- Efficient greener methodology for the preparation of bio-based phase change materials from lipids
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In the present work, a new, highly efficient and simple strategy has been developed for the synthesis of long chain esters from fatty acids and fatty alcohols as phase change materials. Equivalent amounts of the selected starting compounds were taken to the esterification reaction at 110 °C in a solventless medium. In order to catalyze the esterification reaction, non-hygroscopic triphenylphosphine-sulfur trioxide adduct was used (0.83 mmol%) which is an easily accessible compound. The relevant reaction was completed in a very short time (2 h) and under optimized esterification conditions, excellent conversion were reached. The targeted mono ester compounds (15 examples) were obtained in good to excellent yields even after a simple crystallization step (72-99%). Additionally, a catalyst reuse investigation and study covering the scale-up production of stearyl stearate was also carried out. The triphenylphosphine-sulfur trioxide catalyzed solvent free process can compete with existing processes and proved to be a cheaper, practical and environmentally-friendly method for the esterification of fatty acids and alcohols.
- Y?ld?r?m, Ayhan,K?raylar, Kaan
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p. 407 - 413
(2020/11/19)
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- Fatty alcohol synthesis from fatty acids at mild temperature by subsequent enzymatic esterification and metal-catalyzed hydrogenation
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Fatty alcohols are important products in chemical industry to be used in the formulation of surfactants and lubricants. This work describes a two step approach for the production of myristyl alcohol under neat conditions by combining a lipase catalyzed esterification of myristic acid and myristyl alcohol with a ruthenium catalyzed hydrogenation of the intermediate myristyl myristate. The esterification was carried out in a bubble column reactor with the commercial immobilized lipase B from Candida antarctica as a biocatalyst, while the hydrogenation was conducted under pressurized conditions being catalyzed by the homogeneous chemocatalyst Ru-Macho-BH. By investigating the reaction steps separately, comparable reaction rates were found for the esterification of short chain and long chain alcohols. Additionally, the hydrogen pressure could be reduced to 35 bar compared to the current industrial Lurgi process. Characterization of cross interactions by the reactants myristic acid and sodium myristate in the hydrogenation demonstrates that the metal catalyst was completely deactivated, even at a low amount of 0.5 mol% of myristic acid. Complete conversion of myristic acid in the esterification with equal amounts of myristic acid and myristyl alcohol was obtained, overcoming any limitation in the hydrogenation. In comparison to the Lurgi process starting also from fatty acid and fatty alcohols, the chemoenzymatic two step reaction sequence could be realized at lower reaction temperatures of 60 and 100 °C as well as lower hydrogen pressures of 35 bar. This journal is
- Betke, Tobias,Gr?ger, Harald,Kleber, Joscha,Liese, Andreas,Schlipk?ter, Kim E.
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p. 7862 - 7867
(2020/11/02)
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- Manganese Pincer Complexes for the Base-Free, Acceptorless Dehydrogenative Coupling of Alcohols to Esters: Development, Scope, and Understanding
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Aliphatic PNP pincer-supported earth-abundant manganese(I) dicarbonyl complexes behave as effective catalysts for the acceptorless dehydrogenative coupling of a wide range of alcohols to esters under base-free conditions. The reaction proceeds under neat conditions, with modest catalyst loading and releasing only H2 as byproduct. Mechanistic aspects were addressed by synthesizing key species related to the catalytic cycle (characterized by X-ray structure determination, multinuclear (1H, 13C, 31P, 15N, 55Mn) NMR, infrared spectroscopy, inter alia), by studying elementary steps connected to the postulated mechanism, and by resorting to DFT calculations. As in the case of related ruthenium and iron PNP catalysts, the dehydrogenation results from cycling between the amido and amino-hydride forms of the PNP-Mn(CO)2 scaffold. For the dehydrogenation of alcohols into aldehydes, our results suggest that the highest energy barrier corresponds to the hydrogen release from the amino-hydride form, although its value is close to that of the outer-sphere dehydrogenation of the alcohol into aldehyde. This contrasts with the ruthenium and iron catalytic systems, where dehydrogenation of the substrate into aldehyde is less energy-demanding compared to hydrogen release from the cooperative metal-ligand framework.
- Nguyen, Duc Hanh,Trivelli, Xavier,Capet, Frédéric,Paul, Jean-Fran?ois,Dumeignil, Franck,Gauvin, Régis M.
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p. 2022 - 2032
(2017/08/14)
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- Selectivity control in oxidation of 1-tetradecanol on supported nano Au catalysts
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Selective oxidation of tetradecanol, a model higher fatty alcohol, on Au/CeO2-Al2O3 catalyst has been investigated to assess the factors that control selectivity. The analysis of the effect of operation conditions (temperature, run time and alcohol/metal (A/M) ratio) on catalytic performance revealed a quite complex reaction network, in which acid formation starts only after a certain level of conversion is reached. This level depends linearly on the total support surface available, indicating that it must be saturated by species generated by the reaction itself to allow acid formation to start. Addition of water to reaction medium did not modify this level, indicating that such species is not adsorbed water, as previously hypothesized, but probably spilled over hydrogen species. The resulting drastic change in the selectivity trends makes the ratio A/M a critical factor to control selectivity to aldehyde and to acid. Selectivity to ester is less sensible to operation parameters. It is noteworthy that aldehyde yields up to 27% with 90% selectivity, and acid yields up to 40% with 81% selectivity can be reached by proper selection of operation parameters.
- Martínez-González,Ivanova, Svetlana,Domínguez, María I.,Cortés Corberán
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p. 113 - 119
(2016/11/05)
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- Acceptorless dehydrogenative coupling of alcohols catalysed by ruthenium PNP complexes: Influence of catalyst structure and of hydrogen mass transfer
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Base-free catalytic acceptorless dehydrogenative homo-coupling of alcohols to esters under neat conditions was investigated using a combined organometallic synthesis and kinetic modelling approach. The considered bifunctional ruthenium aliphatic PNP complexes are very active, affording TONs up to 15,000. Notably, gas mass transfer issues were identified, which allowed us to rationalize previous observations. Indeed, the reaction kinetics are limited by the rate of transfer from the liquid phase to the gas phase of the hydrogen co-produced in the reaction. Mechanistically speaking, this relates to the interconverting couple amido monohydride/amino bishydride. Overcoming this by switching into the chemical regime leads to an initial turnover frequency increase from about 2000 up to 6100?h?1. This has a significant impact when considering assessment of novel or reported catalytic systems in this type of reaction, as overlooking of these engineering aspects can be misleading.
- Zhang, Lei,Raffa, Guillaume,Nguyen, Duc Hanh,Swesi, Youssef,Corbel-Demailly, Louis,Capet, Frédéric,Trivelli, Xavier,Desset, Simon,Paul, Sébastien,Paul, Jean-Fran?ois,Fongarland, Pascal,Dumeignil, Franck,Gauvin, Régis M.
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p. 331 - 343
(2016/07/06)
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- Unprecedented reductive esterification of carboxylic acids under hydrogen by reusable heterogeneous platinum catalysts
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Supported metal catalysts have been tested for an unprecedented reductive dimerization of carboxylic acids to esters under 8 bar hydrogen in solvent-free conditions. Among various metal-loaded tin oxide catalysts, platinum-loaded tin dioxide (Pt/SnO2) shows the highest ester yield for the reaction of dodecanoic acid. Among Pt catalysts on various supports, Lewis acidic oxides, especially SnO2, show high activity. The most active catalyst, 5 wt% Pt/SnO2 reduced at 100°C, is effective for the reductive esterification of various carboxylic acids, and the catalyst is reusable for nine cycles, demonstrating the first successful example for the title reaction. Infrared (IR) studies of a model compound (formic acid) on some metal oxides indicate a strong Lewis acid-base interaction between SnO2 and the carbonyl oxygen. For Pt/SnO2 catalysts with different Pt particle sizes, the activity increases with decreasing size of Pt metal. A cooperative catalysis of the Pt metal nanoparticles and the Sn4+ Lewis acid sites is proposed.
- Touchy, Abeda S.,Kon, Kenichi,Onodera, Wataru,Shimizu, Ken-Ichi
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p. 1499 - 1506
(2015/05/19)
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- Heterogeneous selective oxidation of fatty alcohols: Oxidation of 1-tetradecanol as a model substrate
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s Selective oxidation of fatty alcohols, i.e., linear long-chain alkanols, has been scarcely investigated to date, despite its potential application in high value chemical's production. We report for the first time the liquid phase heterogeneous oxidation of 1-tetradecanol, used as a model molecule for fatty alcohols, according to green chemistry principles by using a Au/CeO2-Al2O3 catalyst and O2 as oxidant at normal pressure. High selectivity to tetradecanal (ca. 80%) or to tetradecanoic acid (60-70%) are reached at medium conversion (up to 38%), depending on the reaction conditions used. Comparison with similar tests of 1-octanol oxidation shows that the increase of the carbon chain length decreases the alcohol conversion and the formation of ester, probably due to a greater steric effect.
- Corberán, Vicente Cortés,Gómez-Avilés, Almudena,Martínez-González, Susana,Ivanova, Svetlana,Domínguez, María I.,González-Pérez, María Elena
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- Enabling industrial biocatalytic processes by application of silicone-coated enzyme preparations
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Composite particles of the commercial lipase preparation NZ435 and silicone (silcoat-NZ435) have recently been described as promising biocatalysts for synthetic use. In this study, their actual potential for enhanced performance in industrial applications was evaluated, focusing on scenarios where carrier disintegration and catalyst leaching constitute key limitations. All three investigated model reactions, the syntheses of myristyl myristate, poly(ethylene glycol) 400-coconut fatty acid monoester and ethylene oxide and propylene oxide copolymer (EO/PO)-oleic acid diester, were considerably improved in terms of the maximal number of reaction cycles performed with the same batch of catalyst, and consequently in terms of the obtainable product amount. The total turnover numbers (TTN) increased by a factor up to 50, making the realization of this type of reactions in an industrial process more feasible. The utility of silcoat-NZ435 for stereoselective transformations was demonstrated with the enantioselective acylation of 1-phenylethanol with vinyl butyrate, in which full retention of the excellent stereoselectivity of native NZ435 was observed. Moreover, it was demonstrated for the first time that the methodology by which silcoat-catalysts are obtained can be successfully transferred to alternative carriers and enzymes (e.g., protease, esterase and laccase), opening a broad field for the implementation and advancement of biocatalysis in industrial processes. Copyright
- Nieguth,Eckstein,Wiemann,Thum,Ansorge-Schumacher
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experimental part
p. 2522 - 2528
(2011/11/29)
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- Oxone/sodium chloride: A simple and efficient catalytic system for the oxidation of alcohols to symmetric esters and ketones
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An efficient method for the oxidation of alcohols is presented. The use of catalytic amounts of sodium chloride in combination with oxone allows the conversion primary aliphatic alcohols to symmetric esters. Secondary alcohols can be easily oxidized to ketones, and benzylic alcohols are converted to the corresponding aldehydes. The method is cost effective and enviromentally benign. Copyright Taylor & Francis Group, LLC.
- Schulze, Agnes,Pagona, Georgia,Giannis, Athanassios
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p. 1147 - 1156
(2007/10/03)
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- PROCESS FOR PRODUCING CARBOXYLIC ACID ESTER AND ESTERIFICATION CATALYST
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A process for carboxylic acid ester production by which a carboxylic acid ester comprising an alcohol and a carboxylic acid each having 10 or more carbon atoms can be produced in a high yield. The catalyst used can be reused. The process generates a small amount of wastes and is less apt to pose an environmental problem. Also provided is an esterification catalyst usable in the process. In the esterification of a C10 or higher carboxylic acid and a C10 or higher alcohol, use is made, as a catalyst, of a hydrate of a salt of at least one metal selected among aluminum, gallium, indium, iron, cobalt, nickel, zinc, zirconium, hafnium, and niobium.
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Page/Page column 16-17
(2008/06/13)
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- Ruthenium-Catalyzed Oxidative Transformation of Alcohols and Aldehydes to Esters and Lactones
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Primary alcohols undergo oxidative condensation upon treatment with RuH2(PPh3)4 catalyst to give esters and molecular hydrogen.Similarly, 1,4- and 1,5-diols can be converted into the corresponding γ- and δ-lactones, respectively.The lactonization is greatly enhanced by accepting hydrogen with an appropriate hydrogen acceptor such as acetone.Primary alcohols are oxidized chemoselectively in the presence of secondary alcohols to give the corresponding lactones.These reactions are operationally simple and highly efficient for synthesis of esters and lactones from alcohols.The principle of the oxidative condensation of alcohols can be extended to ester formation from aldehydes and alcohols.The ruthenium-catalyzed reaction of aldehydes with water gives esters, while the same reaction in the presence of a hydrogen acceptor gives carboxylic acids.The key step of these reactions is the oxidative addition of ruthenium into the OH bonds of alcohols and subsequent β-elimination of (RuH) species to give the corresponding carbonyl compounds.
- Murahashi, Shun-Ichi,Naota, Takeshi,Ito, Keiichiro,Maeda, Yoshihiro,Taki, Hiroshi
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p. 4319 - 4327
(2007/10/02)
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- Conditions for the Microbial Oxidation of Various Higher Alcohols in Isooctane
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The substrate specifities and reaction conditions for the microbial oxidation of higher alcohols in isooctane were investigated using Rhodococcus equi cells grown on n-tetradecane as the sole carbon source.Primary alcohols, C4ca.C14 (even numbers), were oxidized to the corresponding carboxylic acids, with which the substrate alcohols further combined to form esters, and various kinds of secondary decanols were oxidized to the corresponding ketones, suggesting that the substrate specifities of R. equi were not so restricted in isooctane.As to the the reaction conditions, water was positively required for the oxidation of higher alcohols such as 1-tetradecanol in organic solvents such as isooctane, although the amount of water required represented only a small portion of the reaction mixture.On the other hand, ester formation took place in isooctane practically free from water, and the rates of ester formation from 1-tetradecanol and tetradecanoic acid by dried cells increased with an increase in temperature up to 70 deg C in isooctane, while ester formation hardly occured at deg C when intact cells were used in place of dried cells.It was thus suggested that microbial ester formation is less susceptible to the thermal inactivation in the absence of water than in the presence.
- Ueda, Makoto,Mukataka, Sukekuni,Sato, Seigo,Takahashi, Joji
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p. 1533 - 1538
(2007/10/02)
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- Microbial Oxidation of Tetradecanols and Related Substances in Organic Solvents
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Microbial oxidations of n-tetradecane, tetradecanols and tetradecanoic acid were investigated by using intact cells of Corynebacterium equi, a hydrocarbon-assimilating bacterium, in an aqueous phase and organic solvents.The bacterial cells were hydrophobic and could be well dispersed in all organic solvents employed to give homogeneous reaction mixtures, and among them, isooctane was found to be the best for the reaction. n-Tetradecane and tetradecanoic acid were completely oxidized in the agueous phase, but not in isooctane.In contrast, 1-tetradecanol was oxidized much more readily in isooctane than in the aqueous phase, and an oxidation product identified as myristyl myristate was accumulated in isooctane at the conversion rate of 80percent. 2-Tetradecanol was also readily oxidized in isooctane, and 2-tetradecanone was obtained at the conversion rate of nearly 100percent.Similar results were obtained when toluene and n-hexane were used as the solvent in place of isooctane, while no reaction was observed when chloroform was employed.
- Takazawa, Yoshiharu,Sato, Seigo,Takahashi, Joji
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p. 2489 - 2496
(2007/10/02)
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