- Modification of MnFe2O4 surface by Mo (VI) pyridylimine complex as an efficient nanocatalyst for (ep)oxidation of alkenes and sulfides
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In this current paper, we report a new type of heterogeneous molybdenum (+6) complex, prepared by covalent grafting of cis-dioxo?molybdenum (VI) pyridylimine complex on the surface of MnFe2O4 nanoparticles (NP) and characterized using various physicochemical techniques. The recyclable prepared nanocatalyst was tested for sulfoxidation of sulfides and epoxidation of alkenes under solvent-free condition. The catalyst exhibited high turnover frequency for the oxidization of cyclooctene and cyclohexene (10,850 h?1) and thioanisole and dimethyl sulfide (41,250 h?1). The synthesized catalyst was found highly efficient, retrievable and eco-friendly catalyst for the (ep)oxidation of alkenes and sulfides in excellent yields in a short time. Furthermore, the synthesized nanocatalyst can be reused for four runs without apparent loss of its catalytic activity in the oxidation reaction.
- Bouzari, Narges,Bezaatpour, Abolfazl,Babaei, Behnam,Amiri, Mandana,Boukherroub, Rabah,Szunerits, Sabine
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- Method for producing 1,2,4-butanetriol
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The invention provides a method for producing 1,2,4-butanetriol. According to the method, a reaction of 2-butene-1,4-diol and hydrogen peroxide is catalyzed by a tungstate and secondary amine to generate 2,3-epoxy-1,4-butanediol; an epoxy reaction solution is treated by using catalase and then the epoxy reaction solution is directly used for a hydrogenation reaction without separation and purification; under action of a Raney nickel catalyst, the hydrogenation reaction is carried out by adopting a feeding method of slowly pressing the epoxy reaction solution into a hydrogenation kettle; and astabilizing agent is added in a rectification process of 1,2,4-butanetriol to inhibit side reactions such as oxidation, intramolecular dehydration and the like. Compared with the prior art, the preparation method of the 1,2,4-butanetriol provided by the invention has the advantages that the raw materials are easy to obtain, the reaction is stable and is easy to control, purity of the obtained product is high, and the method is very suitable for industrial production. According to the production method provided by the invention, the content of the obtained product 1,2,4-butanetriol is more than99.5%, the content of sensitive impurity 3-hydroxytetrahydrofuran is less than 0.05%, and the content of aldehydes and ketones is less than 10 [mu]g/mL.
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Paragraph 0038-0040; 0052-0053
(2020/01/12)
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- MONOMERS, POLYMERS AND PHOTORESIST COMPOSITIONS
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In one preferred embodiment, polymers are provided that comprise a structure of the following Formula (I): Photoresists that comprises such polymers also are provided.
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Paragraph 0101
(2018/03/25)
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- New perspective to catalytic epoxidation of olefins by Keplerate containing Keggin polyoxometalates
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Different Keggin encapsulated in Keplerate polyoxometalates (Mo72Fe30, PMo12 ? Mo72Fe30, SiMo12 ? Mo72Fe30 and BW12 ? Mo72Fe30) have been synthesized and their catalytic efficiency in the epoxidation of olefins with hydrogen peroxide investigated. Results were confirmed that Keggin encapsulated in Keplerates could show higher catalytic activity than parent ones. These POM catalysts lead to heterogeneous epoxidation of alkenes by hydrogen peroxide with green features of convenient recovery, steady reuse, high conversion and selectivity, and simple preparation.
- Taghiyar, Hamid,Yadollahi, Bahram
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supporting information
p. 98 - 104
(2018/10/05)
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- Stable Copper Nanoparticle Photocatalysts for Selective Epoxidation of Alkenes with Visible Light
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Selective epoxidation of various alkenes with molecular oxygen (O2) under mild conditions is a longstanding challenge in achieving syntheses of epoxides. Cu-based catalysts have been found to be catalytically active for selective epoxidations. However, the application of copper nanoparticles (CuNPs) for photocatalyzed epoxidations is encumbered by the instability of CuNPs in air. Herein we report that CuNPs supported on titanium nitride (TiN) without additional stabilizers not only are stable in air but also can catalyze selective epoxidation of various alkenes with O2 or even air as a benign oxidant under light irradiation. CuNPs remain in the metallic state due to the significant charge transfer that occurs between CuNPs and TiN. The epoxidation is driven by visible light irradiation at moderate temperatures, achieving good to high yields and excellent selectivity. The photocatalytic process is applicable to the selective epoxidation of various alkenes. In this photocatalytic system, reactant alkenes chemically adsorb on CuNPs, forming Cu-alkene surface complexes, and light irradiation can activate the complexes for reaction. The cyclic ether solvent also plays a key role, reacting with O2 on the surface of CuNPs under light irradiation, yielding oxygen adatoms. The activated surface complexes react with the adatoms, yielding the corresponding epoxides. Analysis of the influence of irradiation wavelength and intensity on the epoxidation suggests that light-excited electrons of CuNPs drive the reaction. The adatoms formed react with alkenes, producing the final product epoxides. We also observed interesting product stereoselectivity, predominantly generating the trans isomers for the epoxidation of stilbene (up to 97%). The findings reported here not only provide an effective and selective reaction system for alkene epoxidations but also are a step toward demonstrating the practical use of CuNPs as photocatalysts for various applications.
- Huang, Yiming,Liu, Zhe,Gao, Guoping,Xiao, Gang,Du, Aijun,Bottle, Steven,Sarina, Sarina,Zhu, Huaiyong
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p. 4975 - 4985
(2017/08/17)
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- Synthesis and stereospecificity of 4,5-disubstituted oxazolidinone ligands binding to T-box riboswitch RNA
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The enantiomers and the cis isomers of two previously studied 4,5-disubstituted oxazolidinones have been synthesized, and their binding to the T-box riboswitch antiterminator model RNA has been investigated in detail. Characterization of ligand affinities and binding site localization indicates that there is little stereospecific discrimination for binding antiterminator RNA alone. This binding similarity between enantiomers is likely due to surface binding, which accommodates ligand conformations that result in comparable ligand-antiterminator contacts. These results have significant implications for T-box antiterminator-targeted drug discovery and, in general, for targeting other medicinally relevant RNA that do not present deep binding pockets.
- Orac, Crina M.,Zhou, Shu,Means, John A.,Boehm, David,Bergmeier, Stephen C.,Hines, Jennifer V.
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experimental part
p. 6786 - 6795
(2011/12/04)
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- CONTINUOUS PRODUCTION METHOD OF 1,2,4-BUTANETRIOL
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Disclosed is a method of continuously producing 1,2,4-butanetriol. The method comprises feeding a liquid mixture of 2,3-epoxy-1,4-butanediol and a solvent into a continuous fixed-bed reaction system in which a nickel-based catalyst having a metal surface area of at least 3 m2/g is packed, and continuously hydrogenating the liquid mixture in a hydrogen atmosphere under conditions in which a reaction temperature is 10-250 °C, a reaction pressure is 5-300 atm, and a weight space velocity (LHSV) is 0.1-30 hr-1. Compared to the conventional technology, the present invention is advantageous in that it is possible to produce 1,2,4-butanetriol at high productivity through an environmentally friendly and economical method.
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Page/Page column 7-8
(2008/06/13)
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- Regio- and enantioselective cyclization of epoxy alcohols catalyzed by a [Co(III)(salen)] complex
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The intramolecular cyclization of epoxy alcohols was catalyzed with excellent regio- and enantiocontrol by a [Co(III)(salen)] complex. High endo selectivity was observed for the enantioselective cyclization of terminal epoxy alcohols [Eq. (a)], while the reaction of meso substrates produced novel cyclic and bicyclic ethers in good yields and high enatiopurity. TBME = tert-butyl methyl ether.
- Wu, Michael H.,Hansen, Karl B.,Jacobsen, Eric N.
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p. 2012 - 2014
(2007/10/03)
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- Homogeneous Aqueous Oxidation of Organic Molecules by OxoneR and Catalysis by a Water-Soluble Manganese Porphyrin Complex
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Peroxymonosulfate (KHSO5) oxidizes a wide variety of water-soluble organic molecules in aqueous solutions, and the reactions are generally more rapid in phosphate buffer (pH 6-7) than in pure water.A water-soluble porphyrin complex, meso-tetrakis(4-N-methylpyridyl)porphyrinatomanganese(III) chloride, catalyzes epoxidation and hydroxylation under neutral pH conditions.
- Zheng, Tu-Cai,Richardson, David E.
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p. 833 - 836
(2007/10/02)
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- Surfactant products containing 1,3,4-butanetriol
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What is provided herein are new and useful surfactants characterized by having a large number of hydroxyl hydrophilic groups therein with the formula: STR1 where R is a long chain alkyl group, Z is O or --NH, and n=1-4.
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