmania chagasi. The low synthetic cost of these MBHA, green synthetic protocols, easy one-step synthesis from commercially available and cheap reagents as well as the very good antileishmanial activity obtained for 14 and 16 (IC₅₀ values of 6.88μgmL⁻¹ and 11.06μgmL⁻¹ respectively on L. amazonensis; 9.58μgmL⁻¹ and 14.34μgmL⁻¹ respectively on L. chagasi) indicates that these MBHA can be a novel and promising class of anti-parasitic compounds. Copyright © 2010 Elsevier Inc. All rights reserved.

  3. Emulsion Synthesis of Size-Tunable CH3NH3PbBr3 Quantum Dots: An Alternative Route toward Efficient Light-Emitting Diodes.

    Science.gov (United States)

    Huang, Hailong; Zhao, Fangchao; Liu, Lige; Zhang, Feng; Wu, Xian-gang; Shi, Lijie; Zou, Bingsuo; Pei, Qibing; Zhong, Haizheng

    2015-12-30

    We report a facile nonaqueous emulsion synthesis of colloidal halide perovskite quantum dots by controlled addition of a demulsifier into an emulsion of precursors. The size of resulting CH3NH3PbBr3 quantum dots can be tuned from 2 to 8 nm by varying the amount of demulsifier. Moreover, this emulsion synthesis also allows the purification of these quantum dots by precipitation from the colloidal solution and obtains solid-state powder which can be redissolved for thin film coating and device fabrication. The photoluminescence quantum yields of the quantum dots is generally in the range of 80-92%, and can be well-preserved after purification (∼80%). Green light-emitting diodes fabricated comprising a spin-cast layer of the colloidal CH3NH3PbBr3 quantum dots exhibited maximum current efficiency of 4.5 cd/A, power efficiency of 3.5 lm/W, and external quantum efficiency of 1.1%. This provides an alternative route toward high efficient solution-processed perovskite-based light-emitting diodes. In addition, the emulsion synthesis is versatile and can be extended for the fabrication of inorganic halide perovskite colloidal CsPbBr3 nanocrystals.

  4. Synthesis of palladium nanoparticles with leaf extract of Chrysophyllum cainito (Star apple) and their applications as efficient catalyst for C-C coupling and reduction reactions

    Science.gov (United States)

    Majumdar, Rakhi; Tantayanon, Supawan; Bag, Braja Gopal

    2017-10-01

    A simple green chemical method for the one-step synthesis of palladium nanoparticles (PdNPs) has been described by reducing palladium (II) chloride with the leaf extract of Chrysophyllum cainito in aqueous medium. The synthesis of the palladium nanoparticles completed within 2-3 h at room temperature, whereas on heat treatment (70-80 °C), the synthesis of colloidal PdNPs completed almost instantly. The stabilized PdNPs have been characterized in detail by spectroscopic, electron microscopic and light scattering measurements. The synthesized PdNPs have been utilized as a green catalyst for C-C coupling reactions under aerobic and phosphine-free conditions in aqueous medium. In addition, the synthesized PdNPs have also been utilized as a catalyst for a very efficient sodium borohydride reduction of 3- and 4-nitrophenols. The synthesized PdNPs can retain their catalytic activity for several months.

  5. Autographa californica multiple nucleopolyhedrovirus ac66 is required for the efficient egress of nucleocapsids from the nucleus, general synthesis of preoccluded virions and occlusion body formation

    International Nuclear Information System (INIS)

    Ke Jianhao; Wang Jinwen; Deng Riqiang; Wang Xunzhang

    2008-01-01

    Although orf66 (ac66) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is conserved in all sequenced lepidopteran baculovirus genomes, its function is not known. This paper describes generation of an ac66 knockout AcMNPV bacmid mutant and analyses of the influence of ac66 deletion on the virus replication in Sf-9 cells so as to determine the role of ac66 in the viral life cycle. Results indicated that budded virus (BV) yields were reduced over 99% in ac66-null mutant infected cells in comparison to that in wild-type virus infected cells. Optical microscopy revealed that occlusion body synthesis was significantly reduced in the ac66 knockout bacmid-transfected cells. In addition, ac66 deletion interrupted preoccluded virion synthesis. The mutant phenotype was rescued by an ac66 repair bacmid. On the other hand, real-time PCR analysis indicated that ac66 deletion did not affect the levels of viral DNA replication. Electron microscopy revealed that ac66 is not essential for nucleocapsid assembly, but for the efficient transport of nucleocapsids from the nucleus to the cytoplasm. These results suggested that ac66 plays an important role for the efficient exit of nucleocapsids from the nucleus to the cytoplasm for BV synthesis as well as for preoccluded virion and occlusion synthesis

  6. Search for highly efficient, stereoselective, and practical synthesis of complex organic compounds of medicinal importance as exemplified by the synthesis of the C21-C37 fragment of amphotericin B.

    Science.gov (United States)

    Wang, Guangwei; Xu, Shiqing; Hu, Qian; Zeng, Fanxing; Negishi, Ei-ichi

    2013-09-23

    Highly stereoselective: A highly efficient, stereoselective and practical synthesis of the C21-C37 fragment of amphotericin B was realized in 25 % overall yield in eight longest linear steps from commercially available ethyl (S)-3-hydroxybutyrate by using Fráter-Seebach alkylation, Brown crotylboration, Negishi coupling, Heck reaction, and Horner-Wadsworth-Emmons (HWE) olefination as key steps (see diagram). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Poly(4-VinylpyridiniumHydrogen Sulfate Catalyzed an Efficient and Ecofriendly Protocol for the One-Pot Multicomponent Synthesis of 1,8-Acridinediones in Aqueous Medium

    Directory of Open Access Journals (Sweden)

    Janardhan Banothu

    2013-01-01

    Full Text Available Highly efficient, ecofriendly, and improved protocol for the synthesis of 1,8-acridinediones has been developed via one-pot multicomponent condensation of 1,3-cyclohexanedione/dimedone, aromatic aldehydes, and ammonium acetate utilizing poly(4-vinylpyridiniumhydrogen sulfate as catalyst in aqueous medium. Excellent yields in shorter reaction time, simple work-up procedure, easy recovery, and reusability of the catalyst are attractive features of this green protocol.

  8. Efficient Synthesis of 5-(Substituted)benzyl-2,4-Dihydro-3H-1,2,4-Triazol-3-Ones Using Microwave Irradiation

    International Nuclear Information System (INIS)

    Kahveci, B.; Mentese, E.; Ozil, M.

    2013-01-01

    A growing body of literature has shown the effectiveness of using microwave irradiation in chemical reactions. The aim of this study is to demonstrate a rapid and highly efficient synthesis of some new 5-aryl-2,4-dihydro-3H-1,2,4-triazol-3-ones from ethoxycarbonylhydrazones in the presence of ammonium acetate by using microwave heating for the first time. (author)

  9. p -Dimethylaminopyridine (DMAP: A highly efficient catalyst for one pot, solvent free synthesis of substituted 2-amino-2-chromenes under microwave irradiation

    Directory of Open Access Journals (Sweden)

    Kamlesh R. Desale

    2012-01-01

    Full Text Available A highly efficient, green and expeditious method is described for the synthesis of substituted 2-amino-2-chromenes employing one pot three component condensation of aromatic aldehydes, malononitrile and activated phenol in presence of p-dimethylaminopyridine (10 mol % as a catalyst under microwave irradiation. The present method is operationally simple and offers many advantages such as high yield, short reaction time and simple workup.

  10. Potassium phthalimide as efficient basic organocatalyst for the synthesis of 3,4-disubstituted isoxazol-5(4H-ones in aqueous medium

    Directory of Open Access Journals (Sweden)

    Hamzeh Kiyani

    2017-01-01

    Full Text Available Potassium phthalimide (PPI is employed as an efficient and effective basic organocatalyst for the one-pot three-component reaction of β-oxoesters with hydroxylamine hydrochloride and various aromatic aldehydes. This cyclocondensation reaction was performed in water as an environmentally benign solvent at room temperature giving 3,4-disubstituted isoxazol-5(4H-ones in good to excellent yields. PPI was found to be an effective organocatalyst for the synthesis of isoxazol-5(4H-one system. The advantages of this method are efficiency, clean, easy work-up, high yields, shorter reaction times, inexpensive, and readily available catalyst.

  11. Efficient synthesis of tungsten oxide hydrate-based nanocomposites for applications in bifunctional electrochromic-energy storage devices

    Science.gov (United States)

    Chang, Xueting; Hu, Ruirui; Sun, Shibin; Lu, Tong; Liu, Tao; Lei, Yanhua; Dong, Lihua; Yin, Yansheng; Zhu, Yanqiu

    2018-05-01

    In this work, we realized the large-scale synthesis of WO3 · H2O nanoflakes (NFs), g-C3N4/WO3 · H2O nanocomposite (NC) and graphene (G)/WO3 · H2O NC via a sonochemical process with tungsten salt as the precursor, g-C3N4 or G sheets as the supports, and distilled water as the solvent. Both the g-C3N4/WO3 · H2O NC and G/WO3 · H2O NC exhibited much better electrochromic (EC) performance (higher coloration efficiencies and faster response times) than that of the WO3 · H2O NFs. Using the WO3 · H2O-based materials as electrode materials, EC batteries that integrate the energy storage and EC functions in one device have been assembled. The energy status of the EC batteries could be visually indicated by the reversible color variations. Compared with the plain WO3 · H2O-based EC batteries, the NC-based EC batteries possessed a lower color contrast between the charged and discharged conditions but much longer discharge durations. The EC batteries could be quickly charged in a few seconds by adding H2O2, and the charged batteries exhibited significantly-enhanced discharging durations in comparison with the initial ones. The g-C3N4/WO3 · H2O NC-EC batteries charged by a small amount of H2O2 could produce a long discharging duration up to 760 min.

  12. Organic-inorganic hybrid supermicroporous iron(III) phosphonate nanoparticles as an efficient catalyst for the synthesis of biofuels.

    Science.gov (United States)

    Pramanik, Malay; Bhaumik, Asim

    2013-06-24

    Here we report a novel family of crystalline, supermicroporous iron(III) phosphonate nanomaterials (HFeP-1-3, HFeP-1-2, and HFeP-1-4) with different Fe(III)-to-organophosphonate ligand mole ratios. The materials were synthesized by using a hydrothermal reaction between benzene-1,3,5-triphosphonic acid and iron(III) chloride under acidic conditions (pH ≈ 4.0). Powder X-ray diffraction, N2 sorption, transmission and scanning electron microscopy (TEM and SEM) image analysis, thermogravimetric and differential thermal analysis (TGA-DTA), and FTIR spectroscopic tools were used to characterize the materials. The triclinic crystal phase [P1(2) space group] of the hybrid iron phosphonate was established by a Rietveld refinement of the PXRD analysis of HFeP-1-3 by using the MAUD program. The unit cell parameters are a = 8.749(1), b = 8.578(1), c = 17.725(3) Å; α = 104.47(3), β = 97.64(1), γ = 113.56(3)°; and V = 1013.41 Å(3). With these crystal parameters, we proposed an 24-membered-ring open framework structure for HFeP-1. Compound HFeP-1-3, with an starting Fe/ligand molar ratio of 3.0, shows the highest Brunauer-Emmett-Telller (BET) surface area of 556 m(2) g(-1) and uniform supermicropores of approximately 1.1 nm. The acidic surface of the porous iron(III) phosphonate nanoparticles was used in a highly efficient and recyclable catalytic transesterification reaction for the synthesis of biofuels under mild reaction conditions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A Novel and Efficient Five-Component Synthesis of Pyrazole Based Pyrido[2,3-d]pyrimidine-diones in Water: A Triply Green Synthesis

    Directory of Open Access Journals (Sweden)

    Majid M. Heravi

    2016-04-01

    Full Text Available A novel one pot synthesis of pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine-diones, via a five-component reaction, involving, hydrazine hydrate, ethyl acetoacetate, and 1,3-dimethyl barbituric acid, an appropriate aryl aldehydes and ammonium acetate catalyzed via both of heterogeneous and homogeneous catalysis in water, is reported.

  14. Synthesis of 4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX) Using Heteropolyacids as Efficient and Recyclable Heterogeneous Catalysts

    Science.gov (United States)

    Bayat, Yadollah; Azizkhani, Vahid

    2012-07-01

    4,10-Dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane (TEX) is well known as an efficient explosive compound. It is usually prepared via nitration of a precursor with a mixture of concentrated nitric and sulfuric acid. However, there are many difficulties with the use of old methods, such as strong acidic and thermal conditions, which cause product decomposition, low yields, hazardous wastes, and product separation difficulties. In this article, the use of an efficient catalytic and mild reaction conditions for TEX synthesis is reported for the first time. It has been well documented that heteropolyacids (HPAs) are efficient green catalysts for use as a nitric acid activator. This strategy provided milder and higher yield conditions for nitration reactions. In addition, the reactions can be reasonably run at lower temperatures in a short time.

  15. Rational design and synthesis of efficient Carbon and/or Silica functional nanomaterials for electrocatalysis and nanomedicine

    Science.gov (United States)

    Da Silva, Rafael

    In nanomaterials there is a strong correlation between structure and properties. Thus, the design and synthesis of nanomaterials with well-defined structures and morphology is essential in order to produce materials with not only unique but also tailorable properties. The unique properties of nanomaterials in turn can be taken advantage of to create materials and nanoscale devices that can help address important societal issues, such as meeting renewable energy sources and efficient therapeutic and diagnostic methods to cure a range of diseases. In this thesis, the different synthetic approaches I have developed to produce functional nanomaterials composed of earth-abundant elements (mainly carbon and silica) at low cost in a very sustainable manner are discussed. In Chapter 1, the fundamental properties of nanomaterials and their properties and potential applications in many areas are introduced. In chapter 2, a novel synthetic method that allows polymerization of polyaniline (PANI), a conducting polymer, inside cylindrical channel pores of nanoporous silica (SBA-15) is discussed. In addition, the properties of the III resulting conducting polymer in the confined nanochannel spaces of SBA-15, and more importantly, experimental demonstration of the use of the resulting hybrid material (PANI/SBA-15 material) as electocatalyst for electrooxidation reactions with good overpotential, close to zero, are detailed. In chapter 3, the synthetic approach discussed in Chapter 2 is further extended to afford nitrogen- and oxygen-doped mesoporous carbons. This is possible by pyrolysis of the PANI/SBA-15 composite materials under inert atmosphere, followed by etching away their silica framework. The high catalytic activity of resulting carbon-based materials towards oxygen reduction reaction despite they do not possess any metal dopants is also included. The potential uses of nanomaterials in areas such as nanomedicine need deep understanding of the biocompatibility/ toxicity of

  16. Efficient synthesis of 2-bromo-1-[18F]fluoroethane and its application in the automated preparation of 18F-fluoroethylated compounds

    International Nuclear Information System (INIS)

    Comagic, S.; Piel, M.; Schirrmacher, R.; Hoehnemann, S.; Roesch, F.

    2002-01-01

    An efficient synthesis of 2-bromo-1-[ 18 F]fluoroethane from commercially available 1,2-dibromoethane and its integration into an automated preparation device was developed for the routine synthesis of 18 F-fluoroethylated compounds. The 1,2-dibromoethane was reacted with the [ 18 F]fluoride/Kryptofix[reg]2.2.2./carbonate complex in acetonitrile at 70 deg. C for 3 min resulting in 60-70% radiochemical yields. The crude reaction mixture was diluted with water, loaded on a LiChrolute(reg]EN-cartridge, eluted with acetonitrile and passed through an AluminaB[reg]-cartridge. This method provides 2-bromo-1-[ 18 F]fluoroethane with 98% radiochemical purity and 18 F-fluoroethylated compounds

  17. Efficient synthesis of novel NK1 receptor antagonists: selective 1,4-addition of grignard reagents to 6-chloronicotinic acid derivatives.

    Science.gov (United States)

    Hoffmann-Emery, Fabienne; Hilpert, Hans; Scalone, Michelangelo; Waldmeier, Pius

    2006-03-03

    A new efficient synthesis of two novel classes of NK1 receptor antagonists, among them befetupitant and netupitant, starting from 6-chloronicotinic acid is described. The introduction of the o-tolyl substituent at C4 of the pyridine ring was achieved by a one-pot selective 1,4-Grignard addition/oxidation sequence to 6-chloronicotinic acid or a derivative of it. The scope of this addition/oxidation sequence was examined. It was also shown that the carboxylic function can be converted to a methyl amino group by a Hofmann rearrangement followed by reduction. Furthermore, a new high-yielding synthesis of 2-(3,5-bistrifluoromethylphenyl)-2-methyl propionic acid based on the carbonylation of the tertiary alcohol obtained by Grignard addition of 3,5-bis(trifluoromethyl)bromobenzene to acetone was established.

  18. Magnetic iron oxide/phenylsulfonic acid: A novel, efficient and recoverable nanocatalyst for green synthesis of tetrahydrobenzo[b]pyrans under ultrasonic conditions.

    Science.gov (United States)

    Elhamifar, Dawood; Ramazani, Zahra; Norouzi, Meysam; Mirbagheri, Reza

    2018-02-01

    A novel magnetic iron oxide supported phenylsulfonic acid (Fe 3 O 4 @Ph-SO 3 H) with core-shell structure is prepared, characterized and applied as efficient nanocatalyst for green synthesis of tetrahydrobenzo[b]pyrans. The Fe 3 O 4 @Ph-SO 3 H was prepared via modification of magnetic iron oxide cores with 1,4-bis(triethoxysilyl)benzene (BTEB) followed by sulfonation of aromatic rings. The Fe 3 O 4 @Ph-SO 3 H was characterized using FTIR, TGA, PXRD, SEM, TEM, VSM and EDX techniques. This was effectively applied for synthesis of tetrahydrobenzo[b]pyrans in water as green solvent at room temperature under ultrasonic conditions. The products were obtained in high to excellent yields at short times. The recoverability, reusability and durability of this nanocatalyst were studied under applied reaction conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Utilizing metal tolerance potential of soil fungus for efficient synthesis of gold nanoparticles with superior catalytic activity for degradation of rhodamine B.

    Science.gov (United States)

    Bhargava, Arpit; Jain, Navin; Khan, Mohd Azeem; Pareek, Vikram; Dilip, R Venkataramana; Panwar, Jitendra

    2016-12-01

    In recent years, the surging demand of nanomaterials has boosted unprecedented expansion of research for the development of high yielding and sustainable synthesis methods which can deliver nanomaterials with desired characteristics. Unlike the well-established physico-chemical methods which have various limitations, biological methods inspired by mimicking natural biomineralization processes have great potential for nanoparticle synthesis. An eco-friendly and sustainable biological method that deliver particles with well-defined shape, size and compositions can be developed by selecting a proficient organism followed by fine tuning of various process parameter. The present study revealed high metal tolerance ability of a soil fungus Cladosporium oxysporum AJP03 and its potential for extracellular synthesis of gold nanoparticles. The morphology, composition and crystallinity of nanoparticles were confirmed using standard techniques. The synthesized particles were quasi-spherical in shape with fcc packing and an average particle size of 72.32 ± 21.80 nm. A series of experiments were conducted to study the effect of different process parameters on particle size and yield. Biomass: water ratio of 1:5 and 1 mM precursor salt concentration at physiological pH (7.0) favoured the synthesis of well-defined gold nanoparticles with maximum yield. The as-synthesized nanoparticles showed excellent catalytic efficiency towards sodium borohydride mediated reduction of rhodamine B (2.5 × 10(-5) M) within 7 min of reaction time under experimental conditions. Presence of proteins as capping material on the nanoparticle surface was found to be responsible for this remarkable catalytic efficiency. The present approach can be extrapolated to develop controlled and up-scalable process for mycosynthesis of nanoparticles for diverse applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Microwave-promoted Morita-Baylis-Hillman reactions: efficient synthesis of new monoacylglycerols (MAGs) as potential anti-parasitic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Suervy C.O.; Lima Junior, Claudio G.; Silva, Fabio P.L.; Andrade, Natalia G.; Barbosa, Ticiano P.; Vasconcellos, Mario L.A.A., E-mail: mlaav@quimica.ufpb.br [Universidade Federal da Paraiba, Joao Pessoa, PB (Brazil). Dept. de Quimica

    2011-09-15

    In this article we describe microwave irradiation promoting the synthesis of a hydrophilic monoacylglycerol, MAG, by hydrolysis of acrylate (15 min, 100%). After, MAG was transformed in hydrophilic Morita-Baylis-Hillman adducts (MBHA), (54-82%, pathway 1). In pathway 2, the different lipophilic MBHAs were prepared in high yields (90-100%) and transformed on hydrophilic MBHA, in 70-90%. Through the high temperature synthesis of one MBHA, a unprecedented indolizine formation was detected by GC-MS,. All results are in agreement with the new unified mechanism to the Morita-Baylis-Hillman reaction. These new monoacylglycerols, as well the its synthetic precursors, are new potential antiparasitic compounds. (author)

  1. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    KAUST Repository

    Chinnusamy, Tamilselvi R.

    2012-05-09

    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. A new Ni(II complex as a novel and efficient recyclable catalyst for the synthesis of pyrano[2,3-d]pyrimidines

    Directory of Open Access Journals (Sweden)

    M. Habibi Kheirabadi

    2016-12-01

    Full Text Available A simple and highly efficient one-pot three-component synthesis of a series of pyrido[2,3-d]pyrimidines from the condensation of barbituric acid, malononitrile and aromatic aldehydes using catalytic amount of a new Ni(II complex based on 5-nitro-N1-((pyridin-2-ylmethylene benzene-1,2-diamine (NiL is reported. This new heterogeneous catalyst has the advantages of being environmentally friendly, simple work-up and high yields character.

  3. Sulfonic Acid Functionalized Nano-γ-Al2O3: A New, Efficient, and Reusable Catalyst for Synthesis of 3-Substituted-2H-1,4-Benzothiazines

    Directory of Open Access Journals (Sweden)

    Wei Lin Li

    2013-01-01

    Full Text Available A simple and efficient synthetic protocol has been developed for the synthesis of 3-substituted-2H-1,4-benzothiazines by using a novel sulfonic acid functionalized nano-γ-Al2O3 catalyst, devoid of corrosive acidic, and basic reagents. The developed method has the advantages of good to excellent yields, short reaction times, operational simplicity, and a recyclable catalyst. The catalyst can be prepared by a simple procedure from inexpensive and readily available nano-γ-Al2O3 and has been shown to be recoverable and reusable up to six cycles without any loss of activity.

  4. Nanocrystalline magnesium oxide: an efficient promoter and heterogeneous nano catalyst for the one-pot synthesis of pyrazolotriazoles in green medium

    Science.gov (United States)

    Naeimi, Hossein; Rashid, Zahra; Zarnani, Amir-Hassan; Ghahremanzadeh, Ramin

    2014-05-01

    A simple, efficient, and relatively clean method for the synthesis of pyrazolo[1,2- a][1,2,4]triazole derivatives via a one-pot three-component reaction of aromatic aldehydes, 4-phenyl-1,2,4-triazolidine-3,5-dione, and malononitrile or alkyl cyanoacetates in the presence of a catalytic amount of nanocrystalline (NC) magnesium oxide has been developed. This method has several advantages such as, high to excellent product yields, reusability of catalyst, and simple work-up procedure in the nontoxic medium.

  5. A study of the efficiency and the problem of sulfonation of several condensing reagents and their mechanisms for the chemical synthesis of deoxyoligoribonucleotides.

    Science.gov (United States)

    Seth, A K; Jay, E

    1980-01-01

    The efficiencies and problems of sulfonation of several condensing reagents for deoxyoligoribonucleotide synthesis have been studied. While 2,4,6-triisopropylbenzenesulfonyl chloride (TPSC1) gave very low yield and slow rate of coupling, the new 1:3 mixture of TPSC1 and tetrazole afforded excellent yield and extremely fast rate of reaction with the lowest rate of sulfonation. The difference and advantages of this mixture over triisopropylbenzenesulfonyl tetrazole (TPSTe) and mesitylenesulfonyl tetrazole (MSTe) are discussed. Mechanisms for the coupling reactions with these condensing reagents to account for the difference in their rates and yields of coupling are discussed. PMID:6894029

  6. Rational Design, Efficient Synthesis, Biological Evaluation of New Ν,Ν'-bis-substituted Butylimidazole Analogs as Potent Angiotensin Receptor Blockers

    Czech Academy of Sciences Publication Activity Database

    Agelis, G.; Resvani, A.; Koukoulitsa, C.; Afantitis, A.; Melagraki, G.; Siafaka, A.; Gkini, E.; Tůmová, Tereza; Spyridaki, K.; Kalavrizioti, D.; Androutsou, M-E.; Slaninová, Jiřina; Liapakis, G.; Vlahakos, D.; Mavromoustakos, T.; Matsoukas, J.

    2012-01-01

    Roč. 18, S1 (2012), S123-S123 ISSN 1075-2617. [European Peptide Symposium /32./. 02.09.2012-07.09.2012, Athens] Institutional research plan: CEZ:AV0Z40550506 Keywords : angiotensin II AT1 receptor * in vitro * antagonism * inhibitor * in vitro antagonism * synthesis Subject RIV: CE - Biochemistry

  7. Immobilized Cu (II)—Amino Acid Complexes as Prospective Highly Efficient Catalytic Materials: Synthesis, Structural Characterization and Catalytic Activities

    Science.gov (United States)

    Pálinkó, István; Ordasi, Adrien; Kiss, János T.; Labádi, Imre

    2008-11-01

    In this work the covalent anchoring of N-or C-protected Cu(II)—L-tyrosine complexes onto a swellable resin or surface-modified silica gel is described. Experimental conditions (solvents, the availability of ligands) of the synthesis were varied; the structures (by IR spectroscopy) and the superoxide dismutase activities of the anchored complexes were studied.

  8. An Efficient Method for the Synthesis of Peptoids with Mixed Lysine-type/Arginine-type Monomers and Evaluation of Their Anti-leishmanial Activity.

    Science.gov (United States)

    Bolt, Hannah L; Denny, Paul W; Cobb, Steven L

    2016-11-02

    This protocol describes the manual solid-phase synthesis of linear peptoids that contain two differently functionalized cationic monomers. In this procedure amino functionalized 'lysine' and guanido functionalized 'arginine' peptoid monomers can be included within the same peptoid sequence. This procedure uses on-resin (N-(1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl) or Dde protection, orthogonal conditions to the Boc protection of lysine monomers. Subsequent deprotection allows an efficient on-resin guanidinylation reaction to form the arginine residues. The procedure is compatible with the commonly used submonomer method of peptoid synthesis, allowing simple peptoids to be made using common laboratory equipment and commercially available reagents. The representative synthesis, purification and characterization of two mixed peptoids is described. The evaluation of these compounds as potential anti-infectives in screening assays against Leishmania mexicana is also described. The protozoan parasite L. mexicana is a causative agent of cutaneous leishmaniasis, a neglected tropical disease that affects up to 12 million people worldwide.

  9. Green synthesis of 3,4-dihydropyrimidinones using nano Fe3O4@meglumine sulfonic acid as a new efficient solid acid catalyst under microwave irradiation

    Directory of Open Access Journals (Sweden)

    Leila Moradi

    2018-01-01

    Full Text Available Design, synthesis and characterization of nano Fe3O4@meglumine sulfonic acid as a new solid acid catalyst for the simple and green one pot multicomponent synthesis of 3,4-dihydropyrimidin-2(1H-ones/thiones was studied. New solid acid catalyst was prepared through a clean and simple protocol and characterized using FTIR, VSM, TGA, SEM, elemental analysis (CHN and XRD techniques. Heterogenization of homogeneous catalyst as a green approach is a useful method for enhancing the efficiency of catalyst. Presented study was a new method for attachment of homogeneous highly soluble catalyst (meglumine sulfate to the magnetite nanoparticle surfaces for preparing a heterogeneous and effective catalyst. Obtained heterogeneous and reusable solid acid catalyst has high performance in the synthesis of Biginelli compounds. The reaction was performed under microwave irradiation as a rapid and green condition. Easy work up as well as excellent yield (90–98% of products in short reaction times (40–200 s and reusable catalyst are the main advantages of presented procedure. Reaction products were characterized in details using physical and chemical techniques such as melting point, 1H NMR, 13C NMR and FTIR.

  10. Synthesis of Won-WX2 (n=2.7, 2.9; X=S, Se) Heterostructures for Highly Efficient Green Quantum Dot Light-Emitting Diodes

    KAUST Repository

    Han, Shikui

    2017-07-04

    Preparation of two-dimensional (2D) heterostructures is important not only fundamentally, but also technologically for applications in electronics and optoelectronics. Herein, we report a facile colloidal method for the synthesis of WOn -WX2 (n=2.7, 2.9; X=S, Se) heterostructures by sulfurization or selenization of WOn nanomaterials. The WOn -WX2 heterostructures are composed of WO2.9 nanoparticles (NPs) or WO2.7 nanowires (NWs) grown together with single- or few-layer WX2 nanosheets (NSs). As a proof-of-concept application, the WOn -WX2 heterostructures are used as the anode interfacial buffer layer for green quantum dot light-emitting diodes (QLEDs). The QLED prepared with WO2.9 NP-WSe2 NS heterostructures achieves external quantum efficiency (EQE) of 8.53 %. To our knowledge, this is the highest efficiency in the reported green QLEDs using inorganic materials as the hole injection layer.

  11. A simple and efficient approach for synthesis of 1,4-dihydro-pyridines using nano-crystalline solid acid catalyst

    Directory of Open Access Journals (Sweden)

    A. Moatari

    2013-09-01

    Full Text Available A simple highly versatile and efficient synthesis of various 1,4-dihydropyridines in the condensation of aromatic aldehydes with β-dicarbonyl compounds and ammonium acetate in the presence of nano-sulfated zirconia, nano-structured ZnO, nano-γ-alumina and nano-ZSM-5 zeolites, as catalyst in the ethanol at moderate temperature is presented. The advantages of method are short reaction times and milder conditions and easy work-up. The catalysts can be recovered for the subsequent reactions and reused without any appreciable loss of efficiency.DOI: http://dx.doi.org/10.4314/bcse.v27i3.12

  12. DNA repair genes RAD52 and SRS2, a cell wall synthesis regulator gene SMI1, and the membrane sterol synthesis scaffold gene ERG28 are important in efficient Agrobacterium-mediated yeast transformation with chromosomal T-DNA.

    Science.gov (United States)

    Ohmine, Yuta; Satoh, Yukari; Kiyokawa, Kazuya; Yamamoto, Shinji; Moriguchi, Kazuki; Suzuki, Katsunori

    2016-04-02

    Plant pathogenic Agrobacterium strains can transfer T-DNA regions of their Ti plasmids to a broad range of eukaryotic hosts, including fungi, in vitro. In the recent decade, the yeast Saccharomyces cerevisiae is used as a model host to reveal important host proteins for the Agrobacterium-mediated transformation (AMT). Further investigation is required to understand the fundamental mechanism of AMT, including interaction at the cell surface, to expand the host range, and to develop new tools. In this study, we screened a yeast mutant library for low AMT mutant strains by advantage of a chromosome type T-DNA, which transfer is efficient and independent on integration into host chromosome. By the mutant screening, we identified four mutant strains (srs2Δ, rad52Δ, smi1Δ and erg28Δ), which showed considerably low AMT efficiency. Structural analysis of T-DNA product replicons in AMT colonies of mutants lacking each of the two DNA repair genes, SRS2 and RAD52, suggested that the genes act soon after T-DNA entry for modification of the chromosomal T-DNA to stably maintain them as linear replicons and to circularize certain T-DNA simultaneously. The cell wall synthesis regulator SMI1 might have a role in the cell surface interaction between the donor and recipient cells, but the smi1Δ mutant exhibited pleiotropic effect, i.e. low effector protein transport as well as low AMT for the chromosomal T-DNA, but relatively high AMT for integrative T-DNAs. The ergosterol synthesis regulator/enzyme-scaffold gene ERG28 probably contributes by sensing a congested environment, because growth of erg28Δ strain was unaffected by the presence of donor bacterial cells, while the growth of the wild-type and other mutant yeast strains was suppressed by their presence. RAD52 and the DNA helicase/anti-recombinase gene SRS2 are necessary to form and maintain artificial chromosomes through the AMT of chromosomal T-DNA. A sterol synthesis scaffold gene ERG28 is important in the high-efficiency

  13. Efficient One-Pot Synthesis and pH-Dependent Tuning of Photoluminescence and Stability of Au18(SC2H4CO2H)14Cluster.

    Science.gov (United States)

    Itteboina, Ramakrishna; Madhuri, U Divya; Ghosal, Partha; Kannan, Monica; Sau, Tapan K; Tsukuda, Tatsuya; Bhardwaj, Shweta

    2018-02-08

    Developing efficient ways to control the nanocluster properties and synthesize atomically precise metal nanoclusters are the foremost goals in the field of metal nanocluster research. In this article, we demonstrate that the direct synthesis of atomically precise, hydrophilic metal nanoclusters as well as tuning of their properties can be achieved by an appropriate selection of reactants, binding ligand, and their proportions. Thus, a facile, single-step method has been developed for the direct synthesis of Au 18 (SC 2 H 4 CO 2 H) 14 nanocluster in an aqueous medium under ambient conditions. The synthesis does not require any pH or temperature control and postsynthesis size-separation step. The use of a hydrophilic, bifunctional short carbon-chain capping ligand, HSC 2 H 4 CO 2 H, allows tuning of cluster properties such as the photoluminescence and stability in an aqueous medium via the variation of pH of the cluster solution. By using a phase transfer catalyst, the nanoclusters can also be transferred into toluene solvent, which further enhances the nanocluster photoluminescence. The formation, composition, and purity of the product clusters have been characterized by using a number of methods such as the polyacrylamide gel electrophoresis, UV-visible and FTIR spectroscopies, transmission electron microscopy, energy dispersive X-ray analysis, thermogravimetric analysis, X-ray photoelectron spectroscopy, and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. Gold nanoclusters with properties such as water solubility, water-to-organic phase-transfer ability, and tunable stability and photoluminescence are promising for various studies and applications. The work reveals a few principles that can be helpful in the development of a general toolbox for the rational design of size-selective synthesis and properties tuning of the metal nanoclusters.

  14. Rumen microbial protein synthesis and nitrogen efficiency as affected by tanniferous and non-tanniferous forage legumes incubated individually or together in Rumen Simulation Technique.

    Science.gov (United States)

    Grosse Brinkhaus, Anja; Bee, Giuseppe; Schwarm, Angela; Kreuzer, Michael; Dohme-Meier, Frigga; Zeitz, Johanna O

    2018-03-01

    A limited availability of microbial protein can impair productivity in ruminants. Ruminal nitrogen efficiency might be optimised by combining high-quality forage legumes such as red clover (RC), which has unfavourably high ruminal protein degradability, with tanniferous legumes like sainfoin (SF) and birdsfoot trefoil (BT). Silages from SF and from BT cultivars [Bull (BB) and Polom (BP)] were incubated singly or in combination with RC using the Rumen Simulation Technique (n = 6). The tanniferous legumes, when compared to RC, changed the total short-chain fatty acid profile by increasing propionate proportions at the expense of butyrate. Silage from SF contained the most condensed tannins (CTs) (136 g CT kg -1 dry matter) and clearly differed in various traits from the BT and RC silages. The apparent nutrient degradability (small with SF), microbial protein synthesis, and calculated content of potentially utilisable crude protein (large with SF) indicated that SF had the greatest efficiency in ruminal protein synthesis. The effects of combining SF with RC were mostly linear. The potential of sainfoin to improve protein supply, demonstrated either individually or in combination with a high-performance forage legume, indicates its potential usefulness in complementing protein-deficient ruminant diets and high-quality forages rich in rumen-degradable protein. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  15. Efficient routes toward the synthesis of the D-rhamno-trisaccharide related to the A-band polysaccharide of Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Aritra Chaudhury

    2014-07-01

    Full Text Available The present work describes efficient avenues for the synthesis of the trisaccharide repeating unit [α-D-Rhap-(1→3-α-D-Rhap-(1→3-α-D-Rhap] associated with the A-band polysaccharide of Pseudomonas aeruginosa. One of the key steps involved 6-O-deoxygenation of either partially or fully acylated 4,6-O-benzylidene-1-thiomannopyranoside by radical-mediated redox rearrangement in high yields and regioselectivity. The D-rhamno-thioglycosides so obtained allowed efficient access to the trisaccharide target via stepwise glycosylation as well as a one-pot glycosylation protocol. In a different approach, a 4,6-O-benzylidene D-manno-trisaccharide derivative was synthesized, which upon global 6-O-deoxygenation followed by deprotection generated the target D-rhamno-trisaccharide. The application of the reported regioselective radical-mediated deoxygenation on 4,6-O-benzylidene D-manno thioglycoside (hitherto unexplored has potential for ramification in the field of synthesis of oligosaccharides based on 6-deoxy hexoses.

  16. Nitric Oxide Regulates Skeletal Muscle Fatigue, Fiber Type, Microtubule Organization, and Mitochondrial ATP Synthesis Efficiency Through cGMP-Dependent Mechanisms.

    Science.gov (United States)

    Moon, Younghye; Balke, Jordan E; Madorma, Derik; Siegel, Michael P; Knowels, Gary; Brouckaert, Peter; Buys, Emmanuel S; Marcinek, David J; Percival, Justin M

    2017-06-10

    Skeletal muscle nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathways are impaired in Duchenne and Becker muscular dystrophy partly because of reduced nNOSμ and soluble guanylate cyclase (GC) activity. However, GC function and the consequences of reduced GC activity in skeletal muscle are unknown. In this study, we explore the functions of GC and NO-cGMP signaling in skeletal muscle. GC1, but not GC2, expression was higher in oxidative than glycolytic muscles. GC1 was found in a complex with nNOSμ and targeted to nNOS compartments at the Golgi complex and neuromuscular junction. Baseline GC activity and GC agonist responsiveness was reduced in the absence of nNOS. Structural analyses revealed aberrant microtubule directionality in GC1 -/- muscle. Functional analyses of GC1 -/- muscles revealed reduced fatigue resistance and postexercise force recovery that were not due to shifts in type IIA-IIX fiber balance. Force deficits in GC1 -/- muscles were also not driven by defects in resting mitochondrial adenosine triphosphate (ATP) synthesis. However, increasing muscle cGMP with sildenafil decreased ATP synthesis efficiency and capacity, without impacting mitochondrial content or ultrastructure. GC may represent a new target for alleviating muscle fatigue and that NO-cGMP signaling may play important roles in muscle structure, contractility, and bioenergetics. These findings suggest that GC activity is nNOS dependent and that muscle-specific control of GC expression and differential GC targeting may facilitate NO-cGMP signaling diversity. They suggest that nNOS regulates muscle fiber type, microtubule organization, fatigability, and postexercise force recovery partly through GC1 and suggest that NO-cGMP pathways may modulate mitochondrial ATP synthesis efficiency. Antioxid. Redox Signal. 26, 966-985.

  17. Novel protocol for the chemical synthesis of crustacean hyperglycemic hormone analogues--an efficient experimental tool for studying their functions.

    Directory of Open Access Journals (Sweden)

    Alessandro Mosco

    Full Text Available The crustacean Hyperglycemic Hormone (cHH is present in many decapods in different isoforms, whose specific biological functions are still poorly understood. Here we report on the first chemical synthesis of three distinct isoforms of the cHH of Astacus leptodactylus carried out by solid phase peptide synthesis coupled to native chemical ligation. The synthetic 72 amino acid long peptide amides, containing L- or D-Phe³ and (Glp¹, D-Phe³ were tested for their biological activity by means of homologous in vivo bioassays. The hyperglycemic activity of the D-isoforms was significantly higher than that of the L-isoform, while the presence of the N-terminal Glp residue had no influence on the peptide activity. The results show that the presence of D-Phe³ modifies the cHH functionality, contributing to the diversification of the hormone pool.

  18. Novel Protocol for the Chemical Synthesis of Crustacean Hyperglycemic Hormone Analogues — An Efficient Experimental Tool for Studying Their Functions

    Science.gov (United States)

    Mosco, Alessandro; Zlatev, Vientsislav; Guarnaccia, Corrado; Pongor, Sándor; Campanella, Antonella; Zahariev, Sotir; Giulianini, Piero G.

    2012-01-01

    The crustacean Hyperglycemic Hormone (cHH) is present in many decapods in different isoforms, whose specific biological functions are still poorly understood. Here we report on the first chemical synthesis of three distinct isoforms of the cHH of Astacus leptodactylus carried out by solid phase peptide synthesis coupled to native chemical ligation. The synthetic 72 amino acid long peptide amides, containing L- or D-Phe3 and (Glp1, D-Phe3) were tested for their biological activity by means of homologous in vivo bioassays. The hyperglycemic activity of the D-isoforms was significantly higher than that of the L-isoform, while the presence of the N-terminal Glp residue had no influence on the peptide activity. The results show that the presence of D-Phe3 modifies the cHH functionality, contributing to the diversification of the hormone pool. PMID:22253873

  19. Highly efficient synthetic method onpyroacm resin using the boc SPPS protocol for C-terminal cysteine peptide synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Juvekar, Vinayak; Kim, Kang Tae; Gong, Young Dae [Innovative Drug Library Research Center, Dept. of Chemistry, College of Science, Dongguk University, Seoul (Korea, Republic of)

    2017-01-15

    A very effective process on Pyroacm resin was developed for solid-phase peptide synthesis (SPPS) of C-terminal cysteine and cysteine ester peptides. The process uses cysteine side chain anchoring to the Pyroacm resin and the Boc protocol for SPPS. The Pyroacm resin showed remarkable stability under standard trifluoromethanesulfonic acid (TFMSA) cleavage condition. TFMSA cleavage of protecting groups generates a peptide-linked resin, which can be subjected to peptide modification reactions. Finally, the peptide can be cleaved from the resin using methoxycarbonylsulfenyl chloride. The utility of this protocol was demonstrated by its applications to the synthesis of model peptides, key intermediates in the preparation of natural products riparin 1.2 and a-factor.

  20. An efficient microwave-assisted synthesis and biological properties of polysubstituted pyrimidinyl- and 1,3,5-triazinylphosphonic acids

    Czech Academy of Sciences Publication Activity Database

    Jansa, Petr; Hradil, Ondřej; Baszczyňski, Ondřej; Dračínský, Martin; Klepetářová, Blanka; Holý, Antonín; Balzarini, J.; Janeba, Zlatko

    2012-01-01

    Roč. 68, č. 3 (2012), s. 865-871 ISSN 0040-4020 R&D Projects: GA AV ČR KJB400550903; GA MŠk 1M0508 Grant - others:K.U. Leuven(BE) GOA 10/014 Institutional research plan: CEZ:AV0Z40550506 Keywords : phosphonic acids * pyrimidines * 1,3,5-triazines * microwave-assisted synthesis * influenza virus Subject RIV: CC - Organic Chemistry Impact factor: 2.803, year: 2012

  1. BF3.SiO2: an efficient catalyst for the synthesis of azo dyes at room temperature

    Directory of Open Access Journals (Sweden)

    Bi Bi Fatemeh Mirjalili

    2012-07-01

    Full Text Available A rapid one-pot method has been developed for the synthesis of azo dyes via ‎sequential diazotization–diazo coupling of aromatic amines with coupling agents at room ‎temperature in the presence of BF3.SiO2 as acidic catalyst. The obtained aryl diazonium salts bearing silica supported boron tri-flouride counter ion‎ was sufficiently stable to be kept at room ‎temperature in the dry state.‎

  2. Spontaneous dimerization of allenes in situ: an efficient synthesis of substituted 1,2-dimethylenecyclobutanes with high regio- and stereoselectivities.

    Science.gov (United States)

    Miao, Maozhong; Wang, Wenmin; Yang, Weijun; Xu, Lijun; Ma, Jing; Ren, Hongjun

    2015-10-05

    An intermolecular [2+2] cycloaddition reaction for the synthesis of 1,2-dimethylenecyclobutane derivatives from the commercially available starting materials aryl acetylenes, nBuLi, formamides, and trimethylsilyl cyanide (TMSCN) has been achieved. This reaction displays high regio- and stereoselectivities due to the captodative effect. The mechanism of the reaction has been investigated by the deuterium labeling experiments and DFT calculations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Green Chemistry Approach for Efficient Synthesis of Schiff Bases of Isatin Derivatives and Evaluation of Their Antibacterial Activities

    Directory of Open Access Journals (Sweden)

    Jnyanaranjan Panda

    2013-01-01

    Full Text Available Microwave-assisted organic synthesis, a green chemistry approach, is nowadays widely used in the drug synthesis. Microwave-assisted synthesis improves both throughput and turnaround time for medicinal chemists by offering the benefits of drastically reduced reaction times, increased yields, and pure products. Schiff bases are the important class of organic compounds due to their flexibility, and structural diversities due to the presence of azomethine group which is helpful for elucidating the mechanism of transformation and rasemination reaction in biological system. This novel compound could also act as valuable ligands for the development of new chemical entities. In the present work, some Schiff bases of Isatin derivatives was synthesized using microwave heating method. Schiff base of Isatin were synthesized by condensation of the keto group of Isatin with different aromatic primary amines. They were characterized by means of spectral data and subsequently subjected to the in vitro antibacterial activities against gram positive and gram negative strains of microbes. It was observed that the compound with electron withdrawing substituents exhibited good antibacterial activities against almost all the micro organisms.

  4. An Efficient Protocol for the Synthesis of Quinoxaline Derivatives at Room Temperature Using Recyclable Alumina-Supported Heteropolyoxometalates

    Directory of Open Access Journals (Sweden)

    Diego M. Ruiz

    2012-01-01

    Full Text Available We report a suitable quinoxaline synthesis using molybdophosphovanadates supported on commercial alumina cylinders as catalysts. These catalysts were prepared by incipient wetness impregnation. The catalytic test was performed under different reaction conditions in order to know the performance of the synthesized catalysts. The method shows high yields of quinoxaline derivatives under heterogeneous conditions. Quinoxaline formation was obtained using benzyl, o-phenylenediamine, and toluene as reaction solvent at room temperature. The CuH2PMo11VO40 supported on alumina showed higher activity in the tested reaction. Finally, various quinoxalines were prepared under mild conditions and with excellent yields.

  5. Environment-friendly green chemistry approaches for an efficient synthesis of 1-amidoalkyl-2-naphthols catalyzed by tannic acid

    Directory of Open Access Journals (Sweden)

    Rajesh K. Singh

    2018-01-01

    Full Text Available A new, facile, cost-effective and environment-friendly protocol is reported for the synthesis of 1-amidoalkyl-2-naphthols exploring tannic acid as a novel, cheap and biodegradable catalyst. β-naphthol is condensed with substituted aromatic aldehydes and various amides using catalytic amount of tannic acid in the absence of solvent under thermal (hot plate and oil bath and microwave irradiation techniques. This green protocol offers many advantages such as short reaction time, use of environment-friendly and cheap catalyst and good to excellent yields.

  6. Synthesis and antioxidant efficiency of a new amphiphilic spin-trap derived from PBN and lipoic acid.

    Science.gov (United States)

    Durand, G; Polidori, A; Salles, J P; Prost, M; Durand, P; Pucci, B

    2003-08-18

    The synthesis of a new amphiphilic antioxidant called PBNLP and derived from both alpha-phenyl-N-tert-butyl nitrone (PBN) and lipoic acid was described. Grafting a lactobionamide moiety onto the aromatic group of the PBN provided the water solubility of this compound. In vitro preliminary biological evaluations of its antioxidant capacity were performed using the KRL biological test based on free radical-induced hemolysis. The PBNLP induces a protection of erythrocytes against exogenous free radicals higher than that measured with lipoic acid or PBN alone or with lipoic acid or PBN derivatives in admixtures.

  7. An efficient one-pot multi component synthesis of polyhydroquinoline derivatives through Hantzsch reaction catalysed by Gadolinium triflate

    Directory of Open Access Journals (Sweden)

    S. Sheik Mansoor

    2017-02-01

    Full Text Available Gadolinium(III trifluoromethanesulfonate (Gadolinium triflate Gd(OTf3 catalysed efficient Hantzsch reaction via four-component coupling reactions of aldehydes, 5,5-dimethyl-1,3-cyclohexaedione (dimedone, ethyl acetoacetate and ammonium acetate at ambient temperature was described as the preparation of polyhydroquinoline derivatives. The process presented here is operationally simple, environmentally benign and has excellent yield. Furthermore, the catalyst can be recovered conveniently and reused efficiently.

  8. A Rapid and Efficient Sonogashira Protocol and Improved Synthesis of Free Fatty Acid 1 (FFA1) Receptor Agonists

    DEFF Research Database (Denmark)

    Christiansen, Elisabeth; Due-Hansen, Maria E; Ulven, Trond

    2010-01-01

    A protocol for rapid and efficient Pd/Cu-catalyzed coupling of aryl bromides and iodides to terminal alkynes has been developed with use of 2-(di-tert-butylphosphino)-N-phenylindole (cataCXium PIntB) as ligand in TMEDA and water. The new protocol successfully couples substrates which failed...... with standard Sonogashira conditions, and enables an efficient general synthetic route to free fatty acid 1 (FFA1) receptor ligands from 3-(4-bromophenyl)propionic acid....

  9. Efficient solar-driven synthesis, carbon capture, and desalinization, STEP: solar thermal electrochemical production of fuels, metals, bleach.

    Science.gov (United States)

    Licht, S

    2011-12-15

    STEP (solar thermal electrochemical production) theory is derived and experimentally verified for the electrosynthesis of energetic molecules at solar energy efficiency greater than any photovoltaic conversion efficiency. In STEP the efficient formation of metals, fuels, chlorine, and carbon capture is driven by solar thermal heated endothermic electrolyses of concentrated reactants occuring at a voltage below that of the room temperature energy stored in the products. One example is CO(2) , which is reduced to either fuels or storable carbon at a solar efficiency of over 50% due to a synergy of efficient solar thermal absorption and electrochemical conversion at high temperature and reactant concentration. CO(2) -free production of iron by STEP, from iron ore, occurs via Fe(III) in molten carbonate. Water is efficiently split to hydrogen by molten hydroxide electrolysis, and chlorine, sodium, and magnesium from molten chlorides. A pathway is provided for the STEP decrease of atmospheric carbon dioxide levels to pre-industial age levels in 10 years. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Methanobactin-Mediated Synthesis of Gold Nanoparticles Supported over Al2O3 toward an Efficient Catalyst for Glucose Oxidation

    Directory of Open Access Journals (Sweden)

    Jia-Ying Xin

    2014-11-01

    Full Text Available Methanobactin (Mb is a copper-binding peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and reduce Au(III to Au(0. In this paper, Au/Al2O3 catalysts prepared by a novel incipient wetness-Mb-mediated bioreduction method were used for glucose oxidation. The catalysts were characterized, and the analysis revealed that very small gold nanoparticles with a particle size <4 nm were prepared by the incipient wetness-Mb-mediated bioreduction method, even at 1.0% Au loading (w/w. The influence of Au loading, calcination temperature and calcination time on the specific activity of Au/Al2O3 catalysts was systematically investigated. Experimental results showed that decomposing the Mb molecules properly by calcinations can enhance the specific activity of Au/Al2O3 catalysts, though they acted as reductant and protective agents during the catalyst preparation. Au/Al2O3 catalysts synthesized by the method exhibited optimum specific activity under operational synthesis conditions of Au loading of 1.0 wt % and calcined at 450 °C for 2 h. The catalysts were reused eight times, without a significant decrease in specific activity. To our knowledge, this is the first attempt at the preparation of Au/Al2O3 catalysts by Mb-mediated in situ synthesis of gold nanoparticles.

  11. Efficient and Scalable Synthesis of 4-Carboxy-Pennsylvania Green Methyl Ester: A Hydrophobic Building Block for Fluorescent Molecular Probes.

    Science.gov (United States)

    Woydziak, Zachary R; Fu, Liqiang; Peterson, Blake R

    2014-01-01

    Fluorinated fluorophores are valuable tools for studies of biological systems. However, amine-reactive single-isomer derivatives of these compounds are often very expensive. To provide an inexpensive alternative, we report a practical synthesis of 4-carboxy-Pennsylvania Green methyl ester. Derivatives of this hydrophobic fluorinated fluorophore, a hybrid of the dyes Oregon Green and Tokyo Green, are often cell permeable, enabling labeling of intracellular targets and components. Moreover, the low pKa of Pennsylvania Green (4.8) confers bright fluorescence in acidic cellular compartments such as endosomes, enhancing its utility for chemical biology investigations. To improve access to the key intermediate 2,7-difluoro-3,6-dihydroxyxanthen-9-one, we subjected bis-(2,4,5-trifluorophenyl)methanone to iterative nucleophilic aromatic substitution by hydroxide on scales of > 40 g. This intermediate was used to prepare over 15 grams of pure 4-carboxy-Pennsylvania Green methyl ester in 28% overall yield without requiring chromatography. This compound can be converted into the amine reactive N -hydroxysuccinimidyl ester in essentially quantitative yield for the synthesis of a wide variety of fluorescent molecular probes.

  12. Synthesis of core-shell heterostructured Cu/Cu2O nanowires monitored by in situ XRD as efficient visible-light photocatalysts

    KAUST Repository

    Chen, Wei

    2013-01-01

    Core-shell heterostructured Cu/Cu2O nanowires with a high aspect ratio were synthesized from Cu foam using a novel oxidation/reduction process. In situ XRD was used as an efficient tool to acquire phase transformation details during the temperature-programmed oxidation of Cu foam and the subsequent reduction process. Based on knowledge of the crucial phase transformation, optimal synthesis conditions for producing high-quality CuO and core-shell Cu/Cu2O nanowires were determined. In favor of efficient charge separation induced by the special core-shell heterostructure and the advanced three-dimensional spatial configuration, Cu/Cu2O nanowires exhibited superior visible-light activity in the degradation of methylene blue. The present study illustrates a novel strategy for fabricating efficiently core-shell heterostructured nanowires and provides the potential for developing their applications in electronic devices, for environmental remediation and in solar energy utilization fields. This journal is © The Royal Society of Chemistry.

  13. Facile and efficient one-pot solvothermal and microwave-assisted synthesis of stable colloidal solutions of MFe{sub 2}O{sub 4} spinel magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Solano, Eduardo; Perez-Mirabet, Leonardo [Universitat Autonoma de Barcelona, Departament de Quimica (Spain); Martinez-Julian, Fernando; Guzman, Roger; Arbiol, Jordi; Puig, Teresa; Obradors, Xavier [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC (Spain); Yanez, Ramon [Universitat Autonoma de Barcelona, Departament de Quimica (Spain); Pomar, Alberto; Ricart, Susagna, E-mail: ricart@icmab.es [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC (Spain); Ros, Josep [Universitat Autonoma de Barcelona, Departament de Quimica (Spain)

    2012-08-15

    Well-defined synthesis conditions of high quality MFe{sub 2}O{sub 4} (M = Mn, Fe, Co, Ni, Zn, and Cu) spinel ferrite magnetic nanoparticles, with diameters below 10 nm, have been described based on facile and efficient one-pot solvothermal or microwave-assisted heating procedures. Both methods are reproducible and scalable and allow forming concentrated stable colloidal solutions in polar solvents, but microwave-assisted heating allows reducing 15 times the required annealing time and leads to an enhanced monodispersity of the nanoparticles. Non-agglomerated nanoparticles dispersions have been achieved using a simple one-pot approach where a single compound, triethyleneglycol, behaves at the same time as solvent and capping ligand. A narrow nanoparticle size distribution and high quality crystallinity have been achieved through selected nucleation and growth conditions. High resolution transmission electron microscopy images and electron energy loss spectroscopy analysis confirm the expected structure and composition and show that similar crystal faceting has been formed in both synthetic approaches. The spinel nanoparticles behave as ferrimagnets with a high saturation magnetization and are superparamagnetic at room temperature. The influence of synthesis route on phase purity and unconventional magnetic properties is discussed in some particular cases such as CuFe{sub 2}O{sub 4}, CoFe{sub 2}O{sub 4}, and ZnFe{sub 2}O{sub 4}.

  14. ZnS nanoparticles as an efficient and reusable heterogeneous catalyst for synthesis of 1-substituted-1 H-tetrazoles under solvent-free conditions

    Science.gov (United States)

    Naeimi, Hossein; Kiani, Fatemeh; Moradian, Mohsen

    2014-09-01

    An efficient and green protocol for the synthesis of 1-substituted-1 H-tetrazoles through cyclization reaction of various primary amines, sodium azide, and triethyl orthoformate was described. In this method, a series of tetrazole derivatives was synthesized by using ZnS nanoparticles as an effective, recoverable, and reusable catalyst under solvent-free conditions. This strategy is a magnificent improvement for the synthesis of these heterocycles due to the non-acidic, clean, and solvent-free conditions via a solid recyclable catalyst. The catalyst was separated by simple filtration and reused seven times without significant loss of activity. The ZnS nanoparticles with high surface area and fine monodisperse particles were prepared using the simple microwave-assisted method without using any surfactant. The ZnS nanoparticle catalyst is a good candidate to replace brønsted acids and metal salts or other catalyst for the preparation of 1-substituted-1 H-tetrazoles in high yields and has potential values for industrial applications.

  15. Efficient synthesis and antimicrobial evaluation of some Mannich bases from 2-arylidine-1-thia-4-azaspiro[4.5]decan-3-ones.

    Science.gov (United States)

    Hussein, Essam M; Masaret, Ghada S; Khairou, Khalid S

    2015-01-01

    Thiazolidinone, has been employed in the preparation of different important drugs required for treatment of inflammations, bacterial infections, and hypertension. Mannich bases have been shown to exhibit diverse biological activities, such as antibacterial, and antifungal activities. Spiroheterocycles including thiazolidine moiety have antimicrobial activity. In this study, a novel, rapid, and efficient protocol is developed for the synthesis of various 2-arylidine-1-thia-4-azaspiro[4.5]decan-3-ones using sodium dodecylbenzene sulfonate (DBSNa) as an inexpensive and readily available reagent in acetic acid at room temperature. High yields, easy work-up, and short reaction times are advantages of this procedure. The synthesized arylidines were undergone Mannich reaction with formaldehyde and secondary amines in absolute ethanol at room temperature to afford the corresponding N-Mannich bases. All prepared Mannich bases were evaluated for their antimicrobial activity. Good activity was noted for Mannich bases from 2-arylidine-1-thia-4-azaspiro[4.5]decan-3-ones, with some members recorded higher antimicrobial activity. Graphical abstractSynthesis of Mannich bases of 2-arylidine-1-thia-4-azaspiro[4.5]decan-3-ones.

  16. Facile and efficient one-pot solvothermal and microwave-assisted synthesis of stable colloidal solutions of MFe2O4 spinel magnetic nanoparticles

    International Nuclear Information System (INIS)

    Solano, Eduardo; Perez-Mirabet, Leonardo; Martinez-Julian, Fernando; Guzmán, Roger; Arbiol, Jordi; Puig, Teresa; Obradors, Xavier; Yañez, Ramón; Pomar, Alberto; Ricart, Susagna; Ros, Josep

    2012-01-01

    Well-defined synthesis conditions of high quality MFe 2 O 4 (M = Mn, Fe, Co, Ni, Zn, and Cu) spinel ferrite magnetic nanoparticles, with diameters below 10 nm, have been described based on facile and efficient one-pot solvothermal or microwave-assisted heating procedures. Both methods are reproducible and scalable and allow forming concentrated stable colloidal solutions in polar solvents, but microwave-assisted heating allows reducing 15 times the required annealing time and leads to an enhanced monodispersity of the nanoparticles. Non-agglomerated nanoparticles dispersions have been achieved using a simple one-pot approach where a single compound, triethyleneglycol, behaves at the same time as solvent and capping ligand. A narrow nanoparticle size distribution and high quality crystallinity have been achieved through selected nucleation and growth conditions. High resolution transmission electron microscopy images and electron energy loss spectroscopy analysis confirm the expected structure and composition and show that similar crystal faceting has been formed in both synthetic approaches. The spinel nanoparticles behave as ferrimagnets with a high saturation magnetization and are superparamagnetic at room temperature. The influence of synthesis route on phase purity and unconventional magnetic properties is discussed in some particular cases such as CuFe 2 O 4 , CoFe 2 O 4 , and ZnFe 2 O 4 .

  17. Efficient synthesis of highly fluorescent nitrogen-doped carbon dots for cell imaging using unripe fruit extract of Prunus mume

    International Nuclear Information System (INIS)

    Atchudan, Raji; Edison, Thomas Nesakumar Jebakumar Immanuel; Sethuraman, Mathur Gopalakrishnan; Lee, Yong Rok

    2016-01-01

    Graphical abstract: The green synthesis of highly fluorescent N-CDs was achieved using the extract of unripe P. mume fruit as a carbon precursor by a one-pot simple hydrothermal-carbonization method. The resulting N-CDs were used as a staining agent for the fluorescence imaging of MDA-MB-231 cells. Display Omitted - Highlights: • The green synthesis of highly fluorescent N-CDs using the extract of unripe P. mume. • The N-CDs were synthesized by one-pot hydrothermal-carbonization method. • This method of synthesis is a simple, cost effective and eco-friendly route. • N-CDs will be a good alternative for fluorescent dyes and SQDs for bio-applications. - Abstract: Highly fluorescent nitrogen-doped carbon dots (N-CDs) were synthesized using the extract of unripe Prunus mume (P. mume) fruit by a simple one step hydrothermal-carbonization method. The N-CDs were synthesized at different pH ranges, 2.3, 5, 7, and 9. The pH of the P. mume extract was adjusted using an aqueous ammonia solution (25%). The optical properties of N-CDs were examined by UV–vis and fluorescence spectroscopy. The N-CDs synthesized at pH 9 emitted high fluorescence intensity compared to other obtained N-CDs. The N-CDs synthesized at pH 9 was further characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform-infra red (FT-IR) spectroscopy. HR-TEM showed that the average size of the synthesized N-CDs was approximately 9 nm and the interlayer distance was 0.21 nm, which was validated by XRD. The graphitic nature of the synthesized N-CDs were confirmed by Raman spectroscopy. XPS and FT-IR spectroscopy confirmed the doping of the nitrogen moiety over the synthesized CDs. The synthesized nitrogen doped CDs (N-CDs) were low toxicity and were used as a staining probe for fluorescence cell imaging.

  18. Efficient synthesis of highly fluorescent nitrogen-doped carbon dots for cell imaging using unripe fruit extract of Prunus mume

    Energy Technology Data Exchange (ETDEWEB)

    Atchudan, Raji; Edison, Thomas Nesakumar Jebakumar Immanuel [School of Chemical Engineering, Yeungnam University, Gyeongsan 38541 (Korea, Republic of); Sethuraman, Mathur Gopalakrishnan, E-mail: mgsethu@gmail.com [Department of Chemistry, Gandhigram Rural Institute-Deemed University, Gandhigram 624 302, Tamilnadu (India); Lee, Yong Rok, E-mail: yrlee@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan 38541 (Korea, Republic of)

    2016-10-30

    Graphical abstract: The green synthesis of highly fluorescent N-CDs was achieved using the extract of unripe P. mume fruit as a carbon precursor by a one-pot simple hydrothermal-carbonization method. The resulting N-CDs were used as a staining agent for the fluorescence imaging of MDA-MB-231 cells. Display Omitted - Highlights: • The green synthesis of highly fluorescent N-CDs using the extract of unripe P. mume. • The N-CDs were synthesized by one-pot hydrothermal-carbonization method. • This method of synthesis is a simple, cost effective and eco-friendly route. • N-CDs will be a good alternative for fluorescent dyes and SQDs for bio-applications. - Abstract: Highly fluorescent nitrogen-doped carbon dots (N-CDs) were synthesized using the extract of unripe Prunus mume (P. mume) fruit by a simple one step hydrothermal-carbonization method. The N-CDs were synthesized at different pH ranges, 2.3, 5, 7, and 9. The pH of the P. mume extract was adjusted using an aqueous ammonia solution (25%). The optical properties of N-CDs were examined by UV–vis and fluorescence spectroscopy. The N-CDs synthesized at pH 9 emitted high fluorescence intensity compared to other obtained N-CDs. The N-CDs synthesized at pH 9 was further characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform-infra red (FT-IR) spectroscopy. HR-TEM showed that the average size of the synthesized N-CDs was approximately 9 nm and the interlayer distance was 0.21 nm, which was validated by XRD. The graphitic nature of the synthesized N-CDs were confirmed by Raman spectroscopy. XPS and FT-IR spectroscopy confirmed the doping of the nitrogen moiety over the synthesized CDs. The synthesized nitrogen doped CDs (N-CDs) were low toxicity and were used as a staining probe for fluorescence cell imaging.

  19. OSU-6: A Highly Efficient, Metal-Free, Heterogeneous Catalyst for the Click Synthesis of 5-Benzyl and 5-Aryl-1H-tetrazoles

    Directory of Open Access Journals (Sweden)

    Baskar Nammalwar

    2015-12-01

    Full Text Available OSU-6, an MCM-41 type hexagonal mesoporous silica with mild Brönsted acid properties, has been used as an efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles from nitriles in DMF at 90 °C. This catalyst offers advantages including ease of operation, milder conditions, high yields, and reusability. Studies are presented that demonstrate the robust nature of the catalyst under the optimized reaction conditions. OSU-6 promotes the 1,3-dipolar addition of azides to nitriles without significant degradation or clogging of the nanoporous structure. The catalyst can be reused up to five times without a significant reduction in yield, and it does not require treatment with acid between reactions.

  20. An adapted route to efficient synthesis of 1,8-dioxooctahydro-xanthene derivatives using InCl3 and (HPO3n as recyclable catalysts

    Directory of Open Access Journals (Sweden)

    Bahador Karami

    2015-09-01

    Full Text Available Indium (III chloride (InCl3 and metaphosphoric acid ((HPO3n were found to be efficient and recyclable catalysts for the synthesis of 1,8-dioxooctahydroxanthene derivatives as biologically important molecules in high turnover numbers and rates. Several substituted xanthenes can be prepared in high yield and purity by direct reaction of cyclic β-diketones and aldehyde derivatives in the presence of a catalytic amount of InCl3 and (HPO3n as Lewis acids and at ambient temperature under solvent-free conditions. This newly reported procedure profit some advantages such as short reaction times, high yields of products, cheap, easy to use, facile practical conditions, and wholesome with green chemistry without using harmful solvents.

  1. Facile and rapid synthesis of divers xanthene derivatives using lanthanum(III chloride/chloroacetic acid as an efficient and reusable catalytic system under solvent-free conditions

    Directory of Open Access Journals (Sweden)

    Pouramiri Behjat

    2017-01-01

    Full Text Available LaCl3/ClCH2COOH was used as an efficient, and recyclable catalytic system for synthesis of 11H-benzo[a]xanthene-11-one, hexahydro-1H-xanthene- 1,8(2H-dione and 11-aryl-10H-diindeno[1,2-b:2′,1′-e]pyran-10,12(11H-dione derivatives via a one-pot three-component reaction of aldehydes, 2-naphthol, and cyclic 1,3-dicarbonyl compounds. The reactions proceeded rapidly at 70°C under solvent-free conditions and the desired products were obtained in good to excellent yields.

  2. Facile One-Pot Synthesis of Amidoalkyl Naphthols and Benzopyrans Using Magnetic Nanoparticle-Supported Acidic Ionic Liquid as a Highly Efficient and Reusable Catalyst

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2017-11-01

    Full Text Available An efficient and eco-friendly procedure for the synthesis of 1-amidoalkyl-2-naphthol and tetrahydrobenzo[b]pyran derivatives has been developed through a one-pot three-component condensation of aldehydes with 2-naphthol and amides, or with malononitrile and dimedone in the presence of magnetic nanoparticle supported acidic ionic liquid (AIL@MNP as a novel heterogeneous catalyst under solvent-free conditions. This new procedure offers several advantages such as short reaction time, excellent yields, operational simplicity and without any tedious work-up for catalyst recovery or product purification. Moreover, the catalyst could be simply separated by an external magnet and reused six times without significant loss of catalytic activity.

  3. Simple and Efficient One-Pot Synthesis, Spectroscopic Characterization and Crystal Structure of Methyl 5-(4-Chlorobenzoyloxy-1-phenyl-1H-pyrazole-3-carboxylate

    Directory of Open Access Journals (Sweden)

    Imtiaz Khan

    2012-07-01

    Full Text Available A facile one-pot synthesis of methyl 5-(4-chlorobenzoyloxy-1-phenyl-1H-pyrazole-3-carboxylate (4 is described. The title compound was efficiently synthesized by the reaction of phenyl hydrazine, dimethyl acetylenedicarboxylate and 4-chlorobenzoyl chloride in dichloromethane under reflux in good yield. The structure of the target compound was deduced by modern spectroscopic and analytical techniques and unequivocally confirmed by a single crystal X-ray diffraction analysis. The crystal of the title compound belongs to orthorhombic system, space group P 21 21 21 with cell parameters a = 6.6491(3 Å, b = 7.9627(6 Å, c = 30.621(5 Å, α = β = γ = 90° and Z = 4. The crystal packing of the compound (4 is stabilized by an offset π-stacking between the planar benzoyl-substituted diazole moieties.

  4. Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications

    Directory of Open Access Journals (Sweden)

    Hua Bing Tao

    2014-06-01

    Full Text Available A biomolecule-assisted pyrolysis method has been developed to synthesize sulfur-doped graphitic carbon nitride (CNS nanosheets. During the synthesis, sulfur could be introduced as a dopant into the lattice of carbon nitride (CN. Sulfur doping changed the texture as well as relative band positions of CN. By growing CN on preformed sulfur-doped CN nanosheets, composite CN/CNS heterojunction nanosheets were constructed, which significantly enhanced the photoelectrochemical performance as compared with various control counterparts including CN, CNS and physically mixed CN and CNS (CN+CNS. The enhanced photoelectrochemical performance of CN/CNS heterojunction nanosheets could be ascribed to the efficient separation of photoexcited charge carriers across the heterojunction interface. The strategy of designing and preparing CN/CNS heterojunction photocatalysts in this work can open up new directions for the construction of all CN-based heterojunction photocatalysts.

  5. Cesium nitrate: As an efficient catalyst for synthesis of gem-dihydroperoxides from aldehydes and ketones using aqueous 30% H2O2

    Directory of Open Access Journals (Sweden)

    Kaveh Khosravi

    2015-12-01

    Full Text Available Gem-dihydroperoxides (DHPs, as key intermediates of aldehydes and ketones, are important precursors in synthesis of anti-malaria drugs and have been used as a solid and powerful oxidant in many oxidation organic reactions. For the importance of gem-DHPs, in this work, cesium nitrate has been used as an efficient and commercially available solid catalyst for catalysis peroxidation of aldehydes and ketones to corresponding gem-DHPs by 30% aqueous hydrogen peroxide at room temperature. The reactions carry on with short time and the products were obtained in excellent yields and high purity. In all reaction, no by-product was observed. This methodology is new, easy, effective, and usable.

  6. Efficient Enzymatic Routes for the Synthesis of New Eight-membered Cyclic β-Amino Acid and β-Lactam Enantiomers

    Directory of Open Access Journals (Sweden)

    Enikő Forró

    2017-12-01

    Full Text Available Efficient enzymatic resolutions are reported for the preparation of new eight-membered ring-fused enantiomeric β-amino acids [(1R,2S-9 and (1S,2R-9] and β-lactams [(1S,8R-3, (1R,8S-3 (1S,8R-4 and (1R,8S-7], through asymmetric acylation of (±-4 (E > 100 or enantioselective hydrolysis (E > 200 of the corresponding inactivated (±-3 or activated (±-4 β-lactams, catalyzed by PSIM or CAL-B in an organic solvent. CAL-B-catalyzed ring cleavage of (±-6 (E > 200 resulted in the unreacted (1S,8R-6, potential intermediate for the synthesis of enantiomeric anatoxin-a. The best strategies, in view of E, reaction rate and product yields, which underline the importance of substrate engineering, are highlighted.

  7. Mannich Bases as Enone Precursors for Water-Mediated Efficient Synthesis of 2,3,6-Trisubstituted Pyridines and 5,6,7,8-Tetrahydroquinolines.

    Science.gov (United States)

    Hanashalshahaby, Essam Hamied Ahmed; Unaleroglu, Canan

    2015-06-08

    A highly efficient, regioselective, and environmentally friendly method has been developed for water-mediated synthesis of 2,3,6-trisubstituted pyridines and 5,6,7,8-tetrahydroquinolines. The introduced method allows easy preparation of various polysubstituted pyridines and 5,6,7,8-tetrahydroquinolines via domino reaction of an enolizable ketone, ammonia and enones derived from different Mannich bases in mild reaction conditions. Montmorillonite K-10 promoted this one-pot three-component reaction and gave both new and known 2,3,6-trisubstituted pyridines and 5,6,7,8-tetrahydroquinolines in good yields. The reaction protocol provides a wide array of functionality in construction of polysubstituted pyridines and 5,6,7,8-tetrahydroquinolines from commercially available starting materials in easily applicable and environmentally friendly conditions.

  8. Efficient continuous-flow synthesis of novel 1,2,3-triazole-substituted β-aminocyclohexanecarboxylic acid derivatives with gram-scale production

    Directory of Open Access Journals (Sweden)

    Sándor B. Ötvös

    2013-07-01

    Full Text Available The preparation of novel multi-substituted 1,2,3-triazole-modified β-aminocyclohexanecarboxylic acid derivatives in a simple and efficient continuous-flow procedure is reported. The 1,3-dipolar cycloaddition reactions were performed with copper powder as a readily accessible Cu(I source. Initially, high reaction rates were achieved under high-pressure/high-temperature conditions. Subsequently, the reaction temperature was lowered to room temperature by the joint use of both basic and acidic additives to improve the safety of the synthesis, as azides were to be handled as unstable reactants. Scale-up experiments were also performed, which led to the achievement of gram-scale production in a safe and straightforward way. The obtained 1,2,3-triazole-substituted β-aminocyclohexanecarboxylates can be regarded as interesting precursors for drugs with possible biological effects.

  9. Indium-mediated allylation in carbohydrate synthesis: A short and efficient approach towards higher 2-acetamido-2-deoxy sugars

    Directory of Open Access Journals (Sweden)

    Christopher Albler

    2014-09-01

    Full Text Available Higher aminosugars are interesting targets in carbohydrate synthesis since these compounds play important roles in biological systems. However, their availability from natural sources is limited. Thus, in order to investigate their biological function, the development of facile and adaptable routes to this class of compounds is of fundamental importance. Our synthetic route towards these target molecules makes use of readily accessible pentoses and hexoses, which are subjected to indium-mediated two-carbon chain elongation. Subsequent ozonolysis and treatment with base yields α,β-unsaturated aldehydes, which are stereoselectively epoxidized using Jørgenson’s protocol. After Wittig chain elongation the obtained allylic epoxides were regio- and stereoselectively opened with trimethylsilyl azide under palladium catalysis. Finally, a suitable deprotection protocol, starting with acidic acetate cleavage and ozonolysis was established. Peracetylation of the products simplifies purification and subsequent azide reduction followed by final deacetylation using methanolic sodium methoxide furnishes the title compounds.

  10. Synthesis and Characterization of Antireflective ZnO Nanoparticles Coatings Used for Energy Improving Efficiency of Silicone Solar Cells

    Science.gov (United States)

    Pîslaru-Dǎnescu, Lucian; Chitanu, Elena; El-Leathey, Lucia-Andreea; Marinescu, Virgil; Marin, Dorian; Sbârcea, Beatrice-Gabriela

    2018-03-01

    The paper proposes a new and complex process for the synthesis of ZnO nanoparticles for antireflective coating corresponding to silicone solar cells applications. The process consists of two major steps: preparation of seed layer and hydrothermal growth of ZnO nanoparticles. Due to the fact that the seed layer morphology influences the ZnO nanoparticles proprieties, the process optimization of the seed layer preparation is necessary. Following the hydrothermal growth of the ZnO nanoparticles, antireflective coating of silicone solar cells is achieved. After determining the functional parameters of the solar cells provided either with glass or with ZnO, it is concluded that all the parameters values are superior in the case of solar cells with ZnO antireflection coating and are increasing along with the solar irradiance.

  11. Nb-Based Zeolites: Efficient bi-Functional Catalysts for the One-Pot Synthesis of Succinic Acid from Glucose

    Directory of Open Access Journals (Sweden)

    Magdi El Fergani

    2017-12-01

    Full Text Available The one-pot production of succinic acid from glucose was investigated in pure hot water as solvent using Nb (0.02 and 0.05 moles%-Beta zeolites obtained by a post-synthesis methodology. Structurally, they are comprised of residual framework Al-acid sites, extra-framework isolated Nb (V and Nb2O5 pore-encapsulated clusters. The Nb-modified Beta-zeolites acted as bi-functional catalysts in which glucose is dehydrated to levulinic acid (LA which, further, suffers an oxidation process to succinic acid (SA. After the optimization of the reaction conditions, that is, at 180 °C, 18 bar O2, and 12 h reaction time, the oxidation of glucose occurred with a selectivity to succinic acid as high as 84% for a total conversion.

  12. Novel approach for heterocyclization: a clean and efficient synthesis and biological evaluation of 4-oxothiazolidines under microwave technique

    International Nuclear Information System (INIS)

    Desai, Krunal G.; Desai, K.R.

    2006-01-01

    A new selective method has been developed for rapid synthesis of 2-(aryl)-3-[2-benzoimidazolythio)-acetamidyl]-4-oxothiazolidines 4a-j by the heterocyclization of 2-{(1H-benzemidazol)-ylthio}-N-benzylidene aceto hydrazide 3a-j with HSCH2COOH under microwave irradiation (MWI) is described. The reaction rate and yield is enhanced tremendously under MWI as compared to conventional methods. All the compounds have been screened for their antifungal activity against Candida albicans and Aspergillus niger, antibacterial activity against Escherchia coli and Staphylococcus aureus. In the primary screening, some of the compounds exhibited appreciable activity. The structures of the synthesized compounds 4a-j have been characterized on the basis of their elemental analysis, IR, HNMR and Mass spectral data. (author)

  13. Alginic acid: A mild and renewable bifunctional heterogeneous biopolymeric organocatalyst for efficient and facile synthesis of polyhydroquinolines.

    Science.gov (United States)

    Dekamin, Mohammad G; Karimi, Zahra; Latifidoost, Zahra; Ilkhanizadeh, Siamand; Daemi, Hamed; Naimi-Jamal, M Reza; Barikani, Mehdi

    2018-03-01

    Alginic acid, a widely used naturally occurring carbohydrate which is generally derived from brown seaweeds, can be considered as a bifunctional heterogeneous and green biopolymeric organocatalyst. Alginic acid, without any post-modification with active Bronsted or Lewis acid centers, was found to be a highly active, cost-effective, commercially-available, renewable and recoverable heterogeneous biopolymeric organocatalyst for the expeditious synthesis of polyhydroquinolines (PHQs). Polyhydroquinolines were synthesized from the four-component Hantzsch reaction of ethyl acetoacetate, different aldehydes, ammonium acetate and cyclic 1,3-diones under mild conditions in high to quantitative yields, 75-97%, using alginic acid. Furthermore, alginic acid was found to be reusable for at least 6 consecutive cycles without considerable loss of its catalytic activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Novel bipyridinyl oxadiazole-based metal coordination complexes: High efficient and green synthesis of 3,4-dihydropyrimidin-2(1H)-ones through the Biginelli reactions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin-Hua; Zhang, E. [Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan 250353 (China); Tang, Gui-Mei, E-mail: meiguit@163.com [Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan 250353 (China); Wang, Yong-Tao, E-mail: ceswyt@qlu.edu.cn [Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan 250353 (China); Cui, Yue-Zhi [Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan 250353 (China); Ng, Seik Weng [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2016-09-15

    Three new metal coordination complexes, namely, [Co(BPO){sub 2}(H{sub 2}O){sub 4}](BS){sub 2}(H{sub 2}O){sub 2} (1), [Co(BPO){sub 2}(H{sub 2}O){sub 4}](ABS){sub 2}(H{sub 2}O){sub 2} (2), [Co(BPO){sub 2}(H{sub 2}O){sub 4}](MBS){sub 2}(H{sub 2}O){sub 2} (3) [BPO=2,5-di(pyridin-4-yl)-1,3,4-oxadiazole, BS=benzenesulphonate, ABS=4-aminobenzenesulphonate, MBS=4-methylbenzenesulphonate] were obtained under hydrothermal conditions. Complexes 1–3 were structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, IR and thermogravimetric analyses (TGA). All of them display a zero-dimensional motif, in which strong intermolecular hydrogen bonding interactions (O–H···O/N) and packing interactions (C–H···π and π···π) make them achieve a three-dimensional supramolecular architecture. The primary catalytic results of these three complexes show that high efficiency for the green synthesis of a variety of 3,4-dihydropyrimidin-2(1H)-ones was observed under solvent free conditions through Biginelli reactions. The present catalytic protocols exhibit advantages such as excellent yield, easy isolation, eco-friendly conditions, and short reaction time. - Graphical abstract: Three new metal coordination complexes with bipyridinyl-oxadiazole were obtained under hydrothermal conditions, which display a zero-dimensional motif, and show high efficiency for the green synthesis of a variety of 3,4-dihydropyrimidin-2(1H)-ones under solvent free conditions through Biginelli reactions. The present catalytic protocols exhibit advantages such as excellent yield, easy isolation, eco-friendly conditions, and short reaction time. Display Omitted.

  15. Efficient lipase-catalyzed Knoevenagel condensation: utilization of biocatalytic promiscuity for synthesis of benzylidene-indolin-2-ones.

    Science.gov (United States)

    Ding, Yan; Xiang, Xinran; Gu, Mengjie; Xu, Haoran; Huang, He; Hu, Yi

    2016-01-01

    Based on the screening of biocatalysts and reaction conditions including solvent, water content, temperature, enzyme loading, and reaction time, lipase from porcine pancreas (PPL) showed the prominent promiscuity for the Knoevenagel condensation between 1,3-dihydroindol-2-one heterocycle and aromatic aldehydes. Under the optimized procedure, both electron-withdrawing and electron-donating substituent of aldehydes substrates could react efficiently, and benzylidene-indolin-2-ones were obtained in excellent yields (75.0-96.6%). Benzylidene-indolin-2-ones derivatives were efficiently synthesized by the Knoevenagel condensation between various aromatic aldehydes and 1,3-dihydroindol-2-one catalyzed by lipase from porcine pancreas with excellent yields obtained.

  16. Synthesis and characterization of highly efficient and stable Pr6O11/Ag3PO4/Pt ternary hybrid structure

    International Nuclear Information System (INIS)

    Deng, Jiatao; Liu, Lin; Niu, Tongjun; Sun, Xiaosong

    2017-01-01

    Highlights: • Visible-light-driven Pr 6 O 11 /Ag 3 PO 4 /Pt photocatalysts were prepared. • Pr 6 O 11 /Ag 3 PO 4 /Pt showed highly efficient and stable photocatalystic activity. • The photocatalytic mechanism of Pr 6 O 11 /Ag 3 PO 4 /Pt composite was given. - Abstract: Ag 3 PO 4 is an excellent photocatalyst with high efficiency and quantum yield, but suffers from the fast recombination of photogenerated electron-hole pairs and photo-corrosion. Hereby, the highly efficient and stable visible-light-driven Pr 6 O 11 /Ag 3 PO 4 /Pt photocatalyst were prepared via a three-step wet chemical approach. The as-prepared Pr 6 O 11 /Ag 3 PO 4 /Pt composite was characterized by X-ray diffraction, US-vis diffuse reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectra and transient photocurrent as well. Comparing with single Pr 6 O 11 or Ag 3 PO 4 , the prepared Pr 6 O 11 /Ag 3 PO 4 /Pt composite exhibited much higher photocatalytic activity and stability for the degradation of Rhodamine B under visible light irradiation (>420 nm). The enhanced photocatalytic performance of Pr 6 O 11 /Ag 3 PO 4 /Pt composite has been attributed to the efficient separation of photo-generated electron-hole pairs through a scheme system composed of Pr 6 O 11, Ag 3 PO 4 and Pt.

  17. I2/K2CO3: An efficient catalyst for the synthesis of 5-aryl-2,6-dicyano ...

    Indian Academy of Sciences (India)

    Photo-induced intramolecular electron transfer (PIET) leading to a charge separation in a supramolecular structure plays a fundamental role in the dynamics of concomitant processes involved in the photosynthesis, in biology, in photonics or in the solar energy conver- sion.3 One of the factors that tune the efficiency of the.

  18. One-Pot Large-Scale Synthesis of Carbon Quantum Dots: Efficient Cathode Interlayers for Polymer Solar Cells.

    Science.gov (United States)

    Yang, Yuzhao; Lin, Xiaofeng; Li, Wenlang; Ou, Jiemei; Yuan, Zhongke; Xie, Fangyan; Hong, Wei; Yu, Dingshan; Ma, Yuguang; Chi, Zhenguo; Chen, Xudong

    2017-05-03

    Cathode interlayers (CILs) with low-cost, low-toxicity, and excellent cathode modification ability are necessary for the large-scale industrialization of polymer solar cells (PSCs). In this contribution, we demonstrated one-pot synthesized carbon quantum dots (C-dots) with high production to serve as efficient CIL for inverted PSCs. The C-dots were synthesized by a facile, economical microwave pyrolysis in a household microwave oven within 7 min. Ultraviolet photoelectron spectroscopy (UPS) studies showed that the C-dots possessed the ability to form a dipole at the interface, resulting in the decrease of the work function (WF) of cathode. External quantum efficiency (EQE) measurements and 2D excitation-emission topographical maps revealed that the C-dots down-shifted the high energy near-ultraviolet light to low energy visible light to generate more photocurrent. Remarkably improvement of power conversion efficiency (PCE) was attained by incorporation of C-dots as CIL. The PCE was boosted up from 4.14% to 8.13% with C-dots as CIL, which is one of the best efficiency for i-PSCs used carbon based materials as interlayers. These results demonstrated that C-dots can be a potential candidate for future low cost and large area PSCs producing.

  19. An Efficient Synthesis of Phenols via Oxidative Hydroxylation of Arylboronic Acids Using (NH42S2O8

    Directory of Open Access Journals (Sweden)

    Claudia A. Contreras-Celedón

    2014-01-01

    Full Text Available A mild and efficient method for the ipso-hydroxylation of arylboronic acids to the corresponding phenols was developed using (NH42S2O8 as an oxidizing agent. The reactions were performed under metal-, ligand-, and base-free conditions.

  20. Synthesis and characterization of a porous and hydrophobic cellulose-based composite for efficient and fast oil-water separation.

    Science.gov (United States)

    Wang, Xiangyun; Xu, Shimei; Tan, Yun; Du, Juan; Wang, Jide

    2016-04-20

    Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, silanized cellulose was prepared by sol-gel reaction between microcrystalline cellulose (MCC) and hexadecyltrimethoxysilane (HDTMS) using for oil-water separation. The silanized cellulose was characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). A higher mass ratio of HDTMS to MCC made silanized cellulose become looser, and showed lower water absorbency. The silanized cellulose exhibited specific separation performance towards vegetable oil-water mixture (not for mineral oil-water mixture) with separation efficiency of 99.93%. Moreover, the separation was fast with a water flux of 4628.5Lm(-2)h(-1). The separation efficiency still remained at 99.77% even after recycling for 10 times. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Atom Efficient Preparation of Zinc Selenates for the Synthesis of Selenol Esters under “On Water” Conditions

    Directory of Open Access Journals (Sweden)

    Luca Sancineto

    2017-06-01

    Full Text Available We describe here an atom efficient procedure to prepare selenol esters in good to excellent yields by reacting [(PhSe2Zn] or [(PhSe2Zn]TMEDA with acyl chlorides under “on water” conditions. The method is applicable to a series of aromatic and aliphatic acyl chlorides and tolerates the presence of other functionalities in the starting material.

  2. Facile and efficient synthesis of benzoxazole derivatives using novel catalytic activity of PEG-SO3H

    Directory of Open Access Journals (Sweden)

    Rupesh V. Chikhale

    2017-07-01

    Full Text Available A highly efficient, simple and rapid method for the preparation of various 2-aminobenzoxazoles and other benzoxazole derivatives using a catalytic amount of poly (ethylene glycol-bound sulfonic acid (PEG-SO3H is described. PEG-SO3H is found to be an economical and reusable catalyst with low catalytic loading. The percent yield was found to be satisfactory, experimental set up and purification of final products are facile and easy.

  3. A Novel and Efficient Synthesis of Hexanitrostilbene by N-Hydroxyphthalimide/FeCl2-Catalyzed Aerobic Dehydrogenation of Hexanitrobibenzyl

    Science.gov (United States)

    Lu, Tingting; Yao, Kai; Mao, Yang; Xu, Jian; Wang, Pengcheng; Lu, Ming

    2013-07-01

    A novel and effective catalytic system containing N-hydroxyphthalimide (NHPI) and FeCl2 is described for the preparation of hexanitrostilbene (HNS) by the dehydrogenation of hexanitrobibenzyl (HNBB) under an oxygen atmosphere. The reaction conditions, such as reaction time, and the amount of NHPI were discussed. The efficient and more environmentally friendly method proved to be a better selection when compared to other previous methods, such as Shipp and Kaplan's method [1].

  4. Efficient phyto-synthesis and structural characterization of rutile TiO2 nanoparticles using Annona squamosa peel extract

    Science.gov (United States)

    Roopan, Selvaraj Mohana; Bharathi, A.; Prabhakarn, A.; Abdul Rahuman, A.; Velayutham, K.; Rajakumar, G.; Padmaja, R. D.; Lekshmi, Mohan; Madhumitha, G.

    2012-12-01

    In the present study, the biosynthesis of rutile TiO2 nanoparticles (TiO2 NPs) was achieved by a novel, biodegradable and convenient procedure using fruit peel Annona squamosa aqueous extract. This is the first report on the new, simple, rapid, eco-friendly and cheaper methods for the synthesis of rutile TiO2 NPs at lower temperature using agricultural waste. Rutile TiO2 NPs were characterized by UV, XRD, SEM, TEM and EDS studies. The UV-Vis spectrophotometer results were promising and showed a rapid production of TiO2 NPs with a surface plasmon resonance occurring at 284 nm. The formation of the TiO2 NPs as observed from the XRD spectrum is confirmed to be TiO2 particles in the rutile form as evidenced by the peaks at 2θ = 27.42°, 36.10°, 41.30° and 54.33° when compared with the literature. The TEM images showed polydisperse nanoparticles with spherical shapes and size 23 ± 2 nm ranges.

  5. One-Step Hydrothermal Synthesis of Small TiO₂ Porous Nanoparticles for Efficient Degradation of Organic Dyes.

    Science.gov (United States)

    Zhang, Jing; Wang, Donghai; Zhang, Haijiao

    2018-05-01

    In the work, small TiO2 porous nanoparticles with an average size of 60 nm have been prepared by a simple, eco-friendly, and one-step hydrothermal method. The TiO2 products are achieved by only using tetrabutyl titanate (TBOT), tetrapropylammonium hydroxide (TPAOH), and water as the starting materials. Various techniques such as SEM, TEM, HRTEM, XRD, Raman, and BET are used to characterize the surface morphology and structural features of products. The growth parameters including reaction time, titanium source and temperature of thermal treatment are systematically investigated. In the synthesis, TPAOH plays a decisive role as structure-directing agent for the formation of desirable TiO2 nanostructure. The photocatalytic tests manifest that the TiO2 nanoparticles annealed at 450 °C shows an outstanding photocatalytic activity for degradation of methyl orange (MO) and rhodamine B (RhB), which is comparable to Degussa P25. The superior performance may mainly come from the contributions of their small particle size and unique nanostructure.

  6. Facile synthesis of thiol-polyethylene glycol functionalized magnetic titania nanomaterials for highly efficient enrichment of N-linked glycopeptides.

    Science.gov (United States)

    Wang, Jiawen; Yao, Jizong; Sun, Nianrong; Deng, Chunhui

    2017-08-25

    As protein N-glycosylation involved in generation and development of various cancers and diseases, it is vital to capture glycopeptides from complex biological samples for biomarker discovery. In this work, by taking advantages of the interaction between titania and thiol groups, thiol-polyethylene glycol functionalized magnetic titania nanomaterials (denoted as Fe 3 O 4 @TiO 2 @PEG) were firstly fabricated as an excellent hydrophilic adsorbent of N-linked glycopeptides. On one hand, the special interaction of titanium-thiol makes the synthetic manipulation simple and provides a new idea for design and synthesis of novel nanomaterials; on the other hand, strong magnetic response could realize rapid separation and the outstanding hydrophilicity of polyethylene glycol makes Fe 3 O 4 @TiO 2 @PEG nanomaterials show superior performance for glycopeptides enrichment with ultralow limit of detection (0.1mol/μL) and high selectivity (1:100). As a result, 24 and 33 glycopeptides enriched from HRP and IgG digests were identified respectively by MALDI-TOF MS, and 300 glycopeptides corresponding to 106 glycoproteins were recognized from merely 2μL human serum, indicating a great potential of Fe 3 O 4 @TiO 2 @PEG nanomaterials for glycoproteomic research. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Highly Efficient One-Pot Synthesis of COS-Based Block Copolymers by Using Organic Lewis Pairs.

    Science.gov (United States)

    Yang, Jia-Liang; Cao, Xiao-Han; Zhang, Cheng-Jian; Wu, Hai-Lin; Zhang, Xing-Hong

    2018-01-31

    A one-pot synthesis of block copolymer with regioregular poly(monothiocarbonate) block is described via metal-free catalysis. Lewis bases such as guanidine, quaternary onium salts, and Lewis acid triethyl borane (TEB) were equivalently combined and used as the catalysts. By using polyethylene glycol (PEG) as the macromolecular chain transfer agent (CTA), narrow polydispersity block copolymers were obtained from the copolymerization of carbonyl sulfide (COS) and propylene oxide (PO). The block copolymers had a poly(monothiocarbonate) block with perfect alternating degree and regioregularity. Unexpectedly, the addition of CTA to COS/PO copolymerization system could dramatically improve the turnover frequency (TOF) of PO (up to 240 h -1 ), higher than that of the copolymerization without CTA. In addition, the conversion of CTA could be up to 100% in most cases, as revealed by ¹H NMR spectra. Of consequence, the number-average molecular weights ( M n s) of the resultant block copolymers could be regulated by varying the feed ratio of CTA to PO. Oxygen-sulfur exchange reaction (O/S ER), which can generate randomly distributed thiocarbonate and carbonate units, was effectively suppressed in all of the cases in the presence of CTA, even at 80 °C. This work presents a versatile method for synthesizing sulfur-containing block copolymers through a metal-free route, providing an array of new block copolymers.

  8. RACK1 depletion in a mouse model causes lethality, pigmentation deficits and reduction in protein synthesis efficiency.

    Science.gov (United States)

    Volta, Viviana; Beugnet, Anne; Gallo, Simone; Magri, Laura; Brina, Daniela; Pesce, Elisa; Calamita, Piera; Sanvito, Francesca; Biffo, Stefano

    2013-04-01

    The receptor for activated C-kinase 1 (RACK1) is a conserved structural protein of 40S ribosomes. Strikingly, deletion of RACK1 in yeast homolog Asc1 is not lethal. Mammalian RACK1 also interacts with many nonribosomal proteins, hinting at several extraribosomal functions. A knockout mouse for RACK1 has not previously been described. We produced the first RACK1 mutant mouse, in which both alleles of RACK1 gene are defective in RACK1 expression (ΔF/ΔF), in a pure C57 Black/6 background. In a sample of 287 pups, we observed no ΔF/ΔF mice (72 expected). Dissection and genotyping of embryos at various stages showed that lethality occurs at gastrulation. Heterozygotes (ΔF/+) have skin pigmentation defects with a white belly spot and hypopigmented tail and paws. ΔF/+ have a transient growth deficit (shown by measuring pup size at P11). The pigmentation deficit is partly reverted by p53 deletion, whereas the lethality is not. ΔF/+ livers have mild accumulation of inactive 80S ribosomal subunits by polysomal profile analysis. In ΔF/+ fibroblasts, protein synthesis response to extracellular and pharmacological stimuli is reduced. These results highlight the role of RACK1 as a ribosomal protein converging signaling to the translational apparatus.

  9. Efficient synthesis of hydroxystyrenes via biocatalytic decarboxylation/deacetylation of substituted cinnamic acids by newly isolated Pantoea agglomerans strains.

    Science.gov (United States)

    Sharma, Upendra K; Sharma, Nandini; Salwan, Richa; Kumar, Rakesh; Kasana, Ramesh C; Sinha, Arun K

    2012-02-01

    Decarboxylation of substituted cinnamic acids is a predominantly followed pathway for obtaining hydroxystyrenes-one of the most extensively explored bioactive compounds in the food and flavor industry (e.g. FEMA GRAS approved 4-vinylguaiacol). For this, mild and green strategies providing good yields with high product selectivity are needed. Two newly isolated bacterial strains, i.e. Pantoea agglomerans KJLPB4 and P. agglomerans KJPB2, are reported for mild and effective decarboxylation of substituted cinnamic acids into corresponding hydroxystyrenes. Key operational parameters for the process, such as incubation temperature, incubation time, substrate concentration and effect of co-solvent, were optimized using ferulic acid as a model substrate. With strain KJLPB4, 1.51 g L⁻¹ 4-vinyl guaiacol (98% yield) was selectively obtained from 2 g L⁻¹ ferulic acid at 28 °C after 48 h incubation. However, KJPB2 provided vanillic acid in 85% yield after 72 h following the oxidative decarboxylation pathway. In addition, KJLPB4 was effectively exploited for the deacetylation of acetylated α-phenylcinnamic acids, providing corresponding compounds in 65-95% yields. Two newly isolated microbial strains are reported for the mild and selective decarboxylation of substituted cinnamic acids into hydroxystyrenes. Preparative-scale synthesis of vinyl guaiacol and utilization of renewable feedstock (ferulic acid extracted from maize bran) have been demonstrated to enhance the practical utility of the process. Copyright © 2011 Society of Chemical Industry.

  10. Efficient synthesis of (S)-N-Boc-3-hydroxypiperidine using an (R)-specific carbonyl reductase from Candida parapsilosis.

    Science.gov (United States)

    Chen, Jingjing; Yan, Ming; Xu, Lin

    2017-03-01

    (S)-N-Boc-3-hydroxypiperidine (S-NBHP) is a critical chiral intermediate in the synthesis of pharmaceuticals, including ibrutinib, the active pharmaceutical ingredient of the new drug Imbruvica approved for the treatment of lymphoma. An (R)-specific carbonyl reductase from Candida parapsilosis (CprCR, also known as R-specific alcohol dehydrogenase) that catalyzes asymmetric reduction to produce (S)-N-Boc-3-hydroxypiperidine (S-NBHP) was identified for the first time. When co-expressed with a glucose dehydrogenase from Bacillus megaterium in Escherichia coli Rosetta (DE3), recombinant crude enzyme exhibited an activity of 9 U/mg with N-Boc-3-piperidone as the substrate and 12 U/mg with glucose as the substrate. The biocatalysis of N-Boc-3-piperidone to S-NBHP using recombinant whole-cell biocatalysts was processed in a water/butyl acetate system as well as an aqueous monophasic system without extra NAD + /NADH. This process showed great commercial potential, with a 100 g/l substrate concentration and a whole cells loading (w/v) of 10%, with the conversion of 97.8% and an e.e. of 99.8% in an aqueous monophasic system.

  11. Facile synthesis of unique NiO nanostructures for efficiently catalytic conversion of CH{sub 4} at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Yucheng; Zhao, Yanting; Ni, Liuliu; Jiang, Kedan; Tong, Guoxiu, E-mail: tonggx@zjnu.cn; Zhao, Yuling; Teng, Botao, E-mail: tbt@zjnu.cn

    2016-01-30

    Graphical abstract: - Highlights: • A simple one-pot thermal decomposition approach for NiO nanostructures. • Revealing the mechanism of morphological evolution. • Investigating the morphology-dependence of catalytic properties. - Abstract: A simple one-pot thermal decomposition approach to the selective synthesis of NiO nanomaterials was developed. The morphologies of the NiO nanomaterials were nanoparticle-based sheets, octahedra, nanosheet-built agglomerates, and nanoparticle-based microspheres. The samples were characterized by field-emission scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and N{sub 2} adsorption analyses. The morphology, crystal size, and texture properties of the products can be easily modulated by selecting various decomposition temperatures and precursors. Samples with high specific surface area and small crystal size were found to easily form at low sintering temperatures and when basic nickel carbonate and nickel oxalate dihydrate were used as precursors. Reduction property and CH{sub 4} conversion, as functions of decomposition temperature and precursor type, were systematically investigated. When NiCO{sub 3}·2Ni(OH){sub 2}·4H{sub 2}O and NiC{sub 2}O{sub 4}·2H{sub 2}O were used as precursors, the as-obtained nanosheet-built agglomerates and nanoparticle-based sheets presented a high CH{sub 4} conversion rate because of the small crystal size and large specific surface area.

  12. Synthesis of nano-patterned and Nickel Silicide embedded amorphous Si thin layer by ion implantation for higher efficiency solar devices

    Science.gov (United States)

    Bhowmik, D.; Bhattacharjee, S.; Lavanyakumar, D.; Naik, V.; Satpati, B.; Karmakar, P.

    2017-11-01

    We report the ion beam based single step synthesis process of surface-patterned amorphous Silicon (a-Si) with a buried plasmon active nickel silicide layer for the realization of cost-effective, higher efficiency Silicon (Si) photovoltaic devices. Simultaneous amorphization, surface pattern formation and buried layer development are achieved by normal incidence 10 keV Ni1+ ion bombardment on Si(100) surface at a fluence of 1 × 1017. Atomic Force Microscopy study shows rim-surrounded crater like periodic nanostructure on the surface whereas cross-sectional Transmission Electron Microscopy detects the amorphization and implant buried layer just below the surface. The distribution of implanted Ni ions and Si vacancies, obtained by the Monte Carlo simulation (SRIM) is consistent with the experimental results. Spatially resolved Electron Energy Loss Spectroscopy measurement detects that the buried layer is nickel silicide. The potential application of such nano-patterned and plasmon active system for future low-cost a-Si based higher efficient Photovoltaic devices is discussed.

  13. Facile synthesis of yeast cross-linked Fe3O4nanoadsorbents for efficient removal of aquatic environment contaminated with As(V).

    Science.gov (United States)

    Rajesh Kumar, S; Jayavignesh, V; Selvakumar, R; Swaminathan, K; Ponpandian, N

    2016-12-15

    A facile solvothermal method was adopted to prepare monodispersed surface functionalized Fe 3 O 4 nanoparticles via self assembly process. The pure yeast, diethylamine functionalized Fe 3 O 4 nanoparticles (DMNPs) and yeast cross-linked Fe 3 O 4 nanoparticles (YcMNPs) were used for the efficient removal of arsenate from aqueous solution. The crystal structure, morphology and magnetic properties of these nanoparticles were characterized by using X-ray diffraction, field emission scanning electron microscopy and vibrating sample magnetometer. The observed physico-chemical properties confirms the metal binding nature of prepared samples. The adsorption of As(V) on the functionalized magnetite nanoparticles was tested under different operating conditions like contact time, adsorbate dosage, adsorbate concentration and pH. The faster removal of As(V) was obtained using YcMNPs (99%) than DMNPs and pure yeast. The adsorption equilibrium data obeys Langmuir isotherm than Freundlich model and the kinetics data well depicts the pseudo-second-order model. The batch column experiment confirms the adequate desorption as well as reusability without significant loss of efficiency. The results reveal the technical feasibility of the prepared nanoparticles for their easy synthesis, recovery, cost effective, eco-friendly and a promising advanced adsorbent for environmental pollution. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Microwave Mediated Organic Reaction: A Convenient Approach for Rapid and Efficient Synthesis of Biologically Active Substituted 1,3-Dihydro-2H-indol-2-one Derivatives

    Directory of Open Access Journals (Sweden)

    Jnyanaranjan Panda

    2013-01-01

    Full Text Available A simple and efficient method has been developed for the synthesis of 1,3-dihydro-2H-indol-2-one derivatives using microwave irradiation technique. By taking advantage of the efficient source of energy of microwave, compound libraries for lead generation and optimization can be assembled in a fraction of time. In the present work, first the Schiff’s bases are synthesized by reaction of isatin with substituted anilines in the presence of acetic acid under microwave heating. Then the condensation of Schiff bases with different secondary amines in the presence of formaldehyde produces Mannich bases. The newly synthesized Mannich bases were characterized by means of spectral data and then evaluated for anthelmintic activity against Pheretima posthuma (Indian earthworm and compared with standard albendazole. The compounds were evaluated at the concentrations of 10, 20, and 50 mg/mL. The effect of the standard drug albendazole at 10 mg/mL was also evaluated. The results of the present study indicate that some of the test compounds significantly demonstrated paralysis and also caused death of worms in a dose-dependent manner.

  15. Electrospinning in Situ Synthesis of Graphene-Doped Porous Copper Indium Disulfide/Carbon Composite Nanofibers for Highly Efficient Counter Electrode in Dye-Sensitized Solar Cells

    International Nuclear Information System (INIS)

    He, Jianxin; Zhou, Mengjuan; Wang, Lidan; Zhao, Shuyuan; Wang, Qian; Ding, Bin; Cui, Shizhong

    2016-01-01

    Highlights: • P-GN@CuInS 2(*) /C nanofibers were fabricated via electrospinning, in situ synthesis. • CuInS 2 nanocrystals were uniformly anchored in wrapped RGO to form nanofiber structure. • P-GN@CuInS 2 /C nanofibers exhibited porous and 3D superfine fiber morphology. • Graphene nanosheets led well-dispersed growth of CuInS 2 nanocrystals in nanofibers. • DSSC assembled using p-GN@CuInS 2 /C CE delivered a conversion efficiency of 7.23%. - Abstract: Porous graphene-doped copper indium disulfide/carbon (p-GN@CuInS 2 /C) composite nanofibers were fabricated via electrospinning, in situ synthesis, and carbonization. A polyacrylonitrile (PAN) solution containing graphene oxide nanosheets, copper dichloride (CuCl 2 ), indium trichloride (InCl 3 ), and thiourea (Tu.) in a mixed solvent of N,N-dimethylformamide/trichloromethane (DMF/CF) was used as the precursor solution for electrospinning. The resulting porous GN@CuInS 2 /C nanofibers were 107 ± 24 nm in diameter, and graphene nanosheets anchored with chalcopyrite CuInS 2 nanocrystals 7–12 nm in diameter were overlapped and embedded in the carbon matrix, aligning along the fiber axial direction. The Brunauer–Emmett–Teller (BET) surface area of the p-GN@CuInS 2 /C composite nanofibers was 795 m 2 /g, with a total pore volume of 0.71 cm 3 /g. These values were significantly larger than those of the sample without graphene and CuInS 2 /C nanofibers. A dye-sensitized solar cell (DSSC) assembled using the p-GN@CuInS 2 /C nanofibers as the counter electrode (CE) delivered a photoelectric conversion efficiency of 7.23%, which was higher than the efficiencies of DSSCs assembled using the samples without graphene (6.48%) and with the CuInS 2 /C nanofibers (5.45%). It was also much higher than that of the DSSC with a Pt CE (6.34%). The excellent photoelectric performance of the p-GN@CuInS 2 /C CE was attributed to its special hierarchical porous structure, which facilitated permeation of the liquid

  16. Controllable synthesis of mesoporous multi-shelled ZnO microspheres as efficient photocatalysts for NO oxidation

    Science.gov (United States)

    Chen, Xiaolang; Zhang, Huiqiang; Zhang, Dieqing; Miao, Yingchun; Li, Guisheng

    2018-03-01

    The successful application of hierarchically porous structure in environmental treatment has provided new insights for solving environmental problems. Hierarchically structured semiconductor materials were considered as promising photocatalysts for NO oxidation in gas phase. Multi-shelled ZnO microspheres (MMSZ) were controllably shaped with hierarchically porous structures via a facile hydrothermal route using amino acid (N-Acetyl-D-Proline) as template and post-calcination treatment. Symmetric Ostwald ripening was used to explain the morphological evolution of hierarchical nanostructure. MMSZ was proved highly efficient for oxidizing NO (400 ppb) in gas phase under UV light irradiation with a much higher photocatalytic removal rate (77.3%) than that of the as-obtained ZnO crystals with other hierachically porous structures, owing to its higher photocurrent intensity. Such greatly enhanced photocatalytic activity can be assigned to the enhanced crystallinity of ZnO, mesopores and unique multi-shelled structure. Enhanced crystallinity promotes photogenerated charges under light irradiation. Mesoporous porosity can ensure enough light scattering between the shells. Multi-shelled structure endows ZnO with higher specific surface area and high frequency of multiple light reflection, resulting in more exposed active sites, higher light utilization efficiency, and fast separation efficiency of photogenerated charge carriers. The experimental results demonstrated that the photogenerated holes (h+) are the main active species. Hierarchically structured ZnO is not only contributed to directly use solar energy to solving various problems caused by atmospheric pollution, but also has potential applications in energy converse and storage including solar cells, lithium batteries, water-splitting, etc.

  17. Superparamagnetic plasmonic nanohybrids: shape-controlled synthesis, TEM-induced structure evolution, and efficient sunlight-driven inactivation of bacteria.

    Science.gov (United States)

    Zhai, Yueming; Han, Lei; Wang, Ping; Li, Gaiping; Ren, Wen; Liu, Ling; Wang, Erkang; Dong, Shaojun

    2011-11-22

    Magnetic materials and noble metal-based multifunctional hybrids have attracted much attention recently due to their unique properties and potential applications in a variety of fields. However, substantial challenges remain to directly obtain water-soluble hybrids with well-defined structures and to directly combine magnetic nanoparticles with nonspherical noble metals. We describe here for the first time a simple solvothermal method to synthesize a series of novel water-soluble nanohybrids composed of shape-tuned Ag cores and a Fe(3)O(4) shell. We found that small Fe(3)O(4) grains can be well-distributed directly on the surface on the Ag seeds. Such hybrids have both plasmonic and significant superparamagnetic properties, enabling magnetic separation. The plasmon resonance frequency of Ag nanostructures can be fine-tuned through the interactions between the two components. In addition, the decorated Fe(3)O(4) nanoparticles stabilized the Ag nanostructures when exposed to air and natural light for a long time. Furthermore, an interesting structural transformation is observed in the one-dimensional Ag-Fe(3)O(4) nanowires under high-energy electron beam. The Ag core can diffuse through the porous iron oxide shell, break away, and result in the formation of Ag nanocluster-decorated iron oxide tubes. Finally, the hybrids acted as a chemical template for the synthesis of Fe(3)O(4)/Au-AgCl double-layer nanotubes that display obvious near-infrared absorption. Importantly, the double-layer nanotubes exhibited enhanced photocatalytic inactivation of bacteria at very low concentrations under natural sunlight. © 2011 American Chemical Society

  18. Simple and efficient protocol for the synthesis of functionalized styrenes from 1,2-dibromoethane and arylboronic acids.

    Science.gov (United States)

    Lando, Vanusa R; Monteiro, Adriano L

    2003-08-07

    [reaction: see text] A simple and efficient protocol for the preparation of functionalized styrenes is disclosed that employs the palladium-catalyzed cross-coupling reaction of arylboronic acids with vinyl bromide, generated in situ from 1,2-dibromoethane. The reaction is carried out under mild reaction conditions. Compared with the cross-coupling reactions usually employed to obtain vinylarenes, this protocol is very simple, overcomes the inconvenience of using of ethylene under pressure, and uses air-stable and widely available arylboronic acids instead of vinyl organometallic reagents.

  19. Efficient synthesis of glycosylated phenazine natural products and analogs with DISAL (methyl 3,5-dinitrosalicylate) glycosyl donors

    DEFF Research Database (Denmark)

    Laursen, Jane B.; Petersen, Lars; Jensen, K.J.

    2003-01-01

    Inspired by the occurrence and function of phenazines in natural products, new glycosylated analogs were designed and synthesized. DISAL (methyl 3,5-dinitrosalicylate) glycosyl donors were used in an efficient and easily-handled glycosylation protocol compatible with combinatorial chemistry....... Benzoylated D-glucose, D-galactose and L-quinovose DISAL glycosyl donors were synthesized in high yields and used under mild conditions to glycosylate methyl saphenate and 2-hydroxyphenazine. The glycosides were screened for biological activity and one compound showed inhibitory activity towards topoisomerase...

  20. Synthesis of vertical MnO2 wire arrays on hemp-derived carbon for efficient and robust green catalysts

    International Nuclear Information System (INIS)

    Yang, MinHo; Kim, Dong Seok; Sim, Jae-Wook; Jeong, Jae-Min; Kim, Do Hyun; Choi, Jae Hyung; Kim, Jinsoo; Kim, Seung-Soo; Choi, Bong Gill

    2017-01-01

    Highlights: • The three-dimensional nanocomposites based on vertical MnO 2 array on hemp-derived carbon (HDC) were prepared by hydrothermal method. • The 3D v-MnO 2 /HDC nanocomposites showed well-defined porous nature with a high specific surface area of 382.3 m 2 g −1 . • PET glycolysis was performed using the 3D v-MnO 2 /HDC nanocomposites as a catalyst, leading to efficient catalytic performance. - Abstract: Three-dimensional (3D) carbon materials derived from waste biomass have been attracted increasing attention in catalysis and materials science because of their great potential of catalyst supports with respect to multi-functionality, unique structures, high surface area, and low cost. Here, we present a facile and efficient way for preparing 3D heterogeneous catalysts based on vertical MnO 2 wires deposited on hemp-derived 3D porous carbon. The 3D porous carbon materials are fabricated by carbonization and activation processes using hemp (Cannabis Sttiva L.). These 3D porous carbon materials are employed as catalyst supports for direct deposition of vertical MnO 2 wires using a one-step hydrothermal method. The XRD and XPS results reveal the crystalline structure of α-MnO 2 wires. The resultant composites are further employed as a catalyst for glycolysis of poly(ethylene terephthalate) (PET) with high conversion yield of 98%, which is expected to be expressly profitable for plastics recycling industry.

  1. Synthesis of pH-sensitive and recyclable magnetic nanoparticles for efficient separation of emulsified oil from aqueous environments

    Science.gov (United States)

    Lü, Ting; Zhang, Shuang; Qi, Dongming; Zhang, Dong; Vance, George F.; Zhao, Hongting

    2017-02-01

    Emulsified oil wastewaters, arisen from oil industry and oil spill accidents, cause severe environmental and ecological problems. In this study, a series of pH-sensitive magnetic nanomaterials (MNPs) were synthesized and characterized for their evaluation in separation of emulsified oil from aqueous environments. A coprecipitation method was used to produce Fe3O4 magnetic nanoparticles that were coated in a 2-step process with first silica to form a surface for anchoring an (3-aminopropyl)triethoxysilane (APTES) molecular layer. Detailed studies were conducted on effects of MNPs dosage, APTES anchoring density (DA) and pH on oil-water separation performance of the synthetic MNPs. Results showed that, under both acidic and neutral conditions, MNPs with high DA exhibited enhanced oil-water separation performance, while under alkaline condition, the oil-water separation process was minimal. Alkaline conditions allowed the MNPs to be recycled up to 9 cycles without showing any significant decrease in oil-water separation efficiency. An examination of the oil-water separation mechanism found that electrostatic interaction and interfacial activity both played important roles in oil-water separation. In conclusion, pH-sensitive MNPs can be easily synthesized and recycled, providing a promising, cost-effective and environmentally-friendly process for the efficient treatment of emulsified oil wastewater.

  2. Metal-organic framework-templated synthesis of magnetic nanoporous carbon as an efficient absorbent for enrichment of phenylurea herbicides.

    Science.gov (United States)

    Liu, Xingli; Wang, Chun; Wu, Qiuhua; Wang, Zhi

    2015-04-22

    Nanoporous carbon with a high specific surface area and unique porous structure represents an attractive material as an adsorbent in analytical chemistry. In this study, a magnetic nanoporous carbon (MNC) was fabricated by direct carbonization of Co-based metal-organic framework in nitrogen atmosphere without using any additional carbon precursors. The MNC was used as an effective magnetic adsorbent for the extraction and enrichment of some phenylurea herbicides (monuron, isoproturon, diuron and buturon) in grape and bitter gourd samples prior to their determination by high performance liquid chromatography with ultraviolet detection. Several important experimental parameters that could influence the extraction efficiency were investigated and optimized. Under the optimum conditions, a good linearity was achieved in the concentration range of 1.0-100.0 ng g(-1) for monuron, diuron and buturon and 1.5-100.0 ng g(-1) for isoproturon with the correlation coefficients (r) larger than 0.9964. The limits of detection (S/N=3) of the method were in the range from 0.17 to 0.46 ng g(-1). The results indicated that the MNC material was stable and efficient adsorbent for the magnetic solid-phase extraction of phenylurea herbicides and would have a great application potential for the extraction and preconcentration of more organic pollutants from real samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Au-Cu core-shell nanocube-catalyzed click reactions for efficient synthesis of diverse triazoles.

    Science.gov (United States)

    Madasu, Mahesh; Hsia, Chi-Fu; Huang, Michael H

    2017-06-01

    Au-Cu core-shell nanocubes and octahedra synthesized in aqueous solution were employed to catalyze a 1,3-dipolar cycloaddition reaction between phenylacetylene and benzyl azide in water at 50 °C for 3 h. Interestingly, the nanocubes were far more efficient in catalyzing this reaction, giving 91% yield of a regioselective 1,4-triazole product, while octahedra only recorded 46% yield. The Au-Cu nanocubes were subsequently employed to catalyze the click reaction between benzyl azide and a broad range of aromatic and aliphatic alkynes. The product yields ranged from 78 to 99%. Clearly the Au-Cu cubes exposing {100} surfaces are an excellent and green catalyst for click reactions.

  4. Sonochemical Synthesis of CdS/C3N4 Composites with Efficient Photocatalytic Performance Under Visible Light Irradiation.

    Science.gov (United States)

    Chai, Bo; Wang, Xing

    2016-02-01

    The CdS/C3N4 composites with efficient photocatalytic performance under visible light irradiation were synthesized by a facile sonochemical route. The as-prepared CdS/C3N4 composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution trans- mission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance absorption spectra (DRS), fourier transform infrared spectroscopy (FTIR) and photoluminescence spectra (PL). The photocatalytic degradation of rhodamine B (RhB) by the CdS/C3N4 composites was explored and optimized, suggesting the optimal amount of CdS in the composites was 50 wt%. The significantly enhanced photocatalytic activity of CdS/C3N4 composites could be attributed to the effectively interfacial transfer of photogenerated charge carriers between CdS and C3N4, which restrained the recombination of electron-hole pairs.

  5. An efficient photochemical route to Pd nanoparticles; application to the one-step synthesis of Pd@polymer nanocomposite films.

    Science.gov (United States)

    Wolak, Séverine; Vidal, Loïc; Becht, Jean-Michel; Michelin, Laure; Balan, Lavinia

    2016-08-26

    We have developed a facile, efficient, low cost and 'green' photochemical approach to preparing surfactant-free Pd nanoparticles and Pd-immobilized@acrylate photo-polymer films at room temperature, under air and without any additional treatment. The reaction system only includes a photo-initiator used as a generator of free radicals and a Pd(II) salt. In ethanol solution, the photochemical reduction of Pd(II) to Pd(0) generates very small metal particles with a narrow size distribution (2-4 nm). Furthermore, we have shown that the formation of Pd nanoparticles from a Pd(II) salt can be reversible thus allowing easy handling and safe storage with the possibility of generating the nanoparticles just before use. In the presence of an acrylate bifunctional monomer, Pd@polymer film was obtained through a 'one-pot, one-step' process resulting from a simultaneous photo-reduction of Pd(II) and photo-polymerization of acrylate units. The simultaneous generation of a 3D polymer network and of metal particles leads to a homogeneous distribution of Pd nanoparticles in the photo-polymer matrix with an average diameter of approximately 3.7 ± 1.1 nm. Such as-prepared Pd@polymer films were found to efficiently catalyze the Mizoroki-Heck reaction in the presence of only 0.9 mequiv. of supported palladium. The major interest of this arrangement is its recoverability and reusability, which makes it very attractive both from a practical and economical viewpoint. Finally, it is worth noting that this innovation offers a great advantage over concurrent methods in that it is simply generated within minutes, it is highly stable, and there is sharp monodispersity in the size of the Pd nanoparticles that can be stored for months without alteration of their physico-chemical properties and catalytic activity.

  6. Synthesis and characterization of Ni-P-Ag composite coating as efficient electrocatalyst for alkaline hydrogen evolution reaction

    International Nuclear Information System (INIS)

    Elias, Liju; Hegde, A. Chitharanjan

    2016-01-01

    Highlights: • Electrocatalytic activity of Ni-P alloy is improved by Ag nanoparticle incorporation. • Ni-P-Ag electrode is developed through sol-enhanced electrodeposition. • Ni-P-Ag composite coating shows better electrocatalytic efficiency for HER. - Abstract: The effect of addition of silver nanoparticle sol (SNS) into Ni-P plating bath was studied in terms of the variation in electrocatalytic behavior of the developed coatings in 1.0 M KOH. Ni-P-Ag composite coating was achieved through direct electrolysis by adding a known quantity of the conventionally prepared SNS into Ni-P bath. Ni-P-Ag coatings electrodeposited galvanostatically on copper under different conditions of the bath was used as electrode material for alkaline hydrogen evolution reaction (HER). The optimal concentration of the SNS required for maximum electrocatalytic activity towards HER was obtained by adding different volumes of SNS (from 0 to 50 mL L −1 ) into the bath. The HER efficiency of the test electrodes in 1.0 M KOH medium was examined using cyclic voltammetry (CV) and chronopotentiometry (CP) techniques. The kinetics of HER on the alloy and composite electrodes were established through Tafel polarization and electrochemical impedance spectroscopy (EIS) analyses. Energy dispersive spectroscopy (EDS) was used to confirm the incorporation of Ag nanoparticles into the Ni-P alloy matrix. The microstructure and morphology of the alloy and composite coatings were analyzed by Scanning Electron Microscopy (SEM). A significant improvement in the electrocatalytic property of nano-Ag derived composite coatings was found, and was attributed to the enhanced electroactive sites of Ag particles. Deposition conditions to maximize the electrocatalytic activity of Ni-P-Ag nanocomposite coatings in relation to traditional Ni-P alloy coatings was arrived, and results are discussed.

  7. The synthesis of polypyrrole@Mn3O4/reduced graphene oxide anode with improved coulombic efficiency

    International Nuclear Information System (INIS)

    Ren, YuRong; Wang, JiaWei; Huang, XiaoBing; Ding, JianNing

    2015-01-01

    Highlights: • A two-step method is employed to fabricate polypyrrole@Mn 3 O 4 /reduced graphene oxide electrodes. • The electrodes coated with polypyrrole deliver a coulombic efficiency of ca.70%. • The composites deliver an initial discharge capacity of ca.1600 mAh g −1 at 60 mA g −1 . - Abstract: A two-step method consisting of an in-situ transformation and an in-situ oxidative polymerization is employed to fabricate polypyrrole@Mn 3 O 4 /reduced graphene oxide composites. The resulting materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Raman. The XRD analysis reveals the formation of Mn 3 O 4 /reduced graphene oxide and polypyrrole@Mn 3 O 4 /reduced graphene oxide. Mn 3 O 4 particles coated with reduced graphene oxide and polypyrrole get an average diameter of ca.27 nm. The TEM images of polypyrrole@Mn 3 O 4 /reduced graphene oxide demonstrate that Mn 3 O 4 /reduced graphene oxide nanocomposites are indeed coated by a transparent polypyrrole film. The FT-IR studies disclose the characteristic functional groups between the respective materials. Moreover, Raman measurements confirm the reduction of graphite oxide to reduced graphene oxide. The result of electrochemical measurement demonstrates that it gets a high initial discharge capacity of ca.1600 mAh g −1 at 60 mA g −1 and the initial charge/discharge efficiency delivers a nice optimization after coated with polypyrrole (ca.45% VS ca.70%). The capacity of polypyrrole@Mn 3 O 4 /reduced graphene oxide can maintain at a level of ca.1000 mAh g −1 in the first five cycles and the rate performance of it is much better than that of Mn 3 O 4 /graphene.

  8. Integrated lipase production and in situ biodiesel synthesis in a recombinant Pichia pastoris yeast: an efficient dual biocatalytic system composed of cell free enzymes and whole cell catalysts

    Science.gov (United States)

    2014-01-01

    Background Lipase-catalyzed biotransformation of acylglycerides or fatty acids into biodiesel via immobilized enzymes or whole cell catalysts has been considered as one of the most promising methods to produce renewable and environmentally friendly alternative liquid fuels, thus being extensively studied so far. In all previously pursued approaches, however, lipase enzymes are prepared in an independent process separated from enzymatic biodiesel production, which would unavoidably increase the cost and energy consumption during industrial manufacture of this cost-sensitive energy product. Therefore, there is an urgent need to develop novel cost-effective biocatalysts and biocatalytic processes with genuine industrial feasibility. Result Inspired by the consolidated bioprocessing of lignocellulose to generate bioethanol, an integrated process with coupled lipase production and in situ biodiesel synthesis in a recombinant P. pastoris yeast was developed in this study. The novel and efficient dual biocatalytic system based on Thermomyces lanuginosus lipase took advantage of both cell free enzymes and whole cell catalysts. The extracellular and intracellular lipases of growing yeast cells were simultaneously utilized to produce biodiesel from waste cooking oils in situ and in one pot. This integrated system effectively achieved 58% and 72% biodiesel yield via concurrent esterified-transesterified methanolysis and stepwise hydrolysis-esterification at 3:1 molar ratio between methanol and waste cooking oils, respectively. Further increasing the molar ratio of methanol to waste cooking oils to 6:1 led to an 87% biodiesel yield using the stepwise strategy. Both water tolerance and methanol tolerance of this novel system were found to be significantly improved compared to previous non-integrated biodiesel production processes using separately prepared immobilized enzymes or whole cell catalysts. Conclusion We have proposed a new concept of integrated biodiesel production

  9. Endoplasmic Reticulum Stress Induced Synthesis of a Novel Viral Factor Mediates Efficient Replication of Genotype-1 Hepatitis E Virus.

    Directory of Open Access Journals (Sweden)

    Vidya P Nair

    2016-04-01

    Full Text Available Hepatitis E virus (HEV causes acute hepatitis in many parts of the world including Asia, Africa and Latin America. Though self-limiting in normal individuals, it results in ~30% mortality in infected pregnant women. It has also been reported to cause acute and chronic hepatitis in organ transplant patients. Of the seven viral genotypes, genotype-1 virus infects humans and is a major public health concern in South Asian countries. Sporadic cases of genotype-3 and 4 infection in human and animals such as pigs, deer, mongeese have been reported primarily from industrialized countries. Genotype-5, 6 and 7 viruses are known to infect animals such as wild boar and camel, respectively. Genotype-3 and 4 viruses have been successfully propagated in the laboratory in mammalian cell culture. However, genotype-1 virus replicates poorly in mammalian cell culture and no other efficient model exists to study its life cycle. Here, we report that endoplasmic reticulum (ER stress promotes genotype-1 HEV replication by inducing cap-independent, internal initiation mediated translation of a novel viral protein (named ORF4. Importantly, ORF4 expression and stimulatory effect of ER stress inducers on viral replication is specific to genotype-1. ORF4 protein sequence is mostly conserved among genotype-1 HEV isolates and ORF4 specific antibodies were detected in genotype-1 HEV patient serum. ORF4 interacted with multiple viral and host proteins and assembled a protein complex consisting of viral helicase, RNA dependent RNA polymerase (RdRp, X, host eEF1α1 (eukaryotic elongation factor 1 isoform-1 and tubulinβ. In association with eEF1α1, ORF4 stimulated viral RdRp activity. Furthermore, human hepatoma cells that stably express ORF4 or engineered proteasome resistant ORF4 mutant genome permitted enhanced viral replication. These findings reveal a positive role of ER stress in promoting genotype-1 HEV replication and pave the way towards development of an efficient

  10. Microwave-Assisted Synthesis of SiC Nanoparticles for the Efficient Adsorptive Removal of Nitroimidazole Antibiotics from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Ali Fakhri

    2017-02-01

    Full Text Available Environmental pollution caused by the improper disposal of pharmaceuticals is a matter of global concern, and warrants immediate attention. Of particular concern is the aquatic contamination caused by the increasing use of antibiotics, which could give rise to superbugs. While researchers have mainly focused on improving the adsorption capacity of mostly activated carbon-based adsorbents, we have developed a non-conventional adsorbent (SiC nanoparticles in the present work for the adsorptive removal of four different nitroimidazole antibiotics, namely metronidazole (MNZ, dimetridazole (DMZ, ronidazole (RNZ, and tinidazole (TNZ. In addition to the unique properties which are inherent to SiC, the present adsorbent not only possesses a high adsorption capacity, but also shows one of the highest adsorption rates; both of which are prerequisites for an efficient and cost-effective adsorption-based separation technology. Silicon carbide (SiC nanoparticles, synthesized by a microwave-assisted method, were thoroughly characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and the Brunauer–Emmett–Teller method. The adsorption isotherm data were accurately described by the Langmuir isotherm model. On the other hand, the adsorption kinetics, closely represented by the pseudo-second order kinetic model, were faster than most previously reported adsorbents. The reaction rate constants were 0.0089, 0.0079, 0.0072, and 0.0055 g/(mg min, for MNZ, DMZ, RNZ, and TNZ, respectively.

  11. Efficient and clean synthesis of graphene supported platinum nanoclusters and its application in direct methanol fuel cell

    International Nuclear Information System (INIS)

    Ji Kai; Chang Gang; Oyama, Munetaka; Shang Xunzhong; Liu Xiong; He Yunbin

    2012-01-01

    Highlights: ► Pt nanoclusters/graphene (PtNCs/graphene) was synthesized within one-step process. ► Environment friendly ascorbic acid was chosen as the reductant. ► The synthesized PtNCs/graphene show superior electrocatalytic activity to methanol. ► PtNCs/graphene show superior electrocatalytic stability in methanol electrooxidation. - Abstract: The graphene supported platinum nanoclusters was synthesized by an efficient and clean method, in which graphene oxide and Pt ion precursor were reduced by ascorbic acid within one-step process. The obtained Pt nanoclusters attached graphene composite (PtNCs/graphene) was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS), which can directly show that Pt nanoclusters successfully formed on graphene and well distributed on the edges and wrinkles of graphene sheets. The further electrochemical characterizations including cyclic voltammograms (CV), current–time methods indicated that PtNCs/graphene has significantly higher electrocatalytic activity and stability for methanol electrooxidation compared to the normal Vulcan XC-72 and graphite supported Pt nanoclusters, which will lead a further application as a new electrode material in direct methanol fuel cell (DMFC).

  12. Synthesis of a red electrophosphorescent heteroleptic iridium complex and its application in efficient polymer light-emitting diodes

    International Nuclear Information System (INIS)

    Zhang Xiuju; Xu Yunhua; Sun Yiheng; Shi Huahong; Zhu Xuhui; Cao Yong

    2007-01-01

    The preparation and characterization of a heteroleptic iridium complex [2-(benzo[b]thiophen-2-yl)pyridine]Ir(III)[2-(4H-1,2,4-triazol-3-yl) pyridine] [(Btp) 2 Ir(PZ)] were reported (2-(benzo[b]thiophen-2-yl)pyridine = Btp; 2-(4H-1,2,4-triazol-3-yl)pyridine = PZ). Electrophosphorescence was investigated in the device structure [indium-tin-oxide (ITO)/poly(ethlenedioxythiophene) (PEDOT)/poly(vinylcarbazole)(PVK)/Poly(9,9-dioctylfluorenyl-2,7-diyl) end capped with dimethylphenyl (PFO): (Btp) 2 Ir(PZ)/Ba/Al] by using this iridium complex as guest and PFO as host. The red electrophosphorescent devices showed a peak emission at approximately 604 nm and shoulder at 654 nm with the Commission International de'Eclairage (CIE) coordinates of (0.64, 0.35) and external quantum efficiency of 7.7% at a doping concentration of 8 wt.% without an electron-transporting material in the emitting layer

  13. Sol-gel synthesis of anatase nanopowders for efficient photocatalytic degradation of herbicide Clomazone in aqueous media

    Directory of Open Access Journals (Sweden)

    Golubović Aleksandar

    2017-01-01

    Full Text Available TiO2 nanopowders were produced by sol-gel technique using TiCl4 as a starting material. For the preparation of crystalline anatase with developed surface area, this aqueous solution has been mixed with 0.05 M or 0.07 M (NH42SO4 solution in a temperature-controlled bath. The pH values of the suspension were 7, 8 or 9. According to the x-ray diffraction (XRD analysis the anatase crystallite sizes were about 12 nm, which coincided with the average particle size revealed by scanning electron microscopy (SEM. The Raman scattering measurements have shown the presence of a small amount of highly disordered brookite phase in addition to dominant anatase phase with similar nanostructure in all synthesized powders. BET measurements revealed that all synthesized catalysts were fully mesoporous, except the sample synthesized with 0.07 M (NH42SO4 at pH=9, which had small amount of micropores. The photocatalytic degradation of herbicide Clomazone was carried out for both the pure active substance and as the commercial product (GAMIT 4-EC under UV irradiation. The best photocatalytic efficiency was obtained for the catalyst with the largest specific surface area, confirming this parameter as crucial for enhanced photocatalytic degradation of the pure active substance and commercial product of herbicide Clomazone. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III45018

  14. Synthesis of vertical MnO2 wire arrays on hemp-derived carbon for efficient and robust green catalysts

    Science.gov (United States)

    Yang, MinHo; Kim, Dong Seok; Sim, Jae-Wook; Jeong, Jae-Min; Kim, Do Hyun; Choi, Jae Hyung; Kim, Jinsoo; Kim, Seung-Soo; Choi, Bong Gill

    2017-06-01

    Three-dimensional (3D) carbon materials derived from waste biomass have been attracted increasing attention in catalysis and materials science because of their great potential of catalyst supports with respect to multi-functionality, unique structures, high surface area, and low cost. Here, we present a facile and efficient way for preparing 3D heterogeneous catalysts based on vertical MnO2 wires deposited on hemp-derived 3D porous carbon. The 3D porous carbon materials are fabricated by carbonization and activation processes using hemp (Cannabis Sttiva L.). These 3D porous carbon materials are employed as catalyst supports for direct deposition of vertical MnO2 wires using a one-step hydrothermal method. The XRD and XPS results reveal the crystalline structure of α-MnO2 wires. The resultant composites are further employed as a catalyst for glycolysis of poly(ethylene terephthalate) (PET) with high conversion yield of 98%, which is expected to be expressly profitable for plastics recycling industry.

  15. Organic Carbonates: Efficient Extraction Solvents for the Synthesis of HMF in Aqueous Media with Cerium Phosphates as Catalysts.

    Science.gov (United States)

    Dibenedetto, Angela; Aresta, Michele; di Bitonto, Luigi; Pastore, Carlo

    2016-01-08

    We describe a process for the selective conversion of C6 -polyols into 5-hydroxymethylfurfural (5-HMF) in biphasic systems of organic carbonate/water (OC/W), with cerium(IV) phosphates as catalysts. Different reaction parameters such as the OC/W ratio, catalyst loading, reaction time, and temperature, were investigated for the dehydration of fructose. Under the best reaction conditions, a yield of 67.7 % with a selectivity of 93.2 % was achieved at 423 K after 6 h of reaction using [(Ce(PO4)1.5 (H2 O)(H3 O)0.5 (H2 O)0.5)] as the catalyst. A maximum yield of 70 % with the same selectivity was achieved after 12 h. At the end of the reaction, the catalyst was removed by centrifugation, the organic phase was separated from water and evaporated in vacuo (with solvent recovery), and solid 5-HMF was isolated (purity >99 %). The recovery and reuse of the catalyst and the relationship between the structure of the OC and the efficiency of the extraction are discussed. The OC/W system influences the lifetime of the catalysts positively compared to only water. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Efficient Synthesis of Highly Photoluminescent Short Dendritic CdSeS/ZnS Quantum Dots for Biolabeling.

    Science.gov (United States)

    Kong, Peng; Zhou, Guangjun; Zhou, Haifeng; Zhou, Juan; Zhang, Xingshuang; Yu, Zhichao

    2016-03-01

    A convenient and efficient approach is reported to synthesize CdSeS with low-cost and low-toxic materials. The influence of the Se/S ratio and reaction time on the photoluminescent properties of CdSeS QDs is investigated through researching the temporal evolution of the absorption and the emission. Following, the high photoluminescent short dendritic green-emitting CdSeS/ZnS QDs are prepared using the method inspired by the successive ion layer adsorption and reaction procedure, which are composed of a CdSeS core and ZnS branches. Transmission electronic microscopy and X-ray diffraction show that the CdSeS/ZnS QDs is in a cubic zinc blende structure. The photoluminescence intensity increase significantly when the ZnS branches form as a result of the charge carriers being confined in the core. The photoluminescence quantum yield of the obtained CdSeS/ZnS core-shell QDs can be up to 90%, which is much higher than that of initial CdSeS QDs (39%). In addition, CdSeS/ZnS QDs have good photoluminescence intensity after they are transferred from organic solvent into aqueous media through ligand replacement using mercaptoacetic acid. Afterwards, the E. Coli O-157 are not only successfully conjugated with CdSeS/ZnS QDs but also present clear images under UV irradiation.

  17. Two-dimensional mesoporous carbon nanosheets and their derived graphene nanosheets: synthesis and efficient lithium ion storage.

    Science.gov (United States)

    Fang, Yin; Lv, Yingying; Che, Renchao; Wu, Haoyu; Zhang, Xuehua; Gu, Dong; Zheng, Gengfeng; Zhao, Dongyuan

    2013-01-30

    We report a new solution deposition method to synthesize an unprecedented type of two-dimensional ordered mesoporous carbon nanosheets via a controlled low-concentration monomicelle close-packing assembly approach. These obtained carbon nanosheets possess only one layer of ordered mesopores on the surface of a substrate, typically the inner walls of anodic aluminum oxide pore channels, and can be further converted into mesoporous graphene nanosheets by carbonization. The atomically flat graphene layers with mesopores provide high surface area for lithium ion adsorption and intercalation, while the ordered mesopores perpendicular to the graphene layer enable efficient ion transport as well as volume expansion flexibility, thus representing a unique orthogonal architecture for excellent lithium ion storage capacity and cycling performance. Lithium ion battery anodes made of the mesoporous graphene nanosheets have exhibited an excellent reversible capacity of 1040 mAh/g at 100 mA/g, and they can retain at 833 mAh/g even after numerous cycles at varied current densities. Even at a large current density of 5 A/g, the reversible capacity is retained around 255 mAh/g, larger than for most other porous carbon-based anodes previously reported, suggesting a remarkably promising candidate for energy storage.

  18. Lanthanide anilido complexes: synthesis, characterization, and use as highly efficient catalysts for hydrophosphonylation of aldehydes and unactivated ketones.

    Science.gov (United States)

    Liu, Chengwei; Qian, Qinqin; Nie, Kun; Wang, Yaorong; Shen, Qi; Yuan, Dan; Yao, Yingming

    2014-06-14

    Lanthanide anilido complexes stabilized by the 2,6-diisopropylanilido ligand have been synthesized and characterized, and their catalytic activity for hydrophosphonylation reaction was explored. A reaction of anhydrous LnCl3 with 5 equivalents of LiNHPh-(I)Pr2-2,6 in THF generated the heterobimetallic lanthanide-lithium anilido complexes (2,6-(I)Pr2PhNH)5LnLi2(THF)2 [Ln = Sm(1), Nd(2), Y(3)] in good isolated yields. These complexes are well characterized by elemental analysis, IR, NMR (for complex ) and single-crystal structure determination. Complexes 1 - 3 are isostructural. In these complexes, the lanthanide metal ion is five-coordinated by five nitrogen atoms from five 2,6-diisopropylanilido ligands to form a distorted trigonal bipyramidal geometry. The lithium ion is coordinated by two nitrogen atoms from two 2,6-diisopropylanilido ligands, and one oxygen atom from a THF molecule. It was found that these simple lanthanide anilido complexes are highly efficient for catalyzing hydrophosphonylation reactions of various aldehydes and unactivated ketones to generate α-hydroxyphosphonates in good to excellent yields (up to 99%) within a short time (5 min for aldehydes, 20 min for ketones). Furthermore, the mechanism of hydrophosphonylation reactions has also been elucidated via(1)H NMR monitoring of reaction.

  19. Synthesis of high efficient Cu/TiO2 photocatalysts by grinding and their size-dependent photocatalytic hydrogen production

    Science.gov (United States)

    Ni, Dawei; Shen, Haiyan; Li, Huiqiao; Ma, Ying; Zhai, Tianyou

    2017-07-01

    Recently, copper species have been extensively investigated to replace Pt as efficient co-catalysts for the evolution of H2 due to their low cost and relatively high activity. Cu nanoparticles less than 5 nm are successfully decorated on TiO2 surface in this work by an easy and mild milling process. These Cu nanoparticles are highly dispersed on TiO2 when the loading amount of Cu is no more than 10 wt%. The sizes of Cu nanoparticles can be controlled by changing the milling environment and decrease in the order of Cu-ethanol > Cu-water > Cu nanoparticles obtained through drying milling. The highest and stable hydrogen generation can be realized on Cu/TiO2 with 2.0 wt% Cu and sizes of Cu nanoparticles ranging from 2 to 4 nm, in which high and stable photocurrent confirms promoted photogenerated charge separation. Smaller Cu clusters are demonstrated to be detrimental to hydrogen evolution at same Cu content. High loading of Cu nanoparticles of 2-4 nm will benefit photogenerated electron-hole recombination and thus decrease the activity of Cu/TiO2. The results here demonstrate the key roles of Cu cluster size in addition to Cu coverage on photocatalytic activity of Cu/TiO2 composite photocatalysts.

  20. In Situ Methylene Capping: A General Strategy for Efficient Stereoretentive Catalytic Olefin Metathesis. The Concept, Methodological Implications, and Applications to Synthesis of Biologically Active Compounds.

    Science.gov (United States)

    Xu, Chaofan; Shen, Xiao; Hoveyda, Amir H

    2017-08-09

    In situ methylene capping is introduced as a practical and broadly applicable strategy that can expand the scope of catalyst-controlled stereoselective olefin metathesis considerably. By incorporation of commercially available Z-butene together with robust and readily accessible Ru-based dithiolate catalysts developed in these laboratories, a large variety of transformations can be made to proceed with terminal alkenes, without the need for a priori synthesis of a stereochemically defined disubstituted olefin. Reactions thus proceed with significantly higher efficiency and Z selectivity as compared to when other Ru-, Mo-, or W-based complexes are utilized. Cross-metathesis with olefins that contain a carboxylic acid, an aldehyde, an allylic alcohol, an aryl olefin, an α substituent, or amino acid residues was carried out to generate the desired products in 47-88% yield and 90:10 to >98:2 Z:E selectivity. Transformations were equally efficient and stereoselective with a ∼70:30 Z-:E-butene mixture, which is a byproduct of crude oil cracking. The in situ methylene capping strategy was used with the same Ru catechothiolate complex (no catalyst modification necessary) to perform ring-closing metathesis reactions, generating 14- to 21-membered ring macrocyclic alkenes in 40-70% yield and 96:4-98:2 Z:E selectivity; here too, reactions were more efficient and Z-selective than when the other catalyst classes are employed. The utility of the approach is highlighted by applications to efficient and stereoselective syntheses of several biologically active molecules. This includes a platelet aggregate inhibitor and two members of the prostaglandin family of compounds by catalytic cross-metathesis reactions, and a strained 14-membered ring stapled peptide by means of macrocyclic ring-closing metathesis. The approach presented herein is likely to have a notable effect on broadening the scope of olefin metathesis, as the stability of methylidene complexes is a generally

  1. High-level accumulation of oleyl oleate in plant seed oil by abundant supply of oleic acid substrates to efficient wax ester synthesis enzymes.

    Science.gov (United States)

    Yu, Dan; Hornung, Ellen; Iven, Tim; Feussner, Ivo

    2018-01-01

    overall yields and the compositions of wax esters can be strongly affected by the availability of acyl-CoA substrates and to a lesser extent, by the characteristics of wax ester synthesis enzymes. For synthesis of oleyl oleate in plant seed oil, appropriate wax ester synthesis enzymes with high catalytic efficiency and desired substrate specificity should be expressed in plant cells; meanwhile, high levels of oleic acid-derived substrates need to be supplied to these enzymes by modifying the fatty acid profile of developing seeds.

  2. Effects of ELOVL4 gene overexpress on the synthesis efficiency of n3 and n6 very long chain polyunsaturated fatty acids

    Directory of Open Access Journals (Sweden)

    Man Yu

    2014-08-01

    Full Text Available AIM:To compare the synthesis efficiency of n3 and n6 very long chain polyunsaturated fatty acid(VLC-PUFAby overexpressing ELOVL4 protein, providing guidance for treating Stargardt-like macular dystrophy(STGD3.METHODS:To establish recombinant adenovirus with the ELOVL4 protein and green fluorescent protein, transferred into cultured PC12 cells. The cells were divided into 3 groups: PC12, PC12+Ad-GFP and PC12+Ad- ELOVL4, former two groups serve as controls. ELOVL4 gene expression was quantified by qRT-PCRs. ELOVL4 protein was analyzed by Western-Blot(WB. The transduced cells were treated with both EPA and AA(1:1. After 48h of incubation, cells were collected, total lipids extracted and fatty acid methyl esters prepared and analyzed by gas chromatography-mass spectrometry(GC-MS. RESULTS: When supplemented together, 20:5n3(EPAand 20:4n6(AAwere efficiently taken up at almost the same amounts in the PC12 cells regardless of ELOVL4 expression. The ELOVL4-expressing cells elongated both EPA and AA to a series of n3 and n6 VLC-PUFAs. From 20:5n3/EPA, 34:5n3 and 36:5n3 account for 0.71% and 1.6%, respectively. From 20:4n6/DHA, 34:4n6 and 36:4n6 were only 0.46% and 0.61%, respectively. The total relative mol% of n3 VLC-PUFAs synthesized from EPA was almost two times that of n6 VLC-PUFAs synthesized from AA.CONCLUSION: ELOVL4 protein preferentially elongates n3 PUFA to VLC-PUFAs over n6 PUFA. Dietary supplementation of appropriate n3/n6 PUFAs may provide STGD3 patients with some therapeutic benefits.

  3. Morphology-Controllable Synthesis of Zn-Co-Mixed Sulfide Nanostructures on Carbon Fiber Paper Toward Efficient Rechargeable Zinc-Air Batteries and Water Electrolysis.

    Science.gov (United States)

    Wu, Xiaoyu; Han, Xiaopeng; Ma, Xiaoya; Zhang, Wei; Deng, Yida; Zhong, Cheng; Hu, Wenbin

    2017-04-12

    It remains an ongoing challenge to develop cheap, highly active, and stable electrocatalysts to promote the sluggish electrocatalytic oxygen evolution, oxygen reduction, and hydrogen evolution reactions for rechargeable metal-air batteries and water-splitting systems. In this work, we report the morphology-controllable synthesis of zinc cobalt mixed sulfide (Zn-Co-S) nanoarchitectures, including nanosheets, nanoplates, and nanoneedles, grown on conductive carbon fiber paper (CFP) and the micronanostructure dependent electrochemical efficacy for catalyzing hydrogen and oxygen in zinc-air batteries and water electrolysis. The formation of different Zn-Co-S morphologies was attributed to the synergistic effect of decomposed urea products and the corrosion of NH 4 F. Among synthesized Zn-Co-S nanostructures, the nanoneedle arrays supported on CFP exhibit superior trifunctional activity for oxygen reduction, oxygen evolution, and hydrogen evolution reactions than its nanosheet and nanoplate counterparts through half reaction testing. It also exhibited better catalytic durability than Pt/C and RuO 2 . Furthermore, the Zn-Co-S nanoneedle/CFP electrode enables rechargeable Zn-air batteries with low overpotential (0.85 V), high efficiency (58.1%), and long cycling lifetimes (200 cycles) at 10 mA cm -2 as well as considerable performance for water splitting. The superior performance is contributed to the integrated nanoneedle/CFP nanostructure, which not only provides enhanced electrochemical active area, but also facilitates ion and gas transfer between the catalyst surface and electrolyte, thus maintaining an effective solid-liquid-gas interface necessary for electrocatalysis. These results indicate that the Zn-Co-S nanoneedle/CFP system is a low cost, highly active, and durable electrode for highly efficient rechargeable zinc-air batteries and water electrolysis in alkaline solution.

  4. Interactions at the Dimer Interface Influence the Relative Efficiencies for Purine Nucleotide Synthesis and Pyrophosphorolysis in a Phosphoribosyltransferase

    Energy Technology Data Exchange (ETDEWEB)

    Canyuk, Bhutorn; Medrano, Francisco J.; Wenck, MaryAnne; Focia, Pamela J.; Eakin, Ann E.; Craig III, Sydney P. (UNC); (Connecticut)

    2010-03-05

    Enzymes that salvage 6-oxopurines, including hypoxanthine phosphoribosyltransferases (HPRTs), are potential targets for drugs in the treatment of diseases caused by protozoan parasites. For this reason, a number of high-resolution X-ray crystal structures of the HPRTs from protozoa have been reported. Although these structures did not reveal why HPRTs need to form dimers for catalysis, they revealed the existence of potentially relevant interactions involving residues in a loop of amino acid residues adjacent to the dimer interface, but the contributions of these interactions to catalysis remained poorly understood. The loop, referred to as active-site loop I, contains an unusual non-proline cis-peptide and is composed of residues that are structurally analogous with Leu67, Lys68, and Gly69 in the human HPRT. Functional analyses of site-directed mutations (K68D, K68E, K68N, K68P, and K68R) in the HPRT from Trypanosoma cruzi, etiologic agent of Chagas disease, show that the side-chain at position 68 can differentially influence the K{sub m} values for all four substrates as well as the k{sub cat} values for both IMP formation and pyrophosphorolysis. Also, the results for the K68P mutant are inconsistent with a cis-trans peptide isomerization-assisted catalytic mechanism. These data, together with the results of structural studies of the K68R mutant, reveal that the side-chain of residue 68 does not participate directly in reaction chemistry, but it strongly influences the relative efficiencies for IMP formation and pyrophosphorolysis, and the prevalence of lysine at position 68 in the HPRT of the majority of eukaryotes is consistent with there being a biological role for nucleotide pyrophosphorolysis.

  5. Facile Synthesis of Unique Hexagonal Nanoplates of Zn/Co Hydroxy Sulfate for Efficient Electrocatalytic Oxygen Evolution Reaction.

    Science.gov (United States)

    Dutta, Soumen; Ray, Chaiti; Negishi, Yuichi; Pal, Tarasankar

    2017-03-08

    Cost-effective, highly active water oxidation catalysts are increasingly being demanded in the field of energy conversion and storage. Herein, a simple modified hydrothermally (MHT) synthesized zinc and cobalt based hydroxyl double salt, that is, Zn 4-x Co x SO 4 (OH) 6 ·0.5H 2 O (ZCS), has been exfoliated for the first time as an efficient electrocatalyst for oxygen evolution reaction (OER) in alkaline medium. Morphology investigation suggests the evolution of unique hexagonal nanoplates of ZCS material. As OER catalyst, it requires only 370 and 450 mV overpotential to achieve 10 and 100 mA cm -2 current density, respectively. More importantly, performance at the overpotential over 400 mV and durability of the designed material have been found to be superior to those of commercial RuO 2 catalyst. In the designed ZCS material trace amounts of cobalt species lead to higher mass activity of 146 A g -1 , compared to that of the RuO 2 catalyst (83 A g -1 ) at the same overpotential of 370 mV. The outstanding activity and stability of the cost-effective material emerges from the promotional effect of Zn ions, which are present as the principal constituent in the electrocatalyst, and they also protect the cobalt ions in the matrix during its long-term electrochemical test. It is important to note that an appropriate ratio of zinc and cobalt ions synergistically helps to create an economically viable and environmentally suitable electrocatalyst in comparison to other related transition metal based materials.

  6. Synthesis of Ce(III)-doped Fe3O4 magnetic particles for efficient removal of antimony from aqueous solution

    International Nuclear Information System (INIS)

    Qi, Zenglu; Joshi, Tista Prasai; Liu, Ruiping; Liu, Huijuan; Qu, Jiuhui

    2017-01-01

    Highlights: • Doping of Ce into Fe 3 O 4 was achieved based on a facile solvothermal method. • After doping, the removal capacity was increased by 5 times for “Sb(V)” and 2 times for “Sb(III)”. • Decreasing pH improved adsorption of Sb(V) but decreased adsorption of Sb(III). • Antimony sorption mechanisms on Ce-doped Fe 3 O 4 were illustrated. - Abstract: Aqueous antimony (Sb) pollution from human activity is of great concern in drinking water due to its adverse health effect. Magnetic Fe 3 O 4 particles, with high separation ability from solution, have been considered as a low-cost Sb adsorbent for contaminants. However, the limited adsorption capacity has restricted its practical application. In this study, a solvothermal approach was developed for doping Ce(III) into Fe 3 O 4 , thereby increasing the adsorption efficacy for both Sb(III) and Sb(V). In contrast to un-doped Fe 3 O 4 , the adsorption capacity towards Sb(III) and Sb(V) in Ce-doped materials increased from 111.4 to 224.2 mg/g and from 37.2 to 188.1 mg/g at neutral pH, respectively. Based on the combined results of XPS, XRD, and FTIR, it confirmed that Ce atom successfully doped into the Fe 3 O 4 structure, resulting in the decreased particle size, increased the surface area, and isoelectric point. Furthermore, the vibrating sample magnetometer (VSM) results showed that the Ce doping process had some side effects on the primitive magnetic property, but remaining the high separation potential during water treatment. According to the high removal efficiency and magnetic property, the Ce-doped Fe 3 O 4 of great simplicity should be a promising adsorbent for aqueous Sb removal.

  7. Synthesis of high efficient Cu/TiO2 photocatalysts by grinding and their size-dependent photocatalytic hydrogen production

    International Nuclear Information System (INIS)

    Ni, Dawei; Shen, Haiyan; Li, Huiqiao; Ma, Ying; Zhai, Tianyou

    2017-01-01

    Highlights: • Cu nanodots were decorated on TiO 2 surface through ball milling method. • Its size distribution was investigated in water and ethanolic medium. • Photocurrent response and hydrogen evolution was improved. • Performance was found to be dependent on size of Cu nanodots. - Abstract: Recently, copper species have been extensively investigated to replace Pt as efficient co-catalysts for the evolution of H 2 due to their low cost and relatively high activity. Cu nanoparticles less than 5 nm are successfully decorated on TiO 2 surface in this work by an easy and mild milling process. These Cu nanoparticles are highly dispersed on TiO 2 when the loading amount of Cu is no more than 10 wt%. The sizes of Cu nanoparticles can be controlled by changing the milling environment and decrease in the order of Cu-ethanol > Cu-water > Cu nanoparticles obtained through drying milling. The highest and stable hydrogen generation can be realized on Cu/TiO 2 with 2.0 wt% Cu and sizes of Cu nanoparticles ranging from 2 to 4 nm, in which high and stable photocurrent confirms promoted photogenerated charge separation. Smaller Cu clusters are demonstrated to be detrimental to hydrogen evolution at same Cu content. High loading of Cu nanoparticles of 2–4 nm will benefit photogenerated electron-hole recombination and thus decrease the activity of Cu/TiO 2 . The results here demonstrate the key roles of Cu cluster size in addition to Cu coverage on photocatalytic activity of Cu/TiO 2 composite photocatalysts.

  8. Beating Bias in the Directed Evolution of Proteins: Combining High-Fidelity on-Chip Solid-Phase Gene Synthesis with Efficient Gene Assembly for Combinatorial Library Construction.

    Science.gov (United States)

    Li, Aitao; Acevedo-Rocha, Carlos G; Sun, Zhoutong; Cox, Tony; Xu, Jia Lucy; Reetz, Manfred T

    2018-02-02

    Saturation mutagenesis (SM) constitutes a widely used technique in the directed evolution of selective enzymes as catalysts in organic chemistry and in the manipulation of metabolic paths and genomes, but the quality of the libraries is far from optimal due to the inherent amino acid bias. Herein, it is shown how this fundamental problem can be solved by applying high-fidelity solid-phase chemical gene synthesis on silicon chips followed by efficient gene assembly. Limonene epoxide hydrolase was chosen as the catalyst in the model desymmetrization of cyclohexene oxide with the stereoselective formation of (R,R)- and (S,S)-cyclohexane-1,2-diol. A traditional combinatorial PCR-based SM library, produced by simultaneous randomization at several residues by using a reduced amino acid alphabet, and the respective synthetic library were constructed and compared. Statistical analysis at the DNA level with massive sequencing demonstrates that, in the synthetic approach, 97 % of the theoretically possible DNA mutants are formed, whereas the traditional SM library contained only about 50 %. Screening at the protein level also showed the superiority of the synthetic library; many highly (R,R)- and (S,S)-selective variants being discovered are not found in the traditional SM library. With the prices of synthetic genes decreasing, this approach may point the way to future directed evolution. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Synthesis of Porous δ-MnO2 Submicron Tubes as Highly Efficient Electrocatalyst for Rechargeable Li-O2 Batteries.

    Science.gov (United States)

    Zhang, Peng; Sun, Dongfei; He, Mu; Lang, Junwei; Xu, Shan; Yan, Xingbin

    2015-06-08

    Lithium-oxygen (Li-O2 ) batteries are receiving intense interest because of their high energy density. A new tubular δ-MnO2 material prepared by a simple hydrothermal synthesis is an efficient electrocatalyst for Li-O2 batteries. The synthesized δ-MnO2 exhibits a unique tubular structure, in which the porous walls are composed of highly dispersed ultrathin δ-MnO2 nanosheets. Such a unique structure and its intrinsic catalytic activity provide the right electrocatalyst characteristics for high-performance Li-O2 batteries. As a consequence, suppressed overpotentials-especially the oxygen evolution reaction overpotential-superior rate capability, and desirable cycle life are achieved with these submicron δ-MnO2 tubes as the electrocatalyst. Remarkably, the discharge product Li2 O2 of the Li-O2 battery exhibits a uniform nanosheet-like morphology, which indicates the critical role of the δ-MnO2 in the electrochemical process, and a mechanism is proposed to analyze the catalysis of δ-MnO2 . © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Free MoS2 Nanoflowers Grown on Graphene by Microwave-Assisted Synthesis as Highly Efficient Non-Noble-Metal Electrocatalysts for the Hydrogen Evolution Reaction.

    Science.gov (United States)

    Cao, Jiamu; Zhang, Xuelin; Zhang, Yufeng; Zhou, Jing; Chen, Yinuo; Liu, Xiaowei

    2016-01-01

    Advanced approaches to preparing non-noble-metal electrocatalysts for the hydrogen evolution reaction (HER) are considered to be a significant breakthrough in promoting the exploration of renewable resources. In this work, a hybrid material of MoS2 nanoflowers (NFs) on reduced graphene oxide (rGO) was synthesized as a HER catalyst via an environmentally friendly, efficient approach that is also suitable for mass production. Small-sized MoS2 NFs with a diameter of ca. 190 nm and an abundance of exposed edges were prepared by a hydrothermal method and were subsequently supported on rGO by microwave-assisted synthesis. The results show that MoS2 NFs were distributed uniformly on the remarkably reduced GO and preserved the outstanding original structural features perfectly. Electrochemical tests show that the as-prepared hybrid material exhibited excellent HER activity, with a small Tafel slope of 80 mV/decade and a low overpotential of 170 mV.

  11. Aminoclay-templated nanoscale zero-valent iron (nZVI) synthesis for efficient harvesting of oleaginous microalga, Chlorella sp. KR-1

    DEFF Research Database (Denmark)

    Lee, Young-Chul; Lee, Kyubock; Hwang, Yuhoon

    2014-01-01

    Synthesis of aminoclay-templated nanoscale zero-valent iron (nZVI) for efficient harvesting of oleaginous microalgae was demonstrated. According to various aminoclay loadings (0, 0.25, 0.5, 1.0, 2.5, 5.0, and 7.5 aminoclay/nZVI ratios), the stability of nZVI was investigated as a function......ZVI composite (ratio 1.0) exhibited a highly positively charged surface (~+40 mV) and a ferromagnetic property (~30 emu/g). On the basis of these characteristics, oleaginous Chlorella sp. KR-1 was harvested within 3 min at a > 20 g/L loading under a magnetic field. In a scaled-up (24L) microalga harvesting...... process using magnetic rods, microalgae were successfully collected by attachment to the magnetic rods or by precipitation. It is believed that this approach, thanks to the recyclability of aminoclay-nZVI composites, can be applied in a continuous harvesting mode....

  12. Non-hazardous biocatalytic oxidation in Nylon-9 monomer synthesis on a 40 g scale with efficient downstream processing.

    Science.gov (United States)

    Milker, Sofia; Fink, Michael J; Rudroff, Florian; Mihovilovic, Marko D

    2017-08-01

    This paper describes the development of a biocatalytic process on the multi-dozen gram scale for the synthesis of a precursor to Nylon-9, a specialty polyamide. Such materials are growing in demand, but their corresponding monomers are often difficult to synthesize, giving rise to biocatalytic approaches. Here, we implemented cyclopentadecanone monooxygenase as an Escherichia coli whole-cell biocatalyst in a defined medium, together with a substrate feeding-product removal concept, and an optimized downstream processing (DSP). A previously described hazardous peracid-mediated oxidation was thus replaced with a safe and scalable protocol, using aerial oxygen as oxidant, and water as reaction solvent. The engineered process converted 42 g (0.28 mol) starting material ketone to the corresponding lactone with an isolated yield of 70% (33 g), after highly efficient DSP with 95% recovery of the converted material, translating to a volumetric yield of 8 g pure product per liter. Biotechnol. Bioeng. 2017;114: 1670-1678. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  13. Unsymmetrical urea and thiourea derivatives: An efficient nano BF 3-SiO 2 catalyzed PEG-400 mediated sonochemical synthesis and biological evaluation

    Directory of Open Access Journals (Sweden)

    D. B. Janakiramudu

    2017-08-01

    Full Text Available An efficient and green approach has been developed for the synthesis of (substituted phenyl-3-(4-(4-nitrophenylthiophenylurea/thiourea derivatives 6(a-j using non-hazardous green solvent, PEG-400 under ultrasound irradiation conditions in the presence of a reusable silica-supported Lewis acid catalyst, nano-BF 3-SiO 2via simple addition reaction of 4-(4-nitrophenylthioaniline (4 with substituted phenyl isocyanates/isothiocyanates 5 (a-j. The advantages of developed method are convenient, offered higher yield of products with purity, less reaction time, easy work-up and reusability of the catalyst. Structures of the title products were established by IR, NMR ( 1H, 13C, mass spectral data and elemental analysis. Antimicrobial activity of the newly synthesized compounds was tested and the bio-screening data disclosed that urea derivatives, 6a and 6d, and thiourea derivatives, 6f, 6i and 6j showed potential antimicrobial activity against the growth of selected microorganisms.

  14. Designed synthesis CuO hollow microboxes coated with Pd nanosheets and SnO2 nanoparticles as a highly efficient Rochow reaction catalyst

    Science.gov (United States)

    Gao, Junjie; Zhang, Zailei; An, Xuebin; Zhang, Yi

    2017-12-01

    We designed and synthesized CuO/SnO2/Pd hollow microboxes, which was developed based on prepared Cu2O cubes coated Pd nanosheets, controlled oxidation of Cu2O/Pd, and etching of Cu2O/CuO/Pd by SnCl4 solution. The catalytic property of the Cu2O, Cu2O/SnO2, Cu2O/Pd/SnO2, Cu2O/Pd, Cu2O/CuO/Pd, CuO/SnO2/Pd, CuO, and commercial catalyst for dimethyldichlorosilane synthesis via the Rochow reaction was investigated. As compared to control samples and commercial catalyst, the prepared CuO/Pd/SnO2 hollow microboxes exhibited much higher silicon conversion (76.6%), which is related to the synergistic effect between CuO, Pd and SnO2, and to the distinct catalyst hollow structure which allows the efficient transportation of the reactant molecules to the active component.

  15. Solution-phase synthesis of a hindered N-methylated tetrapeptide using Bts-protected amino acid chlorides: efficient coupling and methylation steps allow purification by extraction.

    Science.gov (United States)

    Vedejs, E; Kongkittingam, C

    2000-04-21

    N-Benzothiazole-2-sulfonyl (Bts)-protected amino acid chlorides were used to prepare the hindered cyclosporin 8-11 tetrapeptide subunit 1. The synthesis was performed via 3a and the deprotected amines 5a, 13, and 19, including three repeated cycles involving N-methylation using iodomethane/potassium carbonate, deprotection of the Bts group, and N-acylation with a N-Bts-amino acid chloride such as 9b or 9c. Among three Bts cleavage methods compared (H3PO2/THF; NaBH4/EtOH; PhSH/K2CO3), the third gave somewhat higher overall yields. N-Acylation of 5a with the Bts-protected N-methylamino acid chloride 10b followed by deprotection was also highly efficient and could be used as an alternative route to 11. Each of the deprotected amines was isolated without chromatography using simple extraction methods to remove neutral byproducts. The tetrapeptide 1 was obtained in analytically pure form as the monohydrate.

  16. Magnetic Nanoparticle Immobilized N-Propylsulfamic Acid as a Recyclable and Efficient Nanocatalyst for the Synthesis of 2H-indazolo[2,1-b]phthalazine-triones in Solvent-Free Conditions: Comparison with Sulfamic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Rostami, Amin; Tahmasbi, Bahman; Yari, Ako [Univ. of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2013-05-15

    N-Propylsulfamic acid supported onto magnetic Fe{sub 3}O{sub 4} nanoparticles (MNPs-PSA) was used as an efficient and magnetically recoverable catalyst for synthesis of 2H-Indazolo[2,1-b]phthalazine-1,6,11(13H)-trione derivatives from the three-component, one-pot condensation reaction of phthalhydrazide, aromatic aldehydes and cyclic 1,3-diones, in good to excellent yields at 100 .deg. C under solvent-free conditions. The catalyst was easily separated with the assistance of an external magnetic field from the reaction mixture and reused for several consecutive runs without significant loss of its catalytic efficiency. In order to compare, the synthesis of 2H-Indazolo[2,1-b]phthalazine-1,6,11(13H)-trione derivatives in the presence of catalytic amount of sulfamic acid (SA) under same reaction condition was also reported.

  17. Rapid efficient synthesis and characterization of silver, gold, and bimetallic nanoparticles from the medicinal plant Plumbago zeylanica and their application in biofilm control.

    Science.gov (United States)

    Salunke, Gayatri R; Ghosh, Sougata; Santosh Kumar, R J; Khade, Samiksha; Vashisth, Priya; Kale, Trupti; Chopade, Snehal; Pruthi, Vikas; Kundu, Gopal; Bellare, Jayesh R; Chopade, Balu A

    2014-01-01

    -ended AgAuNPs. These NPs also showed antimicrobial and antibiofilm activity against E. coli, A. baumannii, S. aureus, and a mixed culture of A. baumannii and S. aureus. AgNPs inhibited biofilm in the range of 96%-99% and AgAuNPs from 93% to 98% in single-culture biofilms. AuNPs also showed biofilm inhibition, with the highest of 98% in S. aureus. AgNPs also showed good biofilm disruption, with the highest of 88% in A. baumannii. This is the first report on rapid and efficient synthesis of AgNPs, AuNPs and AgAuNPs from P. zeylanica and their effect on quantitative inhibition and disruption of bacterial biofilms.

  18. Poly(4-vinylpyridinium)hydrogen sulfate: a novel and efficient catalyst for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes under conventional heating and ultrasound irradiation.

    Science.gov (United States)

    Khaligh, Nader Ghaffari

    2012-07-01

    A simple and convenient procedure for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes is described through a one-pot condensation of 2-naphthol with aryl aldehydes in the presence of poly(4-vinylpyridinium)hydrogen sulfate as an efficient, cheap, readily synthesized and eco-friendly catalyst in a solvent free media using conventional heating and ultrasound irradiation. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. B2O3/Al2O3 as a new, highly efficient and reusable heterogeneous catalyst for the selective synthesis of β-enamino ketones and esters under solvent-free conditions

    OpenAIRE

    Chen,Jiu-Xi; Zhang,Chang-Fu; Gao,Wen-Xia; Jin,Hui-Le; Ding,Jin-Chang; Wu,Hua-Yue

    2010-01-01

    Boron oxide adsorbed on alumina (B2O3/Al2O3 ) has been found to be a new and highly efficient heterogeneous catalyst for the synthesis of β-enamino ketones and esters by the enamination of various primary and secondary amines with β-dicarbonyl compounds under solvent-free conditions. The important features of this methodology are broad substrate scope, high yield, no requirement of metal catalysts, high regio- and chemoselectivity and environmental friendliness. In addition, the cat...

  20. Highly efficient solid-state synthesis of carbon-encapsulated ultrafine MoO{sub 2} nanocrystals as high rate lithium-ion battery anode

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Boyang, E-mail: byliu@shmtu.edu.cn [Shanghai Maritime University, College of Ocean Science and Engineering (China); Shao, Yingfeng, E-mail: shaoyf@lnm.imech.ac.cn [Chinese Academy of Sciences, State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics (China); Zhang, Yuliang, E-mail: ylzhang@shmtu.edu.cn; Zhang, Fuhua, E-mail: fhzhang@shmtu.edu.cn; Zhong, Ning, E-mail: ningzhong@shmtu.edu.cn [Shanghai Maritime University, College of Ocean Science and Engineering (China); Li, Wenge, E-mail: wgli@shmtu.edu.cn [Shanghai Maritime University, Merchant Marine College (China)

    2016-12-15

    A simple and highly efficient method is developed for the one-step in situ preparation of carbon-encapsulated MoO{sub 2} nanocrystals (MoO{sub 2}@C) with core-shell structure for high-performance lithium-ion battery anode. The synthesis is depending on the solid-state reaction of cyclopentadienylmolybdenum tricarbonyl dimer with ammonium persulfate in an autoclave at 200 °C for 30 min. The large amount of heat generated during the explosive reaction cleaves the cyclopentadiene ligands into small carbon fragments, which form carbon shell after oxidative dehydrogenation coating on the MoO{sub 2} nanocrystals, resulting in the formation of core-shell structure. The MoO{sub 2} nanocrystals have an equiaxial morphology with an ultrafine diameter of 2–8 nm, and the median size is 4.9 nm. Hundreds of MoO{sub 2} nanocrystals are encapsulated together by the worm-like carbon shell, which is amorphous and about 3–5 nm in thickness. The content of MoO{sub 2} nanocrystals in the nanocomposite is about 69.3 wt.%. The MoO{sub 2}@C anode shows stable cyclability and retains a high reversible capacity of 443 mAh g{sup −1} after 50 cycles at a current density of 3 A g{sup −1}, owing to the effective protection of carbon shell.

  1. Highly Efficient Method for the Synthesis of Activated Mesoporous Biocarbons with Extremely High Surface Area for High-Pressure CO2Adsorption.

    Science.gov (United States)

    Singh, Gurwinder; Lakhi, Kripal S; Kim, In Young; Kim, Sungho; Srivastava, Prashant; Naidu, Ravi; Vinu, Ajayan

    2017-09-06

    A simple and efficient way to synthesize activated mesoporous biocarbons (AMBs) with extremely high BET surface area and large pore volume has been achieved for the first time through a simple solid state activation of freely available biomass, Arundo donax, with zinc chloride. The textural parameters of the AMB can easily be controlled by varying the activation temperature. It is demonstrated that the mesoporosity of AMB can be finely tuned with a simple adjustment of the amount of activating agent. AMB with almost 100% mesoporosity can be achieved using the activating agent and the biomass ratio of 5 and carbonization at 500 °C. Under the optimized conditions, AMB with a BET surface area of 3298 m 2 g -1 and a pore volume of 1.9 cm 3 g -1 can be prepared. While being used as an adsorbent for CO 2 capture, AMB registers an impressively high pressure CO 2 adsorption capacity of 30.2 mmol g -1 at 30 bar which is much higher than that of activated carbon (AC), multiwalled carbon nanotubes (MWCNTs), highly ordered mesoporous carbons, and mesoporous carbon nitrides. AMB also shows high stability with excellent regeneration properties under vacuum and temperatures of up to 250 °C. These impressive textural parameters and high CO 2 adsorption capacity of AMB clearly reveal its potential as a promising adsorbent for high-pressure CO 2 capture and storage application. Also, the simple one-step synthesis strategy outlined in this work would provide a pathway to generate a series of novel mesoporous activated biocarbons from different biomasses.

  2. Facile synthesis of ultrafine Co3O4 nanocrystals embedded carbon matrices with specific skeletal structures as efficient non-enzymatic glucose sensors

    International Nuclear Information System (INIS)

    Li, Mian; Han, Ce; Zhang, Yufan; Bo, Xiangjie; Guo, Liping

    2015-01-01

    Highlights: • Novel hyperfine Co 3 O 4 nanocrystals decorated porous carbon matrixes. • Facile synthesis without use of any harmful dispersing reagents or surfactants. • High dispersion degree of Co 3 O 4 nanocrystals and excellent e − transport rates. • A large current sensitivity of 955.9 μA cm −2 mM −1 toward glucose. • Excellent anti-interference and stability for glucose detection. - Abstract: A facile, effective, and environmentally friendly method has been adopted for the first time to prepare tiny Co 3 O 4 nanocrystals embedded carbon matrices without using surfactants, harmful organic reagents or extreme conditions. Structural characterizations reveal that the size-controlled Co 3 O 4 nanocrystals are uniformly dispersed on carbon matrices. Electrochemical measurements reveal that Co 3 O 4 -ordered mesoporous carbon (OMC) can more efficiently catalyze glucose oxidation and acquire better detection parameters compared with those for the Co 3 O 4 -macroporous carbon, Co 3 O 4 -reduced graphene oxide, and free Co 3 O 4 nanoparticles (NPs) (such as: the large sensitivity (2597.5 μA cm −2 mM −1 between 0 and 0.8 mM and 955.9 μA cm −2 mM −1 between 0.9 and 7.0 mM), fast response time, wide linear range, good stability, and surpassingly selective capability to electroactive molecules or Cl − ). Such excellent performances are attributed to the synergistic effect of the following three factors: (1) the high catalytic sites provided by the uniformly dispersed and size-controlled Co 3 O 4 nanocrystals embedded on OMC; (2) the excellent reactant transport efficiency caused by the abundant mesoporous structures of OMC matrix: (3) the improved electron transport in high electron transfer rate (confinement of the Co 3 O 4 NPs in nanoscale spaces ensured intimate contact between Co 3 O 4 nanocrystals and the conducting OMC matrix). The superior catalytic activity and selectivity make Co 3 O 4 -OMC very promising for application in direct

  3. Facile synthesis of ultrafine Co{sub 3}O{sub 4} nanocrystals embedded carbon matrices with specific skeletal structures as efficient non-enzymatic glucose sensors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mian; Han, Ce; Zhang, Yufan; Bo, Xiangjie, E-mail: baoxj133@nenu.edu.cn; Guo, Liping, E-mail: guolp078@nenu.edu.cn

    2015-02-25

    Highlights: • Novel hyperfine Co{sub 3}O{sub 4} nanocrystals decorated porous carbon matrixes. • Facile synthesis without use of any harmful dispersing reagents or surfactants. • High dispersion degree of Co{sub 3}O{sub 4} nanocrystals and excellent e{sup −} transport rates. • A large current sensitivity of 955.9 μA cm{sup −2} mM{sup −1} toward glucose. • Excellent anti-interference and stability for glucose detection. - Abstract: A facile, effective, and environmentally friendly method has been adopted for the first time to prepare tiny Co{sub 3}O{sub 4} nanocrystals embedded carbon matrices without using surfactants, harmful organic reagents or extreme conditions. Structural characterizations reveal that the size-controlled Co{sub 3}O{sub 4} nanocrystals are uniformly dispersed on carbon matrices. Electrochemical measurements reveal that Co{sub 3}O{sub 4}-ordered mesoporous carbon (OMC) can more efficiently catalyze glucose oxidation and acquire better detection parameters compared with those for the Co{sub 3}O{sub 4}-macroporous carbon, Co{sub 3}O{sub 4}-reduced graphene oxide, and free Co{sub 3}O{sub 4} nanoparticles (NPs) (such as: the large sensitivity (2597.5 μA cm{sup −2} mM{sup −1} between 0 and 0.8 mM and 955.9 μA cm{sup −2} mM{sup −1} between 0.9 and 7.0 mM), fast response time, wide linear range, good stability, and surpassingly selective capability to electroactive molecules or Cl{sup −}). Such excellent performances are attributed to the synergistic effect of the following three factors: (1) the high catalytic sites provided by the uniformly dispersed and size-controlled Co{sub 3}O{sub 4} nanocrystals embedded on OMC; (2) the excellent reactant transport efficiency caused by the abundant mesoporous structures of OMC matrix: (3) the improved electron transport in high electron transfer rate (confinement of the Co{sub 3}O{sub 4} NPs in nanoscale spaces ensured intimate contact between Co{sub 3}O{sub 4} nanocrystals and the

  4. Efficient Synthesis of Network Updates

    Science.gov (United States)

    2015-06-17

    Pavol Černý CU Boulder pavol.cerny@colorado.edu Nate Foster Cornell University jnfoster@cs.cornell.edu Abstract Software-defined networking ( SDN ...is revolutionizing the net- working industry, but current SDN programming platforms do not provide automated mechanisms for updating global...configurations on the fly. Implementing updates by hand is challenging for SDN programmers because networks are distributed systems with hun- dreds or thousands

  5. Sulfonic acid functionalized boron nitride nanomaterials as a microwave-assisted efficient and highly biologically active one-pot synthesis of piperazinyl-quinolinyl fused Benzo[c]acridine derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Murugesan, Arul; Gengan, R.M., E-mail: genganrm@dut.ac.za; Krishnan, Anand

    2017-02-15

    Boron nitride nano material based solid acid catalyst was found to be an efficient and reusable sulfonic acid catalyst for the synthesis of one-pot Knoevenagel and Michael type reactions in 3, 3-dimethyl-9-(2-(4-methylpiperazin-1-yl) quinolin-3-yl)-3, 4, 9, 10-tetrahydroacridin-1(2H)-one derivatives under microwave irradiation conditions. The catalyst was prepared by mixing boron nitrile and (3-mercaptopropyl) trimethoxysilane. This is simple and safe method for the preparation of solid acid catalysts. The morphological properties of catalyst determined by using FT-IR, XRD, TEM, SEM and Raman spectroscopy. The synthesised catalyst was employed in Knoevenagel and Michael type reactions to synthesise novel piperazinyl-quinolinyl based acridine derivatives. Furthermore the newly-synthesised compounds have been used for molecular docking in DNA binding studies. The method developed in this study has the advantages of good yield, simplicity coupled with safety and short reaction time. Most importantly it was found that the solid acid catalyst can be recycled with only 5% loss of activity. - Highlights: • One-pot Synthesis of Knoevenagel and Michel type reactions. • Synthesis of Sulfonic acid Functionalized Boron nitride nano materials. • Synthesis of piperazinyl-quinolinyl fused Benzo[c]acridine derivatives under Microwave irradiation. • Molecular docking studies were performed on piperazinyl-quinolinyl acridine derivatives using DNA.

  6. A novel copper complex supported on magnetic reduced graphene oxide: an efficient and green nanocatalyst for the synthesis of 1-amidoalkyl-2-naphthol derivatives

    Science.gov (United States)

    Kooti, M.; Karimi, M.; Nasiri, E.

    2018-02-01

    A new Cu(II) complex supported on magnetic reduced graphene oxide was prepared and characterized by various techniques, such as FT-IR, XRD, SEM, EDX, TEM, TGA, BET, ICP, and VSM. The synthesized nanocomposite, which has size distribution of 25-30 nm, was employed as catalyst in one-pot synthesis of 1-amidoalkyl-2-naphthols via three-component condensation reaction of amides, aromatic aldehydes, and 2-naphthol, under solvent-free conditions. The introduced catalysis procedure for the synthesis of 1-amidoalkyl-2-naphthol derivatives offers several advantages namely, short reaction times, high yields, facile recyclability, and cost effectiveness. [Figure not available: see fulltext.

  7. Efficient synthesis of π-conjugated molecules incorporating fluorinated phenylene units through palladium-catalyzed iterative C(sp2–H bond arylations

    Directory of Open Access Journals (Sweden)

    Fatiha Abdelmalek

    2015-10-01

    Full Text Available We report herein a two or three step synthesis of fluorinated π-conjugated oligomers through iterative C–H bond arylations. Palladium-catalyzed desulfitative arylation of heteroarenes allowed in a first step the synthesis of fluoroaryl-heteroarene units in high yields. Then, the next steps involve direct arylation with aryl bromides catalyzed by PdCl(C3H5(dppb to afford triad or tetrad heteroaromatic compounds via regioselective activation of C(sp2–H bonds.

  8. An efficient, second-generation synthesis of the signature dioxabicyclo[3.2.1]octane core of (+)-sorangicin A and elaboration of the (Z,Z,E)-triene acid system.

    Science.gov (United States)

    Smith, Amos B; Dong, Shuzhi

    2009-03-05

    An efficient, second-generation synthesis of the signature dioxabicyclo[3.2.1]octane core of (+)-sorangicin A (1), in conjunction with an effective, stereocontrolled protocol to arrive at the requisite (Z,Z,E)-triene acid system has been developed. Highlights of the core construction entail a three-component union, a KHMDS-promoted epoxide ring formation-ring opening cascade, a Takai olefination, and a chemoselective Sharpless dihydroxylation. Assembly of the triene acid system was then achieved via Stille cross-coupling with the ethyl ester of (Z,Z)-5-tributylstannyl-2,4-pentadienoic acid, followed by mild hydrolysis preserving the triene configuration.

  9. Brønsted acidic ionic liquid catalyzed an efficient and eco-friendly protocol for the synthesis of 2,4,5-trisubstituted-1H-imidazoles under solvent-free conditions

    Directory of Open Access Journals (Sweden)

    Janardhan Banothu

    2017-05-01

    Full Text Available A simple, highly efficient and eco-friendly protocol for the synthesis of 2,4,5-trisubstituted-1H-imidazoles via one-pot three component condensation of benzil/benzoin, aldehydes and ammonium acetate under solvent-free conditions has been achieved utilizing Brønsted acidic ionic liquid, (4-sulfobutyltris(4-sulfophenyl phosphonium hydrogen sulfate as catalyst. The remarkable features of this methodology are excellent yields in shorter reaction times, cleaner reaction profile, and environmentally benign nature, use of non-toxic, readily synthesizable, inexpensive and recyclable catalyst.

  10. An Efficient Synthesis of 3,4-Dihydro-3-substituted-2H-naphtho[2,1-e][1,3]oxazine Derivatives Catalyzed by Zirconyl(IV) Chloride and Evaluation of its Biological Activities

    Energy Technology Data Exchange (ETDEWEB)

    Kategaonkar, Amol H.; Sonar, Swapnil S.; Pokalwar, Rajkumar U.; Shingate, Bapurao B.; Shingare, Murlidhar S. [Babasaheb Ambedkar Marathwada University, Maharashtra (India); Kategaonkar, Atul H. [Maharashtra Institute of Pharmacy, Maharashtra (India)

    2010-06-15

    An efficient and novel one-pot synthesis of new 3,4-dihydro-3-substituted-2H-naphtho[2,1-e][1,3]oxazine derivatives from 1-naphthol, various anilines and formalin at room temperature grinding is presented. The six-membered N,O-heterocyclic skeleton was constructed via zirconyl(IV) chloride promoted Mannich type reaction. In vitro antimicrobial activities of synthesized compounds have been investigated against Gram-positive Bacillus subtilis, Gram negative Escherichia coli and two fungi Candida albicans and Aspergillus niger in comparison with standard drugs. The results of preliminary bioassay indicate that some of title compounds possess significant antibacterial and antifungal activity.

  11. Melamine Trisulfonic Acid: An Efficient, Heterogeneous and Reusable Catalyst for the Synthesis of 10-Aryl-6,8-dimethyl- 6, 10-dihydro-5-oxa-6,8-diazaanthra [2,3-d][1,3]dioxole- 7,9-diones

    Directory of Open Access Journals (Sweden)

    Weilin Li

    2011-01-01

    Full Text Available Melamine trisulfonic acid was used as an efficient and recyclable catalyst for the one-pot synthesis of 10-aryl-6,8-dimethyl-6,10-dihydro-5-oxa-6,8-diazaanthra[2,3-d][1,3]dioxole-7,9-diones by condensation of 3,4-methylene dioxyphenol, aromatic aldehydes and 1,3-dimethylbarbituric acid under solvent-free conditions. Different types of aromatic. aldehydes were used in the reaction and in all cases the products were obtained in good to excellent yields.

  12. An efficient solvent-free synthesis of meso-substituted dipyrromethanes using SnCl2•2H2O catalysis

    Directory of Open Access Journals (Sweden)

    Kabeer Ahmed Shaikh

    2012-07-01

    Full Text Available Highly rapid and simple methodology has been developed for the quantitative synthesis of meso-substituted dipyrromethanes from lowest pyrrole/aldehyde ratio. The method was carried out by using SnCl2•2H2O as a catalyst under solvent free condition. The method is environmentally friendly, easy to workup, and gives excellent yield of the products.

  13. Remarkably Efficient Synthesis of 2H-Indazole 1-oxides and 2H-Indazoles via Tandem Carbon–Carbon Followed by Nitrogen–Nitrogen Bond Formation

    Science.gov (United States)

    Bouillon, Isabelle; Zajíček, Jaroslav; Pudelová, Naděžda; Krchňák, Viktor

    2009-01-01

    Synthesis of Indazoles Base-catalyzed tandem carbon–carbon followed by nitrogen–nitrogen bond formations quantitatively converted N-alkyl-2-nitro-N-(2-oxo-2-aryl-ethyl)-benzenesulfonamides to 2H-indazoles 1-oxides under mild conditions. Triphenylphosphine or mesyl chloride/triethylamine-mediated deoxygenation afforded 2H-indazoles. PMID:18937414

  14. An azobenzene-containing metal-organic framework as an efficient heterogeneous catalyst for direct amidation of benzoic acids: synthesis of bioactive compounds.

    Science.gov (United States)

    Hoang, Linh T M; Ngo, Long H; Nguyen, Ha L; Nguyen, Hanh T H; Nguyen, Chung K; Nguyen, Binh T; Ton, Quang T; Nguyen, Hong K D; Cordova, Kyle E; Truong, Thanh

    2015-12-14

    An azobenzene-containing zirconium metal-organic framework was demonstrated to be an effective heterogeneous catalyst for the direct amidation of benzoic acids in tetrahydrofuran at 70 °C. This finding was applied to the synthesis of several important, representative bioactive compounds.

  15. Ultrasound-assisted synthesis of β-amino ketones via a Mannich reaction catalyzed by Fe3O4 magnetite nanoparticles as an efficient, recyclable and heterogeneous catalyst

    Directory of Open Access Journals (Sweden)

    Naghi Saadatjoo

    2017-02-01

    The present methodology offers several advantages, such as good yields, short reaction times and a recyclable catalyst with a very easy work up. In addition, the obtained results indicated that MNPs can be used as an effective and inexpensive catalyst for stereoselective synthesis of β-amino carbonyl by a one-pot three component condensation of aldehydes, ketones and amines.

  16. Combining the [2,3] Sigmatropic Rearrangement and Ring-Closing Metathesis Strategies for the Synthesis of Spirocyclic Alkaloids. A Short and Efficient Route to (+/-)-Perhydrohistrionicotoxin

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Hagberg, Lars; Poulsen, Anders

    1999-01-01

    This paper describes the use of selenium-based [2,3] sigmatropic rearrangement in combination with ruthenium-catalyzed ring-closing metathesis (RCM) for the synthesis of azaspiro ring systems, as exemplified by the reactions of model substrates 5 and 6. The methodology has been applied to a short...

  17. An Efficient Procedure Based on a MW-Assisted Horner–Wadsworth-Emmons Reaction for the Synthesis of (Z-3,3-Trisubstituted-a,b-unsaturated Esters

    Directory of Open Access Journals (Sweden)

    Ornella Azzolina

    2010-08-01

    Full Text Available A microwave-assisted HWE olefination process of readily accessible aryl-alkyl ketones has been developed to provide a rapid access to (Z-3,3-trisubstituted-α,β-unsaturated methyl esters, key building blocks for the synthesis of biologically active compounds.

  18. Ammonia treatment of wheat straw. 2. Efficiency of microbial protein synthesis, rumen microbial protein pool size and turnover, and small intestinal protein digestion in sheep.

    NARCIS (Netherlands)

    Oosting, S.J.; Viets, T.C.; Lammers-Wienhoven, S.C.W.; Bruchem, van J.

    1993-01-01

    Ammonia-treated wheat straw (AWS) was compared with untreated wheat straw (UWS) and untreated wheat straw supplemented with urea (SWS) in an experiment with 6 wether sheep. Microbial protein synthesis increased after ammonia treatment due to the higher intake of rumen degradable organic matter (OM).

  19. Self-organized Ruthenium-Barium Core-Shell Nanoparticles on a Mesoporous Calcium Amide Matrix for Efficient Low-Temperature Ammonia Synthesis.

    Science.gov (United States)

    Kitano, Masaaki; Inoue, Yasunori; Sasase, Masato; Kishida, Kazuhisa; Kobayashi, Yasukazu; Nishiyama, Kohei; Tada, Tomofumi; Kawamura, Shigeki; Yokoyama, Toshiharu; Hara, Michikazu; Hosono, Hideo

    2018-03-01

    A low-temperature ammonia synthesis process is required for on-site synthesis. Barium-doped calcium amide (Ba-Ca(NH 2 ) 2 ) enhances the efficacy of ammonia synthesis mediated by Ru and Co by 2 orders of magnitude more than that of a conventional Ru catalyst at temperatures below 300 °C. Furthermore, the presented catalysts are superior to the wüstite-based Fe catalyst, which is known as a highly active industrial catalyst at low temperatures and pressures. Nanosized Ru-Ba core-shell structures are self-organized on the Ba-Ca(NH 2 ) 2 support during H 2 pretreatment, and the support material is simultaneously converted into a mesoporous structure with a high surface area (>100 m 2  g -1 ). These self-organized nanostructures account for the high catalytic performance in low-temperature ammonia synthesis. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Highly Efficient and Facile Method for Synthesis of 2-Substituted Benzimidazoles via Reductive Cyclization of O-Nitroaniline and Aryl Aldehydes

    Directory of Open Access Journals (Sweden)

    Hossein Naeimi

    2012-01-01

    Full Text Available A versatile and convenient synthesis of 2-substituted benzimidazoles, using o-nitroaniline as starting material with several aryl aldehydes, has been accomplished by using a small amount of a reluctant agent. The reaction was carried out under very mild conditions at room temperature. The yields obtained are very good in reasonably short reaction times.

  1. Highly Efficient and Facile Method for Synthesis of 2-Substituted Benzimidazoles via Reductive Cyclization of O-Nitroaniline and Aryl Aldehydes

    OpenAIRE

    Hossein Naeimi; Nasrin Alishahi

    2012-01-01

    A versatile and convenient synthesis of 2-substituted benzimidazoles, using o-nitroaniline as starting material with several aryl aldehydes, has been accomplished by using a small amount of a reluctant agent. The reaction was carried out under very mild conditions at room temperature. The yields obtained are very good in reasonably short reaction times.

  2. Silica sulfuric acid and as an efficient catalyst for the Friedlander quinoline synthesis from simple ketones and ortho - amino aryl ketones under microwave irradiation

    International Nuclear Information System (INIS)

    Zolfigol, M. A.; Salehi, P.; Shiri, M.; Faal Rastegar, T.; Ghaderi, A.

    2008-01-01

    The synthesis of quinoline derivatives via Friedlander method from ortho-amino aryl ketones in the presence of a catalytic amount of silica sulfuric acid under solvent-free condition and microwave irradiation was described. A good range of simple ketones such as cyclohexanone and deoxybenzoin were used

  3. Hantzsch reaction and quinoxaline synthesis using 1-methyl-3-(2-(sulfooxyethyl-1H-imidazol-3-ium chloride as a new, efficient and BrØnsted acidic ionic liquid catalyst

    Directory of Open Access Journals (Sweden)

    Sami Sajjadifar

    2013-10-01

    Full Text Available In this work, the efficiency, generality and applicability of new BrØnsted acidic ionic liquid (BAIL 1-methyl-3-(2-(sulfooxyethyl-1H-imidazol-3-ium chloride {[Msei]Cl} as heterogeneous and green catalyst for organic transformations are studied. Herein, the following one-pot multi-component reactions in the presence of [Msei]Cl are investigated: (i the synthesis of quinoxaline derivatives from the reaction of phenylenediamines and 1,2-diketones in EtOH under mild conditions (room temperature, (ii the preparation of 1,4-dihydropyridines from one-pot multi component condensation of 1,3-dicarbonyl compounds, NH4OAcand aldehydes under solvent-free conditions at moderate temperature (90 °C. High yields, relatively short reaction times, efficiency, generality, clean process, simple methodology, low cost, easy work-up, ease of preparation and regeneration of the catalyst and green conditions (in the synthesis of the quinoxaline derivatives are advantages of the application of [Mesi]Cl as catalyst in the above organic reactions.

  4. Synthesis of green TiO2/ZnO/CdS hybrid nano-catalyst for efficient light harvesting using an elegant pulsed laser ablation in liquids method

    International Nuclear Information System (INIS)

    Gondal, M.A.; Ilyas, A.M.; Fasasi, T.A.; Dastageer, M.A.; Seddigi, Z.S.; Qahtan, T.F.; Faiz, M.; Khattak, G.D.

    2015-01-01

    Graphical abstract: - Highlights: • Facile strategy for synthesis of green catalyst (TiO 2 /ZnO/CdS) was developed. • Clean synthesis of green catalyst was done using pulsed laser ablation in liquids. • Synthesized composite size ranges between 10 and 40 nm confirmed by HRTEM studies. • Enhanced improvement was noticed in the carriers transport in the visible region. • Visible region absorption opens door to many applications for solar energy harvesting. - Abstract: The main limitation on the applications of TiO 2 as a photocatalyst is its large band gap (3.2 eV) which limits its absorption only to the ultraviolet region of the solar spectrum. To overcome this problem, a facile strategy for clean synthesis of a nanocomposite green catalyst of zinc oxide (ZnO), titanium dioxide (TiO 2 ) and cadmium sulphide (CdS) was developed using pulsed laser ablation in liquids (PLAL) technique for the first time to the best of our knowledge. The main aim of addition of ZnO is to reduce the electron–hole recombination in the TiO 2 while CdS is used to increase the light harvesting efficiency of TiO 2 in the visible spectral region. The absorption spectrum of the TiO 2 /ZnO/CdS composite obtained from the UV–vis spectrophotometer exhibits strong absorption in the visible region as compared to the pure TiO 2 whose absorption band lies around 380 nm which is in the UV-region. The morphology of the composite quantum dots was also investigated using high resolution TEM technique which shows that the synthesized composite size ranges between 10 and 40 nm. These nanocomposites have demosntarted noticible improvement in the carriers transport in the visible region which could enhance its efficiency for many applications in the visible region especially for energy harvesting using solar radiations.

  5. Efficient synthesis of 3H-indoles enabled by the lead-mediated α-arylation of β-ketoesters or γ-lactams using aryl azides.

    Science.gov (United States)

    Zhou, Fei; Driver, Tom G

    2014-06-06

    The development of a lead-mediated α-arylation reaction between aryl azides and β-ketoesters or γ-lactams that facilitates the formation of 3H-indoles is disclosed. Twenty-five examples are included which demonstrate the generality of this reaction to access aryl azides bearing tetrasubstituted o-alkyl substituents. When paired with a Staudinger reduction, this reaction streamlines the synthesis of functionalized 3H-indoles.

  6. Palladium-catalyzed intramolecular asymmetric C-H functionalization/cyclization reaction of metallocenes: an efficient approach toward the synthesis of planar chiral metallocene compounds.

    Science.gov (United States)

    Deng, Ruixian; Huang, Yunze; Ma, Xinna; Li, Gencheng; Zhu, Rui; Wang, Bin; Kang, Yan-Biao; Gu, Zhenhua

    2014-03-26

    A palladium-catalyzed asymmetric synthesis of planar chiral metallocene compounds is reported. The reaction stereoselectively functionalized one of the ortho C-H bonds of Cp rings by intramolecular cyclization to form indenone derivatives in high yields with excellent enantioselectivity. The mild set of reaction conditions allowed a wide variety of chiral metallocene compounds to be synthesized with broad functional group tolerance. The influences of preinstalled chiralities on the other Cp-ring were also investigated.

  7. Efficient Synthesis of Ethanol from CH4 and Syngas on a Cu-Co/TiO2 Catalyst Using a Stepwise Reactor

    Science.gov (United States)

    Zuo, Zhi-Jun; Peng, Fen; Huang, Wei

    2016-10-01

    Ethanol synthesis from CH4 and syngas on a Cu-Co/TiO2 catalyst is studied using experiments, density functional theory (DFT) and microkinetic modelling. The experimental results indicate that the active sites of ethanol synthesis from CH4 and syngas are Cu and CoO, over which the ethanol selectivity is approximately 98.30% in a continuous stepwise reactor. DFT and microkinetic modelling results show that *CH3 is the most abundant species and can be formed from *CH4 dehydrogenation or through the process of *CO hydrogenation. Next, the insertion of *CO into *CH3 forms *CH3CO. Finally, ethanol is formed through *CH3CO and *CH3COH hydrogenation. According to our results, small particles of metallic Cu and CoO as well as a strongly synergistic effect between metallic Cu and CoO are beneficial for ethanol synthesis from CH4 and syngas on a Cu-Co/TiO2 catalyst.

  8. Facile in situ synthesis of 2D porous g-C{sub 3}N{sub 4} and g-C{sub 3}N{sub 4}/P25(N) heterojunction with enhanced quantum effect for efficient photocatalytic application

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Mingye [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Wang, Wei, E-mail: wwnjut@hotmail.com [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Zhou, Yingjie [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Lu, Chunhua; Ni, Yaru; Xu, Zhongzi [College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China)

    2015-06-25

    Highlights: • N doped P25 is efficient in synthesizing g-C{sub 3}N{sub 4} with enhanced quantum effect. • The few-layered g-C{sub 3}N{sub 4} has a two-dimensional and porous structure. • The few-layered g-C{sub 3}N{sub 4} is superior to the bulk g-C{sub 3}N{sub 4} for photocatalysis. • Efficient heterojunction is in situ formed between g-C{sub 3}N{sub 4} and N doped P25. • The mass ratio of g-C{sub 3}N{sub 4} to N doped P25 affects the photocatalytic activity. - Abstract: The major challenge of employing photocatalysis for environment protection is to develop high efficient, low cost, and stable semiconductor photocatalysts. In the present study, an in situ annealing strategy is employed for large scale synthesis of two-dimensional (2D) porous graphitic carbon nitride (g-C{sub 3}N{sub 4}) and efficient g-C{sub 3}N{sub 4}/P25(N) (N doped P25) heterojunction with enhanced quantum effect. The P25 not only serves as the template for g-C{sub 3}N{sub 4} polymerization, but is also modified by the N species to enhance the visible light absorption. Compared to the normal bulk g-C{sub 3}N{sub 4}, the 2D porous g-C{sub 3}N{sub 4} with enhanced quantum effect is found to be more efficient in improving the specific surface area and the electron–hole pair’s separation, even its light absorption edge is blue-shifted. Photocatalytic degradation of Rhodamine B (RhB) and phenol indicates the 2D g-C{sub 3}N{sub 4} and g-C{sub 3}N{sub 4}/P25(N) are very efficient and stable under the xenon lamp irradiation. It is also found that the original mass ratio of urea, which is the precursor for g-C{sub 3}N{sub 4} synthesis and P25 modification, to P25 also plays a significant effect on the photocatalytic activity. The optimized photocatalyst (mass ratio of P25 to urea is 1:8) can decompose total RhB aqueous solution (10 mg/L, 100 ml) in 25 min. Based on systematic characterizations and discussions, a possible photocatalytic mechanism for the excellent photocatalytic

  9. A straightforward and efficient method for the synthesis of diversely substituted {beta}-aminoketones and {gamma}-aminoalcohols from 3-(N,N-dimethylamino)propiophenones as starting materials

    Energy Technology Data Exchange (ETDEWEB)

    Abonia, Rodrigo; Arteaga, Danny; Castillo, Juan; Insuasty, Braulio; Quiroga, Jairo; Ortiz, Alejandro, E-mail: rodrigo.abonia@correounivalle.edu.co [Universidad del Valle, Cali (Colombia). Department of Chemistry. Research Group of Heterocyclic Compounds

    2013-09-15

    Libraries of novel {beta}-aminoketones and {gamma}-aminoalcohols showing a wide structural diversity were easily obtained from a simple approach, using 3-(N,N-dimethylamino)propiophenone derivatives as key starting material. The procedure involved initially an N-alkylation of secondary benzylamines with propiophenone salts yielding the desired {beta}-aminoketones. Chemical or catalytic reduction of their carbonyl groups provided the final {gamma}-aminoalcohols in good yields. This protocol proved to be convenient as an alternative route for the synthesis of the local anesthetic Falicain Registered-Sign and for the topic antifungal drug Naftifine Registered-Sign . (author)

  10. A general approach for the synthesis of bimetallic M–Sn (M = Ru, Rh and Ir) catalysts for efficient hydrogenolysis of ester

    KAUST Repository

    Samal, Akshaya Kumar

    2016-11-24

    A versatile synthetic method was applied for the preparation of Sn containing bimetallic catalysts. The synthesis was performed by simply mixing the super hydride [LiB(C2H5)(3)H], with a metal (Ru, Rh or Ir) salt and an organotin complex in tetrahydrofuran solvent without using any surfactant. This leads to the formation of monodispersed M-Sn (M = Ru, Rh or Ir) bimetallic nanoparticles (NPs). These bimetallic catalysts show high performances in the hydrogenolysis of ester to the corresponding alcohol.

  11. Synthesis and Characterization of High Efficiency and Stable Spherical Ag3PO4 Visible Light Photocatalyst for the Degradation of Methylene Blue Solutions

    Directory of Open Access Journals (Sweden)

    Liqin Qin

    2015-01-01

    Full Text Available A facile method for the synthesis of Ag3PO4 visible light photocatalyst has been developed to improve the photocatalytic activity and stability. The as-prepared samples are investigated by X-ray powder diffraction, scanning electron microscopy, infrared spectroscopy, photoluminescence (PL spectroscopy, and UV-Vis diffuse reflectance spectroscopy techniques. The results reveal that the prepared Ag3PO4 has cube structure with a band gap of 2.26 eV. The as-prepared samples show higher photocatalytic activity for methylene blue (MB degradation than that of N-TiO2 under visible light irradiation.

  12. Scalable and Cost-Effective Synthesis of Highly Efficient Fe2N-Based Oxygen Reduction Catalyst Derived from Seaweed Biomass.

    Science.gov (United States)

    Liu, Long; Yang, Xianfeng; Ma, Na; Liu, Haitao; Xia, Yanzhi; Chen, Chengmeng; Yang, Dongjiang; Yao, Xiangdong

    2016-03-09

    A simple and scalable synthesis of a 3D Fe2N-based nanoaerogel is reported with superior oxygen reduction reaction activity from waste seaweed biomass, addressed the growing energy scarcity. The merits are due to the synergistic effect of the 3D porous hybrid aerogel support with excellent electrical conductivity, convenient mass transport and O2 adsorption, and core/shell structured Fe2N/N-doped amorphous carbon nanoparticles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. One-Step Synthesis of B/N Co-doped Graphene as Highly Efficient Electrocatalyst for the Oxygen Reduction Reaction: Synergistic Effect of Impurities.

    Science.gov (United States)

    Mazánek, Vlastimil; Matějková, Stanislava; Sedmidubský, David; Pumera, Martin; Sofer, Zdeněk

    2018-01-19

    In the last decade, numerous studies of graphene doping by various metal and nonmetal elements have been done in order to obtain tailored properties, such as non-zero band gap, electrocatalytic activity, or controlled optical properties. From nonmetal elements, boron and nitrogen were the most studied dopants. Recently, it has been shown that in some cases the enhanced electrocatalytic activity of graphene and its derivatives can be attributed to metal impurities rather than to nonmetal elements. In this paper, we investigated the electrocatalytical properties of B/N co-doped graphene with respect to the content of metallic impurities introduced by the synthesis procedures. For this purpose, a permanganate (Hummers) and a chlorate (Hofmann) route were used for the preparation of the starting graphene oxides (GO). The GO used for the synthesis of B/N co-doped graphene had significantly difference compositions of oxygen functionalities as well as metallic impurities introduced by the different synthetic procedures. We performed a detailed structural and chemical analysis of the doped graphene samples to correlate their electrocatalytic activity with the concentration of incorporated boron and nitrogen as well as metallic impurities. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. A facile and green approach for the controlled synthesis of porous SnO₂ nanospheres: application as an efficient photocatalyst and an excellent gas sensing material.

    Science.gov (United States)

    Manjula, P; Boppella, Ramireddy; Manorama, Sunkara V

    2012-11-01

    A facile and elegant methodology invoking the principles of Green Chemistry for the synthesis of porous tin dioxide nanospheres has been described. The low-temperature (∼50 °C) synthesis of SnO₂ nanoparticles and their self-assembly into organized, uniform, and monodispersed porous nanospheres with high surface area is facilitated by controlling the concentration of glucose, which acts as a stabilizing as well as structure-directing agent. A systematic control on the stannate to glucose molar concentration ratio determines the exact conditions to obtain monodispersed nanospheres, preferentially over random aggregation. Detailed characterization of the structure, morphology, and chemical composition reveals that the synthesized material, 50 nm SnO₂ porous nanospheres possess BET surface area of about 160 m²/g. Each porous nanosphere consists of a few hundred nanoparticles ∼2-3 nm in diameter with tetragonal cassiterite crystal structure. The SnO₂ nanospheres exhibit elevated photocatalytic activity toward methyl orange with good recyclability. Because of the high activity and stability of this photocatalyst, the material is ideal for applications in environmental remediation. Moreover, SnO₂ nanospheres display excellent gas sensing capabilities toward hydrogen. Surface modification of the nanospheres with Pd transforms this sensing material into a highly sensitive and selective room-temperature hydrogen sensor.

  15. Au3+/Au0 Supported on Chromium(III Terephthalate Metal Organic Framework (MIL-101 as an Efficient Heterogeneous Catalystfor Three-Component Coupling Synthesis of Propargylamines

    Directory of Open Access Journals (Sweden)

    Lili Liu

    2017-01-01

    Full Text Available Post-synthesis modification is a useful method for the functionalization of metal–organic frameworks (MOFs. A novel catalyst Au@MIL-101-ED-SA (ED = ethylenediamine, SA = salicylaldehyde, containing coexisting Au3+ ions and Au0 nanoparticles, was prepared successfully by post-synthesis modification with ethylenediamine, salicylaldehyde and gold. Gold nanoparticles supported on MIL-101 (Au@MIL-101 were prepared successfully by the impregnation method. Au@MIL-101-ED-SA and Au@MIL-101 were characterized by N2 adsorption–desorption, X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and inductively coupled plasma-optical emission spectrometry. Au@MIL-101-ED-SA and Au@MIL-101 were applied as environmentally friendly catalysts in the three-component coupling reaction of aldehydes, amines, and alkynes for the preparation of diverse propargylamines. Au@MIL-101-ED-SA contained a fraction of cationic gold (Au3+/Au0 = 0.9 and showed higher catalytic activity than Au@MIL-101, which was prepared by the impregnation method. Furthermore, the reactions were performed under heterogeneous conditions and the novel catalyst was successfully recycled for four consecutive runs.

  16. Synthesis of calcium-phosphorous doped TiO2 nanotubes by anodization and reverse polarization: A promising strategy for an efficient biofunctional implant surface

    Science.gov (United States)

    Alves, Sofia A.; Patel, Sweetu B.; Sukotjo, Cortino; Mathew, Mathew T.; Filho, Paulo N.; Celis, Jean-Pierre; Rocha, Luís A.; Shokuhfar, Tolou

    2017-03-01

    The modification of surface features such as nano-morphology/topography and chemistry have been employed in the attempt to design titanium oxide surfaces able to overcome the current dental implants failures. The main goal of this study is the synthesis of bone-like structured titanium dioxide (TiO2) nanotubes enriched with Calcium (Ca) and Phosphorous (P) able to enhance osteoblastic cell functions and, simultaneously, display an improved corrosion behavior. To achieve the main goal, TiO2 nanotubes were synthetized and doped with Ca and P by means of a novel methodology which relied, firstly, on the synthesis of TiO2 nanotubes by anodization of titanium in an organic electrolyte followed by reverse polarization and/or anodization, in an aqueous electrolyte. Results show that hydrophilic bone-like structured TiO2 nanotubes were successfully synthesized presenting a highly ordered nano-morphology characterized by non-uniform diameters. The chemical analysis of such nanotubes confirmed the presence of CaCO3, Ca3(PO4)2, CaHPO4 and CaO compounds. The nanotube surfaces submitted to reverse polarization, presented an improved cell adhesion and proliferation compared to smooth titanium. Furthermore, these surfaces displayed a significantly lower passive current in artificial saliva, and so, potential to minimize their bio-degradation through corrosion processes. This study addresses a very simple and promising multidisciplinary approach bringing new insights for the development of novel methodologies to improve the outcome of osseointegrated implants.

  17. A highly efficient nano-Fe{sub 3}O{sub 4} encapsulated-silica particles bearing sulfonic acid groups as a solid acid catalyst for synthesis of 1,8-dioxo-octahydroxanthene derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Naeimi, Hossein, E-mail: naeimi@kashanu.ac.ir; Nazifi, Zahra Sadat [University of Kashan, Department of Organic Chemistry, Faculty of Chemistry (Iran, Islamic Republic of)

    2013-11-15

    The functionalization of silica-coated Fe{sub 3}O{sub 4} magnetic nanoparticles (Fe{sub 3}O{sub 4}@SiO{sub 2}) using chlorosulfonic acid were afforded sulfonic acid-functionalized magnetic Fe{sub 3}O{sub 4} nanoparticles (Fe{sub 3}O{sub 4}@SiO{sub 2}–SO{sub 3}H) that can be applied as an organic–inorganic hybrid heterogeneous catalyst. The used Fe{sub 3}O{sub 4} magnetic nanoparticles are 18–30 nm sized that was rapidly functionalized and can be used as catalyst in organic synthesis. The prepared nanoparticles were characterized by X-ray diffraction analysis, magnetization curve, scanning electron microscope, dynamic laser scattering, and FT-IR measurements. The resulting immobilized catalysts have been successfully used in the synthesis of 1,8‐dioxo-octahydroxanthene derivatives under solvent free condition. This procedure has many advantages such as; a much milder method, a shorter reaction time, a wide range of functional group tolerance, and absence of any tedious workup or purification. Other remarkable features include the catalyst can be reused at least five times without any obvious change in its catalytic activity. This procedure also avoids hazardous reagents/solvents, and thus can be an eco-friendly alternative to the existing methods.Graphical AbstractA highly efficient nano-Fe{sub 3}O{sub 4} encapsulated-silica particles bearing sulfonic acid groups as a solid acid catalyst for synthesis of 1,8-dioxo-octahydroxanthene derivatives.

  18. Plant Extract Mediated Eco-Friendly Synthesis of Pd@Graphene Nanocatalyst: An Efficient and Reusable Catalyst for the Suzuki-Miyaura Coupling

    Directory of Open Access Journals (Sweden)

    Mujeeb Khan

    2017-01-01

    Full Text Available Suzuki-Miyaura coupling reaction catalyzed by the palladium (Pd-based nanomaterials is one of the most versatile methods for the preparation of biaryls. However, use of organic solvents as reaction medium causes a big threat to environment due to the generation of toxic byproducts as waste during the work up of these reactions. Therefore, the use of water as reaction media has attracted tremendous attention due to its environmental, economic, and safety benefits. In this study, we report on the synthesis of green Pd@graphene nanocatalyst based on an in situ functionalization approach which exhibited excellent catalytic activity towards the Suzuki–Miyaura cross-coupling reactions of phenyl halides with phenyl boronic acids under facile conditions in water. The green and environmentally friendly synthesis of Pd@graphene nanocatalyst (PG-HRG-Pd is carried out by simultaneous reduction of graphene oxide (GRO and PdCl2 using Pulicaria glutinosa extract (PGE as reducing and stabilizing agent. The phytomolecules present in the plant extract (PE not only facilitated the reduction of PdCl2, but also helped to stabilize the surface of PG-HRG-Pd nanocatalyst, which significantly enhanced the dispersibility of nanocatalyst in water. The identification of PG-HRG-Pd was established by various spectroscopic and microscopic techniques, including, high-resolution transmission electron microscopy (HRTEM, X-ray diffraction (XRD, ultraviolet–visible spectroscopy (UV-Vis, Fourier transform infrared spectroscopy (FT-IR, and Raman spectroscopy. The as-prepared PG-HRG-Pd nanocatalyst demonstrated excellent catalytic activity towards the Suzuki-Miyaura cross coupling reactions under aqueous, ligand free, and aerobic conditions. Apart from this the reusability of the catalyst was also evaluated and the catalyst yielded excellent results upon reuse for several times with marginal loss of its catalytic performance. Therefore, the method developed for the green

  19. Nano magnetite (Fe3O4, an efficient and robust catalyst for the one-pot synthesis of 1-(aryl(piperidin-1-ylmethylnaphthalene-2-ol and 1-(α-amido alkyl-2-naphthol under ultrasound irradiation

    Directory of Open Access Journals (Sweden)

    Masoud Mokhtary

    2017-01-01

    Full Text Available The direct three component reaction via condensation of aldehydes, 2-naphthol and piperidine or acetamide to generate 1-(aryl(piperidin-1-ylmethylnaphthalene-2-ol and N-((2-hydroxy naphthalene-1-yl(arylmethylacetamide derivatives has been carried out over Fe3O4 magnetic nanoparticle with high efficiency under ultrasound irradiation. These reactions were studied under different conditions. In terms of reaction time and yield, it was found that optimum results were obtained for the synthesis of 1-(aryl(piperidin-1-ylmethylnaphthalene-2-ol under solvent free condition and for preparation of N-((2-hydroxynaphthalene-1-yl(arylmethylacetamide in acetic acid under ultrasound irradiation at 80 °C. Clean methodologies, easy workup procedure, and high yields are some advantages of this work.

  20. Rapid and facile CuCl assistant synthesis of PtCu3 nanoframes as efficient catalysts for electroxidation of methanol

    Science.gov (United States)

    Bai, Lei; Bai, Yuwei

    2018-02-01

    Hollow-structured nanomaterials generally showed enhanced catalytic abilities due to their high utilization. In this work, a general method for the synthesis of PtCu3 nanoframes was reported with the employment of hexadecyltrimethylammonium chloride (CTAC), copper(I) chloride, and various kinds of platinum precursors such as K2PtCl6, H2PtCl6, and Pt(acac)2. It was revealed that the presence of CTAC was crucial for the formation of frame structures. On the one hand, CTAC could act as a structure director, and on the other hand, the galvanic replacement and etching effect of the chloride ions together with oxygen was also responsible for the formation of the frame structure. A similar effect was also evidenced in the case of hexadecyltrimethylammonium bromide. Finally, the as-obtained PtCu3 nanoframes demonstrated high catalytic abilities in the oxidation of methanol as a model reaction. [Figure not available: see fulltext.

  1. Synthesis of Supported Ultrafine Non-noble Subnanometer-Scale Metal Particles Derived from Metal-Organic Frameworks as Highly Efficient Heterogeneous Catalysts.

    Science.gov (United States)

    Kang, Xinchen; Liu, Huizhen; Hou, Minqiang; Sun, Xiaofu; Han, Hongling; Jiang, Tao; Zhang, Zhaofu; Han, Buxing

    2016-01-18

    The properties of supported non-noble metal particles with a size of less than 1 nm are unknown because their synthesis is a challenge. A strategy has now been created to immobilize ultrafine non-noble metal particles on supports using metal-organic frameworks (MOFs) as metal precursors. Ni/SiO2 and Co/SiO2 catalysts were synthesized with an average metal particle size of 0.9 nm. The metal nanoparticles were immobilized uniformly on the support with a metal loading of about 20 wt%. Interestingly, the ultrafine non-noble metal particles exhibited very high activity for liquid-phase hydrogenation of benzene to cyclohexane even at 80 °C, while Ni/SiO2 with larger Ni particles fabricated by a conventional method was not active under the same conditions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Efficient synthesis of [18F]FPyME: A new approach for the preparation of maleimide-containing prosthetic groups for the conjugation with thiols.

    Science.gov (United States)

    Cavani, Melanie; Bier, Dirk; Holschbach, Marcus; Coenen, Heinz H

    2017-01-01

    An improved high yielding radiosynthesis of the known thiol-reactive maleimide-containing prosthetic group1-[3-(2-[ 18 F]fluoropyridine-3-yloxy)propyl]pyrrole-2,5-dione ([ 18 F]FPyME) is described. The target compound was obtained by a two-step one-pot procedure starting from a maleimide-containing nitro-precursor that was protected as a Diels-Alder adduct with 2,5-dimethylfurane. Nucleophilic radiofluorination followed by heat induced deprotection through a Retro Diels Alder reaction yielded, after chromatographic isolation, [ 18 F]FPyME with a radiochemical yield of 20% in about 60 min overall synthesis time. A variety of other [ 18 F]fluoropyridine based maleimide-containing prosthetic groups should be accessible via the described synthetic strategy. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Synthesis and characterization of ZnO incorporated magnetically recoverable KIT-6 as a novel and efficient catalyst in the preparation of symmetrical N, N‧-alkylidene bisamides

    Science.gov (United States)

    Saadati-Moshtaghin, Hamid Reza; Zonoz, Farrokhzad Mohammadi; Amini, Mostafa M.

    2018-04-01

    A novel magnetically recoverable nanocomposite consisting of the NiFe2O4 core and KIT-6 mesoporous silica shell incorporated with ZnO nanoparticles was constructed. This nanocomposite was characterized by Fourier transform infrared (FT-IR), powder X-ray diffraction (XRD), Brunauer Emmett Teller (BET), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). This new nanocomposite demonstrated a catalytic performance in the synthesis of symmetrical N,N‧-alkylidene bisamides at the condensation reaction under solvent-free conditions. The nanocatalyst could simply be recovered from the reaction environment by using an exterior magnet and reused five times without a remarkable losing in the catalytic property.

  4. Efficient Synthesis and Characterization of Some Novel Nitro-Schiff Bases and Their Complexes of Nickel(II and Copper(II

    Directory of Open Access Journals (Sweden)

    Hossein Naeimi

    2013-01-01

    Full Text Available Synthesis and characterization of some new Schiff base ligands derived from various diamines and nitrosalicylaldehyde and their complexes of Ni(II and Cu(II are reported. Several spectral techniques such as UV-Vis, FT-IR, and NMR spectra were used to identify the chemical structures of the reported ligands and their complexes. The ligands are found to be bound to the metal atom through the oxygen atoms of the hydroxyl groups and nitrogen atoms of imine groups, which is also supported by spectroscopic techniques. The results obtained by FT-IR and NMR showed that the Schiff base complexes of transition metal (II have square-planar geometry.

  5. Efficient one-pot enzymatic synthesis of alpha-(1 -> 4)-glucosidic disaccharides through a coupled reaction catalysed by Lactobacillus acidophilus NCFM maltose phosphorylase

    DEFF Research Database (Denmark)

    Nakai, Hiroyuki; Dilokpimol, Adiphol; Abou Hachem, Maher

    2010-01-01

    Lactobacillus acidophilus NCFM maltose phosphorylase (LaMalP) of glycoside hydrolase family 65 catalysed enzymatic synthesis of alpha-(1 -> 4)-glucostdic disacchandes from maltose and five monosacchandes in a coupled phosphorolysis/reverse phosphorolysis one-pot reaction Thus phosphorolysis...... of maltose to 0-glucose I -phosphate circumvented addition of costly 0-glucose 1-phosphate for reverse phosphorolysis with different monosacchande acceptors, resulting in 91%, 89%, 88%, 86% and 84% yield of alpha-a-glucopyranosyl-(1 4)-N-acetyl-a-glucosain inopyranose IN-acetyl-maltosamine I, alpha......-fucose and 0.5 M xylose in 02 M phosphate-citrate p1-I 62 These current yields of 0.27-0.34 g of disaccharide products from 10 mL reaction mixtures are easy to scale up and moreover the strategy can be applied to large-scale production of other oligosacchandes from low-cost disacchandes as catalysed...

  6. Self-assembly of hollow MoS{sub 2} microflakes by one-pot hydrothermal synthesis for efficient electrocatalytic hydrogen evolution

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Aishi; Cui, Renjie; He, Yanna; Wang, Qi [Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, Nanjing 210023 (China); Zhang, Jian, E-mail: iamjzhang@njupt.edu.cn [Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, Nanjing 210023 (China); Yang, Jianping [School of Science, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210023 (China); Li, Xing’ao, E-mail: lxahbmy@126.com [Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, Nanjing 210023 (China); School of Science, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210023 (China)

    2017-07-31

    Highlights: • A new hollow MoS{sub 2} microflakes are prepared by hydrothermal synthesis firstly. • SEM and TEM study show the structural nature of hollow microflakes in depth. • The unique hollow structures have large surface area owing to the cavity. • The hollow microflakes show better HER performance than their solid counterparts. - Abstract: Molybdenum disulfide (MoS{sub 2}) has emerged as a promising non-precious metal catalyst for hydrogen evolution reaction (HER) in recent years. Some strategies including nanotechnology as well as atom doping have been employed in the preparing of electrocatalysts for high-activity and stability. To the best of our knowledge, hollow MoS{sub 2} microflakes assembled from ultrathin nanosheets have not been prepared previously. In this work, a simple, facile and environmentally friendly hydrothermal synthesis was utilized for the fabrication of hollow MoS{sub 2} microflakes for the first time. The unique hollow structures have fascinating properties, such as the large surface and low density. The morphology and structure of MoS{sub 2} microflakes were confirmed by XRD, SEM, TEM and Raman. The composition of these materials was identified by the X-ray photoelectron spectroscopy. Notably, the as-prepared hollow MoS{sub 2} microflakes showed better electrocatalytic activity than other samples. The hollow flake-like structure can not only increase the active edge sites owing to the large specific surface area, but also enhance the electron transport to improve the electrocatalytic activity. Benefiting from these factors, the hollow MoS{sub 2} microflakes exhibited electrocatalytic activity and excellent stability with a low overpotential about 85 mV and a Tafel slope of 59 mV per decade.

  7. Synthesis of calcium-phosphorous doped TiO2 nanotubes by anodization and reverse polarization: A promising strategy for an efficient biofunctional implant surface

    International Nuclear Information System (INIS)

    Alves, Sofia A.; Patel, Sweetu B.; Sukotjo, Cortino; Mathew, Mathew T.; Filho, Paulo N.; Celis, Jean-Pierre

    2017-01-01

    Highlights: • A new surface modification methodology for bio-functionalization of TiO2 NTs is addressed • Bone-like structured TiO2 nanotubular surfaces containing Ca and P were synthesized. • Ca/P-doped TiO2 NTs enhanced adhesion and proliferation of osteoblastic-like cells. • The bio-functionalization granted improved bio-electrochemical stability to TiO2 NTs. - Abstract: The modification of surface features such as nano-morphology/topography and chemistry have been employed in the attempt to design titanium oxide surfaces able to overcome the current dental implants failures. The main goal of this study is the synthesis of bone-like structured titanium dioxide (TiO 2 ) nanotubes enriched with Calcium (Ca) and Phosphorous (P) able to enhance osteoblastic cell functions and, simultaneously, display an improved corrosion behavior. To achieve the main goal, TiO 2 nanotubes were synthetized and doped with Ca and P by means of a novel methodology which relied, firstly, on the synthesis of TiO 2 nanotubes by anodization of titanium in an organic electrolyte followed by reverse polarization and/or anodization, in an aqueous electrolyte. Results show that hydrophilic bone-like structured TiO 2 nanotubes were successfully synthesized presenting a highly ordered nano-morphology characterized by non-uniform diameters. The chemical analysis of such nanotubes confirmed the presence of CaCO 3 , Ca 3 (PO 4 ) 2 , CaHPO 4 and CaO compounds. The nanotube surfaces submitted to reverse polarization, presented an improved cell adhesion and proliferation compared to smooth titanium. Furthermore, these surfaces displayed a significantly lower passive current in artificial saliva, and so, potential to minimize their bio-degradation through corrosion processes. This study addresses a very simple and promising multidisciplinary approach bringing new insights for the development of novel methodologies to improve the outcome of osseointegrated implants.

  8. Synthesis of non-ionic surfactants based on alkylene diamine and evaluation of their corrosion inhibition efficiency on carbon steel in formation water

    Directory of Open Access Journals (Sweden)

    A.M. Al-Sabagh

    2017-03-01

    Full Text Available The inhibitive effects of newly synthesized non-ionic surfactant based on alkylene diamine surfactants on X-65 carbon steel in formation water was investigated by means of electrochemical techniques and quantum chemical study. These derivatives were characterized by FT-IR, and the surface tension and thermodynamic parameters were calculated. The polarization showed that the inhibition efficiency of the prepared compounds was increased with increasing the length of the internal alkyl chain between the two terminal amino groups of diamine. The electronic properties obtained using quantum chemical approach were correlated with the experimental inhibition efficiencies. The surface morphology of carbon steel was investigated using SEM.

  9. A Highly Efficient Method for Synthesis of Bisarylmethylidenes of Cyclic Ketones in [BMIm]Cl/NaOH System as New and Recyclable Catalyst

    Directory of Open Access Journals (Sweden)

    Shahrzad Javanshir

    2014-03-01

    Full Text Available An ionic liquid 1-Butyl-3-methylimidazoliumchloride[BMIm]Cl/sodium hydroxide system, was employed as a catalyst for the fast and one-pot crossed aldol-condensation of various aromatic aldehydes and cyclic ketones, to produce a variety of substituted α,α'-bis(benzylidene-cycloalkanones under neat conditions. This process is simple, efficient and environmentally benign and proceeds in high yield and short reaction times. The ionic liquid can be recycled for subsequent reactions without any appreciable loss of efficiency.

  10. Climate and energy efficiency policies: synthesis of France commitments and results; Politiques climat et efficacite energetique. SynthEse des engagements et resultats de la France

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    After a brief recall of the definitions of energy efficiency, of direct and indirect emissions, of total emissions, and of the main French commitments (first climate plan, energy policy orientations in the POPE law, Grenelle de l'Environnement, national action plan for energy efficiency, Grenelle laws), this document briefly presents the current situation and predictions in terms of energy consumption and greenhouse gas emissions. For different sectors, it presents key measures and evokes actual or expected results. These sectors are: energy production, housing and office building, transports, industry, State and local communities, agriculture and forest, information and education, wastes

  11. Melamine trisulfonic acid as a highly efficient catalyst for the synthe-sis of 14-aryl-14H-dibenzo[a,j]xanthenes under solvent-free conditions

    Directory of Open Access Journals (Sweden)

    Abdolkarim Zare

    2014-02-01

    Full Text Available Melamine trisulfonic acid (MTSA is utilized as a highly efficient catalyst for the solvent-free condensation of 2-naphthol with arylaldehydes under conventional thermal or microwave irradiation to give 14-aryl-14H-dibenzo[a,j]xanthenes in high to excellent yields and in short reaction times.

  12. Cs2CO3/[bmim]Br as an Efficient, Green, and Reusable Catalytic System for the Synthesis of N-Alkyl Derivatives of Phthalimide under Mild Conditions

    Directory of Open Access Journals (Sweden)

    Alireza Hasaninejad

    2008-01-01

    Full Text Available Aza-conjugate addition of phthalimide to α,β-unsaturated esters efficiently achieves in the presence of catalytic amount of Cs2CO3 and ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br under mild reaction conditions (70°C to afford N-alkyl phthalimides in high yields and relatively short reaction times.

  13. Natural variation for Fe-efficiency is associated with upregulation of Strategy I mechanisms and enhanced citrate and ethylene synthesis in Pisum sativum L.

    Science.gov (United States)

    Kabir, Ahmad H; Paltridge, Nicholas G; Able, Amanda J; Paull, Jeffrey G; Stangoulis, James C R

    2012-06-01

    Iron (Fe)-deficiency is a common abiotic stress in Pisum sativum L. grown in many parts of the world. The aim of the study was to investigate variation in tolerance to Fe deficiency in two pea genotypes, Santi (Fe-efficient) and Parafield (Fe-inefficient). Fe deficiency caused greater declines in chlorophyll score, leaf Fe concentration and root-shoot development in Parafield compared to Santi, suggesting greater Fe-efficiency in Santi. Fe chelate reductase activity and ethylene production were increased in the roots of Santi and to a lesser extent in Parafield under Fe deficiency, while proton extrusion was only occurred in Santi. Moreover, expression of the Fe chelate reductase gene, FRO1, and Fe transporter, RIT1 were upregulated in Fe-deficient roots of Santi. Expression of HA1 (proton extrusion) was also significantly higher in Santi when compared to Parafield grown in Fe-deficient conditions. Furthermore, the application of the ethylene biosynthesis inhibitor, 1-aminoisobutyric acid reduced the Fe chelate reductase activity, supporting a direct role for ethylene in its induction. A significant increase in root citrate was only observed in Santi under Fe deficiency indicating a role for citrate in the Fe-efficiency mechanism. Taken together, our physiological and molecular data indicate that genotypic variation in tolerance to Fe deficiency in Santi and Parafield plants is a result of variation in a number of Strategy I mechanisms and also suggest a direct role for ethylene in Fe reductase activity. The pea cultivar, Santi provides a new source of Fe-efficiency that can be exploited to breed more Fe-efficient peas.

  14. Methyltrioctylammonium chloride catalysed sonochemical synthesis ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 125; Issue 5. Methyltrioctylammonium chloride catalysed sonochemical synthesis of acridine diones ... The greener, clean and efficient protocol for the synthesis of acridine diones derivatives has been achieved by reacting aromatic aldehyde, dimedone and amines ...

  15. Synthesis of calcium-phosphorous doped TiO{sub 2} nanotubes by anodization and reverse polarization: A promising strategy for an efficient biofunctional implant surface

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Sofia A., E-mail: sofiafonso@msn.com [CMEMS – Center of MicroElectroMechanical Systems, Department of Mechanical Engineering, University of Minho, 4800-058 Guimarães (Portugal); IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Patel, Sweetu B. [IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Department of Mechanical Engineering, Michigan Technological University, 49931 Houghton, MI (United States); Sukotjo, Cortino [IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Departmenmt of Restorative Dentistry, University of Illinois at Chicago, 60612 Chicago, IL (United States); Mathew, Mathew T. [IBTN/US – American Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UIC College of Dentistry, 60612 Chicago, IL (United States); Department of Orthopedic Surgery, Rush University Medical Center, 60612 Chicago, IL (United States); Department of Biomedical Science, UIC School of Medicine at Rockford, 61107 Rockford, IL (United States); Filho, Paulo N. [IBTN/Br – Brazilian Branch of the Institute of Biomaterials, Tribocorrosion and Nanomedicine, UNESP – Universidade Estadual Paulista, Faculdade de Ciências, 17033-360 Bauru, São Paulo (Brazil); Faculdade de Ciências, Departamento de Física, UNESP - Universidade Estadual Paulista, 17033-360 Bauru, São Paulo (Brazil); Celis, Jean-Pierre [Department of Materials Engineering, KU Leuven, 3001 Leuven (Belgium); and others

    2017-03-31

    Highlights: • A new surface modification methodology for bio-functionalization of TiO2 NTs is addressed • Bone-like structured TiO2 nanotubular surfaces containing Ca and P were synthesized. • Ca/P-doped TiO2 NTs enhanced adhesion and proliferation of osteoblastic-like cells. • The bio-functionalization granted improved bio-electrochemical stability to TiO2 NTs. - Abstract: The modification of surface features such as nano-morphology/topography and chemistry have been employed in the attempt to design titanium oxide surfaces able to overcome the current dental implants failures. The main goal of this study is the synthesis of bone-like structured titanium dioxide (TiO{sub 2}) nanotubes enriched with Calcium (Ca) and Phosphorous (P) able to enhance osteoblastic cell functions and, simultaneously, display an improved corrosion behavior. To achieve the main goal, TiO{sub 2} nanotubes were synthetized and doped with Ca and P by means of a novel methodology which relied, firstly, on the synthesis of TiO{sub 2} nanotubes by anodization of titanium in an organic electrolyte followed by reverse polarization and/or anodization, in an aqueous electrolyte. Results show that hydrophilic bone-like structured TiO{sub 2} nanotubes were successfully synthesized presenting a highly ordered nano-morphology characterized by non-uniform diameters. The chemical analysis of such nanotubes confirmed the presence of CaCO{sub 3}, Ca{sub 3}(PO{sub 4}){sub 2}, CaHPO{sub 4} and CaO compounds. The nanotube surfaces submitted to reverse polarization, presented an improved cell adhesion and proliferation compared to smooth titanium. Furthermore, these surfaces displayed a significantly lower passive current in artificial saliva, and so, potential to minimize their bio-degradation through corrosion processes. This study addresses a very simple and promising multidisciplinary approach bringing new insights for the development of novel methodologies to improve the outcome of osseointegrated

  16. STICS: surface-tethered iterative carbohydrate synthesis.

    Science.gov (United States)

    Pornsuriyasak, Papapida; Ranade, Sneha C; Li, Aixiao; Parlato, M Cristina; Sims, Charles R; Shulga, Olga V; Stine, Keith J; Demchenko, Alexei V

    2009-04-14

    A new surface-tethered iterative carbohydrate synthesis (STICS) technology is presented in which a surface functionalized 'stick' made of chemically stable high surface area porous gold allows one to perform cost efficient and simple synthesis of oligosaccharide chains; at the end of the synthesis, the oligosaccharide can be cleaved off and the stick reused for subsequent syntheses.

  17. Bismuth nitrate as an efficient recyclable catalyst for the one-pot multi component synthesis of 1,4-dihydropyridine derivatives through unsymmetrical Hantzsch reaction

    Directory of Open Access Journals (Sweden)

    S. Sheik Mansoor

    2016-09-01

    Full Text Available Bismuth nitrate catalyzed efficient Hantzsch reaction via four-component coupling reactions of aromatic aldehydes, 5,5-dimethyl-1,3-cyclohexanedione (dimedone, ethyl acetoacetate and ammonium acetate at 80 °C temperature was described as the preparation of 1,4-dihydropyridine derivatives. 2-Amino-4-phenyl-3-cyano-7,7-dimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline derivatives are also prepared under the same experimental conditions using aldehydes, dimedone, malononitrile and ammonium acetate in good yield. The higher catalytic activity of Bi(NO3·5H2O is ascribed to its high acidity, thermal stability and water tolerance. The process presented here is operationally simple, environmentally benign and has excellent yield. Furthermore, the catalyst can be recovered conveniently and reused efficiently.

  18. Immobilization of nitrilase on bioinspired silica for efficient synthesis of 2-hydroxy-4-(methylthio) butanoic acid from 2-hydroxy-4-(methylthio) butanenitrile.

    Science.gov (United States)

    Jin, Li-Qun; Guo, Dong-Jing; Li, Zong-Tong; Liu, Zhi-Qiang; Zheng, Yu-Guo

    2016-05-01

    In this paper, a simple and effective method using sodium metasilicate as precursor and amine as additive was first reported to immobilize recombinant nitrilase, for efficient production of 2-hydroxy-4-(methylthio) butanoic acid from 2-hydroxy-4-(methylthio) butanenitrile. High immobilization recovery of enzyme activity (above 90 %) was achieved. The immobilized enzyme displayed better thermal stability, pH stability and shelf life compared to free nitrilase. Moreover, it showed excellent reusability and could be recycled up to 16 batches without significant loss in activity. 200 mM 2-hydroxy-4-(methylthio) butanenitrile was completely converted by the immobilized enzyme within 30 min, and the accumulation amount of 2-hydroxy-4-(methylthio) butanoic acid reached 130 mmol/g of immobilized beads after 16 batches. These encouraging results demonstrated the efficiency of the new technology for nitrilase immobilization, which has great potential in preparation of 2-hydroxy-4-(methylthio) butanoic acid.

  19. Vanillin Synthesis from 4-Hydroxybenzaldehyde

    Science.gov (United States)

    Taber, Douglass F.; Patel, Shweta; Hambleton, Travis M.; Winkel, Emma E.

    2007-01-01

    A regioselective, safe and efficient method for the synthesis of vanillin from 4-hydroxybenzaldehyde is being described. The vanillin derived from the process is cheap and can be used as a flavor or in the paper industry.

  20. Methyltrioctylammonium chloride catalysed sonochemical synthesis ...

    Indian Academy of Sciences (India)

    The greener, clean and efficient protocol for the synthesis of acridine diones derivatives has been achieved by reacting aromatic aldehyde, dimedone and amines using methyltrioctylammonium chloride (Aliquate 336) as a catalyst under ultrasonic irradiations.

  1. Synthesis and characterization of highly efficient and stable Pr{sub 6}O{sub 11}/Ag{sub 3}PO{sub 4}/Pt ternary hybrid structure

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Jiatao; Liu, Lin; Niu, Tongjun; Sun, Xiaosong, E-mail: sunxs@scu.edu.cn

    2017-05-01

    Highlights: • Visible-light-driven Pr{sub 6}O{sub 11}/Ag{sub 3}PO{sub 4}/Pt photocatalysts were prepared. • Pr{sub 6}O{sub 11}/Ag{sub 3}PO{sub 4}/Pt showed highly efficient and stable photocatalystic activity. • The photocatalytic mechanism of Pr{sub 6}O{sub 11}/Ag{sub 3}PO{sub 4}/Pt composite was given. - Abstract: Ag{sub 3}PO{sub 4} is an excellent photocatalyst with high efficiency and quantum yield, but suffers from the fast recombination of photogenerated electron-hole pairs and photo-corrosion. Hereby, the highly efficient and stable visible-light-driven Pr{sub 6}O{sub 11}/Ag{sub 3}PO{sub 4}/Pt photocatalyst were prepared via a three-step wet chemical approach. The as-prepared Pr{sub 6}O{sub 11}/Ag{sub 3}PO{sub 4}/Pt composite was characterized by X-ray diffraction, US-vis diffuse reflectance spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence spectra and transient photocurrent as well. Comparing with single Pr{sub 6}O{sub 11} or Ag{sub 3}PO{sub 4}, the prepared Pr{sub 6}O{sub 11}/Ag{sub 3}PO{sub 4}/Pt composite exhibited much higher photocatalytic activity and stability for the degradation of Rhodamine B under visible light irradiation (>420 nm). The enhanced photocatalytic performance of Pr{sub 6}O{sub 11}/Ag{sub 3}PO{sub 4}/Pt composite has been attributed to the efficient separation of photo-generated electron-hole pairs through a scheme system composed of Pr{sub 6}O{sub 11,} Ag{sub 3}PO{sub 4} and Pt.

  2. Efficiency Assessment of Using Flammable Compounds from Water Treatment and Methanol Production Waste for Plasma Synthesis of Iron-Containing Pigments

    OpenAIRE

    Shekhovtsova, Anastasia; Karengin, Aleksander Grigorievich

    2016-01-01

    This article describes the possibility of applying the low-temperature plasma for obtaining iron-containing pigments from water purification and flammable methanol production waste. In this paper were calculated combustion parameters of water-saltorganic compositions (WSOC) with different consists. Authors determined the modes of energy- efficient processing of the previously mentioned waste in an air plasma. Having considered the obtained results there were carried out experiments with flamm...

  3. A new hypercrosslinked supermicroporous polymer, with scope for sulfonation, and its catalytic potential for the efficient synthesis of biodiesel at room temperature.

    Science.gov (United States)

    Bhunia, Subhajit; Banerjee, Biplab; Bhaumik, Asim

    2015-03-25

    We have designed a new hypercrosslinked supermicroporous polymer (HMP-1) with a BET surface area of 913 m(2) g(-1) by FeCl3 via a catalyzed Friedel-Crafts alkylation reaction between carbazole and α,α'-dibromo-p-xylene. Upon sulfonation HMP-1 yielded a very efficient solid acid catalyst for the production of biodiesels via esterification/transesterification of free fatty acids (FFA)/esters at room temperature.

  4. Lanthanum(III chloride/chloroacetic acid as an efficient and reusable catalytic system for the synthesis of new 1-((2-hydroxynaphthalen-1-yl(phenylmethylsemicarbazides/thiosemicarbazides

    Directory of Open Access Journals (Sweden)

    Behjat Pouramiri

    2017-02-01

    Full Text Available A one-pot, multi-component coupling reaction of aromatic aldehydes, 2-naphthol and semicarbazide (hydrochloride/thiosemicarbazide using LaCl3/ClCH2COOH as an efficient catalyst system under solvent free condition at elevated temperature was investigated. High yields, short reaction time, easy work-up, green environment which requires no toxic organic solvents and reusability of the catalyst are the advantages of this procedure.

  5. Hyperbranched-dendrimer architectural copolymer gene delivery using hyperbranched PEI conjugated to poly(propyleneimine) dendrimers: synthesis, characterization, and evaluation of transfection efficiency

    Science.gov (United States)

    Alavi, Seyyed Jamal; Gholami, Leila; Askarian, Saeedeh; Darroudi, Majid; Massoudi, Abdolhossein; Rezaee, Mehdi; Kazemi Oskuee, Reza

    2017-02-01

    The applications of dendrimer-based vectors seem to be promising in non-viral gene delivery because of their potential for addressing the problems with viral vectors. In this study, generation 3 poly(propyleneimine) (G3-PPI) dendrimers with 1, 4-diaminobutane as a core initiator was synthesized using a divergent growth approach. To increase the hydrophobicity and reduce toxicity, 10% of primary amines of G3-PPI dendrimers were replaced with bromoalkylcarboxylates with different chain lengths (6-bromohexanoic and 10-bromodecanoic). Then, to retain the overall buffering capacity and enhance transfection, the alkylcarboxylate-PPIs were conjugated to 10 kDa branched polyethylenimine (PEI). The results showed that the modified PPI was able to form complexes with the diameter of less than 60 nm with net-positive surface charge around 20 mV. No significant toxicity was observed in modified PPIs; however, the hexanoate conjugated PPI-PEI (PPI-HEX-10% PEI) and the decanoate conjugated PPI-PEI (PPI-DEC-10%-PEI) showed the best transfection efficiency in murine neuroblastoma (Neuro-2a) cell line, even PPI-HEX-10%-PEI showed transfection efficiency equal to standard PEI 25 kDa with reduced toxicity. This study suggested a new series of hyperbranched (PEI)-dendrimer (PPI) architectural copolymers as non-viral gene delivery vectors with high transfection efficiency and low toxicity.

  6. One-step hydrothermal synthesis of In{sub 2.77}S{sub 4} nanosheets with efficient photocatalytic activity under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xiang-feng; Li, Hui; Sun, Yang; Wang, Yi-jin; Zhang, Chen-xu; Gong, Xiao-dong; Wang, Yu-duan; Liu, Yu; Yang, Xin-yue [Shijiazhuang Tiedao University, Hebei Provincial Key Laboratory of Traffic Engineering Materials, School of Materials Science and Engineering, Shijiazhuang (China)

    2017-06-15

    In{sub 2.77}S{sub 4} nanosheets with the band gap energy of 1.75 eV were fast prepared via a hydrothermal process. The structure, morphology and optical properties of the as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy and UV-vis diffuse reflectance spectroscopy, respectively. Rhodamine B, methyl orange and potassium dichromate solution were used to evaluate the degradation efficiency of the as-prepared samples under the visible light, respectively. Experimental results showed that the molar ratio of thioacetamide to indium nitrate hydrate significantly influenced the structure and properties of the as-prepared products. With increasing the molar ratio, the degradation efficiency of rhodamine B solution was firstly increased and then decreased. When the molar ratio was 4:1, the degradation efficiency of the as-prepared sample reached to 96% in 3 min and 100% in 9 min. Moreover, this semiconductor could degrade 88% of methyl orange solution in 30 min and 87% of potassium dichromate solution in 60 min, respectively. (orig.)

  7. Hyperbranched–dendrimer architectural copolymer gene delivery using hyperbranched PEI conjugated to poly(propyleneimine) dendrimers: synthesis, characterization, and evaluation of transfection efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Alavi, Seyyed Jamal [Ferdowsi University of Mashhad, Department of Chemistry, Faculty of Science (Iran, Islamic Republic of); Gholami, Leila [Mashhad University of Medical Sciences, Department of Modern Sciences and Technologies, School of Medicine (Iran, Islamic Republic of); Askarian, Saeedeh [Mashhad University of Medical Sciences, Department of Medical Biotechnology, School of Medicine (Iran, Islamic Republic of); Darroudi, Majid [Mashhad University of Medical Sciences, Nuclear Medicine Research Center (Iran, Islamic Republic of); Massoudi, Abdolhossein [University of Payam noor, Department of Chemistry (Iran, Islamic Republic of); Rezaee, Mehdi; Kazemi Oskuee, Reza, E-mail: Oskueekr@mums.ac.ir [Mashhad University of Medical Sciences, Department of Medical Biotechnology, School of Medicine (Iran, Islamic Republic of)

    2017-02-15

    The applications of dendrimer-based vectors seem to be promising in non-viral gene delivery because of their potential for addressing the problems with viral vectors. In this study, generation 3 poly(propyleneimine) (G3-PPI) dendrimers with 1, 4-diaminobutane as a core initiator was synthesized using a divergent growth approach. To increase the hydrophobicity and reduce toxicity, 10% of primary amines of G3-PPI dendrimers were replaced with bromoalkylcarboxylates with different chain lengths (6-bromohexanoic and 10-bromodecanoic). Then, to retain the overall buffering capacity and enhance transfection, the alkylcarboxylate–PPIs were conjugated to 10 kDa branched polyethylenimine (PEI). The results showed that the modified PPI was able to form complexes with the diameter of less than 60 nm with net-positive surface charge around 20 mV. No significant toxicity was observed in modified PPIs; however, the hexanoate conjugated PPI–PEI (PPI-HEX-10% PEI) and the decanoate conjugated PPI–PEI (PPI-DEC-10%-PEI) showed the best transfection efficiency in murine neuroblastoma (Neuro-2a) cell line, even PPI-HEX-10%-PEI showed transfection efficiency equal to standard PEI 25 kDa with reduced toxicity. This study suggested a new series of hyperbranched (PEI)–dendrimer (PPI) architectural copolymers as non-viral gene delivery vectors with high transfection efficiency and low toxicity.

  8. Efficient expression of nuclear transgenes in the green alga Chlamydomonas: synthesis of an HIV antigen and development of a new selectable marker.

    Science.gov (United States)

    Barahimipour, Rouhollah; Neupert, Juliane; Bock, Ralph

    2016-03-01

    The unicellular green alga Chlamydomonas reinhardtii has become an invaluable model system in plant biology. There is also considerable interest in developing this microalga into an efficient production platform for biofuels, pharmaceuticals, green chemicals and industrial enzymes. However, the production of foreign proteins in the nucleocytosolic compartment of Chlamydomonas is greatly hampered by the inefficiency of transgene expression from the nuclear genome. We have recently addressed this limitation by isolating mutant algal strains that permit high-level transgene expression and by determining the contributions of GC content and codon usage to gene expression efficiency. Here we have applied these new tools and explored the potential of Chlamydomonas to produce a recombinant biopharmaceutical, the HIV antigen P24. We show that a codon-optimized P24 gene variant introduced into our algal expression strains give rise to recombinant protein accumulation levels of up to 0.25% of the total cellular protein. Moreover, in combination with an expression strain, a resynthesized nptII gene becomes a highly efficient selectable marker gene that facilitates the selection of transgenic algal clones at high frequency. By establishing simple principles of successful transgene expression, our data open up new possibilities for biotechnological research in Chlamydomonas.

  9. MOF-derived Cu-Pd/nanoporous carbon composite as an efficient catalyst for hydrogen evolution reaction: A comparison between hydrothermal and electrochemical synthesis

    Science.gov (United States)

    Mandegarzad, Sakineh; Raoof, Jahan Bakhsh; Hosseini, Sayed Reza; Ojani, Reza

    2018-04-01

    In this study, a novel catalyst based on Cu-Pd bimetallic nanoparticles supported on nanoporous carbon composite (NPCC) is successfully fabricated through three-step process and used as an electrocatalyst towards hydrogen evolution reaction (HER). At the first step, MOF-199 is synthesized via two distinct strategies; (1) hydrothermal (HT) and (2) electrochemical (EC). Next, the synthesized MOF-199 is used as a template in order to prepare Cu/NPCC by direct carbonization under N2 atmosphere followed by galvanic replacement reaction of Cu metals by PdII ions. All the prepared materials are characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and nitrogen adsorption/desorption measurements. The effect of synthesis method of MOF-199 on the electrocatalytic activity of the final product towards HER is investigated. The electrochemical measurements indicate that Cu-Pd/NPCC derived from the MOF prepared by EC method (Cu-Pd/NPCC/EC) exhibits an enhanced catalytic activity towards HER in H2SO4 solution than the Cu-Pd/NPCC/HT. This improvement may be attributed to using of supporting electrolyte in the preparation of Cu-Pd/NPCC/EC.

  10. Facile synthesis of N-rich carbon quantum dots by spontaneous polymerization and incision of solvents as efficient bioimaging probes and advanced electrocatalysts for oxygen reduction reaction.

    Science.gov (United States)

    Lei, Zhouyue; Xu, Shengjie; Wan, Jiaxun; Wu, Peiyi

    2016-01-28

    In this study, uniform nitrogen-doped carbon quantum dots (N-CDs) were synthesized through a one-step solvothermal process of cyclic and nitrogen-rich solvents, such as N-methyl-2-pyrrolidone (NMP) and dimethyl-imidazolidinone (DMEU), under mild conditions. The products exhibited strong light blue fluorescence, good cell permeability and low cytotoxicity. Moreover, after a facile post-thermal treatment, it developed a lotus seedpod surface-like structure of seed-like N-CDs decorating on the surface of carbon layers with a high proportion of quaternary nitrogen moieties that exhibited excellent electrocatalytic activity and long-term durability towards the oxygen reduction reaction (ORR). The peak potential was -160 mV, which was comparable to or even lower than commercial Pt/C catalysts. Therefore, this study provides an alternative facile approach to the synthesis of versatile carbon quantum dots (CDs) with widespread commercial application prospects, not only as bioimaging probes but also as promising electrocatalysts for the metal-free ORR.

  11. One-pot solvothermal synthesis of ordered intermetallic Pt2In3 as stable and efficient electrocatalyst towards direct alcohol fuel cell application

    Science.gov (United States)

    Jana, Rajkumar; Peter, Sebastian C.

    2016-10-01

    Ordered intermetallic Pt2In3 nanoparticles have been synthesized by superhydride reduction of K2PtCl4 and InCl3.xH2O precursors using facile, one-pot solvothermal method. We report surfactant free solvothermal synthesis of a novel ordered Pt2In3 intermetallic nanoparticles for the first time. The structure and morphology of the catalyst has been confirmed by powder X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, energy-dispersive spectrometry and X-ray photoelectron spectroscopy. The electrocatalytic properties of the catalysts have been investigated by cyclic voltammetry and chronoamperometry. The as prepared Pt2In3 catalyst exhibit far superior electrocatalytic activity and stability towards alcohol oxidation over commercial Pt/C. The specific activity of as synthesized catalyst was found to be 3.2 and 2.3 times higher than commercial Pt/C for methanol and ethanol oxidation, respectively. This improved activity and durability of the Pt2In3 nanoparticles can make the catalyst an ideal catalyst candidate for direct alcohol fuel cell.

  12. Self-assembly of hollow MoS2 microflakes by one-pot hydrothermal synthesis for efficient electrocatalytic hydrogen evolution

    Science.gov (United States)

    Chen, Aishi; Cui, Renjie; He, Yanna; Wang, Qi; Zhang, Jian; Yang, Jianping; Li, Xing'ao

    2017-07-01

    Molybdenum disulfide (MoS2) has emerged as a promising non-precious metal catalyst for hydrogen evolution reaction (HER) in recent years. Some strategies including nanotechnology as well as atom doping have been employed in the preparing of electrocatalysts for high-activity and stability. To the best of our knowledge, hollow MoS2 microflakes assembled from ultrathin nanosheets have not been prepared previously. In this work, a simple, facile and environmentally friendly hydrothermal synthesis was utilized for the fabrication of hollow MoS2 microflakes for the first time. The unique hollow structures have fascinating properties, such as the large surface and low density. The morphology and structure of MoS2 microflakes were confirmed by XRD, SEM, TEM and Raman. The composition of these materials was identified by the X-ray photoelectron spectroscopy. Notably, the as-prepared hollow MoS2 microflakes showed better electrocatalytic activity than other samples. The hollow flake-like structure can not only increase the active edge sites owing to the large specific surface area, but also enhance the electron transport to improve the electrocatalytic activity. Benefiting from these factors, the hollow MoS2 microflakes exhibited electrocatalytic activity and excellent stability with a low overpotential about 85 mV and a Tafel slope of 59 mV per decade.

  13. Straightforward and highly efficient catalyst-free one-step synthesis of 2-(purin-6-yl)acetoacetic acid ethyl esters, (purin-6-yl)acetates, and 6-methylpurines through S(N)Ar-based reactions of 6-halopurines with ethyl acetoacetate.

    Science.gov (United States)

    Qu, Gui-Rong; Mao, Zhi-Jie; Niu, Hong-Ying; Wang, Dong-Chao; Xia, Chao; Guo, Hai-Ming

    2009-04-16

    A novel approach to the synthesis of purines bearing functionalized carbon substituents or methyl in position 6 was developed. Under different reaction conditions, 6-halopurine derivatives could react with ethyl acetoacetate efficiently to yield 2-(purin-6-yl)acetoacetic acid ethyl esters, (purin-6-yl)acetates and 6-methylpurines respectively. No metal catalyst and ligand were required.

  14. Synthesis of WO{sub n}-WX{sub 2} (n=2.7, 2.9; X=S, Se) heterostructures for highly efficient green quantum dot light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Shikui; Tan, Chaoliang; Zhang, Xiao; Chen, Junze; Huang, Ying; Chen, Bo; Luo, Zhimin; Ma, Qinglang; Sindoro, Melinda; Zhang, Hua [Center for Programmable Materials, School of Materials Science and Engineering, Nanyang Technological University, Singapore (Singapore); Yang, Xuyong [Luminous. Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore (Singapore); Zhu, Yihan; Han, Yu [Advanced Membranes and Porous Materials Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia); Zhang, Hao; Li, Hai; Huang, Xiao; Huang, Wei [Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech) (China); Qi, Xiaoying [Singapore Institute of Manufacturing Technology, Singapore (Singapore); Sun, Xiao Wei [Luminous. Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore (Singapore); Dept. of Electrical and Electronic Engineering, College of Engineering, Southern Univ. of Science and Technology, Nanshan, Shenzhen, Guangdong (China)

    2017-08-21

    Preparation of two-dimensional (2D) heterostructures is important not only fundamentally, but also technologically for applications in electronics and optoelectronics. Herein, we report a facile colloidal method for the synthesis of WO{sub n}-WX{sub 2} (n=2.7, 2.9; X=S, Se) heterostructures by sulfurization or selenization of WO{sub n} nanomaterials. The WO{sub n}-WX{sub 2} heterostructures are composed of WO{sub 2.9} nanoparticles (NPs) or WO{sub 2.7} nanowires (NWs) grown together with single- or few-layer WX{sub 2} nanosheets (NSs). As a proof-of-concept application, the WO{sub n}-WX{sub 2} heterostructures are used as the anode interfacial buffer layer for green quantum dot light-emitting diodes (QLEDs). The QLED prepared with WO{sub 2.9} NP-WSe{sub 2} NS heterostructures achieves external quantum efficiency (EQE) of 8.53 %. To our knowledge, this is the highest efficiency in the reported green QLEDs using inorganic materials as the hole injection layer. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Synthesis of hierarchical porous δ-MnO2 nanoboxes as an efficient catalyst for rechargeable Li-O2 batteries

    Science.gov (United States)

    Zhang, Jian; Luan, Yanping; Lyu, Zhiyang; Wang, Liangjun; Xu, Leilei; Yuan, Kaidi; Pan, Feng; Lai, Min; Liu, Zhaolin; Chen, Wei

    2015-09-01

    A rechargeable lithium-oxygen (Li-O2) battery with a remarkably high theoretical energy storage capacity has attracted enormous research attention. However, the poor oxygen reduction and oxygen evolution reaction (ORR and OER) activities in discharge and charge processes cause low energy efficiency, poor electrolyte stability and short cycle life. This requires the development of efficient cathode catalysts to dramatically improve the Li-O2 battery performances. MnO2-based materials are recognized as efficient and low-cost catalysts for a Li-O2 battery cathode. Here, we report a controllable approach to synthesize hierarchical porous δ-MnO2 nanoboxes by using Prussian blue analogues as the precursors. The obtained products possess hierarchical pore size and an extremely large surface area (249.3 m2 g-1), which would favour oxygen transportation and provide more catalytically active sites to promote ORR and OER as the Li-O2 battery cathode. The battery shows enhanced discharge capacity (4368 mA h g-1@0.08 mA cm-2), reduced overpotential (270 mV), improved rate performance and excellent cycle stability (248 cycles@500 mA h g-1 and 112 cycles@1000 mA h g-1), in comparison with the battery with a VX-72 carbon cathode. The superb performance of the hierarchical porous δ-MnO2 nanoboxes, together with a convenient fabrication method, presents an alternative to develop advanced cathode catalysts for the Li-O2 battery.A rechargeable lithium-oxygen (Li-O2) battery with a remarkably high theoretical energy storage capacity has attracted enormous research attention. However, the poor oxygen reduction and oxygen evolution reaction (ORR and OER) activities in discharge and charge processes cause low energy efficiency, poor electrolyte stability and short cycle life. This requires the development of efficient cathode catalysts to dramatically improve the Li-O2 battery performances. MnO2-based materials are recognized as efficient and low-cost catalysts for a Li-O2 battery

  16. Facile synthesis of N-rich carbon quantum dots by spontaneous polymerization and incision of solvents as efficient bioimaging probes and advanced electrocatalysts for oxygen reduction reaction

    Science.gov (United States)

    Lei, Zhouyue; Xu, Shengjie; Wan, Jiaxun; Wu, Peiyi

    2016-01-01

    In this study, uniform nitrogen-doped carbon quantum dots (N-CDs) were synthesized through a one-step solvothermal process of cyclic and nitrogen-rich solvents, such as N-methyl-2-pyrrolidone (NMP) and dimethyl-imidazolidinone (DMEU), under mild conditions. The products exhibited strong light blue fluorescence, good cell permeability and low cytotoxicity. Moreover, after a facile post-thermal treatment, it developed a lotus seedpod surface-like structure of seed-like N-CDs decorating on the surface of carbon layers with a high proportion of quaternary nitrogen moieties that exhibited excellent electrocatalytic activity and long-term durability towards the oxygen reduction reaction (ORR). The peak potential was -160 mV, which was comparable to or even lower than commercial Pt/C catalysts. Therefore, this study provides an alternative facile approach to the synthesis of versatile carbon quantum dots (CDs) with widespread commercial application prospects, not only as bioimaging probes but also as promising electrocatalysts for the metal-free ORR.In this study, uniform nitrogen-doped carbon quantum dots (N-CDs) were synthesized through a one-step solvothermal process of cyclic and nitrogen-rich solvents, such as N-methyl-2-pyrrolidone (NMP) and dimethyl-imidazolidinone (DMEU), under mild conditions. The products exhibited strong light blue fluorescence, good cell permeability and low cytotoxicity. Moreover, after a facile post-thermal treatment, it developed a lotus seedpod surface-like structure of seed-like N-CDs decorating on the surface of carbon layers with a high proportion of quaternary nitrogen moieties that exhibited excellent electrocatalytic activity and long-term durability towards the oxygen reduction reaction (ORR). The peak potential was -160 mV, which was comparable to or even lower than commercial Pt/C catalysts. Therefore, this study provides an alternative facile approach to the synthesis of versatile carbon quantum dots (CDs) with widespread

  17. Ultrasonic and hydrothermal mediated synthesis routes for functionalized Mg-Al LDH: Comparison study on surface morphology, basic site strength, cyclic sorption efficiency and effectiveness.

    Science.gov (United States)

    Ezeh, Collins I; Tomatis, Marco; Yang, Xiaogang; He, Jun; Sun, Chenggong

    2018-01-01

    Amine functionalized layered double hydroxide (LDHs) adsorbents prepared using three different routes: co-precipitation, sono-chemical and ultrasonic-assisted high pressure hydrothermal. The prepared adsorbent samples were characterized using X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning electron microscope-Energy dispersive X-ray spectroscopy (SEM-EDX), Temperature Programmed Desorption (TPD), Brunauer-Emmett-Teller (BET), and Thermogravimetric analysis (TGA), respectively. The performance of the prepared adsorbents was tested in a controlled thermal-swing adsorption process to measure its adsorption capacity, regeneration and cyclic efficiencies subsequently. The characterisation results were compared with those obtained using the conventional preparation routes but taking into account of the impact of sonochemical and hydrothermal pre-treatment on textural properties, adsorption capacity, regeneration and cyclic efficiencies. Textural results depicts a surge in surface area of the adsorbent synthesised by hydrothermal route (311m 2 /g) from 25 to 171m 2 /g for conventional and ultrasonic routes respectively. Additionally, it has been revealed from the present study that adsorbents prepared using ultrasonic-assisted hydrothermal route exhibit a better CO 2 uptake capacity than that prepared using sonochemical and conventional routes. Thus, the ultrasonic-assisted hydrothermal treatment can effectively promote the adsorption capacity of the adsorbent. This is probably due to the decrease of moderate (M-O) and weak (OH - groups) basic sites with subsequent surge in the number of strong basic sites (O 2- ) resulting from the hydrothermal process. Moreover, the cyclic adsorption efficiency of the ultrasonic mediated process was found to be 76% compared with 60% for conventional and 53% for hydrothermal routes, respectively. According to the kinetic model analysis, adsorption mechanism is mostly dominated by physisorption before amine

  18. Magnetic Cross-Linked Enzyme Aggregates (mCLEAs) of Candida antarctica Lipase: An Efficient and Stable Biocatalyst for Biodiesel Synthesis

    Science.gov (United States)

    Cruz-Izquierdo, Álvaro; Picó, Enrique A.; López, Carmen; Serra, Juan L.; Llama, María J.

    2014-01-01

    Enzyme-catalyzed production of biodiesel is the object of extensive research due to the global shortage of fossil fuels and increased environmental concerns. Herein we report the preparation and main characteristics of a novel biocatalyst consisting of Cross-Linked Enzyme Aggregates (CLEAs) of Candida antarctica lipase B (CALB) which are covalently bound to magnetic nanoparticles, and tackle its use for the synthesis of biodiesel from non-edible vegetable and waste frying oils. For this purpose, insolubilized CALB was covalently cross-linked to magnetic nanoparticles of magnetite which the surface was functionalized with –NH2 groups. The resulting biocatalyst combines the relevant catalytic properties of CLEAs (as great stability and feasibility for their reutilization) and the magnetic character, and thus the final product (mCLEAs) are superparamagnetic particles of a robust catalyst which is more stable than the free enzyme, easily recoverable from the reaction medium and reusable for new catalytic cycles. We have studied the main properties of this biocatalyst and we have assessed its utility to catalyze transesterification reactions to obtain biodiesel from non-edible vegetable oils including unrefined soybean, jatropha and cameline, as well as waste frying oil. Using 1% mCLEAs (w/w of oil) conversions near 80% were routinely obtained at 30°C after 24 h of reaction, this value rising to 92% after 72 h. Moreover, the magnetic biocatalyst can be easily recovered from the reaction mixture and reused for at least ten consecutive cycles of 24 h without apparent loss of activity. The obtained results suggest that mCLEAs prepared from CALB can become a powerful biocatalyst for application at industrial scale with better performance than those currently available. PMID:25551445

  19. Microwave-assisted solvothermal synthesis of flower-like Ag/AgBr/BiOBr microspheres and their high efficient photocatalytic degradation for p-nitrophenol

    International Nuclear Information System (INIS)

    Li, Tingting; Luo, Shenglian; Yang, Lixia

    2013-01-01

    Flower-like Ag/AgBr/BiOBr microspheres were successfully fabricated by the approach of microwave-assisted solvothermal and in situ photo-assisted reduction. A reactive ionic liquid 1-hexadecyl-3-methylimidazolium bromide ([C 16 mim]Br) was employed as Br source in the presence of surfactant polyvinylpyrrolidone (PVP). The photocatalytic activity of Ag/AgBr/BiOBr towards the decomposition of p-nitrophenol under visible light irradiation was evaluated. The results indicated that Ag/AgBr/BiOBr showed enhanced photocatalytic activity towards p-nitrophenol, comparing with P25, BiOBr and Ag/AgBr. More than 96% of p-nitrophenol was decomposed in 3.5 h under visible-light irradation. The excellent photocatalytic activity of flower-like Ag/AgBr/BiOBr microspheres can be attributed to the large specific surface area, strong visible-light absorption, suitable energy band structure and surface plasmon resonance effect of Ag nanoparticles. The possible photocatalytic mechanism was proposed based on the active species test and band gap structure analysis. - Graphical abstract: The photocatalytic reaction mechanisms of the as-prepared Ag/AgBr/BiOBr. Display Omitted - Highlights: • Successful synthesis of flower-like Ag/AgBr/BiOBr microspheres. • The Ag/AgBr/BiOBr showed much higher photocatalytic activity towards p-nitrophenol as compared to BiOBr and Ag/AgBr. • The reasons for the excellent photocatalytic activity are the large specific surface area, strong visible-light absorption and surface plasmon resonance effect of Ag nanoparticles. • The O 2 · − , Br 0 and photogenerated h + play key roles in the photocatalytic degradation process

  20. One-pot solvothermal synthesis of ordered intermetallic Pt{sub 2}In{sub 3} as stable and efficient electrocatalyst towards direct alcohol fuel cell application

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Rajkumar; Peter, Sebastian C., E-mail: sebastiancp@jncasr.ac.in

    2016-10-15

    Ordered intermetallic Pt{sub 2}In{sub 3} nanoparticles have been synthesized by superhydride reduction of K{sub 2}PtCl{sub 4} and InCl{sub 3}.xH{sub 2}O precursors using facile, one-pot solvothermal method. We report surfactant free solvothermal synthesis of a novel ordered Pt{sub 2}In{sub 3} intermetallic nanoparticles for the first time. The structure and morphology of the catalyst has been confirmed by powder X-ray diffraction, transmission electron microscopy, field emission scanning electron microscopy, energy-dispersive spectrometry and X-ray photoelectron spectroscopy. The electrocatalytic properties of the catalysts have been investigated by cyclic voltammetry and chronoamperometry. The as prepared Pt{sub 2}In{sub 3} catalyst exhibit far superior electrocatalytic activity and stability towards alcohol oxidation over commercial Pt/C. The specific activity of as synthesized catalyst was found to be ~3.2 and ~2.3 times higher than commercial Pt/C for methanol and ethanol oxidation, respectively. This improved activity and durability of the Pt{sub 2}In{sub 3} nanoparticles can make the catalyst an ideal catalyst candidate for direct alcohol fuel cell. - Graphical abstract: The ordered structure of Pt{sub 2}In{sub 3} nanoparticles synthesized by solvothermal method has confirmed through XRD and TEM. Cyclic voltametry and chronoamperometry showed improved catalytic activity and stability compared to commercial Pt/C. - Highlights: • Ordered Pt{sub 2}In{sub 3} nanoparticles were synthesized by solvothermal method. • Electrooxidation of alcohols on Pt{sub 2}In{sub 3} catalyst was investigated in acidic medium. • Pt{sub 2}In{sub 3} catalyst has superior catalytic activity compared to commercial Pt/C. • Pt{sub 2}In{sub 3} catalyst exhibited much higher stability than commercial Pt/C.

  1. Magnetic Cross-Linked Enzyme Aggregates (mCLEAs of Candida antarctica lipase: an efficient and stable biocatalyst for biodiesel synthesis.

    Directory of Open Access Journals (Sweden)

    Álvaro Cruz-Izquierdo

    Full Text Available Enzyme-catalyzed production of biodiesel is the object of extensive research due to the global shortage of fossil fuels and increased environmental concerns. Herein we report the preparation and main characteristics of a novel biocatalyst consisting of Cross-Linked Enzyme Aggregates (CLEAs of Candida antarctica lipase B (CALB which are covalently bound to magnetic nanoparticles, and tackle its use for the synthesis of biodiesel from non-edible vegetable and waste frying oils. For this purpose, insolubilized CALB was covalently cross-linked to magnetic nanoparticles of magnetite which the surface was functionalized with -NH2 groups. The resulting biocatalyst combines the relevant catalytic properties of CLEAs (as great stability and feasibility for their reutilization and the magnetic character, and thus the final product (mCLEAs are superparamagnetic particles of a robust catalyst which is more stable than the free enzyme, easily recoverable from the reaction medium and reusable for new catalytic cycles. We have studied the main properties of this biocatalyst and we have assessed its utility to catalyze transesterification reactions to obtain biodiesel from non-edible vegetable oils including unrefined soybean, jatropha and cameline, as well as waste frying oil. Using 1% mCLEAs (w/w of oil conversions near 80% were routinely obtained at 30°C after 24 h of reaction, this value rising to 92% after 72 h. Moreover, the magnetic biocatalyst can be easily recovered from the reaction mixture and reused for at least ten consecutive cycles of 24 h without apparent loss of activity. The obtained results suggest that mCLEAs prepared from CALB can become a powerful biocatalyst for application at industrial scale with better performance than those currently available.

  2. One-pot evaporation–condensation strategy for green synthesis of carbon nitride quantum dots: An efficient fluorescent probe for ion detection and bioimaging

    International Nuclear Information System (INIS)

    Yin, Ying; Zhang, Yumin; Gao, Tangling; Yao, Tai; Han, Jiecai; Han, Zhengbin; Zhang, Zhihua; Wu, Qiong; Song, Bo

    2017-01-01

    Herein, highly blue graphitic carbon nitride quantum dots (g-CNQDs) were synthesized by one-step microwave-assisted evaporation–condensation strategy using bulk g-C 3 N 4 as the precursor within 5 min. In contrast with conventional chemical routes, the as-synthesized g-CNQDs exhibited a high crystalline quality, excellent fluorescence characteristics, and a narrow size distribution with an average diameter of 3.5 ± 0.5 nm. More importantly, by using a household microwave oven, this method has the advantages of wide accessibility, environmental friendliness, a high yield of ∼40%, and can be facilely synthesized in a large scale (scaled up to a gram scale). Notably, owing to the absence of any organic reagents, the blueas-prepared g-CNQDs show the excitation wavelength-independent photoluminescence (PL) behavior. Moreover, benefiting from the stable PL emission, good water solubility, and extraordinary biocompatibility with a high quantum yield of ∼17%, the fluorescent g-CNQDs can serve as a potential sensitive and selective probe for Fe 3+ detection with a super low detection limit of 2 nM and an effective labeling agent for live-cell imaging. This work provides a unique opportunity to obtain g-CNQDs in large scale via a facile route, which may pave the way for the further design of g-CNQDs with other applications. - Highlights: • Green synthesis of g-CNQDs via one-step evaporation-condensation method. • The g-CNQDs have shown high crystalline quality and intrinsic fluorescence features. • The fluorescent g-CNQDs can serve as a sensitive and selective probe to detect Fe 3+ ions with a low detection limit of 2 nM. • g-CNQDs can serve as an effective labeling agent for live-cell imaging with extraordinary biocompatibility.

  3. One-pot evaporation–condensation strategy for green synthesis of carbon nitride quantum dots: An efficient fluorescent probe for ion detection and bioimaging

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Ying; Zhang, Yumin [Center for Composite Materials, Harbin Institute of Technology, Harbin 150001 (China); Gao, Tangling [Institute of Petrochemistry, Heilongjiang Academy of Sciences, Harbin 150040 (China); Yao, Tai [Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150001 (China); Han, Jiecai [Center for Composite Materials, Harbin Institute of Technology, Harbin 150001 (China); Han, Zhengbin, E-mail: hanzhengbin@hit.edu.cn [School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Zhang, Zhihua [Liaoning Key Materials Laboratory for Railway, School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Wu, Qiong [School of Life Science and Technology, Harbin Institute of Technology, Harbin 150001 (China); Song, Bo, E-mail: songbo@hit.edu.cn [Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150001 (China); Department of Physics, Harbin Institute of Technology, Harbin 150001 (China)

    2017-06-15

    Herein, highly blue graphitic carbon nitride quantum dots (g-CNQDs) were synthesized by one-step microwave-assisted evaporation–condensation strategy using bulk g-C{sub 3}N{sub 4} as the precursor within 5 min. In contrast with conventional chemical routes, the as-synthesized g-CNQDs exhibited a high crystalline quality, excellent fluorescence characteristics, and a narrow size distribution with an average diameter of 3.5 ± 0.5 nm. More importantly, by using a household microwave oven, this method has the advantages of wide accessibility, environmental friendliness, a high yield of ∼40%, and can be facilely synthesized in a large scale (scaled up to a gram scale). Notably, owing to the absence of any organic reagents, the blueas-prepared g-CNQDs show the excitation wavelength-independent photoluminescence (PL) behavior. Moreover, benefiting from the stable PL emission, good water solubility, and extraordinary biocompatibility with a high quantum yield of ∼17%, the fluorescent g-CNQDs can serve as a potential sensitive and selective probe for Fe{sup 3+} detection with a super low detection limit of 2 nM and an effective labeling agent for live-cell imaging. This work provides a unique opportunity to obtain g-CNQDs in large scale via a facile route, which may pave the way for the further design of g-CNQDs with other applications. - Highlights: • Green synthesis of g-CNQDs via one-step evaporation-condensation method. • The g-CNQDs have shown high crystalline quality and intrinsic fluorescence features. • The fluorescent g-CNQDs can serve as a sensitive and selective probe to detect Fe{sup 3+} ions with a low detection limit of 2 nM. • g-CNQDs can serve as an effective labeling agent for live-cell imaging with extraordinary biocompatibility.

  4. Synthesis and molecular docking against dihydrofolate reductase of novel pyridin-N-ethyl-N-methylbenzenesulfonamides as efficient anticancer and antimicrobial agents

    Science.gov (United States)

    Debbabi, Khaled F.; Bashandy, Mahmoud S.; Al-Harbi, Sami A.; Aljuhani, Enas H.; Al-Saidi, Hamed M.

    2017-03-01

    This article describes the synthesis of some novel sulfonamides having biologically active pyridine 21-28. Starting with 4-(1-(2-(2-cyanoacetyl)hydrazono)ethyl)-N-ethyl-N-methylbenzenesulfonamide (2), which was prepared from condensation of acetophenone derivative 1 with 2-cyanoacetohydrazide. Interaction of compound 2 with different aldehydes namely 4-fluorobenzaldehyde, 4-hydroxybenzaldehyde and 4-N,N-dimethylbenzaldehyde afforded the corresponding hydrazono-ethyl-N-ethyl-N-methylbenzene sulfonamides 18-20 respectively, which when reacted with malononitrile and ethyl cyanoacetate afforded compounds 21-26 respectively. These compounds 21-26 can be prepared by another reaction route by interaction of compounds 2 with arylidine malononitrile and arylidine ethyl cyanoacetate in refluxing dioxane in the presence of trimethylamine as catalyst. Interaction of compound 2 with malononitrile and ethyl cyanoacetate afforded oxopyridine derivatives 27 and 28 respectively. All the new prepared compounds were evaluated for their antitumor activities against the cell lines MCF-7 in comparison with the reference drug Doxorubicin using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay. Compounds 25, 21, 23 with SI values of 9.72, 9.71, 8.81 respectively, exhibited better activity than doxorubicin (Dox) as a reference drug with SI value of 8.49. In addition, compounds 25, 27 and 22 exhibited anti-bacterial activity against gram-negative bacteria (Klebsiella pneumoniae) with inhibition zones 22.6, 20.3 and 19.3 mm respectively, which were more active than gentamicin as a reference drug with inhibition zone 17.3 mm. Molecular Operating Environment (MOE) performed virtual screening using molecular docking studies of the synthesized compounds. The results indicated that some synthesized compounds suitable inhibitor against dihydrofolate reductase (DHFR) enzyme (PDB SD: 4DFR) with further modification.

  5. Efficient synthesis, structural characterization and anti-microbial activity of chiral aryl boronate esters of 1,2-O-isopropylidene-α-D-xylofuranose.

    Science.gov (United States)

    Trivedi, Rajiv; Rami Reddy, E; Kiran Kumar, Ch; Sridhar, B; Pranay Kumar, K; Srinivasa Rao, M

    2011-07-01

    A simple and efficient synthetic approach toward a series of chiral aryl boronate esters, starting from D-xylose, as anti-microbial agents, is described herein. Minimum inhibitory concentration and zone of inhibition revealed that these derivatives exhibit potent anti-bacterial and anti-fungal properties. Herein, we report the first anti-microbial activity of this class of compounds. All products have been characterized by NMR ((1)H, (13)C and (11)B), IR, elemental and mass spectral study. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. The Forest Industry Program. Synthesis; Efficient use of energy and other resources; Effektivare energi- och resursanvaendning. Syntes av det skogsindustriella programmet

    Energy Technology Data Exchange (ETDEWEB)

    Mattsson, Carl

    2009-02-15

    In 1997 Vaermeforsk together with the Industry launched 'The Forest Industry Programme' and has since then financed more than 70 projects. The scope of the Programme is focused on short term improvements of energy use and efficient use of feed stock. The programme complements other efforts undertaken by the Industry on its own and in joint programmes at research institutes and Universities. The report explores the achievements within the programme and identifies loopholes and challenges for the future. The report is structured according to main process stages and highlights the state of the art at each stage. Sludge Combustion in the bark boiler is still the main choice for remediation. Methods to increase dry matter content such as drying and dewatering as a pre stage before combustion have been explored. No firm conclusions can be drawn from the studies. Further efforts concerning recovery of residuals such as de-inked pulp sludge have been identified but not as a subject to the programme. Bark - The importance of fractions (as a result of drying etc) in the combustion process has been explored thoroughly. A variety of methods to increase drying efficiency have been tested and the conclusion is that the choice of method depends on the mill design. Bark boiler - A vast experience of burning internal fuels such as bark and sludge with high efficiency and low emissions has been gained. New plant design has been explored as well as techniques to upgrade old boiler plants with high commercial potential for the operator due to increased expected life time. Recovery boiler - Significant efforts has been devoted to comply with the increased restrictions on emissions not the least in the design of the next generation of boilers. A principle for dividing and sharing the NO{sub x} burden between mills has been developed and implemented successfully. Soothing/sooth intervals, cracking and best choice of materials for the super heater to increase life time are other

  7. An efficient synthesis of β-amino ketone compounds through one-pot three-component Mannich-type reactions using bismuth nitrate as catalyst

    Directory of Open Access Journals (Sweden)

    S. Sheik Mansoor

    2015-07-01

    Full Text Available Three components one-pot Mannich reaction of aromatic ketone, aromatic aldehyde and aromatic amines has been efficiently catalyzed by recyclable bismuth nitrate (Bi(NO33, BN at ambient temperature to give various β-amino carbonyl compounds in high yields. This method has advantages of mild condition, no environmental pollution, and simple work-up procedures. Most importantly, β-amino carbonyl compounds with ortho-substituted aromatic amines are obtained in acceptable to moderate yields by this methodology.

  8. Efficiency Assessment of Using Flammable Compounds from Water Treatment and Methanol Production Waste for Plasma Synthesis of Iron-Containing Pigments

    Science.gov (United States)

    Shekhovtsova, Anastasia P.; Karengin, Alexander G.

    2016-08-01

    This article describes the possibility of applying the low-temperature plasma for obtaining iron-containing pigments from water purification and flammable methanol production waste. In this paper were calculated combustion parameters of water-saltorganic compositions (WSOC) with different consists. Authors determined the modes of energy- efficient processing of the previously mentioned waste in an air plasma. Having considered the obtained results there were carried out experiments with flammable dispersed water-saltorganic compositions on laboratory plasma stand. All the experimental results are confirmed by calculations.

  9. A novel l-amino acid ionic liquid for quick and highly efficient synthesis of oxime derivatives – An environmental benign approach

    Directory of Open Access Journals (Sweden)

    Parasuraman Karthikeyan

    2016-11-01

    Full Text Available A mild, efficient, and eco-friendly procedure for the conversion of aliphatic, alicyclic and aromatic carbonyl compounds into the corresponding oximes, was catalyzed by a novel imidazolium based ionic liquid coupled with amino acid (asparagine (l-AAIL, l-Amino acid functionalized ionic liquid catalytic system. The quantitative conversion of aryl and alkyl carbonyl compounds into the corresponding oximes was achieved by simply grinding at ambient temperature using 0.05 mmol of catalyst in 50 s. In addition, this L-AAIL catalyst exhibited good reusability for five consecutive trials without significant loss of its catalytic activity.

  10. Synthesis of ammonia using sodium melt

    OpenAIRE

    Kawamura, Fumio; Taniguchi, Takashi

    2017-01-01

    Research into inexpensive ammonia synthesis has increased recently because ammonia can be used as a hydrogen carrier or as a next generation fuel which does not emit CO2. Furthermore, improving the efficiency of ammonia synthesis is necessary, because current synthesis methods emit significant amounts of CO2. To achieve these goals, catalysts that can effectively reduce the synthesis temperature and pressure, relative to those required in the Haber-Bosch process, are required. Although severa...

  11. Hierarchical structured carbon derived from bagasse wastes: A simple and efficient synthesis route and its improved electrochemical properties for high-performance supercapacitors

    Science.gov (United States)

    Feng, Haobin; Hu, Hang; Dong, Hanwu; Xiao, Yong; Cai, Yijin; Lei, Bingfu; Liu, Yingliang; Zheng, Mingtao

    2016-01-01

    Bagasse-derived hierarchical structured carbon (BDHSC) with tunable porosity and improved electrochemical performance is prepared via simple and efficient hydrothermal carbonization combined with KOH activation. Experimental results show that sewage sludge acts as a cheap and efficient structure-directing agent to regulate the morphology, adjust the porosity, and thus improve the supercapacitive performance of BDHSC. The as-resulted BDHSC exhibits an interconnected framework with high specific surface area (2296 m2 g-1), high pore volume (1.34 cm3 g-1), and hierarchical porosity, which offer a more favorable pathway for electrolyte penetration and transportation. Compared to the product obtained from bagasse without sewage sludge, the unique interconnected BDHSC exhibits enhanced supercapacitive performances such as higher specific capacitance (320 F g-1), and better rate capability (capacitance retention over 70.8% at a high current density of 50 A g-1). Moreover, the BDHSC-based symmetric supercapacitor delivers a maximum energy density of over 20 Wh kg-1 at 182 W kg-1 and presents an excellent long-term cycling stability. The developed approach in the present work can be useful not only in production of a variety of novel hierarchical structured carbon with promising applications in high-performance energy storage devices, but also in high-value utilization of biomass wastes and high-ash-content sewage sludge.

  12. Facile and Scalable Synthesis of Robust Ni(OH)2Nanoplate Arrays on NiAl Foil as Hierarchical Active Scaffold for Highly Efficient Overall Water Splitting.

    Science.gov (United States)

    Niu, Shuai; Jiang, Wen-Jie; Tang, Tang; Zhang, Yun; Li, Ji-Hui; Hu, Jin-Song

    2017-08-01

    Developing highly efficient low-cost electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline electrolyte is essential to advance water electrolysis technology. Herein, Ni(OH) 2 nanoplates aligned on NiAl foil (Ni(OH) 2 /NiAl) are developed by simply dealloying NiAl foil in KOH, which exhibits high electrocatalytic activity for OER with a small overpotential of 289 mV to achieve 10 mA cm -2 and outstanding durability with no detectable degradation during long-term operation. Furthermore, such Ni(OH) 2 /NiAl can effectively act as an active and robust hierarchical scaffold to simply electrodeposit other catalysts with intrinsically higher activity such as NiMo and NiFe nanoparticles for highly efficient HER and OER, respectively. The prepared NiFe/Ni(OH) 2 /NiAl displays superior OER catalytic activity with overpotentials of 246, 315, and 374 mV at 10, 100, and 500 mA cm -2 , respectively. While NiMo/Ni(OH) 2 /NiAl catalyst exhibits remarkable HER performance with a small overpotential of 78 mV to deliver 10 mA cm -2 . Consequently, the electrolysis device composed of the above two electrocatalysts demonstrates superb water splitting performance with a cell voltage of 1.59 V at 10 mA cm -2 . These results open up opportunities to explore and optimize low-cost advanced catalysts for energy applications.

  13. Hydrothermal synthesis of novel g-C3N4/BiOCl heterostructure nanodiscs for efficient visible light photodegradation of Rhodamine B

    Science.gov (United States)

    Song, Lingjun; Pang, Youyong; Zheng, Yanjun; Ge, Lei

    2017-08-01

    Novel g-C3N4/BiOCl heterojunction nanodiscs were synthesized by a facile hydrothermal method. A series of two-dimensional (2D) g-C3N4/BiOCl hybrids featuring tetragonal nanodisc-like BiOCl modified with ultrathin graphitic carbon nitride (g-C3N4) nanosheets were prepared via in situ deposition of BiOCl nuclei onto protonated g-C3N4. The ultrathin g-C3N4 was produced by pyrolysis of melamine using NH4Cl as a dynamic gas template. X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, electron spin resonance spectroscopy, and photoluminescence emission spectroscopy were employed to study the microstructures, composition, morphologies, and optical properties of the as-prepared hybrids. The photocatalytic activity of these heterojunction photocatalysts was investigated by degradation of rhodamine B (RhB) under visible light irradiation. The results revealed that the hybrid photocatalysts exhibited improved efficiency for RhB photodegradation compared to BiOCl and g-C3N4. Enhanced photocatalytic performance is mainly attributed to the heterojunction structure at the interface between BiOCl nanodiscs and g-C3N4 nanosheets, resulting in efficient charge separation and migration. Furthermore, the photosensitization of RhB also plays a crucial role in the photodegradation process over pure BiOCl under visible light.

  14. Strategy for the Realization of Efficient Solution-Processable Phosphorescent Organic Light-Emitting Devices: Design and Synthesis of Bipolar Alkynylplatinum(II) Complexes.

    Science.gov (United States)

    Kong, Fred Ka-Wai; Tang, Man-Chung; Wong, Yi-Chun; Ng, Maggie; Chan, Mei-Yee; Yam, Vivian Wing-Wah

    2017-05-10

    A new class of highly luminescent bipolar alkynylplatinum(II) complexes has been synthesized, characterized, and applied as phosphorescent dopants in the fabrication of solution-processable organic light-emitting devices (OLEDs). Through the incorporation of a delicate balance of electron-donating carbazole moieties and electron-accepting phenylbenzimidazole or oxadiazole moieties into the platinum(II) core, the platinum(II) complexes have been demonstrated to exhibit bipolar charge transport character with high photoluminescence quantum yields of up to 0.75 in thin films. The introduction of meta-linkages into the complexes further helps weaken the donor-acceptor interactions, facilitating better carrier-transporting abilities. More importantly, high-performance solution-processable green-emitting OLEDs with maximum current efficiencies of up to 57.4 cd A -1 and external quantum efficiencies of up to 16.0% have been realized. This is among the best performances for solution-processable phosphorescent OLEDs reported based on platinum(II) complexes as well as bipolar metal complexes.

  15. Efficient screening methods for glucosyltransferase genes in Lactobacillus strains

    NARCIS (Netherlands)

    Kralj, S; van Geel-schutten, GH; van der Maarel, MJEC; Dijkhuizen, L

    Limited information is available about homopolysaccharide synthesis in the genus Lactobacillus . Using efficient screening techniques, extracellular glucosyltransferase (GTF) enzyme activity, resulting in alpha-glucan synthesis from sucrose, was detected in various lactobacilli. PCR with degenerate

  16. Efficient screening methods for glucosyltransferase genes in Lactobacillus strains

    NARCIS (Netherlands)

    Kralj, S.; Geel van - Schutten, G.H.; Maarel, M.J.E.C. van der; Dijkhuizen, L.

    2003-01-01

    Limited information is available about homopolysaccharide synthesis in the genus Lactobacillus. Using efficient screening techniques, extracellular glucosyltransferase (GTF) enzyme activity, resulting in α-glucan synthesis from sucrose, was detected in various lactobacilli. PCR with degenerate

  17. Novel synthesis of manganese and vanadium mixed oxide (V2O5/OMS-2) as an efficient and selective catalyst for the oxidation of alcohols in liquid phase

    International Nuclear Information System (INIS)

    Mahdavi, Vahid; Soleimani, Shima

    2014-01-01

    Graphical abstract: Oxidation of various alcohols is studied in the liquid phase over new composite mixed oxide (V 2 O 5 /OMS-2) catalyst using tert-butyl hydroperoxide (TBHP). The activity of V 2 O 5 /OMS-2 samples was considerably increased with respect to OMS-2 catalyst and these samples are found to be suitable for the selective oxidation of alcohols. - Highlights: • V 2 O 5 /K-OMS-2 with different V/Mn molar ratios prepared by the impregnation method. • Oxidation of alcohols was studied in the liquid phase over V 2 O 5 /K-OMS-2 catalyst. • V 2 O 5 /K-OMS-2 catalyst had excellent activity for alcohol oxidation. • Benzyl alcohol oxidation using excess TBHP followed a pseudo-first order kinetic. • The selected catalyst was reused without significant loss of activity. - Abstract: This work reports the synthesis and characterization of mixed oxide vanadium–manganese V 2 O 5 /K-OMS-2 at various V/Mn molar ratios and prepared by the impregnation method. Characterization of these new composite materials was made by elemental analysis, BET, XRD, FT-IR, SEM and TEM techniques. Results of these analyses showed that vanadium impregnated samples contained mixed phases of cryptomelane and crystalline V 2 O 5 species. Oxidation of various alcohols was studied in the liquid phase over the V 2 O 5 /K-OMS-2 catalyst using tert-butyl hydroperoxide (TBHP) and H 2 O 2 as the oxidant. Activity of the V 2 O 5 /K-OMS-2 samples was increased considerably with respect to K-OMS-2 catalyst due to the interaction of manganese oxide and V 2 O 5 . The kinetic of benzyl alcohol oxidation using excess TBHP over V 2 O 5 /K-OMS-2 catalyst was investigated at different temperatures and a pseudo-first order reaction was determined with respect to benzyl alcohol. The effects of reaction time, oxidant/alcohol molar ratio, reaction temperature, solvents, catalyst recycling potential and leaching were investigated

  18. Recent advances in efficient and selective synthesis of di-, tri-, and tetrasubstituted alkenes via Pd-catalyzed alkenylation-carbonyl olefination synergy.

    Science.gov (United States)

    Negishi, Ei-ichi; Huang, Zhihong; Wang, Guangwei; Mohan, Swathi; Wang, Chao; Hattori, Hatsuhiko

    2008-11-18

    Although generally considered competitive, the alkenylation and carbonyl olefination routes to alkenes are also complementary. In this Account, we focus on these approaches for the synthesis of regio- and stereodefined di- and trisubstituted alkenes and a few examples of tetrasubstituted alkenes. We also discuss the subset of regio- and stereodefined dienes and oligoenes that are conjugated. Pd-catalyzed cross-coupling using alkenyl metals containing Zn, Al, Zr, and B (Negishi coupling and Suzuki coupling) or alkenyl halides and related alkenyl electrophiles provides a method of alkenylation with the widest applicability and predictability, with high stereo- and regioselectivity. The requisite alkenyl metals or alkenyl electrophiles are most commonly prepared through highly selective alkyne addition reactions including (i) conventional polar additions, (ii) hydrometalation, (iii) carbometalation, (iv) halometalation, and (v) other heteroatom-metal additions. Although much more limited in applicability, the Heck alkenylation offers an operationally simpler, viable alternative when it is highly selective and satisfactory. A wide variety of carbonyl olefination reactions, especially the Wittig olefination and its modifications represented by the E-selective HWE olefination and the Z-selective Still-Gennari olefination, collectively offer the major alternative to the Pd-catalyzed alkenylation. However, the carbonyl olefination method fundamentally suffers from more limited stereochemical options and generally lower stereoselectivity levels than the Pd-catalyzed alkenylation. In a number of cases, however, very high (>98%) stereoselectivity levels have been attained in the syntheses of both E and Z isomers. The complementarity of the alkenylation and carbonyl olefination routes provide synthetic chemists with valuable options. While the alkenylation involves formation of a C-C single bond to a CC bond, the carbonyl olefination converts a CO bond to a CC bond. When a

  19. Synthesis of arabinoxylan fragments

    DEFF Research Database (Denmark)

    Underlin, Emilie Nørmølle; Böhm, Maximilian F.; Madsen, Robert

    , or production of commercial chemicals which are mainly obtained from fossil fuels today.The arbinoxylan fragments have a backbone of β-1,4-linked xylans with α-L-arabinose units attached at specific positions. The synthesis ultilises an efficient synthetic route, where all the xylan units can be derived from D...

  20. Synthesis and Characterization of Mixed Iron-Manganese Oxide Nanoparticles and Their Application for Efficient Nickel Ion Removal from Aqueous Samples

    Science.gov (United States)

    Serra, Antonio; Monteduro, Anna Grazia; Padmanabhan, Sanosh Kunjalukkal; Licciulli, Antonio; Bonfrate, Valentina; Salvatore, Luca; Calcagnile, Lucio

    2017-01-01

    Mixed iron-manganese oxide nanoparticles, synthesized by a simple procedure, were used to remove nickel ion from aqueous solutions. Nanostructures, prepared by using different weight percents of manganese, were characterized by transmission electron microscopy, selected area diffraction, X-ray diffraction, Raman spectroscopy, and vibrating sample magnetometry. Adsorption/desorption isotherm curves demonstrated that manganese inclusions enhance the specific surface area three times and the pores volume ten times. This feature was crucial to decontaminate both aqueous samples and food extracts from nickel ion. Efficient removal of Ni2+ was highlighted by the well-known dimethylglyoxime test and by ICP-MS analysis and the possibility of regenerating the nanostructure was obtained by a washing treatment in disodium ethylenediaminetetraacetate solution. PMID:28804670