- Epoxide yield determination of oils and fatty acid methyl esters using 1H NMR
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Product mixtures of epoxidized fatty compounds can be analyzed by using 1H NMR. Conversion of double bonds and selectivities to different products can easily be calculated. Moreover, if diunsaturated substrates are used in epoxidation reactions, yields to mono- and diepoxidized products can be determined. The effectiveness of this method is proven by comparing some NMR results with those found by GC analysis.
- Aerts, Hans A. J.,Jacobs, Pierre A.
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Read Online
- Synthesis of carbonated fatty methyl esters using supercritical carbon dioxide
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The two-step syntheses of the cyclic carbonates carbonated methyl oleate (CMO) and carbonated methyl linoleate (CML) are reported. First, synthesis of epoxides through well-precedented chemical reactions of unsaturated fatty methyl esters with hydrogen peroxide and formic acid was accomplished. Next, a carbonation reaction with a simple tetrabutylammonium bromide catalyst was performed, allowing the direct incorporation of carbon dioxide into the oleochemical. These syntheses avoid the use of the environmentally unfriendly phosgene. The carbonated products are characterized by IR, 1H NMR, and 13C NMR spectroscopy and studied by thermogravimetric analysis (TGA). Also reported is the synthesis of a similar cyclic carbonate from the commercially available 2-ethylhexyl epoxy soyate. These carbonates show properties that may make them useful as petrochemical replacements or as biobased industrial product precursors.
- Doll, Kenneth M.,Erhan, Sevim Z.
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Read Online
- Azide derivatives of soybean oil and fatty esters
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An environmentally friendly water-based pathway to form the azide derivatives of soybean oil and fatty esters is reported. This entails first the formation of epoxides and then the azidization of the epoxides. The azidization reaction is carried out at high yields in water with only a small amount of an ionic liquid as a catalyst. The distribution of azide and alcohol functionalities on the fatty acid moiety is approximately random. This reaction has been applied to methyl oleate, methyl linoleate, soybean oil, and methyl soyate. The resulting structures have been studied by NMR.
- Biswas, Atanu,Sharma, Brajendra K.,Willett,Advaryu, Atanu,Erhan,Cheng
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Read Online
- A silicododecamolybdate/pyridinium-tetrazole hybrid molecular salt as a catalyst for the epoxidation of bio-derived olefins
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The hybrid polyoxometalate (POM) salt (Hptz)4[SiMo12O40]?nH2O (1) (ptz = 5-(2-pyridyl)tetrazole) has been prepared, characterized by X-ray crystallography, and examined as a catalyst for the epoxidation of cis-cyclooctene (Cy) and bio-derived olefins, namely dl-limonene (Lim; a naturally occurring monoterpene found in the rinds of citrus fruits), methyl oleate and methyl linoleate (fatty acid methyl esters (FAMEs) obtained by transesterification of vegetable oils). The crystal structure of 1 consists of α-Keggin-type heteropolyanions, [SiMo12O40]4-, surrounded by space-filling and charge-balancing 2-(tetrazol-5-yl)pyridinium (Hptz+) cations, as well as by a large number of water molecules of crystallization (n = 9). The water molecules mediate an extensive three-dimensional (3D) hydrogen-bonding network involving the inorganic anions and organic cations. For the epoxidation of the model substrate Cy in a nonaqueous system (tert-butylhydroperoxide as oxidant), the catalytic performance of 1 (100% epoxide yield at 24 h, 70 °C) was superior to that of the tetrabutylammonium salt (Bu4N)4[SiMo12O40] (2) (63% epoxide yield at 24 h), illustrating the role of the counterion Hptz+ in enhancing catalytic activity. The hybrid salt 1 was effective for the epoxidation of Lim (69%/85% conversion at 6 h/24 h) and the FAMEs (87–88%/100% conversion at 6 h/24 h), leading to useful bio-based products (epoxides, diepoxides and diol products).
- Nunes, Martinique S.,Neves, Patrícia,Gomes, Ana C.,Cunha-Silva, Luís,Lopes, André D.,Valente, Anabela A.,Pillinger, Martyn,Gon?alves, Isabel S.
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- Heterogeneous catalysis with an organic-inorganic hybrid based on MoO3chains decorated with 2,2′-biimidazole ligands
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The discovery of selective heterogeneous catalytic systems for industrial oxidation processes remains a challenge. Molybdenum oxide-based polymeric hybrid materials have been shown to be oxidation catalysts under mild reaction conditions, although difficulties remain with catalyst recovery/reuse since most perform as homogeneous catalysts or possess low activity. The present study shows that the hybrid material [MoO3(2,2′-biimidazole)]·H2O (1) is a superior catalyst regarding these issues. The structure of1was confirmed (by single crystal and synchrotron X-ray powder diffraction) to comprise one-dimensional chains of corner-sharing {MoO4N2} octahedra. Strong MoO?H-N hydrogen bonds separate adjacent chains to afford parallel channels that are occupied by disordered water molecules. Hybrid1was additionally characterised by FT-IR spectroscopy,1H and13C MAS NMR, scanning electron microscopy and thermogravimetric analysis. The catalytic studies highlighted the versatility of1for oxidation reactions withtert-butylhydroperoxide as oxidant. By complementing with characterisation studies, it was verified that the reaction occurs in the heterogeneous phase, the catalyst has good stability and is recoverableviasimple procedures. The chemical reaction scope covered epoxidation and sulfoxidation, and the substrate scope included biomass-deriveddl-limonene and fatty acid methyl esters to give renewable bio-products, as well as thiophene and thioanisole substrates.
- Amarante, Tatiana R.,Neves, Patrícia,Almeida Paz, Filipe A.,Gomes, Ana C.,Pillinger, Martyn,Valente, Anabela A.,Gon?alves, Isabel S.
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p. 2214 - 2228
(2021/04/12)
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- Ionic ammonium and anilinium based polymolybdate hybrid catalysts for olefin epoxidation
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Ionic polymolybdate hybrids (IPH) are interesting catalysts for liquid phase olefin epoxidation with tert-butylhydroperoxide; (tbhp), e.g. conversion of terpenic and fatty acid methyl ester (FAME) components of biomass to useful bio-products. IPHs may be easily prepared, under clean, mild, aqueous phase conditions. The type of organic precursor and the synthesis conditions influence the structural features of the IPHs. In this work, IPH epoxidation catalysts possessing one- (1-D) or two-dimensional (2-D) structures were investigated, which included the new materials 1-D methylammonium ammonium trimolybdate [Mo3O10?CH3NH3·NH4] (1) and 2-D bis(2,5-dimethylanilinium) pentamolybdate [Mo5O16?2(NH3C6H3(CH3)2)] (4) with solved structures, and 1-D bis(3,5-dimethylanilinium) trimolybdate [Mo3O10·2(NH3C6H3(CH3)2)] (2), bis(4-methylanilinium) trimolybdate [Mo3O10·2(NH3C6H4CH3)] (3), 2-D bis(anilinium) pentamolybdate [Mo5O16?2(NH3C6H5)] (5), bis(4-methylanilinium) pentamolybdate [Mo5O16?2(NH3C6H4CH3)] (6) and bis(4-ethylanilinium) pentamolybdate [Mo5O16?2(NH3C6H4C2H5)] (7). Systematic characterisation and catalytic studies helped gain insights into structure-activity relationships. The best-performing catalyst (2) was effective for the epoxidation of the FAMEs such as, methyl oleate which gave 92% methyl 9,10-epoxyoctadecanoate yield, at 99% conversion, at 70 °C. The reaction conditions (temperature, type of cosolvent and oxidant) influenced the catalytic reaction. Catalytic performance in consecutive batch runs was steady, and the structural features were essentially preserved.
- Bo?ek, Barbara,Neves, Patrícia,?asocha, Wies?aw,Valente, Anabela A.
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- Selective Epoxidation of Fatty Acids and Fatty Acid Methyl Esters by Fungal Peroxygenases
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Recently discovered fungal unspecific peroxygenases from Marasmius rotula and Chaetomium globosum catalyze the epoxidation of unsaturated fatty acids (FA) and FA methyl esters (FAME), unlike the well-known peroxygenases from Agrocybe aegerita and Coprinopsis cinerea. Reactions of a series of unsaturated FA and FAME with cis-configuration revealed high (up to 100 %) substrate conversion and selectivity towards epoxidation, although some significant differences were observed between enzymes and substrates with the best results being obtained with the C. globosum enzyme. This and the M. rotula peroxygenase appear as promising biocatalysts for the environmentally-friendly production of reactive FA epoxides given their self-sufficient monooxygenase activity and the high conversion rate and epoxidation selectivity.
- Aranda, Carmen,Olmedo, Andrés,Kiebist, Jan,Scheibner, Katrin,del Río, José C.,Martínez, Angel T.,Gutiérrez, Ana
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p. 3964 - 3968
(2018/08/11)
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- Chemistry and Catalytic Performance of Pyridyl-Benzimidazole Oxidomolybdenum(VI) Compounds in (Bio)Olefin Epoxidation
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The chemistry and catalytic performance of the dichlorido complex [MoO2Cl2(pbim)] (1) [pbim = 2-(2-pyridyl)-benzimidazole] in the epoxidation of olefins is reported. Complex 1 acts as a precatalyst and is more effective with tert-butylhydroperoxide (TBHP) as the oxidant than with aq. hydrogen peroxide: the cis-cyclooctene (Cy) reaction with TBHP gave 98 % epoxide yield at 70 °C/24 h. Catalyst characterization showed that 1 is transformed in situ to the oxidodiperoxido complex [MoO(O2)2(pbim)] (2), with H2O2 and a hybrid molybdenum(VI) oxide solid formulated as [MoO3(pbim)] (3) with TBHP. The hybrid material 3 was prepared on a larger scale and explored for the epoxidation of the biorenewable olefins methyl oleate, methyl linoleate, and (R)-(+)-limonene. With TBHP as the oxidant, 3 acts as a source of soluble active species of the type 2. A practical method for recycling oxidodiperoxidomolybdenum(VI) catalysts for the Cy/TBHP reaction is demonstrated by using an ionic liquid as the solvent for the molecular catalyst 2.
- Neves, Patrícia,Nogueira, Lucie S.,Gomes, Ana C.,Oliveira, Tania S. M.,Lopes, André D.,Valente, Anabela A.,Gon?alves, Isabel S.,Pillinger, Martyn
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p. 2617 - 2627
(2017/05/29)
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- Triazolyl, Imidazolyl, and Carboxylic Acid Moieties in the Design of Molybdenum Trioxide Hybrids: Photophysical and Catalytic Behavior
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Three organic ligands bearing 1,2,4-triazolyl donor moieties, (S)-4-(1-phenylpropyl)-1,2,4-triazole (trethbz), 4-(1,2,4-triazol-4-yl)benzoic acid (trPhCO2H), and 3-(1H-imidazol-4-yl)-2-(1,2,4-triazol-4-yl)propionic acid (trhis), were prepared to evaluate their coordination behavior in the development of molybdenum(VI) oxide organic hybrids. Four compounds, [Mo2O6(trethbz)2]·H2O (1), [Mo4O12(trPhCO2H)2]·0.5H2O (2a), [Mo4O12(trPhCO2H)2]·H2O (2b), and [Mo8O25(trhis)2(trhisH)2]·2H2O (3), were synthesized and characterized. The monofunctional tr-ligand resulted in the formation of a zigzag chain [Mo2O6(trethbz)2] built up from cis-{MoO4N2} octahedra united through common μ2-O vertices. Employing the heterodonor ligand with tr/-CO2H functions afforded either layer or ribbon structures of corner- or edge-sharing {MoO5N} polyhedra (2a or 2b) stapled by tr-links in axial positions, whereas -CO2H groups remained uncoordinated. The presence of the im-heterocycle as an extra function in trhis facilitated formation of zwitterionic molecules with a protonated imidazolium group (imH+) and a negatively charged -CO2- group, whereas the tr-fragment was left neutral. Under the acidic hydrothermal conditions used, the organic ligand binds to molybdenum atoms either through [N-N]-tr or through both [N-N]-tr and μ2-CO2- units, which occur in protonated bidentate or zwitterionic tetradentate forms (trhisH+ and trhis, respectively). This leads to a new zigzag subtopological motif (3) of negatively charged polyoxomolybdate {Mo8O25}n2n- consisting of corner- and edge-sharing cis-{MoO4N2} and {MoO6} octahedra, while the tetradentate zwitterrionic trhis species connect these chains into a 2D net. Electronic spectra of the compounds showed optical gaps consistent with semiconducting behavior. The compounds were investigated as epoxidation catalysts via the model reactions of achiral and prochiral olefins (cis-cyclooctene and trans-β-methylstyrene) with tert-butylhydroperoxide. The best-performing catalyst (1) was explored for the epoxidation of other olefins, including biomass-derived methyl oleate, methyl linoleate, and prochiral dl-limonene.
- Lysenko, Andrey B.,Senchyk, Ganna A.,Domasevitch, Konstantin V.,Kobalz, Merten,Krautscheid, Harald,Cichos, Jakub,Karbowiak, Miroslaw,Neves, Patrícia,Valente, Anabela A.,Gon?alves, Isabel S.
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p. 4380 - 4394
(2017/04/26)
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- Mild catalytic oxidations of unsaturated fatty acid methyl esters (FAMEs) by oxovanadium complexes
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A selection of unsaturated fatty acid methyl esters, namely methyl oleate (C18:1), methyl linoleate (C18:2) and methyl linolenate (C18:3) has been oxidized under mild homogeneous catalytic conditions, using a series of oxovanadium(IV) complexes containing 4-acyl-5-pyrazolone donor ligands with different substituents on acyl residue. The main goal was to evaluate the catalytic role exerted by oxovanadium(IV) metal center, as precursor complex, in the selective oxyfunctionalization of carbon-carbon double bonds of these bio-renewable resources, as a greener alternative to more drastic processes currently used at the industrial level. The three substrates, oxidized using tert-butylhydroperoxide as main oxidant, with or without solvents, showed high conversions of starting materials and high selectivities in the formation of corresponding mono- di- and tri-epoxides, especially under solvent-less conditions. Investigations on a probable catalytic cycle mechanism operative in the tert-butylhydroperoxide oxidation of a simple FAME model substrate, have been performed by means of ESI-MS.
- Cecchini, Martina Maya,De Angelis, Francesco,Iacobucci, Claudio,Reale, Samantha,Crucianelli, Marcello
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p. 120 - 128
(2016/03/22)
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- Cooperative catalyst system for the synthesis of oleochemical cyclic carbonates from CO2 and renewables
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Phosphonium salts and various (transition-) metals were studied as catalysts in the synthesis of carbonated oleochemicals from the corresponding epoxides and carbon dioxide. In combination with tetra-n-butylphosphonium bromide molybdenum compounds were identified as highly active co-catalysts for the formation of cyclic carbonates. The co-catalyst accelerates the conversion of the epoxidized fatty acid ester considerably. The chemo- as well as the stereoselectivity of the carbonated oleochemicals can be controlled by the choice of the catalyst and the reaction conditions. Under optimized reaction conditions this new catalyst system allows the conversion of both mono- and polyepoxidized oleo compounds into the corresponding carbonates in good to excellent yields up to >99% under comparatively mild reaction conditions. This procedure has been applied to the synthesis of a potential renewable plasticizer and works well even at larger scale (200 g).
- Tenhumberg, Nils,Büttner, Hendrik,Sch?ffner, Benjamin,Kruse, Daniela,Blumenstein, Michael,Werner, Thomas
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supporting information
p. 3775 - 3788
(2016/07/07)
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- Plasticizer and surfactant formation from food-waste- and algal biomass-derived lipids
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The potential of lipids derived from food-waste and algal biomass (produced from food-waste hydrolysate) for the formation of plasticizers and surfactants is investigated herein. Plasticizers were formed by epoxidation of double bonds of methylated unsaturated fatty acids with in situ generated peroxoformic acid. Assuming that all unsaturated fatty acids are convertible, 0.35 and 0.40 g of plasticizer can be obtained from 1 g of crude algae- or food-waste-derived lipids, respectively. Surfactants were formed by transesterification of saturated and epoxidized fatty acid methyl esters (FAMEs) with polyglycerol. The addition of polyglycerol would result in a complete conversion of saturated and epoxidized FAMEs to fatty acid polyglycerol esters. This study successfully demonstrates the conversion of food-waste into value-added chemicals using simple and conventional chemical reactions.
- Pleissner, Daniel,Lau, Kin Yan,Zhang, Chengwu,Lin, Carol Sze Ki
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p. 1686 - 1691
(2015/06/02)
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- Chemical characterization and physical properties of solvents derived from epoxidized methyl soyate
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Reactions of epoxidized methyl soyate (EMS) with alcohols, carbon dioxide, and acetone yielded liquids with solvent properties that make them more suitable than methyl soyate for dissolving polar substances. The reactions of EMS in the presence of Amberlyst-15 with alcohols, including methanol, ethanol, n-butanol, and 2-methoxyethanol, produced a series of solvents containing ether (-OR) and alcohol (-OH) groups. Reactions of EMS with carbon dioxide and acetone gave products with carbonate and ketonide functional groups, respectively. The complex mixture of compounds present in the product, EMS(MeOH), resulting from the reaction of EMS with MeOH, was characterized by MS and NMR investigations. In addition to products resulting from MeOH addition across the epoxide ring, were major amounts of cyclic tetrahydrofuran derivatives that were derived from reactions of methyl linoleate (18:2) with MeOH. All of the solvents were characterized by high boiling points and low vapor pressures. Their viscosities were higher than that of methyl soyate. Especially notable were their very high Kauributanol values, which ranged from 280 to 852, all of which are much higher than that (57) of methyl soyate. Such high KB values indicate that these solvents have very favorable solubilizing properties, which is illustrated by the ability of EMS(MeOH) to readily dissolve both polar (e.g., MeOH) and non-polar (e.g., hexane) compounds.
- Riley, Sean J.,Verkade, John G.,Angelici, Robert J.
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p. 589 - 601
(2015/03/14)
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- Immobilized oxo-vanadium Schiff base on graphene oxide as an efficient and recyclable catalyst for the epoxidation of fatty acids and esters
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Oxo-vanadium Schiff base was covalently immobilized onto chemically functionalized graphene oxide (GO) using 3-aminopropyltriethoxysilane as a coupler. The loading of vanadyl Schiff base onto GO nanosheets was confirmed by FTIR, XRD, TGA, and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The synthesized heterogeneous catalyst was found to be efficient and selective for the epoxidation of fatty acids and esters using t-butyl hydroperoxide (TBHP) as an oxidant. Interestingly, the immobilized catalyst showed a higher catalytic efficiency than the homogeneous vanadyl acetylacetonate. The recycling experiment results indicated that the catalyst was highly stable and maintained very high activity, and selectivity even after being used for six cycles. This journal is the Partner Organisations 2014.
- Verma, Sanny,Aila, Mounika,Kaul, Savita,Jain, Suman L.
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p. 30598 - 30604
(2014/08/05)
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- Factors affect on the synthesis of silica-pillared zirconium phosphate with template-directing self-assembly method and its epoxidation catalytic performance
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A series of silica-pillared zirconium phosphate materials with ordered structure were synthesized using hexadecylamine (HDA) as expanding agent, dodecyl dimethyl benzyl ammonium chloride (DDBAC) as template agent and tetraethyl orthosilicate (TEOS) as silica source. The textural properties of the materials can be effectively controlled by adjusting the dosage of HDA, DDBAC and TEOS. Furthermore, a template-directing self-assembly mechanism was proposed based on the synthesis. In the epoxidation of methyl soyate, the prepared materials showed excellent performance with 95.9 % conversion of double bonds and 84.7 % epoxy selectivity. This result is determined by the large surface area and the ordered interlayer structure. Graphical Abstract: Series silica-pillared zirconium phosphate materials with ordered structure were synthesized. The textural properties of the materials can be effectively controlled by adjusting the dosage of each reaction species. A template-directing self-assembly mechanism was proposed based on the synthesis. The materials show excellent catalytic performance on the epoxidation of methyl soyate.[Figure not available: see fulltext.]
- Liu, Wenjin,Wang, Hongning,He, Mengyao,Zhong, Jing,Chen, Ruoyu
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p. 663 - 673
(2014/04/03)
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- Selective oxidation reactions of natural compounds with hydrogen peroxide mediated by methyltrioxorhenium
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We have investigated the oxidative behaviour of natural compounds such as methyl abietate (1), farnesyl acetate (2), a-ionone (3), β-ionone (4), methyl linolelaidate (5), methyl linolenate (6) and bergamottin (7) with the oxidant system methyltrioxo-rhenium/ H2O2/pyridine. The reactions, performed in CH2Cl2/H2O at 25 °C, have shown good regioand stereoselectivity. The oxidation products were isolated by HPLC or silica gel chromatography and characterized by MS(EI), 1H-, 13C-NMR, APT, gCOSY, HSQC, TOCSY and NOESY measurements. The selectivity seems to be controlled by the nucleophilicity of double bonds and by stereoelectronic and steric effects.
- Amato, Maria E.,Ballistreri, Francesco P.,Pappalardo, Andrea,Tomaselli, Gaetano A.,Toscano, Rosa M.,Sfrazzetto, Giuseppe Trusso
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p. 13754 - 13763
(2014/01/06)
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- Substrate dependent synergetic and antagonistic interaction of ammonium halide and polyoxometalate catalysts in the synthesis of cyclic carbonates from oleochemical epoxides and CO2
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Organic halides and polyoxometalates (POMs) were studied as catalyst systems for the insertion of carbon dioxide into epoxides originating from plant oils as biogenic feedstock. In the formation of methyl oleate carbonate, synergistic rate acceleration and increased cis-selectivity were observed using ammonium halide and transition metal substituted silicotungstate POMs catalysts in a combined system. Mechanistic insight into the cooperative action was gained by kinetic measurements and analysis of the stereochemical outcome of the reaction. For poly-epoxidised oleochemicals as substrates, the simple ammonium halide catalyst gave better performance as side reactions were encountered with the POM-containing system.
- Langanke, Jens,Greiner, Lasse,Leitner, Walter
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supporting information
p. 1173 - 1182
(2013/06/27)
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- A non-canonical caleosin from Arabidopsis efficiently epoxidizes physiological unsaturated fatty acids with complete stereoselectivity
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In plants, epoxygenated fatty acids (EFAs) are constituents of oil seeds as well as defence molecules and components of biopolymers (cutin, suberin). While the pleiotropic biological activities of mammalian EFAs have been well documented, there is a paucity of information on the physiological relevance of plant EFAs and their biosynthesis. Potential candidates for EFA formation are caleosin-type peroxygenases which catalyze the epoxidation of unsaturated fatty acids in the presence of hydroperoxides as co-oxidants. However, the caleosins characterized so far, which are mostly localized in seeds, are poor epoxidases. In sharp contrast, quantitative RT-PCR analysis revealed that PXG4, a class II caleosin gene, is expressed in roots, stems, leaves and flowers of Arabidopsis. Expressed in yeast, PXG4 encodes a calcium-dependent membrane-associated hemoprotein able to catalyze typical peroxygenase reactions. Moreover, we show here that purified recombinant PXG4 is an efficient fatty acid epoxygenase, catalyzing the oxidation of cis double bonds of unsaturated fatty acids. Physiological linoleic and linolenic acids proved to be the preferred substrates for PXG4; they are oxidized into the different positional isomers of the monoepoxides and into diepoxides. An important regioselectivity was observed; the C-12,13 double bond of these unsaturated fatty acids being the least favored unsaturation epoxidized by PXG4, linolenic acid preferentially yielded the 9,10-15,16-diepoxide. Remarkably, PXG4 catalyzes exclusively the formation of (R),(S)-epoxide enantiomers, which is the absolute stereochemistry of the epoxides found in planta. These findings pave the way for the study of the functional role of EFAs and caleosins in plants. 2012 The Authors Journal compilation
- Blee, Elizabeth,Flenet, Martine,Boachon, Benoit,Fauconnier, Marie-Laure
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p. 3981 - 3995
(2013/01/13)
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- ADDUCTS OF LEVULINIC DERIVATIVES WITH EPOXIDIZED FATTY ACID ESTERS AND USES THEREOF
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The present disclosure relates to methods of preparation of compounds resulting from the reaction of levulinic esters and epoxidized unsaturated fatty acid esters. The compounds are useful as renewable biomass-based plasticizers for a variety of polymers. Mono-, di- and tri-ketal adducts formed in a reaction between alkyl esters of levulinate and epoxidized unsaturated fatty acid esters derived from vegetable oils are also disclosed.
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Page/Page column 19-20
(2010/11/27)
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- Hydrolysis of Mono- and Diepoxyoctadecanoates by Alumina
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In this study it is shown that the epoxide derivative of oleic acid, methyl 9, 10-epoxyoctadecanoate, is readily hydrolyzed to a diol when exposed to a commercial preparation of neutral alumina. Comparison of 1H and 13C NMR spectra of the diol with those of standards showed that the product was the threo isomer. When methyl 9, 10-12, 13-diepoxyoctadecanoate was treated with alumina, a mixture of dihydroxytetrahydrofuran regioisomers, methyl 9, 12-epoxy-10, 13-dihydroxystearate and methyl 10, 13-epoxy-9, 12-dihydroxystearale, was obtained. These results show that alumina is an unsuitable support for epoxidation catalysts. However, alumina-catalyzed hydrolysis of fatty epoxides is an efficient way to synthesize polyhydroxy materials, and these materials are suitable for several industrial applications.
- Piazza, George J.,Nunz, Alberto,Foglia, Thomas A.
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p. 901 - 904
(2007/10/03)
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- Oxygenated Fatty Acids with Anti-rice Blast Fungus Activity in Rice Plants
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Expecting that the different characteristics of rice plants against rice blast fungus, that is, susceptibility of the weaker cultivar, Sasanishiki and resistance of the stronger cultivars, Fukuyuki and Fukunishiki, may be due to the absence or presence of anti-fungus compounds in the rice plants, the anti-rice blast fungus substances in these three kinds of rice plants were explored.We found five epoxides and five allyl alcohols as anti-rice blast fungus compounds.The epoxides were 12,13-epoxy- and 9,10-epoxylinoleic acids, and 15,16-epoxy-, 12,13-epoxy-, and 9,10-epoxylinolenic acids.The allyl alcohols are 13-hydroxy and 9-hydroxy linoleic acids, and 16-hydroxy, 13-hydroxy, and 9-hydroxy linolenic acids.In inoculated Sasanishiki, the activity is due to the formation of the allyl alcohols.
- Kato, Tadahiro,Yamaguchi, Yoshihiro,Namai, Tsuneo,Hirukawa, Toshifumi
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p. 283 - 287
(2007/10/02)
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- Structural Elucidation of Naturally Occurring 9,12,13-Trihydroxy Fatty Acids by a Synthetic Study
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Our investigation on anti-rice blast fungus materials from the rice plant has already led to the isolation of various types of oxygenated unsaturated fatty acids, which play an essential role in the defense of the rice plant against this fungus.Among those isolated were 9,12,13-trihydroxy C-18 fatty acids.We have determined the relative stereochemistry of the trihydroxy acid by synthesizing the possible stereoisomers.This paper describes the details of our synthetic study, demonstrating the fatty acid to be 9S,12S,13S-trihydroxyoctadeca-10E,15Z-dienoic acid and its 15-dihydro analogue.The absolute configuration was determined by observing a positive Cotton effect in the CD spectrum of the benzoate derivative of the natural material.
- Kato, Tadahiro,Yamaguchi, Yoshihiro,Hirukawa, Toshifumi,Hoshino, Naoko
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p. 1349 - 1357
(2007/10/02)
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- Conversion of Linoleic and Latex Furanoid Acid to Fish C18 Dimethyl Furanoid Isomers
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Methyl 9(10),12(13)-dioxo-octadecanoate (derived from methyl linoleate) and 10,13-dioxo-11-methyloctadecanoate (derived from the latex of the rubber plant) were methylated at the methylene carbons located between the two oxo-groups (using MeI, KOH in DMSO) and cyclodehydration furnished a mixture of methyl 9(10),12(13)-epoxy-10(11),11(12)-dimethyloctadeca-9(10),11(12)-dienoates and methyl 10,13-epoxy-11,12-dimethyloctadeca-10,12-dienoate respectively.
- Jie, Marcel S. F. Lie Ken,Ahmad, Fasih
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p. 1110 - 1111
(2007/10/02)
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