- Eco-Friendly Natural Clay: Montmorillonite Modified with Nickel or Ruthenium as an Effective Catalyst in Gamma-Valerolactone Synthesis
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Ni/Ru metals supported on cheap and available support montmorillonite K10 were used for the selective hydrogenation of levulinic acid to γ-valerolactone. Different loadings of the metals were applied by the impregnation method, and detailed characterization was performed (UV–VIS, XRD, TPR, TPD, particle size distribution, SEM, XRF). Metals’ homogeneous distribution on the surface was confirmed. The selectivity to the desired product was almost independent on the used material. A detailed study of the influence of solvents on the studied reaction was also performed—protic alcohol-based solvents caused the formation of levulinic and valeric acid esters in the reaction mixture. The selectivity was influenced mainly by the alcohol structure (the highest selectivity obtained using isopropyl alcohol and sec-butanol). Mainly the solvent’s donor number (except ethanol) influenced the reaction rate. The prepared catalysts are promising, available, and cheap materials for the studied reaction. Solvent may significantly influence the yield of γ-valerolactone. Graphic Abstract: [Figure not available: see fulltext.].
- ?erveny, Libor,Trejbal, Ji?í,Vaňková, Michaela,Vrbková, Eva,Vysko?ilová, Eli?ka
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- Development and Validation of a Novel Free Fatty Acid Butyl Ester Gas Chromatography Method for the Determination of Free Fatty Acids in Dairy Products
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Accurate quantification of free fatty acids in dairy products is important for both product quality control and legislative purposes. In this study, a novel fatty acid butyl ester method was developed, where extracted free fatty acids are converted to butyl esters prior to gas chromatography with flame ionization detection. The method was comprehensively validated to establish linearity (20-700 mg/L; R2 > 0.9964), limits of detection (5-8 mg/L), limits of quantification (15-20 mg/L), accuracy (1.6-5.4% relative error), interday precision (4.4-5.3% relative standard deviation), and intraday precision (0.9-5.6% relative standard deviation) for each individual free fatty acid. A total of 17 dairy samples were analyzed, covering diverse sample matrices, fat content, and degrees of lipolysis. The method was compared to direct on-column injection and fatty acid methyl ester methods and overcomes limitations associated with these methods, such as either column-phase absorption or deterioration, accurate quantification of short-chain free fatty acids, and underestimation of polyunsaturated free fatty acid.
- Mannion, David T.,Furey, Ambrose,Kilcawley, Kieran N.
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p. 499 - 506
(2019/01/08)
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- Preparation of valeric acid and valerate esters from biomass-derived levulinic acid using metal triflates + Pd/C
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Recently, great attention has been paid to the study of the conversion of biomass-derived compounds to value-Added chemicals. Levulinic acid (LA) is a versatile and valuable chemical and its various applications have been described. The selective conversion of biomass-derived LA to produce valeric acid and valerate esters was successfully performed in the presence of H2, in which metal triflates and Pd/C were used as the catalysts. Under optimal conditions, a 99% conversion of LA and a 92% selectivity of valeric acid was obtained with Hf(OTf)4 and Pd/C as the catalysts at a relatively low temperature of 150 °C. Moreover, the metal center of the catalyst, the solvent, the reaction temperature and other reaction conditions were studied. In addition, the results of the recycling experiment exhibited that the catalysts continued to have a satisfactory activity after being reused 5 times.
- Zhou, Jian,Zhu, Rui,Deng, Jin,Fu, Yao
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p. 3974 - 3980
(2018/09/11)
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- Sol-gel immobilisation of lipases: Towards active and stable biocatalysts for the esterification of valeric acid
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Alkyl esters are high added value products useful in a wide range of industrial sectors. A methodology based on a simple sol-gel approach (biosilicification) is herein proposed to encapsulate enzymes in order to design highly active and stable biocatalysts. Their performance was assessed through the optimization of valeric acid esterification evaluating the effect of different parameters (biocatalyst load, presence of water, reaction temperature and stirring rate) in different alcoholic media, and comparing two different methodologies: conventional heating and microwave irradiation. Ethyl valerate yields were in the 80–85% range under optimum conditions (15 min, 12% m/v biocatalyst, molar ratio 1:2 of valeric acid to alcohol). Comparatively, the biocatalysts were slightly deactivated under microwave irradiation due to enzyme denaturalisation. Biocatalyst reuse was attempted to prove that good reusability of these sol-gel immobilised enzymes could be achieved under conventional heating.
- Cebrián-García, Soledad,Balu, Alina M.,García, Araceli,Luque, Rafael
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- Highly efficient transformation of Γ-valerolactone to valerate esters over structure-controlled copper/zirconia catalysts prepared via a reduction-oxidation route
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Design and development of novel and efficient catalysts are crucial but challenging for the catalytic conversion of biomass and derivatives to fuels and chemicals. In this paper, a novel separate nucleation and aging steps assistant reduction-oxidation strategy was developed to synthesis CuO/ZrO2 complex precursor with homogeneously distributed Cu and Zr components, which can be used as an ideal precursor for the synthesis of highly dispersed Cu/ZrO2 catalyst. Characterization results revealed that homogeneous dispersion of CuO, high surface area of ZrO2 support with controlled porous structure, and strong interaction between CuO and ZrO2 in CuO/ZrO2 precursor could lead to the enhanced Cu dispersion and the formation of Cu+ active centers. The synthesized Cu/ZrO2 catalysts exhibited excellent catalytic performance (85.4% conversion of GVL and 98.0% selectivity of pentyl valerate) in the catalytic transformation of GVL to valerate esters, more efficient than that of Cu/ZrO2-CP and Cu/ZrO2-CH catalysts prepared via co-precipitation and chemisorption hydrolysis methods, respectively. The superior catalytic performance was mainly attributed to both the cooperation of Cu0 and Cu+ species and the highly dispersed surface Cu0, thereby improving the adsorption and polarization of C[dbnd]O bond in GVL and the following dissociation of H2 to produce active hydrogen for the hydrogenation step during the catalytic transformation of GVL. Moreover, such copper-based catalysts exhibited potential applications in the exploitation and utilization of biomass resources with significantly enhanced efficiency.
- Liu, Shanshan,Fan, Guoli,Yang, Lan,Li, Feng
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p. 180 - 188
(2017/07/10)
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- Deep eutectic solvent choline chloride·2CrCl3·6H2O: An efficient catalyst for esterification of formic and acetic acid at room temperature
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A highly efficient and selective method for esterification of formic and acetic acid with alcohols has been achieved at room temperature, with the choline chloride (ChCl)/chromium(iii) chloride hexahydrate (CrCl3·6H2O) deep eutectic solvent as a catalyst. High yields and good selectivities of organic esters are obtained using DES [ChCl][CrCl3·6H2O]2 with the molar ratio 5:1 (carboxylic acids:alcohols) at room temperature in 24 h. The ease of recovery and reusability of DES with high catalytic activity makes this method efficient and practical.
- Cao, Jin,Qi, Bin,Liu, Jun,Shang, Yuhan,Liu, Huiwen,Wang, Wenjing,Lv, Jia,Chen, Zhiyan,Zhang, Haibo,Zhou, Xiaohai
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p. 21612 - 21616
(2016/03/08)
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- Synthesis of carboxylic acid esters in the presence of micro- and mesoporous aluminosilicates
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The catalytic properties of zeolites HY, HBeta, and HZSM-12 and of mesoporous amorphous aluminosilicate in liquid-phase esterification of aliphatic (monobasic C1-C18, dibasic C6, C10) and aromatic (benzoic, trimellitic, phthalic) carboxylic acids with butanol were studied. Zeolite HBeta appeared to be the most active catalyst. Procedures were developed for preparing esters in the presence of zeolitic catalyst HBeta, ensuring 100% selectivity of ester formation at 90-98% conversion of the acid.
- Grigor'Eva,Suleimanova,Agliullin,Kutepov
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p. 773 - 779
(2015/01/30)
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- Catalytic conversion of biomass-derived levulinic acid to valerate esters as oxygenated fuels using supported ruthenium catalysts
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The development of the catalytic conversion of biomass-based platform molecules into oxygenated fuel molecules is of great significance in order to reduce the dependence on fossil resources and to solve environmental problems. Alkyl valerate esters were proven to have the potential to be renewable additives of gasoline and diesel. In this work, we studied the hydrogenation of levulinic acid (LA) to valerate esters over supported Ru catalysts, and found that the acidity was an important factor for the catalyst performance. A bifunctional catalyst Ru/SBA-SO3H was developed as an active catalyst, and a highest yield of 94% to ethyl valerate (EV) was achieved. The catalyst was characterized by nitrogen adsorption/desorption methods, X-ray power diffraction (XRD), transmission electron spectroscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The effects of reaction conditions were comprehensively investigated and probable reaction pathways were proposed and verified. The conversion of LA to various alkyl valerate esters can also be catalyzed by the bifunctional catalyst. In addition, supported Cu and Ni catalysts were also screened under similar reaction conditions as Ru-based catalysts, and the combination of Ni/SBA-15 and SBA-SO3H exhibited activity for the conversion of LA to EV.
- Pan, Tao,Deng, Jin,Xu, Qing,Xu, Yang,Guo, Qing-Xiang,Fu, Yao
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p. 2967 - 2974
(2013/10/08)
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- Ruthenium-catalyzed hydrogenation of levulinic acid: Influence of the support and solvent on catalyst selectivity and stability
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The catalytic performance of 1 wt% Ru-based catalysts in the hydrogenation of levulinic acid (LA) has been studied at 40 bar H2 and 473 K. This was done by assessing the influence of the support acidity (i.e., Nb 2O5, TiO2, H-β, and H-ZSM5) and solvent (i.e., dioxane, 2-ethylhexanoic acid (EHA), and neat LA). The Ru/TiO2 gave excellent selectivity to γ-valerolactone (GVL) (97.5%) at 100% conversion and was remarkably stable even under severe reaction conditions. Ru/H-ZSM5 showed a 45.8% yield of pentanoic acid (PA) and its esters in dioxane, which is the first example of this one-pot conversion directly from LA at 473 K. The gradual deactivation of zeolite-supported catalysts in EHA and neat LA was mainly caused by dealumination, as confirmed by 27Al MAS NMR. Coke buildup originated from angelicalactone and, remarkably, occurred preferentially in the zigzag channels of H-ZSM5 as shown by systematic shifts in the XRD patterns. The GVL ring-opening step is considered to be the rate-determining step on the pathway to PA, necessitating an acidic support.
- Luo, Wenhao,Deka, Upakul,Beale, Andrew M.,Van Eck, Ernst R.H.,Bruijnincx, Pieter C.A.,Weckhuysen, Bert M.
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p. 175 - 186
(2013/05/09)
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- Synthesis of short chain alkyl esters using cutinase from Burkholderia cepacia NRRL B2320
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Short chain alkyl esters are well appreciated for fruity flavors they provide. These are mainly applied to the fruit-flavored products like jam, jelly, beverages, wine and dairy. Cutinase from Burkholderia cepacia NRRL B 2320 was found to be active in catalyzing the synthesis of alkyl esters in organic solvent. The optimal temperature range for the enzyme catalyzed synthesis was found to be from 35 °C to 40 °C. The maximum conversion (%) during synthesis of ester was obtained for butyric acid (C4) and valeric acid (C5) with butanol reflecting the specificity of the enzyme for short-chain length fatty acids. In case of alcohol specificity, butanol was found to be most preferred substrate by the enzyme and conversion (%) decreased with increasing carbon chain length of alcohol used in the esterification reaction. The kinetic analysis for the synthesis of butyl butyrate by varying concentration of one substrate at a time (butanol or butyric acid), showed that Ping-Pong Bi Bi model with acid inhibition and influence of initial water is most suitable model for the prediction of the reaction kinetics.
- Dutta, Kasturi,Dasu, Veeranki Venkata
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experimental part
p. 150 - 156
(2012/07/01)
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- Oxidation of substituted β-diketones with hydrogen peroxide: Synthesis of esters through the formation of bridged 1,2,4,5-tetraoxanes
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Acid-catalyzed oxidation of alkyl- and benzyl-substituted -diketones by hydrogen peroxide at 79-120C in a mixture of an alcohol and a strong acid (sulfuric acid, tetrafluoroboric acid, or perchloric acid) gave the corresponding esters through the formation of bridged 1,2,4,5-tetraoxanes. Georg Thieme Verlag Stuttgart · New York.
- Terentev, Alexander O.,Borisov, Dmitry A.,Yaremenko, Ivan A.,Ogibin, Yuri N.,Nikishin, Gennady I.
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experimental part
p. 1145 - 1149
(2010/06/14)
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- Carbonylation of alcohols in the Pd(OAc)2/TsOH/molten salt system
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A non-phosphine catalytic system, Pd(OAc)2/TsOH/NBu 4Br, is suggested for the synthesis of acids by the carbonylation of alcohols.
- Eliseev, Oleg L.,Bondarenko, Tatyana N.,Stepin, Nikolai N.,Lapidus, Albert L.
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p. 107 - 109
(2007/10/03)
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- Radical-mediated Carbonylation of Alkyl Iodides in Aqueous Media
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Radical-mediated single carbonylation of alkyl iodides furnishing carboxylic acids proceeded in water using phosphinic acid as a radical initiator in the presence of a surfactant (CTAB). On the other hand, formation of double carbonylation product (α-keto carboxylic acid) along with single carbonylation product was observed for the first time, when the reaction was carried out in aqueous ethanol without any surfactants.
- Sugiura, Masaharu,Hagio, Hiroyuki,Kobayashi, Shu
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p. 898 - 899
(2007/10/03)
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- Preparation of organic acids
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This invention relates to a process for producing one or more organic acids in high purity which process comprises (i) oxidizing in a liquid oxidation reactor one or more organic liquids with essentially pure oxygen or oxygen-enriched air containing at least about 50% oxygen, at a temperature sufficiently stable to prevent cycling of reaction rate, to produce a crude reaction product fluid, and (ii) refining said crude reaction product fluid to give said one or more organic acids in high purity. The oxidation temperature is preferably controlled to within about ±3° C. of a target temperature. The organic acids described herein is useful in a variety of applications, such as intermediates in the manufacture of chemical compounds, pharmaceutical manufacture and the like.
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- Structure-function correlation in lipase catalysed esterification reactions of short and medium carbon chain length alcohols and acids
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An attempt has been made to correlate the carbon chain lengths of acids and alcohols to the extent of esterification in the Rhizomucor miehei lipase catalyzed esterification reactions involving acids of carbon chain length C2-C5 and alcohols of carbon chain length C1-C8.
- Divakar, Soundar
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p. 1919 - 1922
(2007/10/03)
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- High pressure mechanistic diagnosis in Baeyer-Villiger oxidation of aliphatic ketones
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The pressure effect is examined in Baeyer-Villiger oxidation of aliphatic ketones. This effect is small, reflected in slightly negative activation volumes (-2 to -8 cm3 mol-1). These values allow the picturing of the volume profile. They refer to a late transition step and give support for a rate-determining migration step experiencing full concertedness.
- Jenner, Gérard
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p. 8969 - 8971
(2007/10/03)
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- Catalytic processes of oxidation by hydrogen peroxide in the presence of Br2 or HBr. Mechanism and synthetic applications
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The mechanism and the synthetic applications for the oxidation of alcohols, ethers, and aldehydes by H2O2 catalyzed by Bf2 or Br- in a liquid two-phase system (aqueous and organic) are reported. Aliphatic and benzylic primary alcohols and ethers show an opposite behavior, which has been rationalized on the ground of the different electronic configurations of the intermediate alkyl (π-type) and acyl (σ-type) radicals and their influence on enthalpic and polar effects. A two-phase system is particularly useful also for an efficient benzylic bromination by Br2 or Br-; the substitution of the benzyl bromide by OH, OR, and OCOR regenerates Br-, which can be recycled. The evaluation of the relative reactivities of the involved substrates and intermediates has allowed to develop a variety of simple, facile, convenient, and selective syntheses of alcohols, aldehydes, ketones, esters, and benzyl bromides, which fulfill the conditions for practical applications.
- Amati, Alessandro,Dosualdo, Gabriele,Zhao, Lihua,Bravo, Anna,Fontana, Francesca,Minisci, Francesco,Bjorsvik, Hans-Rene
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p. 261 - 269
(2013/09/08)
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- A New and Selective Metal-Catalyzed Baeyer-Villiger Oxidation Procedure
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A new, highly selective and high yielding procedure is described for the Baeyer-Villiger oxidation, using a tin-catalyst and bis(trimethylsilyl) peroxide (BTP).
- G?ttlich, Richard,Yamakoshi, Koichi,Sasai, Hiroaki,Shibasaki, Masakatsu
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p. 971 - 973
(2007/10/03)
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- Microwave-promoted lipase-catalyzed reactions. Resolution of (±)-1-phenylethanol
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Microwave irradiation increased enzymatic affinity and selectivity of supported lipases in esterification and transesterification reactions carried out in dry media and at temperature near 100°C.
- Carrillo-Munoz, Jose-Ramon,Bouvet, Denis,Guibe-Jampel, Eryka,Loupy, Andre,Petit, Alain
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p. 7746 - 7749
(2007/10/03)
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- Tetramethylammonium phenyltrialkylborates in the photoinduced electron transfer reaction with benzophenone. Generation of alkyl radicals and their addition to activated alkenes
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Photoinduced one electron oxidation of tetramethylammonium phenyltrialkylborates by the excited state of benzophenone in an acetonitrile/benzene solution containing an excess of activated alkene produces substantially more than one equivalent of the alkyl radicals. The corresponding adducts of alkyl radicals to the alkenes are produced in good yields. No phenyl radical adducts are observed.
- Polykarpov, Alexander Y.,Neckers, Douglas C.
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p. 5483 - 5486
(2007/10/02)
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- Mild, one-pot conversion of carboxylic acids into esters using phase transfer catalysis
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One-pot conversion of carboxylic acids into esters under the influence of phase transfer catalysis is reported.The method is shown to work satisfactorily for optically active acids having epimerisable α-hydrogen.
- Puntambekar, Hemalata M,Naik, D G,Kapadi, A H
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p. 793 - 794
(2007/10/02)
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- HOF·CH3CN, made directly from F2 and water, as an ecologically friendly oxidizing reagent
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The complex HOF·CH3CN, made directly from fluorine and aqueous acetonitrile, was used for oxidation of secondary alcohols and for Baeyer Villiger oxidation of ketones. By using 18O labeled reagent it was found that the ketone oxidation proceeds through the original dioxirane mechanism which Baeyer and Villiger suggested a century ago for reactions with peracids but was later discounted.
- Rozen, Shlomo,Bareket, Yifat,Kol, Moshe
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p. 8169 - 8178
(2007/10/02)
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- β-Hydroxyethyl ester as a protecting group for carboxylic acids
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Use of β-hydroxyethyl esters as protecting groups for carboxylic acids is demonstrated.Their easy transesterification is also shown.
- Puntambekar, Hemalata M.,Naik, D. G.,Kapadi, A. H.
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p. 684 - 687
(2007/10/02)
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- REACTIONS CO-H2 EN CATALYSE HOMOGENE. HYDROCARBONYLATION DE BUTANOLS EN PRESENCE DE CATALYSEURS AU COBALT ET AU RUTHENIUM
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The four butanols were converted into C5 homologous alcohols in the presence of cobalt-ruthenium binary catalysts.The behaviour of each alcohol was examined againts catalyst composition and promoting agent.The best results were obtained with Co/Ru molar ratios close to 5.The chain-lengthening mechanism is supposed to involve an olefinic intermediate (at least for s- and t-butanol) which is subsequently hydroformylated.The cocatalytic effect of ruthenium is, however, still unclear.
- Andrianary, P.,Jenner, G.
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- ACTIVITY OF RUTHENIUM/IODINE CATALYSTS FOR THE CARBONYLATION OF ESTERS TO GIVE CARBOXYLIC ACIDS
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Homogeneous ruthenium/iodide systems under a pressure of carbon monoxide effectively catalyze the isomerization of methyl formate to acetic acid with yields in the range of 70percent.If alkyl acetates are treated with CO/H2, the dominant process is the carbonylation of the alkoxy moiety rather than the homologation of the acetyl or alkoxy moieties; e.g. n-butyl acetate is converted mainly into valeric acid and its derivatives, along with acetic acid and butane.Only in the case of methyl acetate is homologation of the alkoxy moity, to give ethyl acetate along with acetic acid, the major process.This duality of behaviour can be rationalized in terms of η2-acetyl intermediates, which can be hydrogenated to ethanol rather than hydrolyzed to acetic acid.Ester carbonylation is shown to be fast compared with alcohol carbonylation or acid homologation; esters are probably intermediates in the last process.
- Luetgendorf, Mathias,Elvevoll, Edel O.,Roeper, Michael
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- Quarternary Ammonium Salts for Butylation and Mass Spectral Identification of Volatile Organic Acids
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The esterification method described by Greeley (J.Chromatogr. 1974, 88, 229) was modified to overcome the problem of volatile acid evaporation during sample workup procedures.After solvent extraction from an aqueous sample, the acids were converted to their butyl ester derivatives in a two step process.Firstly, an involatile quarternary ammonium salts was formed which allowed concentration by solvent evaporation without loss of volatile acids.The acid salts were then converted to butyl esters by heating in the presence of n-butyl bromide and the esters were separated on a support- coated open tabular (SCOT) OV17 capillary column.The recovery and butylation yield were shown to be quantitative for isobutyric acid and the linearities and limits of detection are given for the five C4-C5 aliphatic acids.The mass spectra of butyl esters contain abundant rearrangement ions not present in methyl, ethyl, trimethylsilyl, or aryl esters which enable their rapid identification.The method was applied to the analysis of volatile urinary acids from a patient with Maple Syrup Urine Disease and showed conclusively the presence of both 2-methylbutyric and isovaleric acids.
- Burke, Daniel G.,Halpern, Berthold
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p. 822 - 826
(2007/10/02)
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- Infrared Spectra of the n-Butyl and n-Pentyl Radicals
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The n-butyl (CH3CH2CH2CH2), n-butyl-1,1-d2 (CH3CH2CH2CD2), n-pentyl (CH3CH2CH2CH2CH2), and n-pentyl-1,1-d2 (CH3CH2CH2CH2CD2) radicals have been generated in argon matrices by UV irradiation of the corresponding diacyl peroxides.The infrared spectra of the radicals reveal that the vibrational modes may be separated into two parts: the first consists of a number of modes characteristic for the primary radical center; the second consists of those vibrations of the nonradical portion of the chain which appear to be similar to those found for closed-shell hydrocarbons.
- Pacansky, J.,Gutlerrez, A.
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p. 3074 - 3079
(2007/10/02)
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- Acid-induced 13C Nuclear Magnetic Resonance Chemical Shift Changes of Ether and Ester Carbon Atoms
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13C N.m.r. chemical shifts of ehters dissolved in tetrachloromethane are displaced on addition of trifluoroacetic acid.The displacements result from independent interactions of the acid with the substrate oxygen atoms and alkyl residues.The structure-dependent and stereoselective shift changes are useful for signal assignments, structure determination, conformational analysis, assessment of the distribution of rapidly interconverting conformers of esters, and estimation of the relative basicity of ethers.
- Begtrup, Mikael
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p. 1609 - 1618
(2007/10/02)
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- Reaction of Lithium Dialkylcuprates with S-2-Pyridiyl Thioates in the Presence of Oxygen. A Carboxylic Ester Synthesis
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Reaction of lithium dialkylcuprates with S-2-pyridyl thioates in the presence of oxygen affords carboxylic esters in high yields, whereas under nitrogen it affords ketones.
- Kim, Sunggak,Lee, Jae In,Chung, Bong Young
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p. 1231 - 1232
(2007/10/02)
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