- Diversification of shotgun process
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Three protocols for shotgun process are put forth in which simultaneous multi-fold reactions occur exclusively to each other. The first one involves simple combination of selective and non-selective reactions. Even if the simple protocol fails to give rise to the high selectivity, satisfactory outcome can be achieved by kinetic control or adjustment of functional groups.
- Nagano, Yoshifumi,Orita, Akihiro,Otera, Junzo
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- ALKYLATIONS EN ABSENCE DE SOLVANT ORGANIQUE. EFFETS D'ADDITION D'OXYDES MINERAUX ET DE SELS D'AMMONIUM - II. PREPARATION AISEE D'ESTERS PAR ALKYLATION DE L'ANION ACETATE DANS DES CONDITIONS DOUCES ET ECONOMIQUES
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Allyl, benzyl, n-butyl, n-octyl and cetyl acetates are obtained in very good yields (>=92percent) at room temperature by reacting finely-ground CH3COOK and the corresponding alkyl bromide without any solvent and in the presence of catalytic amounts of tetra-alkyl ammonium salts (NBu4Br or Aliquat 336).Effects of addition of mineral oxides have been studied: catalytic effects due to small quantities of TiO2, ZrO2, talc, glass dust and Celite, inhibition effects by large amounts of these solids or their highly hydroxylated analogues (alumina and silica gel).
- Barry, J.,Bram, G.,Decodts, G.,Loupy, A.,Pigeon, P.,Sansoulet, J.
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- Organotin catalysts rafted onto cross-linked polystyrene supports through polar spacers
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The present study investigates the suitability of a HypoGel support bearing oligomeric poly(ethylene glycol) (PEG) chains to act as an insoluble carrier for grafted organotin catalysts. Through the introduction of polar spacers, an improved swelling and site accessibility in the polar media typically involved in transesterification reactions are targeted. Advanced structural investigation shows that quantitative conversion into the targeted HypoGel-supported organotin trichloride is hampered by the existence of intra-and/or intermolecular donor-acceptor O → Sn interactions caused by the presence of donor moieties in the PEG-linker. Support is provided to the proposal that the latter interactions are at the origin of the moderate catalytic performance displayed by these HypoGel-supported catalysts, achieving only 41% conversion after 2 hours in the transesterification of ethyl acetate and n-octanol. In contrast with similar organotin catalysts supported by an alkyl spacer, the HypoGel-supported materials appear to be poorly recyclable and display poor leaching resistance. Copyright
- Pinoie, Vanja,Biesemans, Monique,Willem, Rudolph
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- An Efficient Acylation of Tertiary Alcohols with Isopropenyl Acetate Mediated by an Oxime Ester and Cp*2Sm(thf)2
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An efficient method for the acylation of tertiary alcohols with isopropenyl acetate (1) by the use of an oxime and Cp*2Sm(thf)2 as catalyst was developed. Thus, various types of tertiary alcohols could be acylated with 1 in the presence of a catalytic amount of cyclohexanone oxime acetate (2) and Cp*2Sm(thf)2 under mild conditions to form the corresponding acetates in excellent yields. Acid-sensitive terpene alcohols such as linalool were successfully acetylated by the present method to give acetyl linalool in quantitative yield. This method enables an alternative acylation of tertiary alcohols under acid-free conditions.
- Tashiro, Daisuke,Kawasaki, Yumi,Sakaguchi, Satoshi,Ishii, Yasutaka
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- Alkylation of potassium acetate in "dry media" thermal activation in commercial microwave ovens
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Microwave irradiation using commercial domestic ovens is very efficient to activate potassium acetate on alumina in the absence of solvent ("dry media") giving rise to remarkable rate enhancements in alkylation reactions with long chain halides. These reactions can be performed quantitatively on appreciable amounts of materials in open standard pyrex vessels.
- Bram, Georges,Loupy, Andre,Majdoub, Mustapha,Gutierrez, Elvira,Ruiz-Hitzsky, Eduardo
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- Discriminating between dispersion and lyoprotection effects in biocatalysis in organic media
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The increment of activity and solubility in 1,4-dioxane of lipase B from Candida antarctica, lipase from Pseudomonas cepacia, and subtilisin, were investigated as a function of the methoxypoly(ethylene glycol)-protein (PEG-protein) ratio employed during lyophilization. Both activity and solubility markedly increased as the PEG-protein ratio was increased. The increment of activity at low PEG-protein ratios, however, was much higher than that of solubility. These data suggest that the PEG-induced activation effect is due mainly to a lyoprotection effect rather than to relaxation of diffusional limitations.
- Secundo, Francesco,Carrea, Giacomo,Veronese, Francesco Maria
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- A powerful tool for acid catalyzed organic addition and substitution reactions
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A novel green chemistry tool for acid catalyzed reactions has been developed. The multipurpose tool is based on the ability of dry solid materials to donate protons (H+) to starting materials combined with the simultaneous use of a nucleophile (e.g. NaI). The methods enable the following reactions to be conducted at 20-50 °C: selective addition of iodine or alcohols to more substituted carbon in R2CCH2 systems (R ≠ H), esterification reactions, e.g. free fatty acids with methanol, and at higher temperatures, (60-100 °C): esterification of free fatty acids with hindered alcohols (isopropanol), addition of iodine to CC bonds, opening of oxygen(s) containing heterocyclic rings, selective substitution of primary OH groups to iodine in the presence of other functional groups or secondary alcohol groups, esterification of alcohols with nitriles (R-CN), transesterification of fatty acid triglycerides to biodiesel and selective derivatization of primary hydroxyl groups (-CH2OH) over secondary moieties of sugars without any protection. Most of the reactions were also performed by a re-used Dowex cation exchange resin.
- Turhanen, Petri A.,Veps?l?inen, Jouko J.
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- Erbium(III) triflate as an extremely active acylation catalyst
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Erbium(III) triflate is a powerful catalyst for the acylation of alcohols and phenols. The reaction works well for a large variety of simple and functionalized substrates by using different kinds of acidic anhydrides {Ac 2O, (EtCO)2O, [(CH3)3CO] 2O, Bz2O, and (CF3CO)2O} without isomerisation of chiral centres. Moreover, the catalyst can be easily recycled and reused without significant loss of activity.
- Procopio, Antonio,Dalpozzo, Renato,De Nino, Antonio,Maiuolo, Loredana,Russo, Beatrice,Sindona, Giovanni
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- ALKYLATION OF ANIONS ON SOLID INORGANIC SUPPORTS : AN INTERPRETATION OF THE FUNCTIONS OF THE SUPPORTS
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In the anionic alkylation (CH3CO2K + n C8H17Br) on solid inorganic supports, silica impregnated with cationic surfactant appear to be as effective as alumina, while silica bearing ammonium groups covalently bonded to the support (SPHEROSIL QMA) exhibits increased effectiveness.An interpretation based upon the superficial charge of the solid surfaces is proposed.
- Bram, G.,Decodts, G.
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- INORGANIC SOLIDS IN "DRY MEDIA" AN EFFICIENT WAY FOR DEVELOPING MICROWAVE IRRADIATION ACTIVATED ORGANIC REACTIONS
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"Dry media" microwave irradiation accelerates pinacol rearrangement (on montmorillonite) or acetate alkylation (on alumina or silicagel) without the hazards due to high pressures in vessels when using solvents.
- Gutierrez, E.,Loupy, A.,Bram, G.,Ruiz-Hitzky, E.
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- Interface synthesis, characterization and catalytic properties of dialkyldichlorotin and tetraalkyl distannoxane functionalities grafted to insoluble polystyrene beads by a hexamethylene spacer
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Insoluble polystyrene-grafted compounds of the type [(P-H) (1-t){P-(CH2)6SnBuCl2}t] and [(P-H)(1-t)({P-(CH2)6-SnBuX} 2O)t/2], where (P-H) represents a cross-linked polystyrene, X is Cl, OH or OOCCH3, and t is the degree of functionalization, were synthesized from Amberlite XE-305, a polystyrene cross-linked with divinylbenzene. The compounds were characterized by elemental analysis, IR and Raman spectroscopy, solid-state 13C and 117Sn NMR spectroscopy and, where appropriate, by 119Sn hr-MAS NMR spectroscopy. The influence of the variable t and tin functionality on the catalytic activity of these compounds was assessed in the transesterification reaction of ethyl acetate with octanol. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Biesemans, Monique,Mercier, Frederic A. G.,Van Poeck, Manu,Martins, Jose C.,Dumartin, Gilles,Willem, Rudolph
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- A new Br?nsted acid MIL-101(Cr) catalyst by tandem post-functionalization; synthesis and its catalytic application
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A new heterogeneous Br?nsted solid acid catalyst was prepared by tandem post-functionalization of MIL-101(Cr) and utilized for acetic acid esterification and alcoholysis of epoxides under solvent-free conditions. First, MIL-101(Cr) was functionalized with pyrazine to achieve MIL-101(Cr)-Pyz. Afterwards, the nucleophilic reaction of MIL-101(Cr)-Pyz with 1,3-propane sultone and next acidification with diluted sulfuric acid gave MIL-101(Cr)-Pyz-RSO3H Br?nsted solid acid catalyst. Various characterization methods such as Fourier transformation infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), elemental analysis (CHNS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersiveX-ray(EDX) spectroscopy, thermal analysis (TGA/DTA), acid–base titration, and N2 adsorption/desorption analysis were employed to fully characterize the prepared catalyst. The catalyst showed high activity compared to unmodified MIL-101(Cr) in both catalytic acetic acid esterification and alcoholysis of epoxides. It can also be readily isolated from the reaction mixture and reused three times without major decrease in its activity.
- Mortazavi, Saeideh-Sadat,Abbasi, Alireza,Masteri-Farahani, Majid
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- N-bromosuccinimide (NBS), a novel and highly effective catalyst for acetylation of alcohols under mild reaction conditions
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A variety of alcohols were acetylated in good to excellent yields with acetic anhydride in the presence of a catalytic N-bromosuccinimide (NBS) in CH2Cl2 and at room temperature. The reactions are clean and almost in all cases no detectable byproduct were observed.
- Karimi,Seradj
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- A carbonyl oxide route to antimalarial Yingzhaosu A analogues: Synthesis and antimalarial activity
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Ozonolysis of R-carvone and in situ trapping with primary alcohols ROH (R = Me, Et, Bu, Pent, Oct) produces hydroperoxy ketals (5a-e) as a 1:1 mixture of diastereomers. Cyclisation of these intermediates with catalytic sodium methoxide in methanol produces the corresponding endoperoxide derivatives (6a-6e). The pentyl and octyl endoperoxide derivatives demonstrate reasonable antimalarial potency in vitro against the HB3 strain of Plasmodium falciparum. A mechanism for antimalarial action involving the formation of a C-centred radical is proposed.
- O'Neill, Paul M.,Searle, Natalie L.,Raynes, Kaylene J.,Maggs, James L.,Ward, Stephen A.,Storr, Richard C.,Park, B.Kevin,Posner, Gary H.
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- Efficient cenosphere supported catalyst for the esterification of n-octanol with acetic acid
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An efficient heterogeneous acid catalyst was developed using cenospheres, a byproduct of coal-fired thermal power plants by the method of wet impregnation. Catalyst characterization was carried out using various analytical techniques, namely, Fourier transform infrared, X-ray diffraction, field emission gun scanning electron microscopy and Brunauer–Emmett–Teller surface area and surface acidity analysis. The characterization revealed the excellent catalytic activity of the catalyst for the esterification reaction of n-octanol and acetic acid. Various reaction parameters, namely, catalyst loading, a molar ratio of alcohol/acid and reaction temperature were evaluated and optimized by response surface methodology using the Box–Behnken model. The response surface methodology model equations corresponding to the conversion of acid and % yield of ester were developed. The model well predicted the optimal reaction conditions, which were validated experimentally with good agreement. The excellent catalytic performance was observed in the esterification reaction with high conversion of acid (95.34%) and high yield of n-octyl acetate (94.81%). Reusability study of the catalyst showed that the catalyst could be used efficiently up to three reaction cycles. This study explores the use of cenospheres to prepare a solid acid catalyst for the industrially important esterification reactions.
- Chandane, Vishal S.,Rathod, Ajit P.,Wasewar, Kailas L.,Sonawane, Shriram S.
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- Phase-Transfer Catalysis by Poly(ethylene glycol)s of β-Thioethyl Chloride Reactions
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Neighboring sulfur participation is a facile process for β-thioethyl derivatives.In the present work we examine the ability of phase-transfer catalysis by poly(ethylene glycol)s to make direct substitution, elimination, and oxidation competitive with neighboring sulfur participation for reaction of mustard chlorohydrin (1).
- Harris, J. Milton,Paley, M. Steven,Sedaghat-Herati, M. R.,McManus, Samuel P.
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- A novel 3-nitrobenzeneboronic acid as an extremely mild and environmentally benign catalyst for the acetylation of alcohols under solvent-free conditions
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A novel 3-nitrobenzeneboronic acid is found to catalyse efficiently the acetylation of a wide range of alcohols as well as phenols with acetic anhydride in good to excellent yields at room temperature under solvent-free conditions. The reactions are clean and the catalyst is mild such that highly sensitive functional groups including oximes are stable to the reaction conditions.
- Tale,Adude
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- Partial purification of Nigella sativa L. seed lipase and its application in transesterification reactions
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Nigella sativa L. seed lipase isolated from defatted seeds was partially purified and used as catalyst in transesterification reactions. Purification of an ammonium sulfate-precipitated sample (at 35% saturation, Nigella PL) by DEAE ion-exchange chromatography increased the specific activity from 13.9 to 156.7 U/mg protein. Nigella PL and Nigella CPL (the partially purified enzyme sample obtained by DEAE ion-exchange chromatography) catalyzed the transesterification of vinyl acetate with octanol, with racemic sulcatol (6-methyl-5-hepten-2-ol), and with racemic trans-sobrerol (trans-p-menth-6-ene-2,8-diol) in different organic solvents. Both activity and enantioselectivity of the enzyme samples used for these biotransformations were affected by the nature of the organic solvent.
- Tuter, Melek,Secundo, Francesco,Riva, Sergio,Ayse Aksoy,Ustun, Guldem
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- Selective acylation of aliphatic alcohols in the presence of phenolic hydroxyl groups
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A new and efficient method for the selective acylation of aliphatic hydroxyl groups in the presence of phenolic groups using a mixture of trimethyl orthoacetate and trimethylsilyl chloride at room temperature is reported. The reactions are selective, high yielding and complete within 3-6 h.
- Sabitha, Gowravaram,Subba Reddy, Basi V.,Kiran Kumar Reddy, Garudammagari S.,Yadav, Jhillu S.
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- Grafted Polyethylene Glycol–Graphene Oxide as a Novel Triphase Catalyst for Carbenes and Nucleophilic Substitution Reactions
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Abstract: Separation and reusability had been main problems for the using of polyethylene glycol (PEG) as phase transfer catalysts (PTCs). To solve these problems, PEG was firstly and successfully grafted on graphene oxide (GO) using BF3·C2H5OC2H5 as Lewis acid catalyst. The solid GO-PEG composites were systemically investigated by characterization techniques (TG, FT-IR, XPS, ICP-AES etc.) and then applied to some carbenes and nucleophilic substitution reactions as novel triphase catalysts. As the results, GO-PEG showed not only equally excellent catalytic activity (≥ 93% yield of 7,7-dichlorobicyclo[4.1.0]heptane and iodooctane) but also incomparable reusability (≥ 85% yield of iodooctane after using for four times) in comparison with traditional PTCs (PEG). Graphic Abstract: [Figure not available: see fulltext.].
- Yang, Xiaohai,Zhai, Jie,Xu, Tongchun,Xue, Bing,Zhu, Jie,Li, Yongxin
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- Scope and limitations of the use of grafted undecyltin trichloride as a catalyst for transesterifications: Effect of tin loading on catalytic activity, recyclability, and leaching
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The effect of the tin loading (functionalization degree t) on the catalytic activity and recyclability is investigated for a polystyrene-grafted undecyltin trichloride catalyst, P-C11-SnCl3, in transesterification reactions involving either a primary or a secondary alcohol. For the latter, the achieved conversion degree in the first run is about 20% lower than with the primary alcohol. In subsequent runs, the reaction rates are strongly influenced by the tin loading of the catalyst. Unlike low-loaded P-C11-SnCl3 catalysts (t ≈ 0.10), high-loaded catalysts (t ≈ 0.20) display a simultaneous T g increase (from 53 °C to 107 °C after 5 runs) and conversion decrease (from 52% to 15%) upon increasing number of runs, ascribed to reduced mobility of the organotin moieties resulting from undesired cross-linking at the reaction interface. Confirmation for the fact that, in this case, the catalytic performance is dominated by conformational mobility issues is found in the comparison between transesteriflcations involving either primary or secondary alcohols. Whereas a Tg increase is not associated with a reduced conversion degree for primary alcohols, a clear decrease in conversion is observed for secondary alcohols, illustrating that steric issues are especially pronounced in a low-mobility (high-loaded) system and are of no importance in high-mobility (low-loaded) systems. This also affects the leaching resistance of the compounds, the high-loaded catalysts displaying substantially higher tin leaching (311 ± 278 ppm) than the low-loaded ones (10 ± 8 ppm).
- Pinoie, Vanja,Biesemans, Monique,Willem, Rudolph
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- Method for synthesizing ester through catalytic esterification of ionic liquid
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The invention relates to a method for synthesizing ester through catalytic esterification of ionic liquid. The method comprises the following step: carrying out an esterification reaction on carboxylic acid and an organic matter containing a hydroxyl group under the catalysis of the ionic liquid to obtain an esterification product, wherein the general formula of the ionic liquid is [Bu3PR]N(CF3SO2)2, and R is a C8-C16 straight chain or branched chain alkyl group. According to the above technical scheme, the method for synthesizing the ester through catalytic esterification of the ionic liquid is high in catalyst catalytic activity, high in reaction selectivity, few in by-products, high in reaction rate and high in catalyst recycling performance.
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Paragraph 0028-0030; 0035-0039
(2021/06/22)
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- ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
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An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
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Paragraph 0013; 0028
(2021/01/29)
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- A New Protocol for Catalytic Reduction of Alkyl Chlorides Using an Iridium/Bis(benzimidazol-2′-yl)pyridine Catalyst and Triethylsilane
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The reduction of alkyl chlorides using triethylsilane is investigated. Primary, secondary, tertiary, and benzylic C-Cl bonds are effectively converted into C-H bonds using an [IrCl(cod)] 2/2,6-bis(benzimidazol-2′-yl)pyridine catalyst system. This catalyst system is quite simple since the tridentate N-ligand can be easily prepared in one step from commercially available reagents.
- Fukuyama, Takahide,Hamada, Yuki,Ryu, Ilhyong
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p. 3404 - 3408
(2021/07/14)
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- Second-Generation meta-Phenolsulfonic Acid-Formaldehyde Resin as a Catalyst for Continuous-Flow Esterification
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A second-generation m-phenolsulfonic acid-formaldehyde resin (PAFR II) catalyst was prepared by condensation polymerization of sodium m-phenolsulfonate and paraformaldehyde in an aqueous H2SO4 solution. This reusable, robust acid resin catalyst was improved in both catalytic activity and stability, maintaining the characteristics of the previous generation catalyst (p-phenolsulfonic acid-formaldehyde resin). PAFR II was applied in the batchwise and continuous-flow direct esterification without water removal and provided higher product yields in continuous-flow esterification than any other commercial ion-exchanged acid catalyst tested.
- Hu, Hao,Ota, Hajime,Baek, Heeyoel,Shinohara, Kenta,Mase, Toshiaki,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
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supporting information
p. 160 - 163
(2020/01/02)
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- Accelerating Biphasic Biocatalysis through New Process Windows
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Process intensification through continuous flow reactions has increased the production rates of fine chemicals and pharmaceuticals. Catalytic reactions are accelerated through an unconventional and unprecedented use of a high-performance liquid/liquid counter current chromatography system. Product generation is significantly faster than in traditional batch reactors or in segmented flow systems, which is exemplified through stereoselective phase-transfer catalyzed reactions. This methodology also enables the intensification of biocatalysis as demonstrated in high yield esterifications and in the sesquiterpene cyclase-catalyzed synthesis of sesquiterpenes from farnesyl diphosphate as high-value natural products with applications in medicine, agriculture and the fragrance industry. Product release in sesquiterpene synthases is rate limiting due to the hydrophobic nature of sesquiterpenes, but a biphasic system exposed to centrifugal forces allows for highly efficient reactions.
- Huynh, Florence,Tailby, Matthew,Finniear, Aled,Stephens, Kevin,Allemann, Rudolf K.,Wirth, Thomas
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supporting information
p. 16490 - 16495
(2020/07/17)
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- A rings-in-pores net: Crown ether-based covalent organic frameworks for phase-transfer catalysis
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We herein present a new family of crown ether-based covalent organic frameworks (CE-COFs) for the first time. The CE-COFs show excellent phase-transfer catalytic performance in various nucleophilic substitution reactions.
- Guo, Wen-Di,Hu, Bingwen,Jiang, Wei-Ling,Lou, Xiaobing,Ma, De-Li,Qi, Qiao-Yan,Shen, Ji-Chuang,Shen, Ming,Yang, Hai-Bo,Zhao, Xin
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supporting information
p. 595 - 598
(2020/01/29)
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- Synthesis of task-specific imidazolium ionic liquid as an efficient catalyst in acetylation of alcohols, phenols, and amines
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Herein, we report the synthesis of task-specific amino-functionalized imidazolium ionic liquid, acetate1-(2-tert-butoxycarbonylamino-ethyl)-3-methyl-3H-imidazol-1-ium; (Boc-NH-EMIM.OAc), as an efficient catalyst for the acetylation of alcohols, phenols, and amines in the presence of acetic anhydride (acetylating reagent). Remarkably, acetic anhydride in the presence of 10?molpercent of catalyst (Boc-NH-EMIM.OAc) under solvent-free conditions showed excellent acetylation activity in shorter duration of time. On the basis of this, a general procedure for acetylation of alcohols, phenols, and amines has been developed. The ionic liquid (Boc-NH-EMIM.OAc) can be readily recovered and reused successfully up to four consecutive cycles without any significant loss of its catalytic activity. We have been able to show that this acetylating method has many advantages. It gives high yields, takes shorter time, and develops the possibility of benign environmental-friendly process.
- Chaubey, Snehkrishn A.,Mishra, Roli
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p. 3259 - 3268
(2020/04/17)
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- Application of Yttrium Iron Garnet as a Powerful and Recyclable Nanocatalyst for One-Pot Synthesis of Pyrano[2,3-c]pyrazole Derivatives under Solvent-Free Conditions
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The application of yttrium iron garnet (YIG) superparamagnetic nanoparticles as a new recyclable and highly efficient heterogeneous magnetic catalyst for one-pot synthesis of pyrano[2,3-c]pyrazole derivatives under solvent-free conditions, as well as etherification and esterification reactions are described. The advantages of the proposed method include the lack of organic solvents, clean reaction, rapid removal of the catalyst, short reaction times, excellent yields, and recyclability of the catalyst.
- Sedighinia,Badri,Kiasat
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p. 1755 - 1763
(2020/01/11)
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- Amide/Iminium Zwitterionic Catalysts for (Trans)esterification: Application in Biodiesel Synthesis
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A class of zwitterionic organocatalysts based on an amide anion/iminium cation charge pair has been developed. The zwitterions are easily prepared by reacting aziridines with aminopyridines. They are catalytically applicable to transesterifications and dehydrative esterifications. Mechanistic studies reveal that the amide anion and iminium cation work synergistically in activating the reaction partners, with the iminium cationic moiety interacting with the carbonyl substrates through nonclassical hydrogen bonding. The reaction can be applied to large-scale synthesis of biodiesel under mild conditions.
- Lam, Ying-Pong,Ng, Wing-Hin,Tan, Fei,Tse, Ying-Lung Steve,Wang, Xinyan,Yeung, Ying-Yeung
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p. 8083 - 8092
(2019/08/26)
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- Oxidative esterification of aliphatic aldehydes and alcohols with ethanol over gold nanoparticle catalysts in batch and continuous flow reactors
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Selective esterification of aliphatic aldehydes and alcohols with ethanol in the absence of a base is a more difficult reaction than that with methanol. Gold nanoparticles on ZnO were found to catalyze the oxidative esterification of octanal to ethyl octanoate with high selectivity. In addition, it was found that Au/ZnO was the most effective catalyst for yielding the desired ethyl ester without a base by direct esterification of 1-octanol with ethanol. As far as we know, this is the first report on oxidative esterification to give aliphatic ethyl esters from less reactive aliphatic alcohols and aldehydes without a base. The optimal size of gold NPs ranged from 2 to 6 nm and the presence of Au(0) was indispensable for this reaction. Au/ZnO exhibited the highest catalytic activity in both batch and flow reactors. The conversion was maintained for more than 20 h with 95% selectivity to the desired ethyl ester in the flow system.
- Taketoshi,Ishida,Murayama, Toru,Honma, Tetsuo,Haruta, Masatake
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- Manganese-mediated acetylation of alcohols, phenols, thiols, and amines utilizing acetic anhydride
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Manganese(II) chloride-catalyzed acetylation of alcohols, phenols thiols and amines with acetic anhydride is reported. This method is environment-friendly and economically viable as it involves inexpensive, relatively benign catalyst, mild reaction condition, and simple workup. Acetylation is performed under the solvent-free condition at ambient temperature and acetylated products obtained in good to excellent yields. Primary, secondary heterocyclic amines, and phenols with various functional groups are smoothly acetylated in good yields. This method exhibits exquisite chemoselectivity, the amino group is preferentially acetylated in the presence of a hydroxyl/thiol group.
- Jain, Isha,Sharma, Ramandeep,Malik, Payal
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supporting information
p. 2952 - 2960
(2019/09/13)
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- Selective hydrodeoxygenation of biomass-derived furfural-acetone to prepare 1-octyl acetate
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A green and efficient catalytic system for the one-pot production of 1-octyl acetate from biomass-derived furfural-acetone (FFA) under mild conditions was developed by selective hydrodeoxygenation over Pd/C and Sc(OTf)3 as a cocatalytic system in acetic acid. The effects of reaction conditions on product distribution have been systematically investigated. The highest 1-octyl acetate yield of 90% can be obtained under mild conditions (150 °C, 2 MPa H2, 2 h). Tetrahydrofuran ring opening and ester bond selective cleavage were found to be the key steps. In these steps, due to its suitable Lewis acidity, Sc(OTf)3 can not only promote ring-opening esterification but also selectively activate the secondary alcohol ester bond to achieve high selectivity for 1-octyl acetate. NMR and MS methods were utilized to investigate the reaction process. In addition, after 8 cycles of the Pd/C catalyst, the 1-octyl acetate yield gradually decreased from 90% to 80%. The decrease, according to XPS determination, in catalytic efficiency of the Pd/C catalyst was mainly due to the partial oxidation of metal Pd through air contact during post-treatment.
- Liu, Xuyang,Li, Yanbing,Deng, Jin,Fu, Yao
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supporting information
p. 4532 - 4540
(2019/08/22)
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- Esterification of Tertiary Amides by Alcohols Through C?N Bond Cleavage over CeO2
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CeO2 has been found to promote ester forming alcoholysis reactions of tertiary amides. The present catalytic system is operationally simple, recyclable, and it does not require additives. The esterification process displays a wide substrate scope (>45 examples; up to 93 % isolated yield). Results of a density functional theory (DFT) study combined with in situ FT-IR observations indicate that the process proceeds through rate limiting addition of a CeO2 lattice oxygen to the carbonyl group of the adsorbed acetamide species with energy barrier of 17.0 kcal/mol. This value matches well with experimental value (17.9 kcal/mol) obtained from analysis of the Arrhenius plot. Further studies by in situ FT-IR and temperature programmed desorption using probe molecules demonstrate that both acidic and basic properties are important, and consequently, CeO2 showed the best performance for the C?N bond cleavage reaction.
- Toyao, Takashi,Nurnobi Rashed, Md.,Morita, Yoshitsugu,Kamachi, Takashi,Hakim Siddiki,Ali, Md. A.,Touchy,Kon, Kenichi,Maeno, Zen,Yoshizawa, Kazunari,Shimizu, Ken-ichi
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p. 449 - 456
(2018/09/11)
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- Lipase-mediated selective acetylation of primary alcohols in ethyl acetate
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An environmental friendly process to selectively acetylate primary alcohols was demonstrated. The esterification process consists of treatment of a primary alcohol in the presence of immobilized C. antarctica lipase (Novozyme-435) in ethyl acetate at room temperature. Primary alcohols were acetylated in the presence of secondary alcohols and phenols.
- de Souza, Ernane C.,Romero-Ortega, Moises,Olivo, Horacio F.
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supporting information
p. 287 - 290
(2017/12/29)
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- Ester Synthesis in Water: Mycobacterium smegmatis Acyl Transferase for Kinetic Resolutions
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The acyl transferase from Mycobacterium smegmatis (MsAcT) catalyses transesterification reactions in aqueous media because of its hydrophobic active site. Aliphatic cyanohydrin and alkyne esters can be synthesised in water with excellent and strikingly opposite enantioselectivity [(R);E>37 and (S);E>100, respectively]. When using this enzyme, the undesired hydrolysis of the acyl donor is an important factor to take into account. Finally, the choice of acyl donor can significantly influence the obtained enantiomeric excesses. (Figure presented.).
- de Leeuw, Nicolas,Torrelo, Guzman,Bisterfeld, Carolin,Resch, Verena,Mestrom, Luuk,Straulino, Emanuele,van der Weel, Laura,Hanefeld, Ulf
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p. 242 - 249
(2017/11/16)
-
- Enzymatic chemical transformations of aldehydes, ketones, esters and alcohols using plant fragments as the only biocatalyst: Ximenia americana grains
-
The present study demonstrated the ability of Ximenia american as a biocatalyst in reduction, hydrolysis and esterification reactions. The reduction reactions of aldehydes and ketones, ester hydrolysis and esterification of alcohols were carried out with interesting results. Reduction of ketones afforded yields of 6–60% with ee in the range of 35–>99% and that of aldehydes in yields of 51–99%. On the other hand, ester hydrolysis afforded yields of 58–98% with ee in the range 34–87%, while esterification of alcohols in 18–99% yields. Experimental conditions for all reactions have been defined using standard substrates as indicated in results and discussion. Some of the products are the potential building blocks for the synthesis of molecules which are of pharmaceutical and agrochemical importance.
- da Silva, Romézio Alves Carvalho,de Mesquita, Bruna Marques,de Farias, Iolanda Frota,do Nascimento, Patrícia Georgiana Garcia,de Lemos, Telma Leda Gomes,Queiroz Monte, Francisco José
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p. 187 - 194
(2018/01/05)
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- Biogenic CuFe2O4 magnetic nanoparticles as a green, reusable and excellent nanocatalyst for acetylation reactions under solvent-free conditions
-
A convenient green method has been developed for the synthesis of biogenic CuFe2O4 magnetic nanoparticles using tea extracts within a very short reaction time. The prepared nanoparticles with an average size of 8.78 nm have been used as an effective catalyst for the acetylation of various alcohols, phenols and amines in good to excellent yields under solvent-free conditions. The catalyst was characterized by XRD, XPS, VSM, SEM and TEM study. A magnetic study of the fresh and recycled catalyst after the fourth cycle was performed by VSM measurement. The main advantages of this protocol are simple biogenic synthesis of the catalyst, a reusable and heterogeneous catalytic system, and short reaction times with excellent yields.
- Chutia, Rituparna,Chetia, Bolin
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p. 15200 - 15206
(2018/09/29)
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- Method for synthesizing ester through quaternary phosphonium salt ionic liquid catalyzed esterification
-
The invention discloses a method for synthesizing an ester through quaternary phosphonium salt ionic liquid catalyzed esterification. The method is characterized in that the esterification product is obtained through an esterification reaction of carboxylic acid and a hydroxyl group-containing organic matter under the catalysis of a quaternary phosphonium salt ion liquid, wherein the general formula of the quaternary phosphonium salt ion liquid is [Bu3PR]X, R is a C6-C16 linear or branched alkyl group, and X is a p-C7H7SO, CF3SO, HSO or H2PO. The method for synthesizing the ester through quaternary phosphonium salt ionic liquid catalyzed esterification has the advantages of high catalytic activity, high reaction selectivity, few byproducts, and high recycling performance of the catalyst.
- -
-
Paragraph 0073-0079; 0082-0085
(2017/08/31)
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- Ethyl acetate as an acetyl surrogate for the iodine catalyzed acetylation of alcohols
-
The use of readily available ethyl acetate in the presence of iodine as an alternative acetylating agent is reported. Amines and phenols were unreactive under the examined reaction conditions, indicating that the method is highly chemoselective.
- Basumatary, Grace,Bez, Ghanashyam
-
supporting information
p. 4312 - 4315
(2017/10/13)
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- By using low-temperature co- melt solvent a method of catalytic ester (by machine translation)
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The invention discloses a method of utilizing low-temperature co- melt solvent catalytic ester method, will be 0.05-0.5 mole of sharemelt solvent of low-temperature co-preprocessing, 1-5 mole of share alcohol and 1-10 mole of share of acid in the reaction vessel, stirring and heating, 25-200 ° C reaction under 2-96h, then the reaction fluid settlement , liquid, organic is accepted after passing an examination the level , get the esterification reaction products of the; reaction after the treatment and recovery of low-temperature co- melt solvent the preprocessing, can be reused. This invention utilizes the easy preparation of low-temperature co- melt solvent the preprocessing of catalytic esterification reaction, the reaction front is homogeneous, can be formed after the reaction of the two-phase reaction in the process of direct dehydration, without adding other dehydrating agent, has the advantages of simple operation, the reaction efficiency is high, corrosion of small equipment, less side reactions, the product quality is good, no pollution to the environment, and the like, it has broad application prospects. (by machine translation)
- -
-
Paragraph 0038; 0039
(2017/01/17)
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- Deep eutectic solvent choline chloride·2CrCl3·6H2O: An efficient catalyst for esterification of formic and acetic acid at room temperature
-
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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- A simple method for the removal of organotin residues from acetates and a homoallylic alcohol prepared from organostannane reagents: Column chromatography using 10%-moist SiO2
-
Simple column chromatography using 10%-moist silica gel enabled efficient removal of organotin residues from geranyl acetate, which was prepared by the acetylation of geraniol with vinyl acetate in the presence of a catalytic amount of a 1,3-dichloro-substituted tetrabutyldistannoxane. The desired acetate contained only 2.4 ppm of organotin residues. In sharp contrast to this, a similar purification method using dry silica as the stationary phase provided acetate containing ca. 5000 ppm of organotin residues.
- Nishida, Takanori,Matsuda, Daiki,Kasuga, Issei,Orita, Akihiro,Otera, Junzo
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p. 1280 - 1282
(2016/11/09)
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- Oxidative "reverse-esterification" of ethanol with benzyl/alkyl alcohols or aldehydes catalyzed by supported rhodium nanoparticles
-
A very unusual role of polystyrene stabilized rhodium (Rh@PS) nanoparticles as a supported catalyst is described for "reverse-esterification" of ethanol with benzyl/alkyl alcohols or aldehydes. Faster and selective oxidation of ethanol to acetaldehyde and H2 under Rh@PS catalyzed conditions which restricted further oxidation of benzyl/alkyl alcohols and their in situ reaction gave the corresponding acetate esters following the dehydrogenative-coupling approach. A hitherto redox dehydrogenative-coupling of ethanol and aldehydes has also been explored for the same acetate ester synthesis under Rh@PS catalyzed conditions.
- Guha, Nitul Ranjan,Sharma, Saurabh,Bhattacherjee, Dhananjay,Thakur, Vandna,Bharti, Richa,Reddy, C. Bal,Das, Pralay
-
supporting information
p. 1206 - 1211
(2016/03/09)
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- Characterization of a new Baeyer-Villiger monooxygenase and conversion to a solely N-or S-oxidizing enzyme by a single R292 mutation
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Background Ar-BVMO is a recently discovered Baeyer-Villiger monooxygenase from the genome of Acinetobacter radioresistens S13 closely related to medically relevant ethionamide monooxygenase EtaA (prodrug activator) and capable of inactivating the imipenem antibiotic. Methods The co-substrate preference as well as steady-state and rapid kinetics studies of the recombinant purified protein were carried out using stopped-flow spectroscopy under anaerobic and aerobic conditions. Kd values were measured by isothermal calorimetry. Enzymatic activity was determined by measuring the amount of product formed using high pressure liquid chromatography or gas chromatography. Site-directed mutagenesis experiments were performed to decipher the role of the active site arginine-292. Results Ar-BVMO was found to oxidize ethionamide as well as linear ketones. Mechanistic studies on the wild type enzyme using stopped-flow spectroscopy allowed for the detection of the characteristic oxygenating C4a-(hydro)peroxyflavin intermediate, which decayed rapidly in the presence of the substrate. Replacement of arginine 292 in Ar-BVMO by glycine or alanine resulted in greatly reduced or no Baeyer-Villiger activity, respectively, demonstrating the crucial role of this residue in catalysis of ketone substrates. However, both the R292A and R292G mutants are capable of carrying out N- and S-oxidation reactions. Conclusions Substrate profiling of Ar-BVMO confirms its close relationship to EtaA; ethionamide is one of its substrates. The active site Arginine 292 is required for its Baeyer-Villiger activity but not for heteroatom oxidation. General significance A single mutation converts Ar-BVMO to a unique S- or N-monooxygenase, a useful biocatalyst for the production of oxidized metabolites of human drug metabolizing enzymes.
- Catucci, Gianluca,Zgrablic, Ivan,Lanciani, Francesco,Valetti, Francesca,Minerdi, Daniela,Ballou, David P.,Gilardi, Gianfranco,Sadeghi, Sheila J.
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p. 1177 - 1187
(2016/07/11)
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- Structural and catalytic characterization of a fungal baeyer-villiger monooxygenase
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Baeyer-Villiger monooxygenases (BVMOs) are biocatalysts that convert ketones to esters. Due to their high regio-, stereo- and enantioselectivity and ability to catalyse these reactions under mild conditions, they have gained interest as alternatives to chemical Baeyer-Villiger catalysts. Despite their widespread occurrence within the fungal kingdom, most of the currently characterized BVMOs are from bacterial origin. Here we report the catalytic and structural characterization of BVMOAFL838 from Aspergillus flavus. BVMOAFL838 converts linear and aryl ketones with high regioselectivity. Steady-state kinetics revealed BVMOAFL838 to show significant substrate inhibition with phenylacetone, which was more pronounced at low pH, enzyme and buffer concentrations. Para substitutions on the phenyl group significantly improved substrate affinity and increased turnover frequencies. Steady-state kinetics revealed BVMOAFL838 to preferentially oxidize aliphatic ketones and aryl ketones when the phenyl group are separated by at least two carbons from the carbonyl group. The X-ray crystal structure, the first of a fungal BVMO, was determined at 1.9 A and revealed the typical overall fold seen in type I bacterial BVMOs. The active site Arg and Asp are conserved, with the Arg found in the ginh position. Similar to phenylacetone monooxygenase (PAMO), a two residue insert relative to cyclohexanone monooxygenase (CHMO) forms a bulge within the active site. Approximately half of the gvariableh loop is folded into a short ?-helix and covers part of the active site entry channel in the non-NADPH bound structure. This study adds to the current efforts to rationalize the substrate scope of BVMOs through comparative catalytic and structural investigation of different BVMOs.
- Ferroni, Felix Martin,Tolmie, Carmien,Smit, Martha Sophia,Opperman, Diederik Johannes
-
-
- Acyl transfer reactions of carbohydrates, alcohols, phenols, thiols and thiophenols under green reaction conditions
-
Acyl transfer reactions of various carbohydrates, alcohols, phenols, thiols and thiophenols were achieved at room temperature in high yields and catalytic efficiency in the presence of methane sulfonic acid, a green organic acid, under solvent-free conditions over short time periods. The method is mild enough to allow acid labile substituents such as isopropylidene acetals and trityl ethers on the reacting substrates to be left completely unaffected. Esterification of free mono- and dicarboxylic acids such as acetic acid, cinnamic acid, sialic acid and tartaric acid with alcohols such as menthol, ethanol, methanol or propylene glycol has also been achieved efficiently at room temperature. A comparative study of the method with the silica-sulfuric acid is also reported.
- Giri, Santosh Kumar,Kartha, K. P. Ravindranathan
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p. 11687 - 11696
(2015/02/19)
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- Sulfonic acid-functionalized periodic mesoporous organosilicas in esterification and selective acylation reactions
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The application of sulfonic acid-functionalized periodic mesoporous organosilicas (PMOs) having either phenyl (1a) or ethyl (1b) bridging groups was investigated in the esterification of a variety of alcohols and fatty acids. It was found that 1b consistently exhibited higher catalytic performance than 1a in the described reaction. In particular, it was proposed that the superior catalytic activity of 1b in esterification of fatty acids with methanol is a result of adequate hydrophobic-hydrophilic surface balance in the ethyl PMO catalyst. In addition, the study of chemoselective acylation of 1,3-butanediol with dodecanoic acid with varied mesoporous silica-supported solid sulfonic acids including both 1a and 1b implies that there is a compromise between the reaction selectivity and the surface physicochemical properties of the employed catalyst. Our results clearly show that the catalyst having high surface hydrophilic nature gives high selectivity toward the formation of mono-acylated products whereas those with relatively high hydrophobic characteristics showed enhanced selectivity toward the formation of di-acylated products.
- Karimi, Babak,Mirzaei, Hamid M.,Mobaraki, Akbar,Vali, Hojatollah
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p. 3624 - 3631
(2015/07/01)
-
- Continuous flow Fischer esterifications harnessing vibrational-coupled thin film fluidics
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Rapid Fischer esterification reactions occur under solventless, continuous flow conditions in dynamic thin films. This methodology uses limited catalyst, require no additional heat input and occurs within the confinements of an inexpensive vortex fluidic device (VFD). The associated mechanoenergy is primarily delivered from two types of vibration, which are manifested in sharp increases in the yield of the reactions. These vibrations promote the existence of Faraday waves that alter the instantaneous shear rates of the reactants within the rotating tube. Tuning the rotational speed of the device allows harmonic vibrations to be utilized in the synthesis of alkyl-based esters within both a high and low contact angle NMR tube. This journal is
- Britton, Joshua,Dalziel, Stuart B.,Raston, Colin L.
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p. 1655 - 1660
(2015/02/02)
-
- Synthesis of lipase nano-bio-conjugates as an efficient biocatalyst: Characterization and activity-stability studies with potential biocatalytic applications
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In the present study, we have synthesized lipase-nano-bio-conjugates via immobilization of various lipases on multiwall carbon nano-tubes (MCNT), in order to construct an efficient and recyclable biocatalytic system. In a screening study lipase Pseudomonas fluorescens (PFL) acted as an efficient biocatalyst (lipase-nano-bio-conjugates) which showed higher retention of lipase activity and protein loading. Consequently the immobilization support : lipase (MCNT : PFL) composition was screened in which MCNT : PFL (2 : 1) was calculated as a robust biocatalyst composition which showed higher activity retention and protein loading. This nano-bio-conjugate was then characterized in detail with physical and biochemical techniques using SEM, TEM, FTIR, Km, Vmax, catalytic efficiency and (%) water content analysis. This developed biocatalyst was further used for practical biocatalytic applications such as O-acylation reactions. Various reaction parameters were optimized in detail like reactant molar ratio (2 : 3.5), solvent, MCNT : PFL biocatalyst amount (36 mg), temperature (50°C) etc. The developed biocatalytic protocol was then extended to synthesize several (twenty-two) industrially important acylated moieties with an excellent yield, these products are well characterized by 1HNMR, 13CNMR and GCMS analysis. Moreover in the present study, we have reviewed the potential industrial applications of various synthesized compounds. Also, we have studied the thermodynamic aspect which demonstrated more feasibility of use of immobilized MCNT : PFL lipase over free lipase. Interestingly, immobilized MCNT : PFL lipase showed 2.3 fold higher catalytic activity than free PFL. Besides this, the biocatalyst was efficiently recycled for up to five cycles. Thus the present protocol demonstrated, (i) synthesis of nano-bio-conjugates as a bio-catalyst, (ii) detailed physical-biochemical characterization of nano-bio-conjugates, (iii) optimization of the biocatalytic protocol (iv) practical biocatalytic applications along with a mechanistic study (v) a thermodynamic feasibility study and (vi) recyclability study. 2015
- Badgujar, Kirtikumar Chandulal,Sasaki, Takehiko,Bhanage, Bhalchandra Mahadeo
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p. 55238 - 55251
(2015/07/07)
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- Visible-light-promoted conversion of alkyl benzyl ether to alkyl ester or alcohol via O-α-sp3 C-H cleavage
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A mild and high-yielding visible-light-promoted conversion of alkyl benzyl ethers to the alkyl esters or alkyl alcohols was developed. Mechanistic studies provided evidence for a radical chain reaction involving the homolytic cleavage of O-α-sp3 C-H bonds in the substrate as one of the propagation steps. We propose that α-bromoethers are key intermediates in the transformation.
- Lu, Ping,Hou, Tianyuan,Gu, Xiangyong,Li, Pixu
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p. 1954 - 1957
(2015/04/27)
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- FUNCTIONALISED MATERIALS, PROCESS FOR THE PRODUCTION AND USES THEREOF
-
The invention relates both to processes for the production of functionalised materials containing alkyl sulfonic acids groups and their use as heterogeneous catalysts. The invention also relates to precursors of these new products and new organopolysiloxane sulfonic acids.
- -
-
Paragraph 0041; 0059
(2015/04/22)
-
- Polystyrene trimethyl ammonium chloride impregnated Rh(0) (Rh@PMe3NCl) as a catalyst and methylating agent for esterification of alcohols through selective oxidation of methanol
-
Rhodium(0) nanoparticle (NP)-impregnated polystyrene trimethyl ammonium chloride (PMe3NCl) resin (Rh@PMe3NCl) under basic conditions acts as a cross-dehydrogenative coupling-methylating (CDCM) agent for the selective oxidation of methanol and its in situ reaction with benzyl/alkyl alcohols allowing methyl group transfer for acetate ester synthesis in a tandem approach. The redox property of methanol which restricts the oxidation of benzyl/alkyl alcohols for product formation is critically investigated.
- Guha, Nitul Ranjan,Bhattacherjee, Dhananjay,Das, Pralay
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p. 2575 - 2580
(2015/06/30)
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- Synthesis of sulfonic acid containing ionic-liquid-based periodic mesoporous organosilica and study of its catalytic performance in the esterification of carboxylic acids
-
A new sulfonic acid containing ionic-liquid-based periodic mesoporous organosilica (PMO-IL-SO3H) material was prepared and its catalytic application was investigated in the esterification of carboxylic acids with alcohols. The PMO-IL-SO3H nanocatalyst was first characterized with diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and nitrogen sorption analysis. Then, the catalytic performance of this material was studied in the esterification of carboxylic acids with short- and long-chain aliphatic alcohols, cyclic alcohols, and benzylic alcohols under solvent-free conditions. The results showed that the catalyst has superior activity for the conversion of several alcohols to afford the corresponding ester products in excellent yields and high purity. Moreover, the catalyst could be recovered and reused several times without a significant decrease in activity and product selectivity. Copyright
- Elhamifar, Dawood,Karimi, Babak,Moradi, Abbas,Rastegar, Javad
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p. 1147 - 1152
(2014/10/16)
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- A method for esterification reaction rate prediction of aliphatic monocarboxylic acids with primary alcohols in 1,4-dioxane based on two parametrical taft equation
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Esterification reaction rates of aliphatic monocarboxylic acids with primary alcohols in 1,4-dioxane as inert solvent were investigated. Acids were esterified with 1-propanol and alcohols with acetic acid as model reactants at a constant temperature of 60°C, at a fixed ionic strength and pH in a batch reactor with a constant volume. For evaluation of reaction rates, an exact kinetic equation for the equilibrium reaction was applied. Under these conditions and for low reactants, concentrations reaction rate depends only on the structure of reactants and, therefore, can be predicted by a correlation equation with two Taft coefficients (inductive and steric effects). From these equations, it is possible to estimate the esterification reaction rate constant for other acid-alcohol pairs. This methodology may also be suitable for other kinetic systems measured under comparable experimental conditions.
- Vojtko, Jan,Tomcik, Peter
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p. 189 - 196
(2014/02/14)
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- Fractional distribution of graphene oxide and its potential as an efficient and reusable solid catalyst for esterification reactions
-
Graphene oxide (GrO) prepared by the Hummers method was separated into three different fractions (GrO5000, GrO2000, and GrOres) on the basis of their dispersion stability in the water. Infrared, nuclear magnetic resonance, X-ray photoelectron spectroscopy, and elemental analyses revealed that GrO5000 possesses a high degree of oxygen functionalities including phenolic, carboxylic, and -OSO2H groups, compared with the other fractions. The GrO5000 was found to be a highly efficient and reusable solid catalyst for the esterification of various carboxylic acids with a variety of alcohols to furnish corresponding esters in high to excellent yields. The catalytic activity of the GrO5000 was attributed to the ability of highly polar GrO5000 scaffold to adsorb/attract reactants, where the acid functionalities of GrO5000 facilitated the esterification process efficiently. The chemical and structural features of GrO5000 were discussed to understand the improved catalytic activity compared with GrO2000 and conventional solid acid catalysts.
- Mungse, Harshal P.,Bhakuni, Niharika,Tripathi, Deependra,Sharma, Om P.,Sain, Bir,Khatri, Om P.
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p. 944 - 951
(2015/02/02)
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- Fractional distribution of graphene oxide and its potential as an efficient and reusable solid catalyst for esterification reactions
-
Graphene oxide (GrO) prepared by the Hummers method was separated into three different fractions (GrO5000, GrO2000, and GrOres) on the basis of their dispersion stability in the water. Infrared, nuclear magnetic resonance, X-ray photoelectron spectroscopy, and elemental analyses revealed that GrO5000 possesses a high degree of oxygen functionalities including phenolic, carboxylic, and -OSO2H groups, compared with the other fractions. The GrO5000 was found to be a highly efficient and reusable solid catalyst for the esterification of various carboxylic acids with a variety of alcohols to furnish corresponding esters in high to excellent yields. The catalytic activity of the GrO5000 was attributed to the ability of highly polar GrO5000 scaffold to adsorb/attract reactants, where the acid functionalities of GrO5000 facilitated the esterification process efficiently. The chemical and structural features of GrO5000 were discussed to understand the improved catalytic activity compared with GrO2000 and conventional solid acid catalysts.
- Mungse, Harshal P.,Bhakuni, Niharika,Tripathi, Deependra,Sharma, Om P.,Sain, Bir,Khatri, Om P.
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p. 944 - 951
(2015/08/25)
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- Heterobimetallic dinuclear lanthanide alkoxide complexes as acid-base difunctional catalysts for transesterification
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A practical lanthanide(III)-catalyzed transesterification of carboxylic esters, weakly reactive carbonates, and much less-reactive ethyl silicate with primary and secondary alcohols was developed. Heterobimetallic dinuclear lanthanide alkoxide complexes [Ln2Na8{(OCH2CH2NMe2)}12(OH)2] (Ln = Nd (I), Sm (II), and Yb (III)) were used as highly active catalysts for this reaction. The mild reaction conditions enabled the transesterification of various substrates to proceed in good to high yield. Efficient activation of transesterification may be endowed by the above complexes as cooperative acid-base difunctional catalysts, which is proposed to be responsible for the higher reactivity in comparison with simple acid/base catalysts.
- Zeng, Ruijie,Sheng, Hongting,Zhang, Yongcang,Feng, Yan,Chen, Zhi,Wang, Junfeng,Chen, Man,Zhu, Manzhou,Guo, Qingxiang
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p. 9246 - 9252
(2014/12/11)
-
- A basic germanodecatungstate with a - 7 charge: Efficient chemoselective acylation of primary alcohols
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The synthesis of highly negatively charged polyoxometalates with electrically and structurally controlled uniform basic sites can lead to the unique base catalysis. In this work, a γ-Keggin germanodecatungstate, [γ-HGeW10O36]7- (A), having a -7 charge was, for the first time, successfully synthesized by the reaction of [γ-H2GeW10O36]6- with one equivalent of [(n-C4H9)4N]OH under non-aqueous conditions. The activities of germanodecatungstates for base-catalyzed reactions dramatically increased with increase in the number negative charges from -6 to -7. In the presence of A, various combinations of acylating agents and primary alcohols including those with acid-sensitive functional groups chemoselectively gave the desired acylated products in high yields even under the stoichiometric conditions.
- Sugahara, Kosei,Satake, Naoto,Kamata, Keigo,Nakajima, Takahito,Mizuno, Noritaka
-
supporting information
p. 13248 - 13252
(2015/01/09)
-
- Synthesis, characterization and application of poly(N,N'-dibromo- Nethylnaphthyl-2,7-disulfonamide) as an efficient catalyst for the acetylation and deacetylation reactions
-
In this work, a novel polymer namely poly(N,N'-dibromo-N-ethylnaphthyl-2,7- disulfonamide) (PBNS) is synthesized and characterized by studying its IR, 1H NMR, 13C NMR and thermal gravimetric analysis (TGA). This polymer is utilized as a highly efficient, heterogeneous and recyclable N-bromo reagent to catalyze acetylation of various compounds such as alcohols, phenols, thiol and amine with acetic anhydride under solvent-free conditions, and also it worthily catalyzes deacetylation of acetate esters in aqueous media.
- Khazaei, Ardeshir,Saednia, Shahnaz,Roshani, Liela,Kazem-Rostami, Masoud,Zare, Abdolkarim
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p. 159 - 167
(2014/05/20)
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- A synthesis of copper based metal-organic framework for O-acetylation of alcohols
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A novel metal-organic framework, Cu-BDC was synthesized by static hydrothermal method using innocuous solvents and characterized by several techniques such as powder XRD, ESR, TG-DTA, elemental analysis, ICP-AES, SEM, EDXS, FT-IR, BET surface area, pore volume and pore size. The catalytic performance of Cu-BDC was explored for O-acetylation of alcohols under solvent-free conditions at room temperature. The catalyst exhibited remarkable activity and reusability affording the desired products in excellent yields.
- Singh, Savita J.,Kale, Sandip R.,Gawande, Manoj B.,Velhinho,Jayaram, Radha V.
-
-
- Cloning and expression of a Baeyer-Villiger monooxygenase oxidizing linear aliphatic ketones from Dietzia sp. D5
-
A Baeyer-Villiger monooxygenase has been identified in the genome sequence of Dietzia sp. D5. Sequence similarity search revealed that the enzyme belongs to a group of BVMOs that are closely related to ethionamide monooxygenase from Mycobacterium tuberculosis (EthA). The BVMO was expressed in E. coli BL21-CodonPlus(DE3)-RP and the best expression was achieved when the E. coli cells were cultivated in terrific broth (TB) at 15 °C and induced with 0.1 mM of IPTG. Since the purified enzyme did not show any measurable activity, the substrate scope of the BVMO has been determined using whole-cell and crude cell extract systems. The enzyme was most active towards linear aliphatic substrates. However, it has shown a moderate degree of conversion for cyclobutanone, 2-methylcyclohexanone, bicyclo[3.2.0]hept-2-en-6-one, phenylacetone and thioanisole. There was no detectable conversion of ethionamide, cyclohexanone and acetophenone.
- Bisagni, Serena,Smus?, Justyna,Chávez, Georgina,Hatti-Kaul, Rajni,Mamo, Gashaw
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p. 161 - 169
(2014/12/11)
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- Functional divergence between closely related Baeyer-Villiger monooxygenases from Aspergillus flavus
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Baeyer-Villiger monooxygenases (BVMOs) catalyse the chemo-, regio- and enantioselective oxidation of ketones to esters and lactones. To date, most of the cloned BVMOs available are derived from bacteria, although Baeyer-Villiger oxidations using fungi have frequently been demonstrated. Here we report the cloning and characterization of four BVMOs from the fungus Aspergillus flavus NRRL3357. Phylogenetic analysis shows these four BVMOs to cluster in a distinct group apart from other well-characterized BVMOs including cyclohexanone, phenylacetone and 4-hydroxyacetophenone monooxygenase. Building on the Grogan classification/clustering of BVMOs, we have designated this new group of BVMOs, Group VI. Group VI BVMOs show an early divergence from the cyclopentanone monooxygenase (CPMO) type BVMOs (Group I). Substrate profiling using cyclic, bicyclic, aliphatic and aryl ketones show a clear divergence in function and specificity not only between this new group of BVMOs and the CPMO-type BVMOs, but also between the four A. flavus BVMO paralogues despite their high sequence similarity. This study not only contributes to the growing number of available BVMOs, but also addresses the current classification of Type I BVMOs, and the usefulness of phylogenetic clustering and prediction of function and selectivity when genome-mining is used to search for new biocatalysts.
- Ferroni,Smit,Opperman
-
-
- Expanding ester biosynthesis in Escherichia coli
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To expand the capabilities of whole-cell biocatalysis, we have engineered Escherichia coli to produce various esters. The alcohol O-acyltransferase (ATF) class of enzyme uses acyl-CoA units for ester formation. The release of free CoA upon esterification with an alcohol provides the free energy to facilitate ester formation. The diversity of CoA molecules found in nature in combination with various alcohol biosynthetic pathways allows for the biosynthesis of a multitude of esters. Small to medium volatile esters have extensive applications in the flavor, fragrance, cosmetic, solvent, paint and coating industries. The present work enables the production of these compounds by designing several ester pathways in E. coli. The engineered pathways generated acetate esters of ethyl, propyl, isobutyl, 2-methyl-1-butyl, 3-methyl-1-butyl and 2-phenylethyl alcohols. In particular, we achieved high-level production of isobutyl acetate from glucose (17.2 g l -1). This strategy was expanded to realize pathways for tetradecyl acetate and several isobutyrate esters.
- Rodriguez, Gabriel M,Tashiro, Yohei,Atsumi, Shota
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p. 259 - 265
(2014/04/03)
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- Silver acetate mediated acetoxylations of alkyl halides
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Silver acetate promotes the acetoxylation of alkyl halides under neutral reaction conditions. The reaction is applicable to primary and activated secondary alkyl halides, and 2,2-dibromoacetophenones for preparing the corresponding acetates in good yields. The presence of ester, amide, nitrile, hydroxy, and OTBDMS functions on the substrate is tolerated.
- Nolla-Saltiel, Roberto,Carrillo-Arcos, Ulises Alonso,Porcel, Susana
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supporting information
p. 165 - 169
(2014/03/21)
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- Efficient direct ester condensation between equimolar amounts of carboxylic acids and alcohols catalyzed by trifluoromethanesulfonic acid (TfOH) in Solkane365mfc
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A simple, practical, and environmentally benign esterification protocol has been devised on the basis of TfOH as the catalyst and Solkane365mfc as the reaction medium. The direct condensation of equimolar amounts of various carboxylic acids and alcohols was conveniently carried out without recourse to any additional water removal technique, giving the desired carboxylic esters in excellent yields.
- Xu, Xiu-Hua,Azuma, Ayaka,Taniguchi, Misaki,Tokunaga, Etsuko,Shibata, Norio
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p. 3848 - 3852
(2013/04/23)
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- Direct dehydrative esterification of alcohols and carboxylic acids with a macroporous polymeric acid catalyst
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A macroporous polymeric acid catalyst was prepared for the direct esterification of carboxylic acids and alcohols that proceeded at 50-80 C without removal of water to give the corresponding esters with high yield. Flow esterification for the synthesis of biodiesel fuel was also achieved by using a column-packed macroporous acid catalyst under mild conditions without removal of water.
- Minakawa, Maki,Baek, Heeyoel,Yamada, Yoichi M. A.,Han, Jin Wook,Uozumi, Yasuhiro
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supporting information
p. 5798 - 5801
(2013/12/04)
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