- Catalytic performance of divanadium-substituted molybdophosphate acid, H5PMo10V2O40, in liquid-phase esterification of hexanoic acid
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Divanadium-substituted molybdophosphate acid, H5PMo 10V2O40, efficiently catalyzes the synthesis of ethylhexanoate from hexanoic acid and ethanol at reflux temperature and under solventless conditions. Comparison of H5PMo10V 2O40 with the other heteropolyacids showed that this catalyst gives the highest total yield of ethylhexanoate. The effects of the molar ratio of acid:alcohol, reaction times, and temperatures were studied.
- Bamoharram, Fatemeh F.,Heravi, Majid M.,Roshani, Mina,Mir, Hamzeh
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- Kinetic model for the esterification of ethyl caproate for reaction optimization
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The present work aims to achieve additional insight on a mechanism describing the fundamental steps involved in the esterification reactions catalyzed by cutinase. The synthesis of ethyl caproate has been used as a model system to obtain a suitable kinetic model to estimate the activation energies involved in the various steps of the reaction pathway. Kinetic measurements have been made for the enzymatic esterification of caproic acid with ethyl alcohol catalyzed by recombinant Fusarium solani pisi cutinase expressed in Saccharomyces cerevisiae SU50. Different temperature conditions, from 25 to 50 C, were tested for two different alcohol/acid molar ratios (R = 1 and R = 2). The third ordered Ping Pong Bi Bi mechanism with alcohol inhibition was shown to be able to describe the experimental results. The model shows that the productivity decreases as the reaction temperature increases.
- De Barros, Dragana P.C.,Pinto, Fatima,Fonseca, Luis P.,Cabral, Joaquim M.S.,Lemos
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- Kinetic cutinase-catalyzed esterification of caproic acid in organic solvent system
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Practical application of any chemical reaction requires the knowledge of its kinetics; in particular if one wishes to be able to describe a chemical reactor over an extended range of reaction conditions or if one intends to optimize the reaction conditions, a suitable kinetic model must be obtained. In order to ensure that the model is applicable over a wide range of experimental conditions it should be based on a mechanistic scheme describing the fundamental steps involved in the reaction; the development of these kind of models can also be used to provide insight into the processes that are taking place. A kinetic study, using experiments carried out in a batch stirred reactor, has been made for the enzymatic esterification of caproic acid with ethyl alcohol catalyzed by Fusarium solani pisi cutinase. Different acid and alcohol concentrations (whilst also varying the acid/alcohol molar ratio) were tested and the results were used to identify the best reaction scheme to describe the results obtained over an extended range of conditions. Several different approaches were used to identify the most adequate mechanistic model, namely by resorting to the quasi stationary state and the rate-limiting hypothesis. The main kinetic characteristics observed in esterification reaction were found to follow an ordered Ping-Pong Bi-Bi mechanism but different modifications were used o ensure that the kinetic model was applicable over the entire range of experimental conditions that were covered.
- De Barros, Dragana P. C.,Lemos, Francisco,Fonseca, Luis P.,Cabral, Joaquim M. S.
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- Fully recyclable Br?nsted acid catalyst systems
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Homogeneous and heterogeneous sulfonic acid catalysts are some of the most common catalysts used in organic chemistry. This work explores an alternative scheme using a fully recyclable polymeric solvent (a poly-α-olefin (PAO)) and soluble PAO-anchored polyisobutylene (PIB)-bound sulfonic acid catalysts. This PAO solvent is nonvolatile and helps to exclude water by its nonpolar nature which in turn drives reactions without the need for distillation of water, avoiding the need for excess reagents. This highly nonpolar solvent system uses polyisobutylene (PIB) bound sulfonic acid catalysts that are phase-anchored in solvents like PAO. The effectivenes of these catalysts was demonstrated by their use in esterifications, acetalizations, and multicomponent condensations. These catalysts and the PAO solvent phase show excellent recyclability in schemes where products are efficiently separated. For example, this non-volatile polymeric solvent and the PIB-bound catalyst can be recycled quantitatively when volatile products are separated and purified by distillation. In other cases, product purification can be effected by product self-separation or by extraction.
- Watson, Christopher B.,Kuechle, Adrianna,Bergbreiter, David E.
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p. 1266 - 1273
(2021/02/26)
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- MOFs based on 1D structural sub-domains with Br?nsted acid and redox active sites as effective bi-functional catalysts
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A novel family of lamellar MOF-type materials, which contain Br?nsted acid sites together with redox active centers, based on assembled 1D organic-inorganic nanoribbons were obtained through direct solvothermal synthesis routes, using specific monotopic benzylcarboxylate spacers with thiol substituents in thepara-position like structural modulator compounds and effective post-synthesis oxidized treatments to generate accessible sulfonic groups. Low-dimensional aluminum metal-organic materials, containing free sulfonic pendant groups (Al-ITQ-SO3H), were successfully tested in several acid reactions, such as acetalization, esterification and ring opening of epoxides with a significant impact on fine chemistry processes. The direct introduction of stabilized Pd nanoparticles, cohabitating with pendant sulfonic groups, allowed the preparation of active bi-functional MOF-type hybrid materials (Al-ITQ-SO3H/Pd) capable of carrying out one-pot two-step oxidation-acetalization reactions, exhibiting high yield and high activity during consecutive catalytic cycles.
- Díaz, Urbano,Moreno, José María,Velty, Alexandra
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p. 3572 - 3585
(2020/06/25)
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- Synthesis of α,β- and β-Unsaturated Acids and Hydroxy Acids by Tandem Oxidation, Epoxidation, and Hydrolysis/Hydrogenation of Bioethanol Derivatives
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We report a reaction platform for the synthesis of three different high-value specialty chemical building blocks starting from bio-ethanol, which might have an important impact in the implementation of biorefineries. First, oxidative dehydrogenation of ethanol to acetaldehyde generates an aldehyde-containing stream active for the production of C4 aldehydes via base-catalyzed aldol-condensation. Then, the resulting C4 adduct is selectively converted into crotonic acid via catalytic aerobic oxidation (62 % yield). Using a sequential epoxidation and hydrogenation of crotonic acid leads to 29 % yield of β-hydroxy acid (3-hydroxybutanoic acid). By controlling the pH of the reaction media, it is possible to hydrolyze the oxirane moiety leading to 21 % yield of α,β-dihydroxy acid (2,3-dihydroxybutanoic acid). Crotonic acid, 3-hydroxybutanoic acid, and 2,3-dihydroxybutanoic acid are archetypal specialty chemicals used in the synthesis of polyvinyl-co-unsaturated acids resins, pharmaceutics, and bio-degradable/ -compatible polymers, respectively.
- Faria, Jimmy,Komarneni, Mallik R.,Li, Gengnan,Pham, Tu,Resasco, Daniel E.,Ruiz, Maria P.,Santhanaraj, Daniel
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supporting information
p. 7456 - 7460
(2020/03/23)
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- Enantioselective Synthesis of β-Amino Acid Derivatives Enabled by Ligand-Controlled Reversal of Hydrocupration Regiochemistry
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A Cu-catalyzed enantioselective hydroamination of α,β-unsaturated carbonyl compounds for the synthesis of β-amino acid derivatives was achieved through ligand-controlled reversal of the hydrocupration regioselectivity. While the hydrocupration of α,β-unsaturated carbonyl compounds to form α-cuprated species has been extensively investigated, we report herein that, in the presence of an appropriate ancillary chiral ligand, the opposite regiochemistry can be observed for cinnamic acid derivatives, leading to the delivery of the copper to the β-position. This copper can react with an electrophilic aminating reagent, 1,2-benzisoxazole, to provide enantioenriched β-amino acid derivatives, which are important building blocks for the synthesis of natural products and bioactive small molecules.
- Buchwald, Stephen L.,Guo, Sheng,Zhu, Jiaqi
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supporting information
p. 20841 - 20845
(2020/09/16)
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- Selective hydrogenation of α,β-unsaturated carbonyl compounds on silica-supported copper nanoparticles
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Silica-supported copper nanoparticles prepared via surface organometallic chemistry are highly efficient for the selective hydrogenation of various α,β-unsaturated carbonyl compounds yielding the corresponding saturated esters, ketones, and aldehydes in the absence of additives. High conversions and selectivities (>99%) are obtained for most substrates upon hydrogenation at 100-150 °C and under 25 bar of H2.
- Mendes-Burak, Jorge,Ghaffari, Behnaz,Copéret, Christophe
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supporting information
p. 179 - 181
(2019/01/04)
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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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- 'Clean' hydrolase reactions using commercial washing powder
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We report the use of commercial laundry powder as a biocatalyst for a range of lipase-catalysed reactions including (trans)esterification, ester hydrolysis and chemoenzymatic epoxidation reactions. The enzymatic laundry powder exhibited excellent stability and recyclability, making it a readily available and cheap biocatalyst for chemical transformations.
- Zhang, Jie,Tonin, Fabio,Zhang, Wuyuan,Hagedoorn, Peter-Leon,Mallée, Lloyd,Hollmann, Frank
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p. 24039 - 24042
(2019/08/15)
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- Exploration of Intrinsic Lipase-Like Activity of Zirconium-Based Metal-Organic Frameworks
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To overcome the disadvantages of natural enzymes, artificial enzyme mimics attracted increasing attention of researchers. Metal-organic frameworks (MOFs) are expected as one of the most appropriate candidates for artificial enzyme mimics. In this work, we demonstrate that the zirconium-based MOF material UiO-66 and its analogues possess intrinsic lipase-like activity and can efficiently catalyze ester hydrolysis, transesterification and esterification reactions. Furthermore, the UiO-66(NH2) exhibits much higher catalytic activity than that of UiO-66, which can be attributed to the synergy effect between the zirconium cluster centres and the amino moieties during the catalytic cycle.
- Liu, Xiao,Qi, Wei,Wang, Yuefei,Su, Rongxin,He, Zhimin
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p. 4579 - 4585
(2018/10/26)
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- 8 - hydroxy quinoline sensitive ionic liquid preparation and its catalytic long-chain fatty acid b method of esterification of
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The invention discloses a preparation method of a temperature sensitive ionic liquid, and a method for catalyzing long-chain fatty acid esterification by using the ionic liquid. A general formula (I) shown in the specification represents the structure of the temperature sensitive ionic liquid, the ionic liquid is formed by a 8-hydroxyquinoline cation and anions comprising a tetrafluoroborate radical, a methane sulfonate radical, a bisulfate ion and a dihydrogen phosphate radical, and the solubility of ionic liquid in ethanol is temperature sensitive. The introduction of a hydroxy group to 8-position of aquinoline ring greatly increases the acidity and improves the esterification reaction yield. The ionic liquid can be mixed with ethanol to form one phase at a high temperature, and the ionic liquid and a product rapidly separate to different phases at room temperature or a low temperature, so the whole reaction system ensures high catalytic efficiency of a homogeneous reaction and makes separation and recovery simple, avoids the limitations of limited two-phase catalytic efficiency and the disadvantage of difficult ion liquid recovery of homogeneous catalysis, and accords with the principle of green chemistry. The esterification yield of the esterification reaction of the long-chain fatty acid under the catalysis of the ionic liquid reaches 90.6-95.5%.
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Paragraph 0048; 0049; 0050; 0051; 0052; 0053-0057
(2017/06/22)
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- Synthesis, characterization and catalytic performance of a novel picolinic acid-12-molybdophosphoric acid hybrid catalyst
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A novel 12-molybdophosphoric acid (HPM)-based complex (H2 PI)2(H 3 O)[PMo12O 40] [Mo2 O5 (H2 O)2 (PI)2 ]?11H2 O (PI-HPM) was prepared by modification with picolinic acid (HPI) and characterized by the methods of Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG), X-ray powder and single crystal diffraction. The complex retained the classical Keggin structure of bulk HPM, there were some strong hydrogen bonds existing between the [PMo12 O40 ]3- polyanion, the [Mo2 O5 (H2 O)2 (PI)2 ] coordination moiety, the protonated HPI and the lattice water molecules. Then PI-HPM was employed as heterogeneous catalyst for esterification reaction to evaluate its acid-catalytic activity. The complex exhibited high activity and good durability in reaction mixtures, indicating that it was a promising heterogeneous acid catalyst for esterification that including the conversion of oleic acid to oleates.
- Liu, Lijun,Wang, Honghong,Gong, Shuwen,Lu, Jing,Zhang, Qian
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p. 1007 - 1013
(2016/06/15)
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- Conversion of ethanol into linear primary alcohols on gold, nickel, and gold–nickel catalysts
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The direct conversion of ethanol into the linear primary alcohols CnH2n+1OH (n = 4, 6, and 8) in the presence of the original mono- and bimetallic catalysts Au/Al2O3, Ni/Al2O3, and Au–Ni/Al2O3 was studied. It was established that the rate and selectivity of the reaction performed under the conditions of a supercritical state of ethanol sharply increased in the presence of Au–Ni/Al2O3. The yield of target products on the bimetallic catalyst was higher by a factor of 2–3 than that reached on the monometallic analogs. Differences in the catalytic behaviors of the Au, Ni, and Au–Ni systems were discussed with consideration for their structure peculiarities and reaction mechanisms.
- Chistyakov,Zharova,Tsodikov,Nikolaev,Krotova,Ezzhelenko
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p. 803 - 811
(2016/12/07)
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- Biocatalytic Characterization of Human FMO5: Unearthing Baeyer-Villiger Reactions in Humans
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Flavin-containing mono-oxygenases are known as potent drug-metabolizing enzymes, providing complementary functions to the well-investigated cytochrome P450 mono-oxygenases. While human FMO isoforms are typically involved in the oxidation of soft nucleophiles, the biocatalytic activity of human FMO5 (along its physiological role) has long remained unexplored. In this study, we demonstrate the atypical in vitro activity of human FMO5 as a Baeyer-Villiger mono-oxygenase on a broad range of substrates, revealing the first example to date of a human protein catalyzing such reactions. The isolated and purified protein was active on diverse carbonyl compounds, whereas soft nucleophiles were mostly non- or poorly reactive. The absence of the typical characteristic sequence motifs sets human FMO5 apart from all characterized Baeyer-Villiger mono-oxygenases so far. These findings open new perspectives in human oxidative metabolism.
- Fiorentini, Filippo,Geier, Martina,Binda, Claudia,Winkler, Margit,Faber, Kurt,Hall, Mélanie,Mattevi, Andrea
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p. 1039 - 1048
(2016/05/19)
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- Ionic liquid-initiated polymerization of epoxides: A useful strategy for the preparation of Pd-doped polyether catalysts
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Palladium compounds (Pd(OAc)2 and Pd(acac)2) were dissolved in commercially available epoxy resins (glycidyl derivatives of bisphenol A and p-aminophenol) and the formulations were polymerized employing the ionic liquid 1-ethyl-2-methylimidazolium acetate (EMIM acetate) as polymerization initiator. Thus, palladium species could be incorporated in the network of the resulting polyether materials. Polymerization reactions were investigated by DSC and the curing behavior of different formulations was compared. High polymerization enthalpies were observed indicating high crosslinking in the materials. Accordingly, the materials exhibited high glass transition temperatures and thermogravimetric data revealed high thermal stability. Due to the good solubility of the palladium compounds in the epoxy resins, a widely homogeneous dispersion of palladium species in the polyether matrix could be realized. This was confirmed by SEM-EDX and TEM measurements. XPS measurements revealed that reduction of Pd(II) to Pd(0) species occurred during catalyst preparation and this was also proven by XRD. The materials were ground and successfully employed as catalysts for the hydrogenation of several alkenes under mild reaction conditions. High conversions and selectivities could be reached within a few hours at room temperature and moderate hydrogen pressure of 2.5 bar. Palladium leaching from the catalysts to reaction solutions was investigated. To determine very low quantities, metal concentrations were enriched by removal of volatile components. Subsequent ICP-AES measurements revealed low palladium contents in the range of a few μg. These amounts correspond to values around 0.007% with respect to palladium originally loaded on the polymer. Catalyst recycling experiments were also carried out and it was shown that the catalysts can be employed in numerous consecutive reactions without any catalyst treatment and without loss of activity. Within a series of reactions, palladium leaching decreased while catalytic activity was not affected.
- Arnold, Ulrich,Altesleben, Christiane,Behrens, Silke,Essig, Sarah,Lautenschütz, Ludger,Schild, Dieter,Sauer, J?rg
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p. 116 - 124
(2015/05/27)
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- Three step auto-tandem catalysed hydroesterification: Access to linear fruity esters from piperylene
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A convenient and selective access to saturated hexanoic esters via hydroesterification of piperylene with synthesis gas and methanol is presented. This is the first three step auto-tandem hydroesterification, which is 100% atom economic proceeding under mild conditions. Our optimisations revealed Pd2(dba)3/1,2-dtbpmb as the best catalytic system. Besides, the reaction also tolerates several alcohols, which offers a broad range of fruity esters. In addition, we present insights into the reaction sequence, investigating whether the reaction proceeds via two- or three-step reaction cascade.
- Neubert, Peter,Steffen, Matthias,Behr, Arno
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p. 122 - 127
(2015/07/15)
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- Ruthenium nanoparticle-intercalated montmorillonite clay for solvent-free alkene hydrogenation reaction
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Well-characterized, ruthenium nanoparticle-intercalated montmorillonite clay was used as a catalyst in solvent-free alkene hydrogenation reactions and the corresponding products were obtained in good yields. The catalytic activity of ruthenium nanoparticle-intercalated montmorillonite clay was successfully tested with 16 different functionalized and non-functionalized alkenes. Apart from alkene reduction, the ruthenium nanoparticle-intercalated montmorillonite clay was also tested in Wittig-type reactions for obtaining dehydrobrittonin A, an important intermediate for the synthesis of brittonin A. Ruthenium nanoparticle-intercalated montmorillonite clay was found to be active in the synthesis of dehydrobrittonin A and brittonin A. The ability to recycle the catalyst nine times, together with low catalyst loading, high catalytic activity and catalytic selectivity were noteworthy advantages of the proposed protocol.
- Upadhyay, Praveenkumar,Srivastava, Vivek
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p. 740 - 745
(2015/02/05)
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- A convenient synthesis and cytotoxic activity of 3-aryl-5-pentyl-1,2,4- oxadiazoles from carboxylic acid esters and arylamidoximes under solvent-free conditions
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The synthesis of 3-aryl-5-pentyl-1,2,4-oxadiazoles from carboxylic acid esters and arylamidoximes in the presence of potassium carbonate is described. The reaction was carried out in a microwave oven without any solvent in much shorter time and in good yields. The structures of the synthesized compounds were elucidated using IR, 1H and 13C NMR spectroscopy and elemental analysis and their antiproliferative activities was evaluated against three different human cell lines.
- Barros, Carlos Jonnatan Pimentel,De Souza, Zilyane Cardoso,De Freitas, Jucleiton José Rufino,Silva, Paulo Bruno Norberto Da,Milit?o, Gardenia Carmen Gadelha,Silva, Teresinha Gon?alves Da,Freitas, Juliano Carlo Rufino,De Freitas Filho, Jo?o Rufino
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p. 2359 - 2362
(2014/07/22)
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- Facile synthesis of mesoporous sulfated Ce/TiO2 nanofiber solid superacid with nanocrystalline frameworks by using collagen fibers as a biotemplate and its application in esterification
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Collagen fibers, one of the most abundant biomass in the natural world, were used as the biomass template to synthesize cerium-doped mesoporous TiO 2 nanofiber (SO42--Cex/TiO 2) solid acid catalysts. The physiochemical properties of the as-prepared catalysts were well characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS). The fibrous morphology of native collagen fibers were found to be well preserved in SO42--Ce x/TiO2, and the acid strength and textural property of the SO42--Cex/TiO2 were adjustable by changing the doping amount of Ce and the curing temperature. The catalytic properties of as-prepared catalysts were evaluated in the esterification reactions. It was found that the SO42--Ce x/TiO2 exhibited high activity under mild reaction conditions. When reacted at 90 °C for 45 min with a catalyst amount of 2 wt%, the conversion yields of ethyl acetate, butyl acetate, hexyl acetate and ethyl caproate were 99.9%, 97.06%, 94.29% and 86.75%, respectively. Additionally, the SO42--Cex/TiO2 solid acid catalyst could be reused at least 6 times without significant loss of activity, exhibiting much better reusability as compared with the SO 42--TiO2* catalyst prepared by conventional approach.
- Xiao, Gao,Zhou, Jianfei,Huang, Xin,Liao, Xuepin,Shi, Bi
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p. 4010 - 4019
(2014/01/06)
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- Catalytic functionalization of methane and light alkanes in supercritical carbon dioxide
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The development of catalytic methods for the effective functionalization of methane yet remains a challenge. The best system known to date is the so-called Catalytica Process based on the use of platinum catalysts to convert methane into methyl bisulfate with a TOF rate of 10-3 s. In this contribution, we report a series of silver complexes containing perfluorinated tris(indazolyl)borate ligands that catalyze the functionalization of methane into ethyl propionate upon reaction with ethyl diazoacetate (EDA) by using supercritical carbon dioxide (scCO2) as the reaction medium. The employment of this reaction medium has also allowed the functionalization of ethane, propane, butane, and isobutane.
- Fuentes, M. Angeles,Olmos, Andrea,Caballero, Ana,Perez, Pedro J.,Munoz, Bianca K.,Jacob, Kane,Etienne, Michel,Gonzalez-Nunez, M. Elena,Mello, Rossella,Asensio, Gregorio
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supporting information
p. 11013 - 11018,6
(2015/01/07)
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- Cloning and expression of a Baeyer-Villiger monooxygenase oxidizing linear aliphatic ketones from Dietzia sp. D5
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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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- Palladium complexes with N-heterocyclic carbene ligands as catalysts for the alkoxycarbonylation of olefins
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Palladium catalysts, generated from Pd(OAc)2 and 2 equiv of N,N-dialkylbenzimidazolium iodide, are effective for the alkoxycarbonylation of olefins in high yields (>90%). Alkoxycarbonylation of 1-hexene in dimethylacetamide is achieved within 24 h at 110 C using 1 mol % catalyst, 1000 psi CO, and ethanol. Reactions can be prepared in air, without the need of an acid additive to produce ethyl 2-methylhexanoate and ethyl heptanoate in approximately a 2:1 ratio.
- Roberts, Gina M.,Pierce, Philip J.,Woo, L. Keith
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p. 2033 - 2036
(2013/05/21)
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- METHOD FOR CONTINUOUSLY PREPARING CARBOXYLIC ACID ESTER
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A method for continuously preparing a carboxylic acid ester is disclosed. In the method of the present invention, a vertical reactor is filled with a solid catalyst, a carboxylic acid and an alcohol are introduced into a lower part of the vertical reactor, esterification is performed to form an esterized mixture, the esterized mixture is output from an upper part of the vertical reactor, and distillation is performed to isolate the carboxylic acid ester. The method of the present invention is simple, easily controlled and environmental friendly, and has significantly high conversion rate and selectivity.
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Paragraph 0024; 0026
(2013/11/19)
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- Lipase-catalyzed synthesis of ethyl hexanoate in microemulsion system
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This paper studied lipase-catalyzed synthesis of ethyl hexanoate in dodecylbenzenesulfonic acid/isooctane/water microemulsion system. The effect of several parameters, such as w0 ([H2O]/[surfactant]) value, reaction time, reaction temperature, oil phase solvent, buffer solution pH value of microemulsion system on the esterification have been investigated. The results showed that the best experimental conditions for catalytic synthesis ethyl hexanoate were as follows: w0 = 4, reaction time 4 h, reaction temperature 40 °C, buffer solution pH 7. Under these conditions, the conversion of ethyl hexanoate can reach 98.5 %. Lipase-catalyzed synthesis of ethyl hexanoate in dodecylbenzenesulfonic acid inverse microemulsion system has triple mechanism, namely acid catalyzes, microemulsion catalyzes and enzyme catalyzes.
- Tan, Zhongqin,Han, Xiaoxiang,Hu, Xiaoli,Du, Huan,Bao, Xiuxiu
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p. 9675 - 9678
(2014/01/06)
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- Practical metal- and additive-free methods for radical-mediated reduction and cyclization reactions
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Two facile, metal- and additive-free protocols for radical dehalogenation, deoxygenation and cyclization reactions are reported. Irradiation by household fluorescent light bulbs or the presence of an air atmosphere is shown to initiate the desired reactions, thus providing highly practical reaction setups for radical-mediated reductions and cyclizations.
- Jiang, Hao,Bak, Jesper R.,Lopez-Delgado, Francisco Javier,Jorgensen, Karl Anker
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supporting information
p. 3355 - 3359
(2013/12/04)
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- Ionic liquid-catalyzed internal redox esterification reaction
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The internal redox esterification of α,β-unsaturated aldehydes and alcohols was carried out using different ionic liquids (ILs) as catalysts and reaction solvents. The basic ionic liquid, 1-butyl-3-methylimidazolium acetate ([bmim]OAc), exhibited the best activity for this reaction. The influences of the amount of ionic liquid catalyst and reaction time on yield of saturated ester have been investigated. The results showed that ionic liquid anions have a crucial effect on the redox esterification of α,β- unsaturated aldehydes and alcohols. The nucleophilic carbenes generated in situ from the ionic liquid cation were believed to be actual active species for this reactions.
- Yu, Yinyin,Hua, Li,Zhu, Wenwen,Shi, Yu,Cao, Ting,Qiao, Yunxiang,Hou, Zhenshan
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p. 1287 - 1298
(2013/03/29)
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- Preparation of esters of mono- or dicarboxylic non-aromatic and aromatic acids
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The present invention relates to a method for preparing a carboxylic acid ester, wherein a carboxylic acid and/or a salt thereof is reacted with an alcohol in the presence of hydrogen chloride (HCl) and water to form the carboxylic acid ester, wherein the reaction is carried out using a starting reaction system wherein the molar ratio of HCl to carboxylic acid is at least 0.075 : 1 and the molar ratio of water to carboxylic acid is at least 0.25 : 1.
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Page/Page column 5
(2012/06/30)
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- P-Sulfonic acid calix[n]arenes as homogeneous and recyclable organocatalysts for esterification reactions
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Esterification yields were significantly improved using calix[n]arenes catalysts under simple conditions. p-Sulfonic acid calix[4]arene and p-sulfonic acid calix[6]arene were powerful organocatalysts in several esterification reactions, which showed activity comparable or even superior to other well-established acids catalysts, such as, sulfuric acid, p-toluenesulfonic acid, and p-hydroxybezenesulfonic acid described in the literature.
- Fernandes, Sergio Antonio,Natalino, Ricardo,Gazolla, Poliana Aparecida Rodrigues,Da Silva, Márcio José,Jham, Gulab Newandram
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experimental part
p. 1630 - 1633
(2012/04/17)
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- Optimized synthesis of (Z)-3-hexen-1-yl caproate using germinated rapeseed lipase in organic solvent
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(Z)-3-hexen-1-yl esters are important green top-note components of food flavors and fragrances. Effects of various process conditions on (Z)-3-hexen-1-yl caproate synthesis employing germinated rapeseed lipase acetone powder in organic solvent were investigated. Rapeseed lipase catalyzed ester formation more efficiently with non-polar compared to polar solvents despite high enzyme stability in both types of solvents. Maximum ester yield (90%) was obtained when 0.125 M (Z)-3-hexen-1-ol and caproic acid were reacted at 25 °C for 48 h in the presence of 50 g/L enzyme in heptane. Enzyme showed little sensitivity towards aw with optimum yield at 0.45, while added water did not affect ester yield. Esterification reduced by increasing molecular sieves (>0.0125%, w/v). The highest yields of caproic acid were obtained with isoamyl alcohol (93%) followed by butanol and (Z)-3-hexen-1-o1 (88%) respectively reflecting the enzyme specificity for straight and branched chain alcohols. Secondary alcohols showed low reactivity, while tertiary alcohol had either very low reactivity or not esterified at all. A good relationship has been found between ester synthesis and the solvent polarity (log P value); while no correlation for the effect of solvents on residual enzyme activity was observed. It may be concluded that germinated rapeseed lipase is a promising biocatalyst for the synthesis of valuable green flavor note compound. The enzyme also showed a wide range of temperature stability (5-50 °C).
- Liaquat, Muhammad
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body text
p. 59 - 65
(2011/07/31)
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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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- Modified grape seed oils
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Edible oils are described which are extracted from dried fermented grape seeds isolated from a fermented grape pomace that has undergone fermentation, e.g., primary fermentation during wine making. The edible oils contain distinguishing flavor and fragrance chemicals evidenced by organoleptic evaluation and chemical analysis, in which these chemicals are substantially lacking in grape seed oils that have been similarly extracted from grape seeds isolated from non-fermented grape pomace.
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- VpAAT1, a gene encoding an alcohol acyltransferase, is involved in ester biosynthesis during ripening of mountain papaya fruit
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Mountain papaya (Vasconcellea pubescens) is a climacteric fruit that develops a strong and characteristic aroma during ripening. Esters are the main volatile compounds produced by the fruit, and most of them are dependent on ethylene. As esters are synthesized through alcohol acyltransferases (AAT), a full-length cDNA (VpAAT1) was isolated that displayed the characteristic motifs of most plant acyltransferases. The full-length cDNA sequence was cloned and expressed in yeasts, obtaining a functional enzyme with high AAT activity toward the formation of benzyl acetate. The transcript accumulation pattern provided by qPCR analysis showed that the VpAAT1 gene is expressed exclusively in fruit tissues and that a high level of transcripts is accumulated during ripening. The increase in VpAAT1 transcripts in fruit is coincident with the increase in AAT activity; transcript accumulation is induced by ethylene, and it is avoided by 1-methylcyclopropene (1-MCP) treatment. The data indicate that VpAAT1 is involved in aroma formation and that ethylene plays a major role in regulating its expression.
- Balbontin, Cristian,Gaete-Eastman, Carlos,Fuentes, Lida,Figueroa, Carlos R.,Herrera, Raul,Manriquez, Daniel,Latche, Alain,Pech, Jean-Claude,Moya-Leon, Maria Alejandra
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experimental part
p. 5114 - 5121
(2011/08/03)
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- Preparation of a carbon-based solid acid catalyst by sulfonating activated carbon in a chemical reduction process
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Sulfonated (SO3H-bearing) activated carbon (AC-SO3H) was synthesized by an aryl diazonium salt reduction process. The obtained material had a SO3H density of 0.64 mmol·g-1 and a specific surface area of 602 m2·g-1. The catalytic properties of ACSO3H were compared with that of two commercial solid acid catalysts, Nafion NR50 and Amberlyst-15. In a 10-h esterification reaction of acetic acid with ethanol, the acid conversion with ACSO3H (78%) was lower than that of Amberlyst-15 (86%), which could be attributed to the fact that the SO3H density of the sulfonated carbon was lower than that of Amberlyst-15 (4.60 mmol·g-1). However, AC-SO3H exhibited comparable and even much higher catalytic activities than the commercial catalysts in the esterification of aliphatic acids with longer carbon chains such as hexanoic acid and decanoic acid, which may be due to the large specific surface area and mesoporous structures of the activated carbon. The disadvantage of AC-SO3H is the leaching of SO3H group during the reactions.
- Liu, Xiao-Yan,Huang, Miao,Ma, Hai-Long,Zhang, Zeng-Qiang,Gao, Jin-Ming,Zhu, Yu-Lei,Han, Xiao-Jin,Guo, Xiang-Yun
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experimental part
p. 7188 - 7196
(2011/02/23)
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- Poly(vinylsulfonic acid)-grafted solid catalysts: New materials for acid-catalysed organic synthetic reactions
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The synthesis, characterisation and application of novel high-density poly(vinylsulfonic acid)-grafted solid acid catalysts are described. A graft, radical polymerization procedure was employed, allowing the immobilisation of the acid form of vinylsulfonic acid monomer onto various carrier materials, such as polystyrene, silica or polysaccharide-based gels. The highest acid-exchange capacity (as determined by acid-base titration methods) achieved with these new materials was 5.2 mmol H+ g-1. The properties of these PVS-grafted materials as solid state acid catalysts have been examined from several perspectives, including their fundamental properties as materials with extremely high acid dissociation characteristics, their structural features as revealed from IR and solid-state NMR measurements, their thermal stability properties, and their surface morphologies, humidity dependencies and functionality. Compared to many other types of acid catalysts, these high-density poly(vinylsulfonic acid)-grafted materials demonstrated superior catalytic performance in esterification, Friedel-Crafts acylation, and condensation reactions. Moreover, these novel materials show high stability, significant anticorrosion capability and can be easily recycled. The Royal Society of Chemistry 2010.
- Okayasu, Teruyuki,Saito, Kei,Nishide, Hiroyuki,Hearn, Milton T. W.
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experimental part
p. 1981 - 1989
(2011/02/23)
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- INFANT FORMULA CONTAINING AN AROMA COMPOSITION FOR USE AS FRAGRANCE
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The invention relates to a nutraceutical composition such as infant formula or infant food comprising a) a defined aroma composition; b) a methodology for developing, maintaining certain aroma constituents in the infant formula and an aroma or fragrance composition to be used to increase the acceptance of a person or an object by the baby or new born.
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- Transfer hydrogenation of olefins catalysed by nickel nanoparticles
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Nickel nanoparticles have been found to effectively catalyse the hydrogen-transfer reduction of a variety of non-functionalised and functionalised olefins using 2-propanol as the hydrogen donor. The heterogeneous process has been shown to be highly chemoselective for certain substrates, with all the corresponding alkanes being obtained in high yields. A synthesis of the natural dihydrostilbene brittonin A?is also reported based on the use of nickel nanoparticles.
- Alonso, Francisco,Riente, Paola,Yus, Miguel
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experimental part
p. 10637 - 10643
(2010/01/16)
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- First iron-catalyzed synthesis of oximes from styrenes
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Aryl-substituted olefins react with t-butyl nitrite and sodium borohydride in the presence of iron(ii)phthalocyanine to give oximes in moderate to high yields.
- Prateeptongkum, Saisuree,Jovel, Irina,Jackstell, Ralf,Vogl, Nadine,Weckbecker, Christoph,Beller, Matthias
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supporting information; experimental part
p. 1990 - 1992
(2009/09/06)
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- MODIFIED GRAPE SEED OILS
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Edible oils are described which are extracted from dried fermented grape seeds isolated from a fermented grape pomace that has undergone fermentation, e.g., primary fermentation during wine making. The edible oils contain distinguishing flavor and fragrance chemicals evidenced by organoleptic evaluation and chemical analysis, in which these chemicals are substantially lacking in grape seed oils that have been similarly extracted from grape seeds isolated from non-fermented grape pomace.
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- Cobalt-catalyzed cross-coupling reaction between functionalized primary and secondary alkyl halides and aliphatic Grignard reagents
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The coupling of primary and secondary unactivated alkyl bromides with alkyl-Grignard reagents was performed in good yields under mild conditions by using a new catalytic system: consisting of cobalt chloride and tetramethylethylenediamine (CoCl2·2 LiI, 4TMEDA). The reaction is very chemoselective since ketone, ester and nitrile functions are tolerated.
- Cahiez, Gerard,Chaboche, Christophe,Duplais, Christophe,Giulliani, Arianna,Moyeux, Alban
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supporting information; experimental part
p. 1484 - 1488
(2009/07/01)
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- METHOD OF MAKING ALKYL ESTERS
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Methods of making alkyl esters are described herein. The methods are capable of using raw, unprocessed, low-cost feedstocks and waste grease. Generally, the method involves converting a glyceride source to a fatty acid composition and esterifying the fatty acid composition to make alkyl esters. In an embodiment, a method of making alkyl esters comprises providing a glyceride source. The method further comprises converting the glyceride source to a fatty acid composition comprising free fatty acids and less than about 1% glyceride by mass. Moreover, the method comprises esterifying the fatty acid composition in the presence of a solid acid catalyst at a temperature ranging firm about 70° C. to about 120° C. to produce alkyl esters, such that at least 85% of the free fatty acids are converted to alkyl esters. The method also incorporates the use of packed bed reactors for glyceride conversion and/or fatty acid esterification to make alkyl esters.
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Page/Page column 5
(2008/06/13)
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- Highly selective hydrogenation of multiple carbon-carbon bonds promoted by nickel(0) nanoparticles
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A new method for the highly stereoselective cis semihydrogenation of internal alkynes, semihydrogenation of terminal alkynes, reduction of dienes to alkenes, and reduction of alkynes and alkenes to alkanes is described based on in situ generated both Ni(0) nanoparticles and molecular hydrogen.
- Alonso, Francisco,Osante, I?aki,Yus, Miguel
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- Silica-supported dendrimer-palladium complex-catalyzed selective hydrogenation of dienes to monoolefins
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The selective hydrogenation of cyclic and acyclic dienes to monoolefins occurs under very mild conditions, in the presence of silica-supported PAMAM-Pd complexes. The activity and selectivity of this reaction is sensitive to the dendrimer structure. These dendritic complexes display excellent recycle properties, retaining activity for up to eight recycles.
- Zweni, Pumza P.,Alper, Howard
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p. 725 - 731
(2007/10/03)
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- A PROCESS FOR THE HYDROGENATION OF A LACTONE OR OF A CARBOXYLIC ACID OR AN ESTER HAVING A GAMMA-CARBONYL GROUP
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The invention provides a process for the hydrogenation of a reactant selected from the group consisting of : (a) a 5- or 6-membered lactone that is substituted at the ring-closing carbon atom and has a proton at a carbon atom adjacent to the ring-closing carbon atom; (b) an ester of a carboxylic acid having a gamma- carbonyl group and a proton at a carbon atom adjacent to the carbon atom of the carbonyl group; and (c) a carboxylic acid having a gamma-carbonyl group and a proton at a carbon atom adjacent to the carbon atom of the carbonyl group, wherein the reactant is contacted with a strongly acidic heterogeneous catalyst comprising a hydrogenating metal, in the presence of hydrogen, at a temperature in the range of from 100 to 350 °C and a pressure in the range of from 1 to 150 bar (absolute). The invention further provides a fuel composition, preferably a diesel composition, comprising di-alkyl 4-methylnonanedioate or di-alkyl 3-ethyl-4-methylheptanedioate.
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Page/Page column 12; 13; 15
(2008/06/13)
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- Cosmetic composition
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The present invention is a cosmetic composition comprising, component (A) and component (B), wherein, (A) is carboxylic acid ester of inulin and/or hydrolyzed inulin whose degree of substitution by acyl group is larger than 1, and (B) is cyclic silicone oil, and the present invention is the oily cosmetic compound further containing oleophilic component. More over, the present invention is the W/O type emulsified cosmetic composition prepared by further adding aqueous component and an emulsifier to above mentioned cosmetic compound. In the present invention, acyl group composing component (A) is desirable to be an acyl group of carbon number 14 to 22. Further, a part or all of acyl group composing component (A) is desirable to be palmiroyl group and/or stearoyl group. Furthermore, the above mentioned cosmetic composition can contain dextrin carboxylic acid ester whose degree of substitution by acyl group is 1.6 to 2.5. The cyclic silicone oil of component (B) is at least one selected from the group consisting of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane. The cosmetic composition of the present invention has light feel and is excellent in stability and fluidity.
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- Facile and efficient oxidative transformation of primary alcohols to methyl esters in water using hypervalent iodine(III) reagents
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A facile and direct oxidative esterification of primary alcohols in water using a combination of the hypervalent iodine(III) reagent, iodosobenzene (PhIO), and KBr has been developed. This methodology is expected to be environmentally benign since it uses a recyclable polymer-supported iodine(III) reagent in water.
- Tohma, Hirofumi,Maegawa, Tomohiro,Kita, Yasuyuki
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p. 723 - 725
(2007/10/03)
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- Facile oxidation of aldehydes to acids and esters with Oxone
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(Matrix presented) A highly efficient, mild, and simple protocol is presented for the oxidation of aldehydes to carboxylic acids utilizing Oxone as the sole oxidant. Direct conversion of aldehydes in alcoholic solvents to their corresponding ester products is also reported. These reactions may prove to be valuable alternatives to traditional metal-mediated oxidations.
- Travis, Benjamin R.,Sivakumar, Meenakshi,Hollist, G. Olatunji,Borhan, Babak
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p. 1031 - 1034
(2007/10/03)
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- METHOD FOR STORING QUATERNARY AMMONIUM SALT
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A method of improving the stability of a quaternary ammonium salt and a method of efficiently preparing the quaternary ammonium salt having improved stability.
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- Microwave promoted facile synthesis of methyl and ethyl carboxylates
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Microwave irradiation of carboxylic acids with trialkyl orthoacetate in solvent-free conditions afforded an efficient method for alkylation of carboxylic acids to corresponding alkyl carboxylates.
- Lee, Jong Chan,Song, In-Goul,Park, Jin Young
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p. 2209 - 2213
(2007/10/03)
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- Process for preparing potassium clavulanate
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A new crystalline form of potassium clavulanate is disclosed. Also disclosed are a process for producing the new crystalline form of potassium clavulanate, pharmaceutical compositions containing it and methods of treating bacterial infections.
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