- Lipase-catalyzed synthesis of ethyl hexanoate in microemulsion system
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This paper studied lipase-catalyzed synthesis of ethyl hexanoate in dodecylbenzenesulfonic acid/isooctane/water microemulsion system. The effect of several parameters, such as w0 ([H2O]/[surfactant]) value, reaction time, reaction temperature, oil phase solvent, buffer solution pH value of microemulsion system on the esterification have been investigated. The results showed that the best experimental conditions for catalytic synthesis ethyl hexanoate were as follows: w0 = 4, reaction time 4 h, reaction temperature 40 °C, buffer solution pH 7. Under these conditions, the conversion of ethyl hexanoate can reach 98.5 %. Lipase-catalyzed synthesis of ethyl hexanoate in dodecylbenzenesulfonic acid inverse microemulsion system has triple mechanism, namely acid catalyzes, microemulsion catalyzes and enzyme catalyzes.
- Tan, Zhongqin,Han, Xiaoxiang,Hu, Xiaoli,Du, Huan,Bao, Xiuxiu
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- Triethylborane-induced radical reactions with gallium- and indium hydrides
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A gallium hydride reagent, HGaCl2, was found to act as a radical mediator. Treatment of alkyl halides with the gallium hydride reagent, generated from gallium trichloride and sodium bis(2-methoxyethoxy)aluminum hydride, provided the corresponding reduced products in excellent yields. Radical cyclization of halo acetals was also successful with not only the stoichiometric gallium reagent but also a catalytic amount of gallium trichloride combined with stoichiometric aluminum hydride as a hydride source. An indium hydride reagent, HInCl2, prepared from indium trichloride and diisobutylaluminum hydride also worked as a radical mediator. HInCl2 could reduce aryl iodides and bromides in the presence of Et3B as a radical initiator.
- Takami, Kazuaki,Mikami, Satoshi,Yorimitsu, Hideki,Shinokubo, Hiroshi,Oshima, Koichiro
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- The combined use of ultrasound and molecular sieves improves the synthesis of ethyl butyrate catalyzed by immobilized Thermomyces lanuginosus lipase
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In this work, the combined use of ultrasound energy and molecular sieves was investigated for the synthesis of ethyl butyrate, ester with mango and banana notes, catalyzed by the immobilized lipase from Thermomyces lanuginosus (Lipozyme TL-IM). Initially, the best concentrations of biocatalysts (35%) and butyric acid (0.7 M) were tested using ultrasound as an alternative to mechanical agitation. The amount of acid in the reaction could be increased by 2-fold when compared to previous works where mechanical agitation was used. In the next step, substrate molar ratio and reaction temperature were optimized and the best conditions were at their lowest levels: 1:1 (acid:alcohol), and 30 °C, reaching 61% of conversion in 6 h. Molecular sieves (3 A?) were added to optimized reaction medium in order to remove the formed water and improve the maximum yield. The reaction yield increased 1.5 times, reaching 90% of conversion in 6 h, when 60 mg of molecular sieves per mmol of butyric acid was used. Finally, the reuse of Lipozyme TL-IM for the ultrasound-assisted synthesis of ethyl butyrate was verified for 10 batches, without any appreciable loss of activity, whereas in systems using mechanical agitation, the biocatalyst was completely inactivated after 5 batches. These results suggest that the combined use of ultrasound and molecular sieves greatly improve esterification reactions by stabilizing the enzyme and increasing yields.
- Paludo, Natalia,Alves, Joana S.,Altmann, Cintia,Ayub, Marco A.Z.,Fernandez-Lafuente, Roberto,Rodrigues, Rafael C.
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- New possibilities in the synthesis of fuel oxygenates from renewable sources
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A general problem in the production of the main types of liquid biofuel, bioethanol and biodiesel, is that renewable resources are not utilized completely. These are ballast polyols: hemicellulose or its structural units, pentaatomic monosaccharides (xylose and arabinose), and biodiesel glycerol. The problem of utilization of these compounds by transforming them into a hydrophobized fuel form by the conversion to cyclic ketals (CK) during condensation with lower carbonyl compounds is reviewed. The CK—ethanol pair significantly increases the octane number and provides phase stability of fuel compositions. The ability of CK to inhibit radical processes responsible for fuel characteristics was studied in model reactions with phenyl radicals and atomic chlorine. The carbon-centered radicals formed in protic media are transformed into more stable cyclic radical cations. Alternative methods of processing natural raw materials using biocatalysis and supercritical fluid technologies are analyzed.
- Varfolomeev,Vol’eva,Komissarova,Kurkovskaya,Malkova,Ovsyannikova,Gumerov,Usmanov
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- Fluorescent microplate assay method for high-throughput detection of lipase transesterification activity
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This study describes a sensitive and fluorescent microplate assay method to detect lipase transesterification activity. Lipase-catalyzed transesterification between butyryl 4-methyl umbelliferone (Bu-4-Mu) and methanol in tert-butanol was selected as the model reaction. The release of 4-methylumbelliferone (4-Mu) in the reaction was determined by detecting the fluorescence intensity at λex 330 nm and λem 390 nm. Several lipases were used to investigate the accuracy and efficiency of the proposed method. Apparent Michaelis constant (Km) was calculated for transesterification between Bu-4-Mu and methanol by the lipases. The main advantages of the assay method include high sensitivity, inexpensive reagents, and simple detection process.
- Zheng, Jianyong,Wei, Wei,Lan, Xing,Zhang, Yinjun,Wang, Zhao
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- Zinc Complexes with Cyanoxime: Structural, Spectroscopic, and Catalysis Studies in the Pivaloylcyanoxime-Zn System
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Reaction of 2-hydroxyimino-4,4-dimethyl-3-oxo-pentanenitrile (common abbreviation HPiCO, pivaloyl-cyanoxime) with zinc sulfate in an aqueous solution results in the formation of the two new complexes: [Zn(PiCO){H(PiCO)2}(H2O)] (I) and tetranuclear Zn complex [Zn4(μ3-OH)2(PiCO)6 (H2O)4] (II). Both complexes were characterized by elemental analysis, IR- and UV-visible spectra, DSC/TGA studies, and X-ray analysis. In complex II, the PiCO- cyanoxime anion adopts three bidentate binding modes: O-monodentate, chelating (κ2), and bridging (2) coordinations. Also, the ligand represents the mixture of two diasteromers (cis-anti and cis-syn) that form five- and six-membered chelate rings with Zn atoms and cocrystallize in one unit cell at population of 0.57-0.43. There are two crystallographically different Zn-centers in the ASU, and two μ3-bridging hydroxo-groups arrange via inversion center the formation of an elegant tetranuclear complex. Each Zn atom has a molecule of coordinated water and is in the distorted octahedral environment. Because of the structural flexibility and multidentate propensity of the pivaloyl-cyanoxime, complex II may act as a structural model of naturally occurring Zn-containing enzymes. Indeed, compound I exhibits an efficient catalytic performance for transesterification reaction of various esters in ethanol under mild reaction conditions. Therefore, obtained results allow assignment of observed activity as green catalysis.
- Opalade, Adedamola A.,Karmakar, Anirban,Rúbio,Pombeiro, Armando J. L.,Gerasimchuk, Nikolay
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- Poly(vinylsulfonic acid)-grafted solid catalysts: New materials for acid-catalysed organic synthetic reactions
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The synthesis, characterisation and application of novel high-density poly(vinylsulfonic acid)-grafted solid acid catalysts are described. A graft, radical polymerization procedure was employed, allowing the immobilisation of the acid form of vinylsulfonic acid monomer onto various carrier materials, such as polystyrene, silica or polysaccharide-based gels. The highest acid-exchange capacity (as determined by acid-base titration methods) achieved with these new materials was 5.2 mmol H+ g-1. The properties of these PVS-grafted materials as solid state acid catalysts have been examined from several perspectives, including their fundamental properties as materials with extremely high acid dissociation characteristics, their structural features as revealed from IR and solid-state NMR measurements, their thermal stability properties, and their surface morphologies, humidity dependencies and functionality. Compared to many other types of acid catalysts, these high-density poly(vinylsulfonic acid)-grafted materials demonstrated superior catalytic performance in esterification, Friedel-Crafts acylation, and condensation reactions. Moreover, these novel materials show high stability, significant anticorrosion capability and can be easily recycled. The Royal Society of Chemistry 2010.
- Okayasu, Teruyuki,Saito, Kei,Nishide, Hiroyuki,Hearn, Milton T. W.
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- Selective reduction of α,β-unsaturated esters with NaBH4-BiCl3 system
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Sodium borohydride-bismuth chloride system was applied for the selective reduction of carbon-carbon double bond of α,β-unsaturated esters with high selectivity.
- Ren,Pan,Dong,Wu
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- Efficient and catalyst-free condensation of acid chlorides and alcohols using continuous flow
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An efficient, catalyst-free continuous flow procedure for the condensation of acid chlorides and alcohols was developed. Different esters could be obtained using this protocol with excellent conversions starting from the corresponding acid chlorides and alcohols in very short reaction times (5-7 min). The reaction was performed solventless for liquid reagents but requires a solvent for solid reagents in order to prevent clogging of the microreactor. Since no catalyst is needed, the purification of the reaction mixture is very straightforward. Scale-up of the reaction to a microreactor with an internal volume of 13.8 ml makes it possible to produce 2.2 g min-1 of ester with an isolated yield of 98% and recuperation of the formed HCl.
- Van Waes, Frederik E. A.,Cukalovic, A.,Stevens, Christian V.,Drabowicz, J.
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- Ultrasound technology and molecular sieves improve the thermodynamically controlled esterification of butyric acid mediated by immobilized lipase from Rhizomucor miehei
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In this research, the effects of ultrasound stirring and the addition of molecular sieves on esterification reactions between butyric acid and several alcohols catalyzed by immobilized lipase from Rhizomucor miehei (Lipozyme RM-IM) were studied. Among the tested alcohols, 1-propanol and isobutanol allowed the highest activities, whereas Lipozyme RM-IM showed poor activities for esterification using secondary and tertiary alcohols. Different solvents were also tested and n-hexane was selected because of its reaction effects, besides being cheaper, available at low boiling point, and ease of recovery. Using the preselected alcohol and solvent, other reaction parameters (butyric acid concentration, temperature, substrate molar rate, and biocatalyst content) were studied to optimize the reaction conditions. Optimal conditions were acid concentration, 0.7 M; substrate molar ratio, 11 alcohol-acid; temperature 45 °C; biocatalyst content, 14% (by substrate mass). Under these conditions, it was possible to obtain a yield of 86% of butyl butyrate in 2.5 h. When molecular sieves (90 mg mmol-1 butytic acid) were added to the reaction, the observed yield increased to 96%. The biocatalyst was used in 5 successive reaction cycles keeping 100% of its initial activity. The overall process productivity was improved 2-fold when compared to the traditional mechanical agitation, showing that ultrasound is a promising technology for application in biocatalysis. The Royal Society of Chemistry.
- Fallavena, Lucas P.,Antunes, Fabio H. F.,Alves, Joana S.,Paludo, Natalia,Ayub, Marco A. Z.,Fernandez-Lafuente, Roberto,Rodrigues, Rafael C.
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- Biocatalytic production of ethyl butyrate from butyric acid with immobilized Candida rugosa lipase on cotton cloth
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A novel method involving polyethylenimine (PEI) coating and glutaraldehyde cross-linking processes was developed to immobilize Candida rugosa lipase onto cotton cloth. After the systematic investigation, the optimal lipase immobilization was achieved when 0.1 g lipase was loaded on 1.5 g support, which was pretreated with 10 ml of 1.0 mg/ml PEI solution at pH 8.0. Subsequent catalytic analysis of immobilized lipase for ethyl butyrate synthesis was also carried out in the Erlenmeyer flasks. The results indicated that when optimal 0.25 M ethanol and 0.6 M butyric acid were catalyzed by the immobilized lipase at 25 °C, the highest conversion yield of 91.2% and 1.27 mmol h-1 g-1 productivity of ethyl butyrate were obtained. Furthermore, a kinetic model of Ping Pong Bi-Bi mode with inhibition of both substrates was proposed and validated by experimental data. To explore the practical potential of immobilized lipase, its operational stability was evaluated and the residual activity was remained about 50% after 12 repeated recycles, with a half-life time of about 300 h for the immobilized lipase. Finally, a recycle batch reactor using immobilized lipase was developed for ethyl butyrate production. The achieved result of 0.85 M final ethyl butyrate concentration, with the conversion of 70.6% and the productivity of 1.45 mmol h-1 g -1, had revealed the promising potential of this immobilized lipase in practical applications.
- Shu, Chengliang,Cai, Jin,Huang, Lei,Zhu, Xiangcheng,Xu, Zhinan
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- Liquid phase esterification of levulinic acid into ethyl levulinate over sulphobenzylated nanoporous Al-SBA-15 catalyst
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Value added chemicals, fuels, and fuel additives can be obtained from cheap bio masses such as levulinic acid. Levulinic acid is the dehydration and hydrolysis products of pentoses and hexoses. The present work deals with the synthesis of sulphobenzylated Al-SBA-15, [SO3H-Bz-Al-SBA-15], characterization by various analytical techniques such as XRD, BET, FT-IR, TGA, DTA, FE-SEM/EDS and HR-TEM/EDX techniques and evaluation of catalytic activity towards esterification of levulinic acid to ethyl levulinate under mild and non corrosive conditions. Sulphonation of the aromatic ring of the benzyl group has been done in different amounts to get nanoporous x% SO3H-Bz-Al-SBA-15 catalysts where (x = 0.02, 0.04, 0.06, 0.08 and 0.10% w/w). Among them 0.08% SO3H-Bz-Al-SBA-15 catalyst showed the highest conversion of levulinic acid (100%) with the highest selectivity towards ethyl levulinate (100%). Esterification of levulinic acid has been carried out with different primary alcohols and all of them yielded 100% selectivity towards alkyl levulinate. However conversion level of levulinic acid was found to be different with different alcohols. Reaction conditions have been optimized. The results were compared with other supported catalysts and discussed.
- Kumaravel, Sakthivel,Thiripuranthagan, Sivakumar,Radhakrishnan, Ramakrishnan,Erusappan, Elangovan,Durai, Mani,Devarajan, Arulselvan,Mukannan, Arivanandhan
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- Reactivity of a Carbon-Supported Single-Site Molybdenum Dioxo Catalyst for Biodiesel Synthesis
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A single-site molybdenum dioxo catalyst, (Oc)2Mo(=O)2@C, was prepared via direct grafting of MoO2Cl2(dme) (dme = 1,2-dimethoxyethane) on high-surface-area activated carbon. The physicochemical and chemical properties of this catalyst were fully characterized by N2 physisorption, ICP-AES/OES, PXRD, STEM, XPS, XAS, temperature-programmed reduction with H2 (TPR-H2), and temperature-programmed NH3 desorption (TPD-NH3). The single-site nature of the Mo species is corroborated by XPS and TPR-H2 data, and it exhibits the lowest reported MoOx Tmax of reduction reported to date, suggesting a highly reactive MoVI center. (Oc)2Mo(=O)2@C catalyzes the transesterification of a variety of esters and triglycerides with ethanol, exhibiting high activity at moderate temperatures (60-90 °C) and with negligible deactivation. (Oc)2Mo(=O)2@C is resistant to water and can be recycled at least three times with no loss of activity. The transesterification reaction is determined experimentally to be first order in [ethanol] and first order in [Mo] with Δ;H? = 10.5(8) kcal mol-1 and Δ;S? = -32(2) eu. The low energy of activation is consistent with the moderate conditions needed to achieve rapid turnover. This highly active carbon-supported single-site molybdenum dioxo species is thus an efficient, robust, and low-cost catalyst with significant potential for transesterification processes.
- Mouat, Aidan R.,Lohr, Tracy L.,Wegener, Evan C.,Miller, Jeffrey T.,Delferro, Massimiliano,Stair, Peter C.,Marks, Tobin J.
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- The preparation of homogeneous triglycerides of eicosapentaenoic acid and docosahexaenoic acid by lipase
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The highly efficient generation of homogeneous triglycerides of either pure eicosapentaenoic acid, 1, or docosahexaenoic acid, 2, by an immobilized nonregiospecific yeast lipase from Candida antarctica is described.
- Haraldsson, Gudmundur G.,Gudmundsson, Birgir Oe.,Almarsson, Oern
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- Effect of the Presence of Surfactants and Immobilization Conditions on Catalysts’ Properties of Rhizomucor miehei Lipase onto Chitosan
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Lipase from Rhizomucor miehei (RML) was immobilized onto chitosan support in the presence of some surfactants added at low levels using two different strategies. In the first approach, the enzyme was immobilized in the presence of surfactants on chitosan supports previously functionalized with glutaraldehyde. In the second one, after prior enzyme adsorption on chitosan beads in the presence of surfactants, the complex chitosan beads-enzyme was then cross-linked with glutaraldehyde. The effects of surfactant concentrations on the activities of free and immobilized RML were evaluated. Hexadecyltrimethylammonium bromide (CTAB) promoted an inhibition of enzyme activity while the nonionic surfactant Triton X-100 caused a slight increase in the catalytic activity of the free enzyme and the derivatives produced in both methods of immobilization. The best derivatives were achieved when the lipase was firstly adsorbed on chitosan beads at 4?°C for 1?h, 220?rpm followed by cross-link the complex chitosan beads-enzyme with glutaraldehyde 0.6% v.v?1 at pH 7. The derivatives obtained under these conditions showed high catalytic activity and excellent thermal stability at 60° and 37?°C. The best derivative was also evaluated in the synthesis of two flavor esters namely methyl and ethyl butyrate. At non-optimized conditions, the maximum conversion yield for methyl butyrate was 89%, and for ethyl butyrate, the esterification yield was 92%. The results for both esterifications were similar to those obtained when the commercial enzyme Lipozyme and free enzyme were used in the same reaction conditions and higher than the one achieved in the absence of the selected surfactant.
- de Oliveira, Ulisses M. F.,Lima de Matos, Leonardo J. B.,de Souza, Maria Cristiane M.,Pinheiro, Bruna B.,dos Santos, José C. S.,Gon?alves, Luciana R. B.
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- Ruthenium Complex-Catalyzed Silylation of Olefins. Selective Synthesis of Allylsilanes
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(1-2;5-6-η-Cyclooctadiene)(1-6-η-cyclooctatriene)ruthenium catalyzes the silylation of olefins at 60-140 deg C to give allylsilanes with good selectivity in high yields.The reactions of trialkylsilane with 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene give the same product, 3-methyl-1-trialkylsilyl-2-butene.Silylation of ethyl (E)-2-butenoate gives ethyl (E)-4-trialkylsilyl-2-butenoate in high yield.
- Hori, Yoji,Mitsudo, Take-aki,Watanabe, Yoshihisa
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- COMPETITIVE TYPE II ELIMINATIONS IN ALIPHATIC IMIDES
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Aliphatic imides have been shown to undergo type II eliminations across the imide moiety in addition to those on the C-alkyl chain and α cleavage reactions.
- Mazzocchi, Paul H.,Jameson, William,Nishiyama, Tomikiro,DeCamp, Ann
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- Ester synthesis using Candida rugosa lipase immobilized on magnetic nanoparticles
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Magnetic nanoparticles were synthesized by co-precipitation under hydrothermal conditions. The average diameter of the magnetic nanoparticles was found to be in the range of 15 ± 5 nm with an average surface area of 112.15 m2 g-1. Immobilization of lipase on magnetite nanoparticles was confirmed by FTIR, differential scanning calorimetry and thermal gravimetric analysis. The activation energy of the free enzyme was 1.9-fold higher than that of the immobilized lipase for hydrolytic reactions. Additionally, the lower KM and higher Vmax values of the immobilized enzyme for hydrolysis of 4-nitrophenyl palmitate indicated an increased efficiency of the immobilized lipase. The immobilized lipase exhibited higher esterification efficiency compared with free lipase for synthesis of ethyl isovalerate. It also exhibited fairly good reusability, with about 8.5% reduction in esterification efficiency for ethyl isovalerate synthesis over ten cycles of reuse.
- Dandavate, Vrushali,Keharia, Haresh,Madamwar, Datta
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- Stability improvement of immobilized Candida antarctica lipase B in an organic medium under microwave radiation
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The influence of microwave heating on the stability of immobilized Candida antarctica lipase B was studied at 100°C in an organic medium. The microwave radiation was carried out before enzymatic reaction (storage conditions) or during the enzymatic catalysis (use conditions). In both cases, enzymatic stability was higher under microwave heating than under conventional thermal heating, in strictly identical operating conditions. Furthermore, the gain of enzymatic stability under microwave heating appears to be higher in a more polar solvent, which interacts strongly with the microwave field. Our results suggest that microwave radiation has an effect, not related to temperature, on the process of enzymatic inactivation.
- Rejasse, Barbara,Lamare, Sylvain,Legoy, Marie-Dominique,Besson, Thierry
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- Cavity-promotion by pillar[5]arenes expedites organic photoredox-catalysed reductive dehalogenations
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The efficiency of the photo-induced electron transfer in photoredox catalysis is limited by the diffusional collision of the excited catalyst and the substrate. We herein present cavity-bound photoredox catalysts, which preassociate the substrates, leading to significantly shortened reaction times. A pillar[5]arene serves as the cavity and phenothiazine as a catalyst in the reductive dehalogenation of aliphatic bromides as a proof of concept reaction.
- Esser, Birgit,Schmidt, Maximilian
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supporting information
p. 9582 - 9585
(2021/09/28)
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- Ball-Milling-Enabled Reactivity of Manganese Metal**
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Efforts to generate organomanganese reagents under ball-milling conditions have led to the serendipitous discovery that manganese metal can mediate the reductive dimerization of arylidene malonates. The newly uncovered process has been optimized and its mechanism explored using CV measurements, radical trapping experiments, EPR spectroscopy, and solution control reactions. This unique reactivity can also be translated to solution whereupon pre-milling of the manganese is required.
- Bolt, Robert R. A.,Browne, Duncan L.,Howard, Joseph L.,Khan, Adam,Magri, Giuseppina,Morrill, Louis C.,Nicholson, William I.,Richards, Emma,Seastram, Alex C.
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supporting information
p. 23128 - 23133
(2021/09/20)
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- Chromium-Catalyzed Production of Diols From Olefins
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Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
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Paragraph 0111
(2021/03/19)
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- Design, Synthesis, and Study of the Insecticidal Activity of Novel Steroidal 1,3,4-Oxadiazoles
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A series of novel steroidal derivatives with a substituted 1,3,4-oxadiazole structure was designed and synthesized, and the target compounds were evaluated for their insecticidal activity against five aphid species. Most of the tested compounds exhibited potent insecticidal activity against Eriosoma lanigerum (Hausmann), Myzus persicae, and Aphis citricola. Compounds 20g and 24g displayed the highest activity against E. lanigerum, showing LC50 values of 27.6 and 30.4 μg/mL, respectively. Ultrastructural changes in the midgut cells of E. lanigerum were detected by transmission electron microscopy, indicating that these steroidal oxazole derivatives might exert their insecticidal activity by destroying the mitochondria and nuclear membranes in insect midgut cells. Furthermore, a field trial showed that compound 20g exhibited effects similar to those of the positive controls chlorpyrifos and thiamethoxam against E. lanigerum, reaching a control rate of 89.5% at a dose of 200 μg/mL after 21 days. We also investigated the hydrolysis and metabolism of the target compounds in E. lanigerum by assaying the activities of three insecticide-detoxifying enzymes. Compound 20g at 50 μg/mL exhibited inhibitory action on carboxylesterase similar to the known inhibitor triphenyl phosphate. The above results demonstrate the potential of these steroidal oxazole derivatives to be developed as novel pesticides.
- Bai, Hangyu,Jiang, Weiqi,Li, Qi,Li, Tian,Ma, Shichuang,Shi, Baojun,Wu, Wenjun
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p. 11572 - 11581
(2021/10/12)
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- Promotion of catalytic properties of vanillin loaded MCM-41 by Cu(I) and Cu(II) for enhanced removal of quinoline contaminants
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In the present study, to enhance removal of quinoline contaminants using natural active component, vanillin was loaded onto the MCM-41 (Mobile Component Material) nanoparticles in a simple way. The product was divided into two parts, which were improved by Copper(I) and Copper(II) salts. Promoted synthetic nanocatalysts (Cu(I)/Van./MCM-41, and Cu(II)/Van./MCM-41) were characterized using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive X-Ray Spectroscopy (EDS), Mapping, Fourier-Transform Infrared Spectroscopy (FTIR), and BET/BJH (Brunauer-Emmett-Teller (BET) and Barret-Joyner-Halenda (BJH)) techniques. To reach optimal conditions, experimental design was performed using Response Surface Methodology (RSM). The experiments were done with the aid of nanocomposites, in presence of ultraviolet radiation without any auxiliary oxidants. Degradation percentages were measured by an Ultraviolet (UV) spectrophotometer. The products were identified using Gas Chromatography–Mass (GC-Mass) technique, and some mechanisms for quinoline removal were proposed. The results indicated that Cu (I) showed better performance in enhanced removal of quinoline than Cu(II).
- Arjmand, Mehdi,Fazaeli, Reza,Ghorbani, Mohammad Hossein,Kamani, Mina
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p. 4833 - 4841
(2020/09/16)
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- Rhodium Porphyrin Catalyzed Regioselective Transfer Hydrogenolysis of C-C σ-Bonds in Cyclopropanes with iPrOH
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A new rhodium porphyrin catalyzed regioselective transfer hydrogenolysis of both activated and unactivated cyclopropanes employing iPrOH as the hydrogen source was discovered. The reaction mechanism for the C-C σ-bond activation of cyclopropanes was identified through an initial radical substitution with rhodium(II) metalloporphyrin radical to give a rhodium porphyrin alkyl, followed by hydrogenolysis with iPrOH to give the corresponding acyclic alkanes and regenerate rhodium(II) metalloporphyrin radical.
- Chen, Chen,Feng, Shiyu,Chan, Kin Shing
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p. 2582 - 2589
(2019/07/02)
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- Method for preparing ethyl butyrate and catalyst used in same
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The invention relates to a method for preparing ethyl butyrate and a catalyst used in the same. The method comprises the following steps: with a modified molecular sieve filled in a tubular fixed bedreactor as a catalyst, mixing raw materials namely butyric acid and ethanol in a certain ratio, vaporizing an obtained mixture with a vaporizer at a certain flow rate, allowing a vaporized mixture toenter a reactor for an esterification reaction so as to obtain a mixture of the ethyl butyrate, water and unreacted raw materials from the outlet of the reactor, carrying out oil-water separation, subjecting an oil phase to rectification separation so as to obtain high-purity ethyl butyrate, wherein the ethyl butyrate reaches a yield of 98% or more, and can reach a selectivity of 99% or above. Themethod provided by the invention has the advantages of simple process flow, capability of continuous production, high selectivity of the catalyst to the ethyl butyrate, no corrosion to equipment, andlow discharge of three wastes.
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Paragraph 0041; 0042; 0043; 0044; 0045; 0047
(2019/05/15)
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- Mechanochemical Activation of Zinc and Application to Negishi Cross-Coupling
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A form independent activation of zinc, concomitant generation of organozinc species and engagement in a Negishi cross-coupling reaction via mechanochemical methods is reported. The reported method exhibits a broad substrate scope for both C(sp3)–C(sp2) and C(sp2)–C(sp2) couplings and is tolerant to many important functional groups. The method may offer broad reaching opportunities for the in situ generation organometallic compounds from base metals and their concomitant engagement in synthetic reactions via mechanochemical methods.
- Cao, Qun,Howard, Joseph L.,Wheatley, Emilie,Browne, Duncan L.
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p. 11339 - 11343
(2018/08/28)
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- A Co2B Mediated NaBH4 Reduction Protocol Applicable to a Selection of Functional Groups in Organic Synthesis
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A high-yielding and high-rate reduction method that operates with alkenes, alkynes, azides, nitriles, and nitroarenes was developed and optimized. The method makes use of sodium borohydride reduction of CoSO4 under release of hydrogen along with the formation of Co2B as a nanoparticle material. The produced Co2B activates the various functional groups for hydride reduction. The protocol was proven to operate with an assortment of functional groups to provide good to excellent yields. Furthermore, the reduction method was successfully adapted, implemented, and developed for a continuous flow approach using the multi-jet oscillating disk (MJOD) flow reactor platform at atmospheric pressure.
- Lundevall, Frida Johanne,Elumalai, Vijayaragavan,Drageset, Audun,Totland, Christian,Bj?rsvik, Hans-René
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supporting information
p. 3416 - 3425
(2018/07/29)
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- Recyclable cobalt(0) nanoparticle catalysts for hydrogenations
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The search for new hydrogenation catalysts that replace noble metals is largely driven by sustainability concerns and the distinct mechanistic features of 3d transition metals. Several combinations of cobalt precursors and specific ligands in the presence of reductants or under high-thermal conditions were reported to provide active hydrogenation catalysts. This study reports a new method of preparation of small, monodisperse Co(0) nanoparticles (3-4 nm) from the reduction of commercial CoCl2 in the absence of ligands or surfactants. High catalytic activity was observed in hydrogenations of alkenes, alkynes, imines, and heteroarenes (2-20 bar H2). The magnetic properties enabled catalyst separation and multiple recyclings.
- Büschelberger, Philipp,Reyes-Rodriguez, Efrain,Sch?ttle, Christian,Treptow, Jens,Feldmann, Claus,Jacobi Von Wangelin, Axel,Wolf, Robert
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p. 2648 - 2653
(2018/05/30)
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- Synthesis of Bis(phosphino)silyl Pincer-Supported Iron Hydrides for the Catalytic Hydrogenation of Alkenes
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The synthesis and characterization of Fe pincer complexes supported by a bis(phosphino)silyl (PSiP) ligand are described. While four-coordinate species of the type (PSiP)FeX (X = halide) proved challenging to access, examples of five-coordinate (PSiP)Fe(II) and (PSiP)Fe(I) species were prepared and crystallographically characterized. In studying the reactivity of such (PSiP)Fe precursors, a variety of iron hydride species were observed and characterized, and interconversion among such complexes facilitated by the coordination of N2 was noted. The structures and spectroscopic features of several such diamagnetic Fe(II) hydrides were elucidated, including that of a unique and highly stable η2-(Si-H)Fe(II) dihydride complex. A surrogate for a low coordinate (PSiP)FeH species in the form of its bis(dinitrogen) adduct was found to be an effective precatalyst for the direct hydrogenation of alkenes, including various mono- and disubstituted aliphatic alkenes, as well as a trisubstituted example. Esters and ethers were found to be well-tolerated by the catalyst, and alkyne hydrogenation was also demonstrated.
- Murphy, Luke J.,Ferguson, Michael J.,McDonald, Robert,Lumsden, Michael D.,Turculet, Laura
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p. 4814 - 4826
(2018/12/11)
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- Hydrogenation of Ketones and Esters Catalyzed by Pd/C?SiO2
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Hydrogenation of unsaturated ketones and esters with molecular hydrogen on the 5%Pd/C?SiO2 heterogeneous catalyst has been studied. The reaction direction and yield are determined by the starting compounds structure. Hydrogenation of unsaturated ketones containing phenyl group at the double carbon–carbon atom is accompanied by the reduction of the ketone group into the alcohol one. Hydrogenation of unsaturated esters is accompanied by transesterification.
- Akchurin,Baibulatov,Dokichev
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p. 195 - 198
(2018/03/26)
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- Efficient Catalytic Greenhouse Gas-Free Hydrogen and Aldehyde Formation from Alcohols
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Catalytic preparation of hydrogen and aldehyde(s) from alcohols, including bioalcohols, without production of carbon monoxide or carbon dioxide.
- -
-
Paragraph 0053; 0054; 0148
(2017/11/07)
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- Palladium nanoparticles stabilised by cinchona-based alkaloids in glycerol: Efficient catalysts for surface assisted processes
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Palladium nanoparticles (PdNPs) were synthesised and fully characterised, both in solution and the solid state, using naturally-occurring cinchona-based alkaloids in neat glycerol. These nano-systems were stable under reaction conditions, finding applications in hydrogenation and hydrodehalogenation processes, as a result of their surface-like behaviour. Their reactivity was improved in relation to that involving PdNPs stabilised by phosphines and also by Pd/C as a heterogenous catalyst, mainly in terms of recyclability. In particular, the colloidal palladium catalyst stabilised by quinidine was highly efficient to promote the hydrodechlorination of aromatic compounds under low dihydrogen pressure. These original catalysts found applications in the synthesis of secondary and tertiary amines including N-substituted anilines, by means of one-pot tandem Pd-catalysed methodologies under smooth conditions. In all of these processes, glycerol performed a crucial function as a liquid support for the immobilisation of nanoparticle-based catalysts, allowing both the stabilisation of the nano-catalysts and easy recycling of the catalytic phase.
- Reina,Pradel,Martin,Teuma,Gómez
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p. 93205 - 93216
(2016/10/11)
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- Evaluation of AgPd Nanoshells in Dual Catalysis: One-Pot Silane Oxidation and Reduction of Organic Compounds
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AgPd nanoshells (AgPd NSs) were used as dual catalysts for hydrogen production and reduction of organic compounds in a one-pot protocol. AgPd NSs were very efficient catalysts for the reduction of several functional groups, including alkenes, alkynes, imines, nitro compounds, and azides. Excellent chemoselectivities were observed for α,β-unsaturated ketones, esters, and cinnamonitrile. Also, deuterium-labeled compounds were prepared by using D2O instead of H2O. A packed-bed reactor containing the immobilized AgPd NSs in silica (AgPd/SiO2) was designed to be used in continuous-flow conditions. An optimized flow system with AgPd NSs was able to give the desired compounds in high conversions with 30–60 min residence time (tR).
- Kisukuri, Camila M.,Reis, Jo?o L. M. S.,Rodrigues, Thenner S.,Camargo, Pedro H. C.,Andrade, Leandro H.
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p. 3657 - 3662
(2016/12/14)
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- P-Sulfonic acid calix[4]arene-functionalized alkyl-bridged organosilica in esterification reactions
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Two new p-sulfonic acid calix[4]arene- and p-sulfonic acid calix[6]arene-functionalized organosilica have been synthesized using a sol-gel method and applied as heterogeneous catalysts in esterification reactions. The catalytic performance was evaluated using the esterification of carboxylic acids with ethanol, and good catalytic activity (i.e., 55-88%) was observed under the optimum reaction conditions. This study reports the first promising example of the successful employment of calix[n]arenes as a heterogeneous catalyst for catalytic esterification. The catalyst was easily separated by filtration and reused five times without any significant loss of activity.
- De Assis,Abranches,Braga,Zu?iga,Sathicq,Romanelli,Sato,Fernandes
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p. 24285 - 24289
(2016/03/15)
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- Conversion of ethanol into linear primary alcohols on gold, nickel, and gold–nickel catalysts
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The direct conversion of ethanol into the linear primary alcohols CnH2n+1OH (n = 4, 6, and 8) in the presence of the original mono- and bimetallic catalysts Au/Al2O3, Ni/Al2O3, and Au–Ni/Al2O3 was studied. It was established that the rate and selectivity of the reaction performed under the conditions of a supercritical state of ethanol sharply increased in the presence of Au–Ni/Al2O3. The yield of target products on the bimetallic catalyst was higher by a factor of 2–3 than that reached on the monometallic analogs. Differences in the catalytic behaviors of the Au, Ni, and Au–Ni systems were discussed with consideration for their structure peculiarities and reaction mechanisms.
- Chistyakov,Zharova,Tsodikov,Nikolaev,Krotova,Ezzhelenko
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p. 803 - 811
(2016/12/07)
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- Formamides as Lewis Base Catalysts in SNReactions—Efficient Transformation of Alcohols into Chlorides, Amines, and Ethers
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A simple formamide catalyst facilitates the efficient transformation of alcohols into alkyl chlorides with benzoyl chloride as the sole reagent. These nucleophilic substitutions proceed through iminium-activated alcohols as intermediates. The novel method, which can be even performed under solvent-free conditions, is distinguished by an excellent functional group tolerance, scalability (>100 g) and waste-balance (E-factor down to 2). Chiral substrates are converted with excellent levels of stereochemical inversion (99 %→≥95 % ee). In a practical one-pot procedure, the primary formed chlorides can be further transformed into amines, azides, ethers, sulfides, and nitriles. The value of the method was demonstrated in straightforward syntheses of the drugs rac-Clopidogrel and S-Fendiline.
- Huy, Peter H.,Motsch, Sebastian,Kappler, Sarah M.
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supporting information
p. 10145 - 10149
(2016/08/16)
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- Cobalt-Catalyzed Csp3?Csp3Homocoupling
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An efficient and easy method for Csp3?Csp3homocoupling was developed using cobalt bromide as catalyst. A series of functionalized alkyl bromides and alkyl chlorides were coupled in high yields under mild conditions. This reaction seems to involve a radical intermediate. (Figure presented.).
- Cai, Yingxiao,Qian, Xin,Gosmini, Corinne
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supporting information
p. 2427 - 2430
(2016/08/16)
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- Biocatalytic Characterization of Human FMO5: Unearthing Baeyer-Villiger Reactions in Humans
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Flavin-containing mono-oxygenases are known as potent drug-metabolizing enzymes, providing complementary functions to the well-investigated cytochrome P450 mono-oxygenases. While human FMO isoforms are typically involved in the oxidation of soft nucleophiles, the biocatalytic activity of human FMO5 (along its physiological role) has long remained unexplored. In this study, we demonstrate the atypical in vitro activity of human FMO5 as a Baeyer-Villiger mono-oxygenase on a broad range of substrates, revealing the first example to date of a human protein catalyzing such reactions. The isolated and purified protein was active on diverse carbonyl compounds, whereas soft nucleophiles were mostly non- or poorly reactive. The absence of the typical characteristic sequence motifs sets human FMO5 apart from all characterized Baeyer-Villiger mono-oxygenases so far. These findings open new perspectives in human oxidative metabolism.
- Fiorentini, Filippo,Geier, Martina,Binda, Claudia,Winkler, Margit,Faber, Kurt,Hall, Mélanie,Mattevi, Andrea
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p. 1039 - 1048
(2016/05/19)
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- A highly reducing metal-free photoredox catalyst: Design and application in radical dehalogenations
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Here we report the use of 10-phenylphenothiazine (PTH) as an inexpensive, highly reducing metal-free photocatalyst for the reduction of carbon-halogen bonds via the trapping of carbon-centered radical intermediates with a mild hydrogen atom donor. Dehalogenations were carried out on various substrates with excellent yields at room temperature in the presence of air.
- Discekici, Emre H.,Treat, Nicolas J.,Poelma, Saemi O.,Mattson, Kaila M.,Hudson, Zachary M.,Luo, Yingdong,Hawker, Craig J.,De Alaniz, Javier Read
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supporting information
p. 11705 - 11708
(2015/07/15)
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- Gold nanoparticles supported on metal oxides as catalysts for the direct oxidative esterification of alcohols under mild conditions
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Gold nanoparticles supported on metal oxides were used to catalyze the direct oxidative esterification of alcohols; esters were obtained using molecular oxygen as an oxidant under ambient temperature and pressure. Higher activities for the reaction between the benzyl alcohol and methanol were obtained over Au/CeO2 and Au/ZrO2 than Au/TiO2 (anatase), Au/HT (hydrotalcite) and Au/Al2O3. These catalysts were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS) and X-ray photoelectron spectroscopy (XPS). The distribution of gold nanoparticles was uniform; no change of chemical states occurred for supports and gold nanoparticles after the catalysts were reused 10 times. The oxidative esterification of various alcohols over these catalysts could also occur under optimized reaction conditions. The substituted benzyl alcohols and cinnamyl alcohols were more active than heterocyclic alcohols and aliphatic alcohols because their α-H could be eliminated more easily during the induction of adsorbed dioxygen. Self-oxidative esterification was available for benzyl alcohol in inert solvents with low polarity indexes. A reaction mechanism was proposed for the synthesis of esters from alcohols with molecular oxygen.
- Wei, Huili,Li, Jingyi,Yu, Jing,Zheng, Jianwei,Su, Haiquan,Wang, Xiaojing
-
-
- Use of Lecitase-Ultra immobilized on styrene-divinylbenzene beads as catalyst of esterification reactions: Effects of ultrasounds
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Abstract In this work it was evaluated for the first time, the ester synthesis catalyzed by the phospholipase Lecitase-Ultra immobilized styrene-divinylbenzene beads (MCI-Lecitase), comparing the mechanical stirring and the ultrasonic energy. It was studied the specificity of the enzyme using carboxylic acids from C4 to C18, as well as the effects of alcohol chain, organic solvents, biocatalyst content, reaction temperature and substrate concentration. Caprylic and myristic acids were those with the highest reaction rates and yields, using ethanol as substrate. The shorter the alcohol chain, the higher the enzyme activity. Regarding the secondary alcohols, while MCI-Lecitase had no activity versus isopropanol, using 2-pentanol the activity was similar to that with 1-pentanol. Comparing the agitation systems, MCI-Lecitase presented an initial reaction rate more than 2-times higher in the ultrasound-assisted reaction than under traditional mechanical stirring. Moreover, under ultrasonic energy the maximum rate was achieved using 0.5 M of substrates, while under mechanical stirring the maximum enzyme activity was reached at 0.3 M of substrates. Concerning the operational stability, MCI-Lecitase was quite unstable, losing its activity after 6 reaction cycles. By adding molecular sieves in the reaction medium, MCI-Lecitase retained 30% of its initial activity after 6 cycles.
- Alves, Joana S.,Garcia-Galan, Cristina,Danelli, Daiane,Paludo, Natália,Barbosa, Oveimar,Rodrigues, Rafael C.,Fernandez-Lafuente, Roberto
-
-
- Reactivity of ethanol over hydroxyapatite-based Ca-enriched catalysts with various carbonate contents
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The Guerbet reaction of ethanol to produce heavier products was performed over a series of extensively characterized carbonate-containing hydroxyapatites (HAPs) with different Ca/P ratios and thus different densities, strengths and natures of acid and bas
- Silvester, Lishil,Lamonier, Jean-Fran?ois,Faye, Jérémy,Capron, Micka?l,Vannier, Rose-No?lle,Lamonier, Carole,Dubois, Jean-Luc,Couturier, Jean-Luc,Calais, Christophe,Dumeignil, Franck
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p. 2994 - 3006
(2015/05/13)
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- PRODUCTION OF BUTYL ACETATE FROM ETHANOL
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A reactive distillation method comprises introducing a feed stream to a reactive distillation column, wherein the feed stream comprises ethanol, contacting the feed stream with one or more catalysts in the reactive distillation column during a distillation, and removing butyl acetate during the distillation from the reactive distillation column as a bottoms stream. The feed stream reacts in the presence of the one or more catalysts to produce a reaction product comprising ethyl acetate, butanol, and water, wherein the butanol and the ethyl acetate react to produce a reaction product comprising the butyl acetate.
- -
-
Paragraph 00136; 00137
(2015/06/18)
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- The combine use of ultrasound and lipase immobilized on co-polymer matrix for efficient biocatalytic application studies
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In this work, we have investigated the combine use of ultrasound and lipase (Pseudomonas cepacia: PCL) immobilized on co-polymer of polyvinyl alcohol (PVA) and chitosan (CHI) for biocatalytic applications. Initially, we have screened different free and immobilized biocatalysts to find-out the robust biocatalyst. The immobilized biocatalyst PVA:CHI:PCL (5:5:2.5) worked as a robust biocatalyst to provide superior conversion (99%) for the synthesis of model ultrasound assisted reaction. Subsequently, various reaction parameters were optimized in details to obtain the higher yield. Besides this, developed biocatalytic protocol was used to synthesize various industrially important butyrate compounds which provided excellent conversion of 99% under ultrasonic conditions. The developed biocatalyst showed excellent recyclability upto studied five cycles under ultrasonic condition. The immobilized PVA:CHI:PCL biocatalyst displayed 2.4 folds higher activity as compared to free lipases in ultrasonic condition. Moreover, PVA:CHI:PCL biocatalyst in ultrasound media showed 4.5 folds higher activity as compared to free lipases in conventional media. The energy assessment was performed which demonstrated feasibility of combine use of immobilization and ultrasonication to carry out efficient biocatalytic process.
- Badgujar, Kirtikumar Chandulal,Bhanage, Bhalchandra Mahadeo
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p. 255 - 264
(2015/10/28)
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- An efficient one-pot oxidative esterification of aldehydes to carboxylic esters using B(C6F5)3-TBHP
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A simple and efficient protocol for oxidative esterification of diverse aldehydes with alcohols was accomplished with tert-butyl hydroperoxide and 1 mol % of tris(pentafluorophenyl)borane [B(C6F5)3] to generate the corresponding esters in good to excellent yields. The present protocol represents compatibility with wide range of functional groups as well as exceptional tolerance toward acid labile protecting groups such as TBDPS, TBDMS, acetonide, and Boc.
- Guggilapu, Sravanthi Devi,Prajapti, Santosh Kumar,Babu, Bathini Nagendra
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supporting information
p. 889 - 892
(2015/02/05)
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- Comparison of the performance of commercial immobilized lipases in the synthesis of different flavor esters
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In this work, it is compared the performance of three commercial lipase preparations (Novozym 435, Lipozyme TL-IM, and Lipozyme RM-IM) in the synthesis of flavor esters obtained by esterification of acetic, propionic, and butyric acids using ethanol, isopropyl alcohol, butanol, or pentanol. A comprehensive comparison was performed verifying activities of these three enzyme preparations versus the different couples of substrates, checking the obtained yields. In general, the longer the acid chain, the higher the reaction yields. Novozym 435 was the most efficient enzyme in most cases, and only Lipozyme RM-IM offered better results than Novozym 435 in the production of ethyl butyrate. Reactions with butyric acid showed the highest conversion rates using all biocatalysts. Using optimal substrates, the reactions catalyzed by the three enzymes were optimized using the response surface methodology, and the catalytic performance of the biocatalysts in repeated batches was assessed. After optimization, yields higher than 90% were obtained for all three enzymes, but Lipozyme TL-IM needed four-times more biocatalyst content than the other two preparations. Novozym 435 kept over 80% of its activity when reused in 9 successive batches, whereas Lipozyme RM-IM can be reused 5 times and Lipozyme TL-IM only 3 times. In general, Novozym 435 showed to be more suitable for these reactions than the other two enzyme preparations.
- Martins, Andrea B.,Da Silva, Alexandre M.,Schein, Mirela F.,Garcia-Galan, Cristina,Zachia Ayub, Marco A.,Fernandez-Lafuente, Roberto,Rodrigues, Rafael C.
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- Solvent stability study with thermodynamic analysis and superior biocatalytic activity of Burkholderia cepacia lipase immobilized on biocompatible hybrid matrix of poly(vinyl alcohol) and hypromellose
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In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:-PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (KD) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the KD-value was found to be less in cyclohexane (0.843 × 10-3) as compared to acetone (1.997 × 10-3), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (Ea) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic e fficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH?), entropy (ΔS?) and Gibb 's free energy (ΔG?) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time. (Graph Presented).
- Badgujar, Kirtikumar C.,Bhanage, Bhalchandra M.
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p. 14808 - 14819
(2015/02/19)
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- Production of Higher Alcohols
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A reactive distillation method comprises introducing a feed stream to a reactive distillation column, contacting the feed stream with one or more catalysts in the reactive distillation column during a distillation, and removing one or more higher alcohols during the distillation from the reactive distillation column as a bottoms stream. The feed stream comprises one or more alpha hydrogen alcohols, and the feed stream reacts in the presence of the one or more catalysts to produce a reaction product comprising the one or more higher alcohols.
- -
-
Paragraph 0198-0200
(2014/09/03)
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- Catalytic functionalization of methane and light alkanes in supercritical carbon dioxide
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The development of catalytic methods for the effective functionalization of methane yet remains a challenge. The best system known to date is the so-called Catalytica Process based on the use of platinum catalysts to convert methane into methyl bisulfate with a TOF rate of 10-3 s. In this contribution, we report a series of silver complexes containing perfluorinated tris(indazolyl)borate ligands that catalyze the functionalization of methane into ethyl propionate upon reaction with ethyl diazoacetate (EDA) by using supercritical carbon dioxide (scCO2) as the reaction medium. The employment of this reaction medium has also allowed the functionalization of ethane, propane, butane, and isobutane.
- Fuentes, M. Angeles,Olmos, Andrea,Caballero, Ana,Perez, Pedro J.,Munoz, Bianca K.,Jacob, Kane,Etienne, Michel,Gonzalez-Nunez, M. Elena,Mello, Rossella,Asensio, Gregorio
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supporting information
p. 11013 - 11018,6
(2015/01/07)
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- METHOD OF PRODUCING ALCOHOLS
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A method of making alcohols involves forming of alcohol esters from liquid alkane halides and a solution of metallic salts of organic acids to produce gaseous alcohol esters for reaction with magnesium or metal hydroxides to form the alcohol and the metal salt of the organic acids. In an improvement method, liquid phase alcohol esters instead of gaseous alcohol esters are produced from liquid alkane halides and a solution of metal salts of organic acids whose alkane esters are less soluble in water than that of the alkane halide and treating of the alcohol ester formed with magnesium or metal hydroxides to form the alcohol and the metal salt of the organic acids.
- -
-
Paragraph 0038-0041
(2013/08/28)
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- SYNTHESIS OF HIGH CALORIC FUELS AND CHEMICALS
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In one embodiment, the present application discloses methods to selectively synthesize higher alcohols and hydrocarbons useful as fuels and industrial chemicals from syngas and biomass. Ketene and ketonization chemistry along with hydrogenation reactions are used to synthesize fuels and chemicals. In another embodiment, ketene used to form fuels and chemicals may be manufactured from acetic acid which in turn can be synthesized from synthesis gas which is produced from coal, biomass, natural gas, etc.
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Paragraph 0085
(2013/05/23)
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- Iron-catalyzed reductive radical cyclization of organic halides in the presence of NaBH4: Evidence of an active hydrido iron(I) catalyst
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Iron made'em: Iron(II) complexes such as FeCl2 and [FeCl 2(dppe)2] (dppe=1,2-bisdiphenylphosphinoethane) are efficient precatalysts for the radical cyclization of unsaturated iodides and bromides in the presence of NaBH4 (see scheme). Cyclic voltammetry studies suggests that the reaction occurs through a radical mechanism via an anionic hydrido iron(I) species as the key intermediate for the activation of the substrates by electron transfer. Copyright
- Ekomie, Audrey,Lefevre, Guillaume,Fensterbank, Louis,Lacote, Emmanuel,Malacria, Max,Ollivier, Cyril,Jutand, Anny
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supporting information; experimental part
p. 6942 - 6946
(2012/10/08)
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- P-Sulfonic acid calix[n]arenes as homogeneous and recyclable organocatalysts for esterification reactions
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Esterification yields were significantly improved using calix[n]arenes catalysts under simple conditions. p-Sulfonic acid calix[4]arene and p-sulfonic acid calix[6]arene were powerful organocatalysts in several esterification reactions, which showed activity comparable or even superior to other well-established acids catalysts, such as, sulfuric acid, p-toluenesulfonic acid, and p-hydroxybezenesulfonic acid described in the literature.
- Fernandes, Sergio Antonio,Natalino, Ricardo,Gazolla, Poliana Aparecida Rodrigues,Da Silva, Márcio José,Jham, Gulab Newandram
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experimental part
p. 1630 - 1633
(2012/04/17)
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- Manganese phthalocyanine immobilized on silica gel: Efficient and recyclable catalyst for single-step oxidative esterification of aldehydes with alcohols
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The functionalization of silica gel was carried out using 3-aminopropyltriethoxysilane as a reactive surface modifier followed by covalent grafting of novel tetrakis-(2-methoxy-4-formylphenoxy)phthalocyaninato manganese(III) acetate complex. The resulting inorganic-organic hybrid material was found to be a highly selective and recyclable catalyst for the single-step synthesis of esters. The catalyst was characterized by elemental analysis (CHN), diffuse reflectance UV-visible, 13C CPMAS and 29Si CPMAS NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area analysis, energy dispersive X-ray fluorescence (ED-XRF), Fourier-transform infrared (FT-IR) and atomic absorption spectroscopy (AAS) techniques, which demonstrates the covalent grafting of the complex onto functionalized silica gel. The catalytic performance of the novel inorganic-organic hybrid catalyst was evaluated in the direct oxidative esterification of aldehydes with alcohols, at ambient temperature, using hydrogen peroxide as an environment friendly oxidant. The hybrid catalyst presented up to 100% of substrate conversion with high turn-over numbers (TONs), up to 100% of selectivity toward the ester product, and can be recovered and reused for multiple cycles without appreciable loss in its catalytic activity.
- Sharma,Gulati, Shikha
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p. 291 - 303
(2012/10/30)
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- Double molecular recognition with aminoorganoboron complexes: Selective alcoholysis of β-dicarbonyl derivatives
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Double duty: Aminoorganoboron (AOB) complexes recognize alcohol and β-dicarbonyl units, and thereby facilitate chemo- and site-selective alcoholysis of the latter (see scheme). The complex activates both reaction partners. This strategy enables C-C, C-N, and C-O bond cleavage in addition/elimination reactions under near neutral pH conditions and provides a new method for functional group conversions. Copyright
- Oishi, Shunsuke,Saito, Susumu
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supporting information; experimental part
p. 5395 - 5399
(2012/06/18)
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- Replacing conventional carbon nucleophiles with electrophiles: Nickel-catalyzed reductive alkylation of aryl bromides and chlorides
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A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (-OH, -NHTs, -OAc, -OTs, -OTf, -COMe, -NHBoc, -NHCbz, -CN, -SO2Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture. The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki-Miyaura, Stille, and Hiyama-Denmark reactions. Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R-X) and no reaction at the nucleophilic carbon (R-[M]) for organoboron (-Bpin), organotin (-SnMe3), and organosilicon (-SiMe2OH) containing organic halides (X-R-[M]). A Hammett study showed a linear correlation of σ and σ(-) parameters with the relative rate of reaction of substituted aryl bromides with bromoalkanes. The small ρ values for these correlations (1.2-1.7) indicate that oxidative addition of the bromoarene is not the turnover-frequency determining step. The rate of reaction has a positive dependence on the concentration of alkyl bromide and catalyst, no dependence upon the amount of zinc (reducing agent), and an inverse dependence upon aryl halide concentration. These results and studies with an organic reductant (TDAE) argue against the intermediacy of organozinc reagents.
- Everson, Daniel A.,Jones, Brittany A.,Weix, Daniel J.
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supporting information; experimental part
p. 6146 - 6159
(2012/05/07)
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