- Surfactant-like Br?nsted acidic ionic liquid as an efficient catalyst for selective Mannich reaction and biodiesel production in water
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Abstract: The current study deals with the applications of a surfactant-like Br?nsted acidic ionic liquid (IL) 1-dodecyl-3-methylimidazolium hydrogen sulfate ([DMIm]HSO4) for Mannich reaction at room temperature. The reaction was efficiently preceded in water as solvent without using any harmful and expensive organic additives. Our findings showed that the reaction is selective for cyclohexanone and no Mannich product was observed when cyclopentanone was used as starting material. Density functional theory (DFT) calculations were performed to provide an evidence about the nature of reactivity of the cyclohexanone/cyclopentanone. The activity of the catalyst was also tested for biodiesel production of fatty acids with methanol and ethanol at mild thermal condition without applying additional water removal steps such as using additives or performing special methodologies like azeotropic distillation. In both reactions, the IL can be recycled and reused several times with relatively constant efficiency. Graphical Abstract: [Figure not available: see fulltext.]
- Vafaeezadeh, Majid,Karbalaie-Reza, Mina,Hashemi, Mohammad Mahmoodi,Soleimany, Kasra Qasempour
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- PS-SO3H@phenylenesilica with yolk-double-shell nanostructures as Efficient and stable solid acid catalysts
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Efficient and stable solid acids have been successfully synthesized by sulfonation of polystyrene (PS) in the hollow interiors of silica-based hollow nanostructures. It was found that larger and smaller inner void spaces result in the formation of PS-SO3H@phenylenesilica respectively with double-shell (DSNs) and yolk-double-shell nanostructure (YDSNs). PS-SO3H@phenylenesilica with DSNs and YDSNs nanostructure shows comparable activity and is more active than Amberlyst-15 in the esterification reaction. PS-SO3H@phenylenesilica with YDSNs nanostructure affords higher activity than that with DSNs nanostructure in the Friedel-Crafts alkylation of toluene with 1-hexene, which is mainly attributed to the fact that the unique YDSNs nanostructure could slow down the swelling rate of PS-SO3H during the catalytic process. More importantly, PS-SO3H@phenylenesilica with YDSNs nanostructure showed much higher recycle stability than Amberlyst-15 in the Friedel-Crafts alkylation of toluene with 1-hexene, probably due to the high thermal stability of the sulfonic acid group and the unique YDSNs nanostructure.
- Zhang, Xiaomin,Zhao, Yaopeng,Yang, Qihua
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- A study on the catalytic activity and theoretical modeling of a novel dual acidic mesoporous silica
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A novel mesoporous silica-functionalized dual Bronsted acidic species has been introduced as an efficient catalyst for solvent-free esterification of fatty acids with ethanol. The structure of the catalyst has been characterized by FT-IR spectroscopy, thermal gravimetric analysis (TGA), TEM and N2 adsorption-desorption. TGA of catalyst 1 showed no weight loss before 200 °C, indicating a high degree of hydrophobicity of the surface of the mesoporous silica. TEM images and nitrogen adsorption-desorption showed no noticeable changes to the structure of the catalyst before and after acid treatment. pH metric analysis was performed for the catalyst to determine the loading of the acidic sites. The structure of the catalyst was modeled by mimicking the surface of functionalized silica gel in the form of a cage-like cluster. Various conformers from the proposed structures were selected and optimized at the B3LYP/6-311++G** level of calculation. Natural bond orbital (NBO) analysis was performed to investigate the nature of hydrogen bonding of the catalyst in more detail. Based on the data gained from the optimized structures of the catalyst, a mechanism was proposed for the esterification reaction.
- Vafaeezadeh, Majid,Fattahi, Alireza
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- Competition balance between mesoporous self-assembly and crystallization of zeolite: A key to the formation of mesoporous zeolite
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A hierarchical meso-/microporous aluminosilicate has been synthesized through kinetic control over the competition balance between mesoporous self-assembly and microporous zeolite crystallization by using hexadecyl trimethyl ammonium bromide (CTAB) and tetrabutylammonium hydroxide (TBAOH) as meso- and micro-porogens, respectively. A very small pH value range of 11.10-11.30, which can be well tuned by added ethanol volume fraction and/or NaOH addition, was found to be suitable for the formation of mesoporous zeolite without phase separation. Balanced inorganic species adsorptions onto the meso- and microtemplates, and the subsequent electrostatic interaction between such adsorption-formed meso- and micro-colloids are discussed and proposed to be the two key underlined mechanisms in the successful synthesis. The material shows perfect crystallization of zeolite frameworks and relatively high surface area and meso-/micropore volumes. The prepared mesoporous zeolite showed much higher catalytic activity in the reaction between lauric acid and ethanol than those when using both amorphous mesoporous materials and conventional ZSM-5 zeolite as catalysts.
- Li, Hua,Wu, Huazhong,Shi, Jian-Lin
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- Cross-Coupling between Functionalized Alkylcopper Reagents and Functionalyzed Alkyl Halides
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Functionalized dialkylzincs treated with Me2Cu(CN)(MgCl)2 in DMPU undergo highly chemoselective cross-coupling reactions with functionalized alkyl iodides or benzylic bromides providing polyfunctional products in good to excellent yields.
- Tucker, Charles E.,Knochel, Paul
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- The nanocomposites of SO3H-hollow-nanosphere and chiral amine for asymmetric aldol reaction
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The nanocomposites formed by SO3H-hollow-nanospheres and chiral amines are highly efficient catalysts for the direct asymmetric aldol reaction of cyclohexanone and 4-nitrobenzaldehyde. The catalyst showed 91% yield with 96% ee under optimized reaction conditions. SO3H-hollow-nanospheres were synthesized by oxidation of thiol-hollow-nanospheres, which were fabricated through a one-pot co-condensation of 1,2-bis(trimethoxysilyl)ethane and 3-mercaptopropyltrimethoxysilane around F127 micelles in the presence of NaOAc. Chiral amines could be combined with SO3H-hollow-nanospheres through facile electrostatic interactions. The obtained nanocomposites showed a much higher reaction rate than the catalyst formed from the combination of chiral amine and SO3H-mesoporous-organosilica (ribbon shaped particles with particle size of tens of micrometres) in the direct asymmetric aldol reaction. This is mainly attributed to the hollow spherical morphology and nano-scale particle size (16-20 nm) of the SO3H-hollow-nanospheres. The Royal Society of Chemistry 2009.
- Gao, Jinsuo,Liu, Jian,Bai, Shiyang,Wang, Peiyuan,Zhong, Hua,Yang, Qihua,Li, Can
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- Effective transesterification of triglyceride with sulphonated modified SBA-15 (SBA-15-SO3H): Screening, process and mechanism
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Different morphologies of ZrO2 were produced by different templates: ZrO2(CaCO3), ZrO2(C12H25SO3Na), ZrO2(C12H25SO4Na), ZrO2(CTAB), and solid superacids, such as ZrO2/SBA-15, SO42-/ZrO2, SO42-/ZrO2/SBA-15, and SBA-15-SO3H. The catalytic transesterification activities of these catalysts were tested. The more highly acidic catalysts and higher surface areas led to higher catalytic activity. In particular, the conversion yield of triglyceride reached 90.1% and was maintained for 90 min at 200 °C with 5.0 wt% SBA-15-SO3H, indicating this material to be one of most effective acid catalysts for the transesterification process. The mechanism indicated that the most important process was the abstraction of hydrogen from alcohols and α-substituted carboxylic glycerides. In the initial transesterification, the alcohol hydrogen atoms could be attracted onto the surface. Then, the nucleophilic attack of the alcohol led to the α-substituted carboxylic glyceride. Finally, monoglycerides, diglycerides or glycerine were released from the surface by proton (H+) replacement.
- Hu, Ningmeng,Kong, Zhaoni,He, Liang,Ning, Ping,Gu, Junjie,Miao, Rongrong,Sun, Xiangqian,Guan, Qingqing,Duan, Peigao
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- Lipase activity and enantioselectivity of whole cells from a wild-type Aspergillius flavus strain
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This study reports the high enantiomeric preference of whole cell lipase from Aspergillus flavus wild-type that allows the preparation of a chiral secondary alcohol. Whole cells prepared from a wild-type Aspergillus flavus strain were used as biocatalysts to prepare (R)-1-phenylethyl acetate. (R)-1-Phenylethanol was esterified into (R)-1-phenylethyl acetate with a 94.6% enantiomeric excess (ee) within 24 h at 40 C and (S)-1-phenylethanol remained in the reaction medium with a >99%ee. Besides, this biocatalyst allows the preparation of ethyl laurate and a mixture of 2-chloro-1-(chloromethyl)ethyl acrylate and 2,3-dichloro-1-propyl acrylate. The ethyl laurate yield was 96%, whereas the synthesis of a mixture of the acrylate regioisomers, 2-chloro-1-(chloromethyl)ethyl acrylate and 2,3-dichloro-1-propyl acrylate gave similar yields to those obtained using commercial lipases.
- Solarte, Carmen,Yara-Varon, Edinson,Eras, Jordi,Torres, Merce,Balcells, Merce,Canela-Garayoa, Ramon
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- Efficient and stable PS-SO3H/SiO2 hollow nanospheres with tunable surface properties for acid catalyzed reactions
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Facile synthesis of hybrid solid acids with finely engineered surface properties was successfully realized via sulfonation of polystyrene (PS) dispersed in nanopores of silica hollow nanosphere modified with different organic group. It was found that octyl or perfluorinated octyl could efficiently increase the surface hydrophobicity of the hybrid solid acids. Benefited from the facile adjustability of the surface properties, the catalytic performance of the solid acids could be readily improved in both the esterification of lauric acid with ethanol and the transterification between tripalmitin and methanol. The solid acid modified with perfluorinated octyl shows even higher activity than liquid sulfuric acid in the transesterification reaction. The octyl group incorporated in the silica shell could also prevent the leaching of PS-SO3H during the catalytic process.
- Chen, Jingjing,Chen, Jian,Zhang, Xiaomin,Gao, Jinsuo,Yang, Qihua
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- Medium-chain fatty acids from Eugenia winzerlingii leaves causing insect settling deterrent, nematicidal, and phytotoxic effects
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Eugenia winzerlingii (Myrtaceae) is an endemic plant from the Yucatan peninsula. Its organic extracts and fractions from leaves have been tested on two phloem-feeding insects, Bemisia tabaci and Myzus persicae, on two plant parasitic nematodes, Meloidogyne incognita and Meloidogyne javanica, and phytotoxicity on Lolium perenne and Solanum lycopersicum. Results showed that both the hexane extract and the ethyl acetate extract, as well as the fractions, have strong antifeedant and nematicidal effects. Gas chromatography-mass spectrometry analyses of methylated active fractions revealed the presence of a mixture of fatty acids. Authentic standards of detected fatty acids and methyl and ethyl derivatives were tested on target organisms. The most active compounds were decanoic, undecanoic, and dodecanoic acids. Methyl and ethyl ester derivatives had lower effects in comparison with free fatty acids. Dose-response experiments showed that undecanoic acid was the most potent compound with EC50 values of 21 and 6 nmol/cm2 for M. persicae and B. tabaci, respectively, and 192 and 64 nmol for M. incognita and M. javanica, respectively. In a phytotoxicity assay, medium-chain fatty acids caused a decrease of 38-52% in root length and 50-60% in leaf length of L. perenne, but no effects were observed on S. lycopersicum. This study highlights the importance of the genus Eugenia as a source of bioactive metabolites for plant pest management.
- Cruz-Estrada, Angel,Ruiz-Sánchez, Esaú,Cristóbal-Alejo, Jairo,González-Coloma, Azucena,Andrés, María Fe,Gamboa-Angulo, Marcela
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- Propoxylated Fatty Thiazole, Pyrazole, Triazole, and Pyrrole Derivatives with Antimicrobial and Surface Activity
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Lauric acid and propylene oxide were used to modify four biologically active heterocycles (thiazole, pyrazole, triazole, and pyrrole) to synthesize 17 new surfactants. The chemical structures of these surfactants were confirmed using infrared and 1H, and 13C nuclear magnetic resonance (NMR) spectroscopy. The surfactants all show good surface activity, low critical micelle concentration (CMC) values, high cloud points, and tight interfacial packing. All showed antimicrobial activity on both bacteria and fungi. In addition, biodegradation testing demonstrated significant breakdown within seven days.
- El-Sayed, Refat,Khairou, Khalid S.
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- Entrapment in polymeric material of resting cells of Aspergillus flavus with lipase activity. Application to the synthesis of ethyl laurate
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The lipase activity of resting cells of Aspergillus flavus was improved by entrapment in various polymeric acrylates (PAAFs). Commercially available ethyl acrylate, butyl acrylate and ethyl methacrylate, and acrylates synthesized from 1,3-dichloropropan-2-ol were used as monomers for the in situ polymerization. The cells were physically entrapped via free-radical-polymerization in aqueous medium or by bulk polymerization. The percentage of resting cells immobilized in the polymers was assessed by analysing the ergosterol content. Bulk polymerization with ethyl methacrylate allowed the greatest incorporation ratio, with 85% of entrapped biocatalyst. Entrapped resting cells were used to prepare ethyl laurate, achieving yields of up to 98%. The specific activity (r) of PAAFs was determined using a batch reactor and a packed-bed reactor (PBR). The highest r was observed for the resting cells entrapped in poly(ethyl methacrylate) using PBR. These results demonstrate that entrapped resting cells of A. flavus can be used to prepare commercial products. the Partner Organisations 2014.
- Yara-Varon,Eras,Torres,Villorbina,Espart,Canela-Garayoa
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- Zirconium-containing metal organic frameworks as solid acid catalysts for the esterification of free fatty acids: Synthesis of biodiesel and other compounds of interest
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Zr-containing metal organic frameworks (MOFs) formed by terephthalate (UiO-66) and 2-aminoterephthalate ligands (UiO-66-NH2) are active and stable catalysts for the acid catalyzed esterification of various saturated and unsaturated fatty acids with MeOH and EtOH, with activities comparable (in some cases superior) to other solid acid catalysts previously reported in literature. Besides the formation of the corresponding fatty acid alkyl esters as biodiesel compounds (FAMEs and FAEEs), esterification of biomass-derived fatty acids with other alcohols catalyzed by the Zr-MOFs allows preparing other compounds of interest, such as oleyl oleate or isopropyl palmitate, with good yields under mild conditions.
- Cirujano,Corma,Llabrés I Xamena
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- Novel synthesized microporous ionic polymer applications in transesterification of Jatropha curcas seed oil with short Chain alcohol
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New suites of sulfonic acid-functionalized microporous ionic polymers (PIPs) catalysts were synthesized with polymer, alkyl bromides, and 1, 3-propane sultone via a two-step procedure. The synthesized microporous PIP catalysts were characterized using FT-IR, SEM-Mapping, XPS, N2 adsorption–desorption isotherms, solid NMR spectroscopy, and element analysis. Esterification of several fatty acids with ethanol, which was used as a model reaction in the stabilization of Jatropha curcas seed oil, was checked over functionalized PIP. We tested the catalytic performance of PIP-C8 on the synthesis of fatty acid esters via the transesterification of J. curcas seed oil with a mixture of short-chain alcohols such as ethanol, ethanol–to–diethyl carbonate (1;1 molar ratio), and ethanol–to–dimethyl carbonate (1:1 molar ratio) with 170 mg of PIP-C8 at reflux temperature with agitation. The PIP-C8 catalyst was particularly effective, having achieved yields of 85%, 94%, and 70% for J. curcas seed oil with ethanol, J. curcas seed oil with ethanol–to–DEC, and J. curcas seed oil with ethanol–to–DMC, respectively, under the optimized reaction conditions. The catalyst could be recycled more than five times without significant deactivation. Kinetic studies performed at different temperatures revealed that the conversion of oleic acid to an ethyl ester follows a first-order reaction. The best catalysts with microporous structure (average pore diameter: 1.7–1.9 nm, pore volume: 0.23–0.33 cm3 g–1) and –SO3H density (0.70–0.84 mmol/gcat) were obtained by 1, 3-propane sultone of the chemically activated. The results indicate that the site activity of functionalized microporous ionic polymer materials shows promising approach for the development of environmentally friendly technology.
- Chang, Tao,Hao, Yongjing,Jinxi, Jinxi,Kai, Kai,Panchal, Balaji,Qin, Shenjun,Sun, Yuzhuang,Zhao, Cunling,Zhao, Qiaojing,Zhu, Zheng
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- Small-Angle Neutron Scattering Study of the Structural Effects of Substitution of Tetramethylammonium for Sodium as the Counterion in Dodecyl Sulfate Micelles
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Small-angle neutron scattering (SANS) data have been obtained at 303 K for aqueous micellar solutions of CH3(CH2)11SO4Na (sodium dodecyl sulfate (SDS)) and CH3(CH2)11SO4N(CH3)4 (tetramethylammonium dodecyl sulfate (TMADS)) and their deuterated analogues CH3(CH2)10CD2SO4Na (D2-SDS) and CH3(CH2)11SO4N(CD3)4 (D12-TMADS).Results have been obtained for 0.4 mol ddm-3 surfactant in various H2O/D2O mixtures and for TMADS as a function of surfactant concentration in D2O.The SANS data are well described by charged, monodisperse hard spheres interacting through a screened Coulomb potential.The asphericity and the polydispersity of the systems were estimated to be small.The deuterium for the deuterated surfactants lies mainly in the Stern region of the micelle and increases contrast between the hydrocarbon core and the water-saturated Stern layer.Therefore, these deuterated micellar systems were used to determine the radius of the dry core, which was then used in the determination of the structural parameters for the micellar systems.The degree of hydration was determined without resorting to the assignment of the values for the water of hydration for the individual ions present.It was found that TMADS micelles are smaller and have a higher charge, smaller degree of aggregation, and less but more deeply penetrating water than do SDS micelles.Both SDS and TMADS micelles had substantial amounts of hydrocarbon residing in the aqueous Stern layer.
- Berr, Stuart S.,Coleman, Michael J.,Jones, Richard R. Marriott,Johnson, James S.
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- Designed synthesis of sulfonated polystyrene/mesoporous silica hollow nanospheres as efficient solid acid catalysts
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We report the successful synthesis of hybrid hollow nanospheres (HNs) with sulfonated polystyrene (PS-SO3H) aligned uniformly in the mesoporous channel of a silica shell. The fabrication process involved the sulfonation of silica HNs with polystyrene highly dispersed in the mesoporous shell which was prepared by co-condensation of a mixture of tetraethoxysilane (TEOS) and alkoxysilyl-functionalized poly(methyl acrylate) (PMA) around PS nanospheres in a base medium using cetyltrimethylammonium bromide (CTAB) as structural directing agent followed by THF treatment. The surface properties of the hybrid HNs were adjusted by the amount of PMA incorporated in the silica shell during the synthesis process and also by modification with an octyl group through a grafting method. The hybrid HNs, with acid exchange capacity in the range 0.8 to 2.0 mmol g-1, could efficiently catalyze the esterification reaction of lauric acidwith ethanol. All hybrid HNs show much higher activity than commercial Amberlyst-15 catalyst and the TOF of the optimized hybrid HNs is almost identical to that of concentrated sulfuric acid. The high activity of the hybrid HNs is mainly attributed to the uniform distribution of the PS-SO3H group in the mesoporous silica shell, the penetrating mesopore, and surface hydrophobicity. It was found that the recycle stability of hybrid HNs could be enhanced greatly by octyl group modification, which may prevent the leaching of PS-SO3H during the catalytic process. the Partner Organisations 2014.
- Zhang, Xiaomin,Zhang, Lei,Yang, Qihua
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- Lipase-catalyzed transformations using poly(ethylene glycol) as solvent
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Candida antarctica lipase catalyzes a number of elementary reactions like alcoholysis, ammoniolysis and aminolysis in poly(ethylene glycol) (PEG) media. Reaction rates were comparable to or better than those observed in conventional organic reaction media and ionic liquids. It is envisaged that PEGs could have added benefits for performing biotransformations with highly polar substrates, which are sparingly soluble in common organic solvents.
- Kidwai, Mazaahir,Poddar, Roona,Bhardwaj, Saurav
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- Design, Synthesis, and Study of the Insecticidal Activity of Novel Steroidal 1,3,4-Oxadiazoles
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A series of novel steroidal derivatives with a substituted 1,3,4-oxadiazole structure was designed and synthesized, and the target compounds were evaluated for their insecticidal activity against five aphid species. Most of the tested compounds exhibited potent insecticidal activity against Eriosoma lanigerum (Hausmann), Myzus persicae, and Aphis citricola. Compounds 20g and 24g displayed the highest activity against E. lanigerum, showing LC50 values of 27.6 and 30.4 μg/mL, respectively. Ultrastructural changes in the midgut cells of E. lanigerum were detected by transmission electron microscopy, indicating that these steroidal oxazole derivatives might exert their insecticidal activity by destroying the mitochondria and nuclear membranes in insect midgut cells. Furthermore, a field trial showed that compound 20g exhibited effects similar to those of the positive controls chlorpyrifos and thiamethoxam against E. lanigerum, reaching a control rate of 89.5% at a dose of 200 μg/mL after 21 days. We also investigated the hydrolysis and metabolism of the target compounds in E. lanigerum by assaying the activities of three insecticide-detoxifying enzymes. Compound 20g at 50 μg/mL exhibited inhibitory action on carboxylesterase similar to the known inhibitor triphenyl phosphate. The above results demonstrate the potential of these steroidal oxazole derivatives to be developed as novel pesticides.
- Bai, Hangyu,Jiang, Weiqi,Li, Qi,Li, Tian,Ma, Shichuang,Shi, Baojun,Wu, Wenjun
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p. 11572 - 11581
(2021/10/12)
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- Tunable aryl imidazolium ionic liquids (TAIILs) as environmentally benign catalysts for the esterification of fatty acids to biodiesel fuel
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Herein, we describe the synthesis of tunable aryl imidazolium ionic liquid catalysts and tested for esterification of fatty acids to biodiesel. In this work, six tunable aryl imidazolium ionic liquids (TAIILs) 1a-1f were prepared. These ionic liquids were used as the economical and reusable catalysts for the synthesis of biodiesel fuels. The reaction has been preceded in a monophase at 80 °C for 4 h, after which the product was separated from the catalyst system by a simple liquid/liquid phase separation at room temperature with excellent yields. With the simple post-process, the catalyst is reusable at least 6 times. This novel method offers a short reaction time, good yields, and environmentally benign characteristics.
- Ho, Wen-Yueh,Lin, Wesley,Lin, Yi-Jyun,Luo, Shun-Yuan,Pantawane, Amit,Su, Po-Fang,Thul, Mayur,Tseng, Shao-An,Wu, Hsin-Ru
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- Method for producing ester based on eco-friendly and high efficiency esterification by using base exchange of salt and the compound thereof
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The present invention relates to an esterification reaction-based eco-friendly and high efficiency ester compound using ion exchange and an ester compound thereof. The esterification generally proceeds by reverse reaction with water, resulting in poor yield of the ester. In order to avoid hydrolysis, the esterification reaction was environmentally or non-limited due to the continuous supply of hydrochloric acid gas or the use of chlorinated thionyl chloride as a noxious substance. To the present invention, a continuous hydrochloric acid gas is provided by ion exchange of a salt, and magnesium sulfate acts as a dehydrating agent to remove water generated in esterification. In addition, the reactants are cheap and the product is also low in harmfulness and easier to handle and thus more efficient reaction is possible.
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Paragraph 0075-0083; 0085
(2021/07/07)
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- One-Pot, Tandem Wittig Hydrogenation: Formal C(sp3)-C(sp3) Bond Formation with Extensive Scope
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A one-pot, tandem Wittig hydrogenation of aldehydes with stabilized ylides is reported, representing a formal C(sp3)-C(sp3) bond construction. The tandem reaction operates under mild conditions, is high yielding, and is broad in scope. Chemoselectivity for olefin reduction is observed, and the methodology is demonstrated in the synthesis of lapatinib analogues and a formal synthesis of (±)-cuspareine. Early insights suggest that the chemoselectivity observed in the reduction step is due to partial poisoning of the catalyst, after step one, thus adding to the power of the one-pot procedure.
- Devlin, Rory,Jones, David J.,Mcglacken, Gerard P.
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supporting information
p. 5223 - 5228
(2020/07/14)
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- Ethyl laurate synthesis method taking deep eutectic solvent based on benzyltrimethylammonium chloride as catalyst
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The invention discloses an ethyl laurate synthesis method taking a deep eutectic solvent BAC-DES based on benzyltrimethyl ammonium chloride as a catalyst. The catalyst BAC-DES is prepared by mixing and reacting benzyltrimethylammonium chloride and p-toluenesulfonic acid according to a molar ratio of 1:3. The ethyl laurate is prepared by carrying out an esterification reaction on lauric acid and excessive anhydrous ethanol at a certain temperature, and sequentially carrying out phase separation, atmospheric distillation, reduced pressure distillation and the like. The eutectic solvent BAC-DES is used as the catalyst for an esterification reaction, has a series of advantages of high catalytic activity, easiness in separation from a reaction system, stable reusability, mild reaction conditions and the like, and greatly reduces the production cost of ethyl laurate while meeting the requirements of a green synthesis process.
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Paragraph 0012-0016
(2020/05/02)
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- Method for synthesizing ethyl laurate based on cetyltrimethylammonium bromide deep eutectic solvent catalyst
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The invention discloses a method for preparing ethyl laurate based on a cetyltrimethylammonium bromide deep eutectic solvent catalyst CTAB-DES. The catalyst CTAB-DES is prepared by mixing cetyltrimethylammonium bromide and p-toluenesulfonic acid according to a molar ratio of 1:3; the ethyl laurate is prepared by carrying out an esterification reaction on lauric acid and excessive absolute ethyl alcohol at a certain temperature, and sequentially carrying out phase separation, atmospheric distillation, reduced pressure distillation and the like. Compared with a traditional protonic acid catalyst, the eutectic solvent used as the catalyst of the esterification reaction has the advantages of low corrosion to equipment, no waste acid discharge, easiness in recycling, mild reaction conditions and the like, and meets the requirements of a green synthesis process while the production cost is reduced.
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Paragraph 0010-0014
(2020/06/02)
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- Sulfonic acid modified hollow polymer nanospheres with tunable wall-thickness for improving biodiesel synthesis efficiency
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Precisely designing the morphology and size of nanostructures is vital in green chemistry as various advanced applications depend upon the shapes and dimensions of the functionalised materials. Herein, we report on a green and efficient self-assembly strategy for synthesising hollow polymeric nanospheres with tunable wall thicknesses. The morphology and shell thickness of the nanospheres can be easily tailored by rationally manipulating monomer and catalyst combinations during the one-pot Friedel-Crafts polymerisation process, without using any templates or surfactants. Heterogeneous solid sulfonic acid catalysts can be easily achievedviathe post-sulfonation strategy. These porous materials have preferable surface areas, ordered hollow pore structures, and accessible acidic sites, and they serve as promising catalysts for biodiesel production. This study provides insights into the production of template- and metal-free based catalysts for biofuel production, which is imperative for the green and efficient design and manufacture of high-activity heterogeneous catalysts.
- Kim, Il,Kim, Ji Su,Song, Wenliang,Varyambath, Anuraj,Zhang, Yu
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p. 3572 - 3583
(2020/08/28)
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- Sulfonated Hyper-cross-linked Porous Polyacetylene Networks as Versatile Heterogeneous Acid Catalysts
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Two highly sulfonated micro/mesoporous polymers, P(1,3-DEB)-SO3H and P(1,4-DEB)-SO3H, with permanent porosity, the specific surface area about 550 m2 ? g?1 and the content of SO3H groups of 2.7 mmol ? g?1 were prepared as new acid Porous Polymer Catalysts, PPCs. The PPCs were achieved by easy sulfonation of parent hyper-cross-linked micro/mesoporous polyacetylene-type networks resulting from a chain-growth homopolymerization of 1,3- and 1,4-diethynylbenzenes. New PPCs are reported as highly active and reusable heterogeneous catalysts of esterification of fatty acids with methanol and ethanol, Prins cyclization of aldehydes with isoprenol and intramolecular Prins cyclization of citronellal to isopulegol. The catalytic activity of the micro/mesoporous PPCs (TON values up to 522 mol ? mol?1) was higher than that of commercial polymer-based heterogeneous catalyst Amberlyst 15 possessing gel texture without permanent pores and that of p-toluenesulfonic acid applied as a homogeneous catalyst.
- Sekerová, Lada,B?ezinová, Pavlína,Do, Thuy Tran,Vysko?ilová, Eli?ka,Krupka, Ji?í,?erveny, Libor,Havelková, Lucie,Bashta, Bogdana,Sedlá?ek, Jan
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p. 1075 - 1084
(2020/01/03)
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- NATURAL BIOSURFACTANT OF ESTER AND MANUFACTURING METHOD THEREOF
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The present invention relates to an ester natural surfactant and a manufacturing method thereof. The present invention relates to an eco-friendly ester natural surfactant having excellent solubility in water and biodegradability, and a manufacturing method thereof. The present invention relates to an ester natural surfactant, and more particularly, to an ester natural surfactant and a method for preparing the same. (by machine translation)
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Paragraph 0125; 0126
(2020/12/11)
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- Method for synthesis of long-chain fatty acid ester derivative
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The invention relates to a method for synthesis of a long-chain fatty acid ester derivative. Specifically, a hydrochloride of glycine methyl ester or glycine ethyl ester is used as a catalyst to catalyze the esterification reaction of long-chain fatty acid. The method includes: subjecting alcohol and long-chain fatty acid to esterification reaction under the action of the catalyst at certain temperature condition, then conducting extraction and precipitation with ethyl acetate, performing flushing with a sodium chloride aqueous solution for purification. A hydrochloride of glycine methyl esteror glycine ethyl ester is adopted as the catalyst, which belongs to a green catalyst, is the development trend of modern chemistry, has the characteristics of no corrosion to the reaction kettle, lowprice, no toxicity and the like, and is suitable for use as a catalyst to produce palmitate and laurate perfume raw materials.
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Paragraph 0017-0018; 0021-0022
(2020/01/12)
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- Preparation method of long-chain ester
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The invention relates to the field of organic synthesis and provides a preparation method of long-chain ester, which comprises the following steps: carrying out esterification reaction of the carboxylic acid and the alcohol through a catalyst and obtaining a long-chain ester phase and a water phase post the standing and layering of the reaction liquid; the catalyst comprises ionic liquid or eutectic solvent; purifying and separating the long-chain ester phase to obtain high-purity long-chain ester; introducing the residual substance again into the esterification reaction system for reaction after the water in the water phase is removed. The yield and the purity of the long-chain ester prepared by the invented method are as high as 99.8% and 99% respectively as indicated by the embodiment of the preparation method.
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Paragraph 0118; 0119; 0120
(2019/03/23)
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- Method for preparing advanced fatty acid ester by using catalysis of solid-supported ionic liquid catalyst
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The invention discloses a method for preparing fatty acid ester by using catalysis of a solid-supported ionic liquid catalyst. The method comprises the following steps of (1) by taking fatty acid and alcohol as raw materials and the solid-supported ionic liquid catalyst as a catalyst, reacting in an oil bath of 60-170 DEG C for 0.5-6 hours; and (2) cooling after reaction is completed, layering the catalyst and a reaction system, carrying out suction filtration on a product to separate a solid catalyst, washing through diethyl ether and drying for direct next reaction. Excessive alcohol is evaporated, and the advanced fatty acid ester and glycerel monostearte are obtained through reduced pressure distillation. The fatty acid ester prepared in the step (1) preferably reacts in the oil bath of 90 DEG C for 2 hours. Fatty acid monoglyceride preferably reacts in the oil bath of 140 DEG C for 45 minutes. The yield and purity of the fatty acid ester prepared through catalysis under the combination of preferred conditions can reach higher values.
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Paragraph 0033-0035
(2017/08/29)
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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 0068; 0069; 0070; 0071; 0072; 0073-0079
(2017/06/22)
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- Efficient flow fischer esterification of carboxylic acids with alcohols using sulfonic acid-functionalized silica as supported catalyst
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Flow Fischer esterification of carboxylic acids using hydroxy-substituted sulfonic acid-functionalized silica (HOSAS) packed into a stainless steel column reactor was investigated. HO-SAS well catalyzed flow esterification of long chain carboxylic acids with methanol within 3min of residence time at 110°C, and the methyl esters were quantitatively obtained. The flow esterification protocol was applied to the synthesis of a variety of esters (19 examples) and scalable synthesis was also successful.
- Furuta, Akihiro,Fukuyama, Takahide,Ryu, Ilhyong
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p. 607 - 612
(2017/06/19)
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- One-pot dichlorinative deamidation of primary β-ketoamides
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An approach to the dichlorinative deamidation of primary β-ketoamides through ketonic cleavage is described, and a series of α,α-dichloroketones were furnished mostly in the presence of TEMPO. Based on control experiments, a mechanism involving tandem dichlorination and deamidation is proposed to interpret the observed reactivity.
- Zheng, Congke,Zhang, Xiaohui,Ijaz Hussain, Muhammad,Huang, Mingming,Liu, Qing,Xiong, Yan,Zhu, Xiangming
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supporting information
p. 574 - 577
(2017/01/16)
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- From Dimethylamine to Pyrrolidine: The Development of an Improved Nickel Pincer Complex for Cross-Coupling of Nonactivated Secondary Alkyl Halides
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Replacement of a dimethyl amino group of the amidobis(amine) nickel(II) pincer complex (1), [(MeN2N)Ni-Cl], by a pyrrolidino group resulted in a new nickel(II) pincer complex (2), [(PyrNMeNN)Ni-Cl]. Complex 2 is an efficient catalyst for Kumada and Suzuki-Miyaura cross-coupling of nonactivated secondary alkyl halides, while complex 1 is largely inactive. The significant activity difference is tentatively attributed to a minimal structural difference, which leads to a more hemilabile ligand.
- Perez Garcia, Pablo M.,Di Franco, Thomas,Epenoy, Alexandre,Scopelliti, Rosario,Hu, Xile
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p. 258 - 261
(2016/01/12)
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- Agent having neurotrophic factor-like activity
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The present invention provides a pharmaceutical agent having high safety and a neurotrophic factor-like activity, which contains, as an active ingredient, any one compound included in fatty acids each having 8 carbon atoms (C8) or having 10 carbon atoms (C10) to 12 carbon atoms (C12) or fatty acid esters thereof, such as 3,7-dimethyloctanoic acid ethyl ester, geranicacidethyl ester, and the like, eachof whichhas 8 carbonatoms (C8), decanoic acid methyl ester, trans-2-decenoic acid, trans-2-decenoic acid methyl ester, trans-2-decenoic acid ethyl ester, trans-2-decenoic acid-2-decenyl ester, trans-2-decenoic acid cyclohexyl ester, trans-2-decenoic acid isopropyl ester, trans-3-decenoic acid methyl ester, trans-9-decenoic acid methyl ester, and the like, each of which has 10 carbon atoms (C10), trans-10-undecenoic acid methyl ester, trans-10-undecenoic acid ethyl ester, and the like, each of which has 11 carbon atoms (C11), and dodecanoic acid, and the like, each of which has 12 carbon atoms (C12), or salts thereof or prodrugs thereof.
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Paragraph 0039-0040
(2016/01/25)
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- Immobilization of lipase on biocompatible co-polymer of polyvinyl alcohol and chitosan for synthesis of laurate compounds in supercritical carbon dioxide using response surface methodology
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Biocompatible co-polymer matrix has great importance for enzyme immobilization and subsequent biocatalytic applications to synthesize important organic moieties. Citronellyl laurate is a fatty-acid-ester having pleasant fruity aroma and widely used as/in emulsifier, lubricant in textile, paint or ink-additives, surfactants, perfumery and food-flavouring ingredient. In present study, Burkholderia cepacia lipase (BCL) was immobilized on biodegradable co-polymer of chitosan (CHI) and polyvinyl alcohol (PVA). The synthesized bio-catalyst {PVA:CHI:BCL (6:4:2.5)} was characterized by SEM, TGA, lipase assay and protein-content analysis. This biocatalyst was applied to synthesize citronellyl laurate in supercritical carbon-dioxide (SC-CO2) using response surface methodology with five-factor-three-level Box-Behnken-design to optimize reaction parameters (citronellol: 8.5 mmol; vinyl laurate: 19.87 mmol; biocatalyst: 175.6 mg; temperature: 46.02 °C; pressure: 8.81 MPa) which provided 94 ± 1.52% yield. The protocol is extended to synthesize various important 12 laurate compounds with excellent yield (90-98%) and noteworthy recyclability (upto studied 5 recycles). Interestingly, immobilized PVA/CHI/lipase biocatalyst showed 4-fold higher bio-catalytic activity than free lipase in SC-CO2. Moreover, the biocatalyst activity assessment study showed remarkable activity-stability of immobilized biocatalyst in SC-CO2 media as compared to free enzyme. Thus, present protocol demonstrated potential biocatalytic applications for synthesis of important laurate compounds with excellent recyclability in SC-CO2 as greener biocatalyst and reaction medium.
- Badgujar, Kirtikumar C.,Bhanage, Bhalchandra M.
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p. 1224 - 1236
(2015/07/08)
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- Use of Lecitase-Ultra immobilized on styrene-divinylbenzene beads as catalyst of esterification reactions: Effects of ultrasounds
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Abstract In this work it was evaluated for the first time, the ester synthesis catalyzed by the phospholipase Lecitase-Ultra immobilized styrene-divinylbenzene beads (MCI-Lecitase), comparing the mechanical stirring and the ultrasonic energy. It was studied the specificity of the enzyme using carboxylic acids from C4 to C18, as well as the effects of alcohol chain, organic solvents, biocatalyst content, reaction temperature and substrate concentration. Caprylic and myristic acids were those with the highest reaction rates and yields, using ethanol as substrate. The shorter the alcohol chain, the higher the enzyme activity. Regarding the secondary alcohols, while MCI-Lecitase had no activity versus isopropanol, using 2-pentanol the activity was similar to that with 1-pentanol. Comparing the agitation systems, MCI-Lecitase presented an initial reaction rate more than 2-times higher in the ultrasound-assisted reaction than under traditional mechanical stirring. Moreover, under ultrasonic energy the maximum rate was achieved using 0.5 M of substrates, while under mechanical stirring the maximum enzyme activity was reached at 0.3 M of substrates. Concerning the operational stability, MCI-Lecitase was quite unstable, losing its activity after 6 reaction cycles. By adding molecular sieves in the reaction medium, MCI-Lecitase retained 30% of its initial activity after 6 cycles.
- Alves, Joana S.,Garcia-Galan, Cristina,Danelli, Daiane,Paludo, Natália,Barbosa, Oveimar,Rodrigues, Rafael C.,Fernandez-Lafuente, Roberto
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- PS-SO3H@phenylenesilica with yolk-double-shell nanostructures as efficient and stable solid acid catalysts
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Efficient and stable solid acids have been successfully synthesized by sulfonation of polystyrene (PS) in the hollow interiors of silica-based hollow nanostructures. It was found that larger and smaller inner void spaces result in the formation of PS-SO3H@phenylenesilica respectively with double-shell (DSNs) and yolk-double-shell nanostructure (YDSNs). PS-SO3H@phenylenesilica with DSNs and YDSNs nanostructure shows comparable activity and is more active than Amberlyst-15 in the esterification reaction. PS-SO3H@phenylenesilica with YDSNs nanostructure affords higher activity than that with DSNs nanostructure in the Friedel-Crafts alkylation of toluene with 1-hexene, which is mainly attributed to the fact that the unique YDSNs nanostructure could slow down the swelling rate of PS-SO3H during the catalytic process. More importantly, PS-SO3H@phenylenesilica with YDSNs nanostructure showed much higher recycle stability than Amberlyst-15 in the Friedel-Crafts alkylation of toluene with 1-hexene, probably due to the high thermal stability of the sulfonic acid group and the unique YDSNs nanostructure.
- Zhang, Xiaomin,Zhao, Yaopeng,Yang, Qihua
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p. 180 - 188
(2015/09/28)
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- Suzuki-miyaura cross-coupling reactions of unactivated alkyl halides catalyzed by a nickel pincer complex
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A nickel(II) pincer complex, [(MeN2N)Ni-Cl], was used to catalyze alkyl-alkyl and alkyl-aryl Suzuki-Miyaura coupling reactions of unactivated alkyl halides. The coupling of 9-alkyl-9-borabicyclo[3.3.1]nonane and 9-phenyl-9-borabicyclo[3.3.1]nonane reagents with alkyl halides was achieved in modest to good yields. The reactions tolerated a variety of useful functional groups including ester, ether, furan, thioether, acetal, and Boc groups. Georg Thieme Verlag Stuttgart, New York.
- Di Franco, Thomas,Boutin, Nicolas,Hu, Xile
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p. 2949 - 2958
(2013/11/06)
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- METHOD OF PRODUCING SATURATED ALKYL ESTERS/ACIDS
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Disclosed herein is the production of saturated alkyl esters or acids from furan materials. The starting compounds contain furan, ketone, and ester or acid functional groups and may be biologically-derived. The method includes hydrogenating the starting compound to form a reduced mixture. The method further includes hydrodeoxygenation of the reduced mixture to yield a saturated alkyl ester or acid. The saturated alkyl ester or acid can be unbranched or branched. The ester and acid products have a wide variety of applications and may be further processed into surfactants, solvents, and lubricants suitable for use in consumer products.
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Paragraph 0062
(2013/03/28)
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- Well-dispersed sulfated zirconia nanoparticles as high-efficiency catalysts for the synthesis of bis(indolyl)methanes and biodiesel
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Well-dispersed sulfated zirconia nanoparticles were synthesized with poly(N-vinylpyrrolidone) as a surfactant. The resultant sulfated zirconia nanoparticles are characterized by SEM, XRD, FT-IR and XPS. These nanoparticles were directly used as catalysts for the synthesis of bis(indolyl)methanes and biodiesel via electrophilic substitution reaction of indole with various aldehydes and the esterification of long-chain free fatty acids and exhibited excellent catalytic activity. The mechanism of the formation of the synthesized zirconia nanoparticles was also proposed.
- Chen, Guochang,Guo, Cun-Yue,Qiao, Hongbin,Ye, Mingfu,Qiu, Xiaoning,Yue, Caibo
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- Specific enzyme-catalyzed hydrolysis and synthesis in aqueous and organic medium using biocatalysts with lipase activity from Aspergillus niger MYA 135
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In the present study, the specific hydrolytic activity of three biocatalysts such as the constitutive mycelium-bound lipase, the induced mycelium-bound lipase and the lyophilized induced supernatant from A. niger MYA 135 was evaluated in both aqueous and organic media.A direct correlation between activity in water and n-hexane was not observed for the same hydrolytic reaction. The n-hexane/water activity ratio (RO/A) was applied to characterize the activity in organic medium. The three biocatalysts showed RO/A values higher than 1 for hydrolysis of long-chain fatty acid esters, demonstrating a higher specific hydrolytic activity in organic solvent than in water. A different behavior was observed during hydrolysis of middle-chain fatty acid esters, which was higher in aqueous medium (R O/Adw) observed in a reaction mixture containing propanol and p-nitrophenyl laurate. Finally, both p-nitrophenyl caprate (C10) and p-nitrophenyl laurate (C12) were preferentially methanolized by the lyophilized induced supernatant, being this lipase activity the most specific biocatalyst preparation under transesterification conditions. A selectivity-based analysis of each lipase preparation toward transesterification or hydrolysis in organic medium was evaluated as well. Springer Science+Business Media, LLC 2012.
- Romero, Cintia M.,Pera, Licia M.,Loto, Flavia,Baigori, Mario D.
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p. 1361 - 1368
(2013/01/15)
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- Solvent-free biocatalytic interesterification of acrylate derivatives
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The ability of diverse commercial lipases and whole cells (fungal resting cells) to synthesise allyl and dichloropropyl acrylate from allyl dodecanoate through an interesterification process is presented. The process was carried out without solvent in a conventional batch system. The best biocatalyst among those studied was the commercial enzyme CALB (Candida antarctica lipase B immobilised onto a macroporous acrylic resin). The reaction was sensitive to water activity, and a decrease in the yield was observed at the highest activity studied. CALB could also be applied to diverse acrylic derivatives, although the yields decreased using either ethyl methacrylate or acrylic acid.
- Yara-Varón, Edinson,Eras Joli, Jordi,Torres, Mercè,Sala, Nuria,Villorbina, Gemma,Méndez, Jonh Jairo,Canela-Garayoa, Ramon
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- Hydrophobic N,N-diarylammonium pyrosulfates as dehydrative condensation catalysts under aqueous conditions
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Oil-soluble N,N-diarylammonium pyrosulfates as nonsurfactant-type catalysts for the dehydrative ester condensation under aqueous conditions are described. Preheat treatment of dibasic sulfuric acid with bulky N,N-diarylamines generates water-tolerant salts of pyrosulfuric acid as active catalyst species. The present catalysts in water can also widely be applied to unusual selective esterifications and dehydrative glycosylation.
- Sakakura, Akira,Koshikari, Yoshiki,Akakura, Matsujiro,Ishihara, Kazuaki
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supporting information; experimental part
p. 30 - 33
(2012/02/14)
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- SBA-15-functionalized sulfonic acid confined acidic ionic liquid: A powerful and water-tolerant catalyst for solvent-free esterifications
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Incorporating a hydrophobic Bronsted acid ionic liquid (HBAIL) inside the nanospaces of SBA-15-Pr-SO3H led to a hydrophobic super Bronsted acid catalyst, which showed excellent catalytic performance in direct esterification of alcohols and carboxylic acids at ambient temperature under solvent-free conditions. The Royal Society of Chemistry 2012.
- Karimi, Babak,Vafaeezadeh, Majid
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supporting information; experimental part
p. 3327 - 3329
(2012/04/23)
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- Ultrasound-assisted synthesis of aliphatic acid esters at room temperature
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This work describes the ultrasound-assisted synthesis of saturated aliphatic esters from synthetic aliphatic acids and either methanol or ethanol. The products were isolated in good yields after short reaction times under mild conditions.
- Hobuss, Cristiane B.,Venzke, Dalila,Pacheco, Bruna S.,Souza, Alexander O.,Santos, Marco A.Z.,Moura, Sidnei,Quina, Frank H.,Fiametti, Karina G.,Vladimir Oliveira,Pereira, Claudio M.P.
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experimental part
p. 387 - 389
(2012/04/23)
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- Antimicrobial evaluation of 4-methylsulfanyl benzylidene/3-hydroxy benzylidene hydrazides and QSAR studies
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A series of 4-methylsulfanyl benzylidene/3-hydroxy benzylidene hydrazides (1-20) was synthesized and tested for in vitro antimicrobial activity against S. aureus, B. subtilis, E. coli, C. albicans and A. niger. The results of antimicrobial studies indicated that 3-phenylacrylic acid-(3-hydroxybenzylidene) -hydrazide, 16, was the most effective as it showed both bactericidal and fungicidal properties and other compounds possessed bacteriostatic/fungistatic activity. The multi-target QSAR model demonstrated that the topological parameter, Balaban topological index (J) is effective in describing the antimicrobial activity of synthesized substituted hydrazides. Springer Science+Business Media, LLC 2010.
- Kumar, Davinder,Narang, Rakesh,Judge, Vikramjeet,Kumar, Devinder,Narasimhan, Balasubramanian
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experimental part
p. 382 - 394
(2012/08/27)
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- Layered metal laurates as active catalysts in the methyl/ethyl esterification reactions of lauric acid
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In this work we report the synthesis, characterization and investigation of the catalytic activity of layered copper(II), manganese(II), lanthanum(III) and nickel(II) laurates in the methyl and ethyl esterification reactions of lauric acid. In the methyl esterification, conversions between 80 and 90% were observed for all catalysts, while for the ethyl esterification only manganese laurate showed reasonable catalytic activity, with conversions close to 75%. Reuse of copper and lanthanum laurates in three cycles of reaction was also investigated and both catalysts preserved the structure and retained catalytic activity close to that observed for the first reaction cycle.
- Da Silva Lisboa, Fabio,Da Costa Gardolinski, Jose Eduardo F.,Cordeiro, Claudiney S.,Wypych, Fernando
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experimental part
p. 46 - 56
(2012/04/04)
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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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- Novel Br?nsted acidic deep eutectic solvent as reaction media for esterification of carboxylic acid with alcohols
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New halogen-free Br?nsted acidic deep eutectic solvents (DES) have been prepared by mixing new quaternary ammonium methanesulfonate salts with p-toluenesulfonic acid (PTSA). They have been used as dual solvent-catalyst for esterification of several carboxylic acids with different alcohols with a reagent molar ratio of 1:1. The method is mild, safe, and simple. Ease of recovery and reusability of DES with high activity makes this method efficient and eco-friendly. The tunability of DES properties, attained by changes in the cation, was performed in order to achieve various esters in good yields.
- De Santi, Valerio,Cardellini, Fabio,Brinchi, Lucia,Germani, Raimondo
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scheme or table
p. 5151 - 5155
(2012/09/25)
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- Direct conversion of acetals to esters with high regioselectivity via O,P-acetals
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A new direct conversion of O,O-acetals to esters via O,P-acetal intermediates was developed. The regioselective cleavage of unsymmetrical cyclic acetals occurred to give the more crowded esters as single isomers.
- Maegawa, Tomohiro,Otake, Kazuki,Goto, Akihiro,Fujioka, Hiromichi
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p. 5648 - 5651
(2011/09/15)
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- Tandem one-pot conversion of aldehydes into ethyl esters
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A facile one-pot synthesis of ethyl esters from aldehydes has been developed. This tandem process involves the formation of a nitrile intermediate obtained from the reaction of an aldehyde with hydroxylamine hydrochloride in dimethylsulfoxide (DMSO) at 100°C and the subsequent reaction of the nitrile with ethanol and sulfuric acid at 130°C. The resulting ethyl ester products were produced in good yields (65-90%) and high purity (>95%).
- Siler, Patrick J.,Chill, Samuel T.,Mebane, Robert C.
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body text
p. 1247 - 1250
(2011/05/02)
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- Dodecanoic acid derivatives: Synthesis, antimicrobial evaluation and development of one-target and multi-target QSAR models
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In this study a series of dodecanoic acid derivatives (1-30) were synthesized and evaluated for in vitro antimicrobial activity against the panel of Gram positive, Gram negative bacterial and fungal strains. 4-Nitro phenyl dodecanoate (4) and quinolin-8-yl dodecanoate (5) emerged as most effective antibacterial agents, and 1-(4-benzylpiperazin- 1-yl) dodecan-1-one (15) was found to be the most effective antifungal agent amongst the synthesized dodecanoic acid derivatives. Quantitative structure activity relationship (QSAR) studies performed by the development of one-target and multi-target models indicated that multitarget model was effective in describing the antimicrobial activity of dodecanoic acid derivatives as well demonstrated the importance of topological parameter, zero-order molecular connectivity index (0X). Springer Science+Business Media, LLC 2010.
- Sarova, Devinder,Kapoor, Archana,Narang, Rakesh,Judge, Vikramjeet,Narasimhan, Balasubramanian
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experimental part
p. 769 - 781
(2012/05/20)
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- Synthesis, antimicrobial evaluation and QSAR studies of 3-ethoxy-4-hydroxybenzylidene/4-nitrobenzylidene hydrazides
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A series of 3-ethoxy-4-hydroxybenzylidene/4-nitrobenzylidene hydrazides (1-20) was synthesized and tested for in vitro antimicrobial activity. The results of antimicrobial studies indicated that the compounds having dinitro, methoxy, hydroxy and nitro substituents on phenyl ring of the aromatic acids were most active ones. The QSAR investigation indicated the importance of the topological parameter, third order molecular connectivity index ( 3χ) in describing the antimicrobial activity of synthesized hydrazides.
- Kumar, Davinder,Kapoor, Archana,Thangadurai, Ananda,Kumar, Pradeep,Narasimhan, Balasubramanian
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experimental part
p. 1293 - 1296
(2012/01/07)
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