- Zr-MOF-808 as Catalyst for Amide Esterification
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In this work, zirconium-based metal–organic framework Zr-MOF-808-P has been found to be an efficient and versatile catalyst for amide esterification. Comparing with previously reported homogeneous and heterogeneous catalysts, Zr-MOF-808-P can promote the reaction for a wide range of primary, secondary and tertiary amides with n-butanol as nucleophilic agent. Different alcohols have been employed in amide esterification with quantitative yields. Moreover, the catalyst acts as a heterogeneous catalyst and could be reused for at least five consecutive cycles. The amide esterification mechanism has been studied on the Zr-MOF-808 at molecular level by in situ FTIR spectroscopic technique and kinetic study.
- Villoria-del-álamo, Beatriz,Rojas-Buzo, Sergio,García-García, Pilar,Corma, Avelino
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supporting information
p. 4588 - 4598
(2020/12/25)
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- PH-Responsive Pickering emulsion stabilized by polymer-coated silica nanoaggregates and applied to recyclable interfacial catalysis
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We first synthesized a diblock copolymer poly[tert-butyl methacrylate]-b-poly[3-(trimethoxysilyl)propyl methacrylate] (PtBMA-b-PTMSPMA) through reversible addition-fragmentation chain transfer (RAFT) living radical polymerization and grafted it onto fumed silica by converting the PTMSPMA segment to silanol and the PtBMA segment to polymethylacrylic acid (PMAA) in the presence of trifluoroacetic acid in order to obtain PMAA brush-coated silica nanoaggregates P-Si. TEM, DLS, FTIR, and TGA results confirmed the successful modification of the starting materials. The nanoaggregates flocculated and stabilized a toluene-in-water Pickering emulsion at low pH, while the nanoaggregates were well dispersed in water and broke the emulsion under both neutral and basic conditions. Alternatively, the addition of acid/base induced emulsification/demulsification cycles that were sustained for several cycles. Moreover, when the P-Si was mixed with Rh-loaded silica, Rh-Si, the mixture had the same pH-responsive Pickering emulsion behavior as the single P-Si. This Pickering emulsion system can be used in the biphasic interfacial catalytic hydrogenation of olefins and had excellent yields under a hydrogen atmosphere. The yield of Pickering emulsion catalysis rapidly reached more than 99% in 3 h, while that of the demulsified mixture failed to reach 20% in 4 h, which verified the promotion of catalysis by the Pickering emulsion. Base-induced demulsification can be used to separate the products and recycle the catalyst. This pH-responsive Pickering emulsion catalytic system was capable of several cycles of reuse, and there was no significant decrease in catalytic efficiency even after eight cycles. This journal is
- Dong, Jinfeng,Luo, Ruidong,Luo, Yunbai
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p. 42423 - 42431
(2020/12/09)
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- A pH-switched Pickering emulsion catalytic system: High reaction efficiency and facile catalyst recycling
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A smart Pickering emulsion catalytic system is constructed, which not only exhibits fivefold reaction rate enhancement effects in comparison to the conventional biphasic system but also can be facilely demulsified by tuning pH, allowing for in situ recycling nanocatalysts.
- Huang, Jianping,Yang, Hengquan
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supporting information
p. 7333 - 7336
(2015/04/27)
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- Facile Protocol for Water-Tolerant "Frustrated Lewis Pair"-Catalyzed Hydrogenation
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Despite rapid advances in the field of metal-free, "frustrated Lewis pair" (FLP)-catalyzed hydrogenation, the need for strictly anhydrous reaction conditions has hampered wide-scale uptake of this methodology. Herein, we report that, despite the generally perceived moisture sensitivity of FLPs, 1,4-dioxane solutions of B(C6F5)3 actually show appreciable moisture tolerance and can catalyze hydrogenation of a range of weakly basic substrates without the need for rigorously inert conditions. In particular, reactions can be performed directly in commercially available nonanhydrous solvents without subsequent drying or use of internal desiccants.
- Scott, Daniel J.,Simmons, Trevor R.,Lawrence, Elliot J.,Wildgoose, Gregory G.,Fuchter, Matthew J.,Ashley, Andrew E.
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p. 5540 - 5544
(2015/09/15)
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- Tuning the wettability of mesoporous silica for enhancing the catalysis efficiency of aqueous reactions
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A series of mesoporous silica-based catalysts with finely-tuned surface wettability have been synthesized, of which the catalysis efficiency towards aqueous hydrogenations is highly dependent on their surface wettability and can be five times higher than that of the commercial Pd/C catalyst. This journal is the Partner Organisations 2014.
- Fu, Luman,Li, Shuru,Han, Zhongyuan,Liu, Huifang,Yang, Hengquan
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supporting information
p. 10045 - 10048
(2014/08/18)
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- Nematicidal activity of natural ester compounds and their analogues against pine wood nematode, bursaphelenchus xylophilus
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In this study, we evaluated the nematicidal activity of natural ester compounds against the pine wood nematode, Bursaphelenchus xylophilus, to identify candidates for the development of novel, safe nematicides. We also tested the nematicidal activity of synthesized analogues of these ester compounds to determine the structure-activity relationship. Among 28 ester compounds tested, isobutyl 2-methylbutanoate, 3-methylbutyl 2-methylbutanoate, 3-methylbutyl tiglate, 3-methyl-2-butenyl 2- methylbutanoate, and pentyl 2-methylbutanoate showed strong nematicidal activity against the pine wood nematode at a 1 mg/ mL concentration. The other ester compounds showed weak nematicidal activity. The LC50 values of 3-methylbutyl tiglate, isobutyl 2-methylbutanoate, 3-methylbutyl 2-methylbutanoate, 3-methyl-2-butenyl 2-methylbutanoate, and pentyl 2- methylbutanoate were 0.0218, 0.0284, 0.0326, 0.0402, and 0.0480 mg/mL, respectively. The ester compounds described herein merit further study as potential nematicides for pine wood nematode control.
- Seo, Seon-Mi,Kim, Junheon,Koh, Sang-Hyun,Ahn, Young-Joon,Park, Il-Kwon
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p. 9103 - 9108
(2015/03/14)
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- Fluorous 4-N,N-dimethylaminopyridium iodide: Recyclable organocatalysts by precipitation for acylation reaction at room temperature
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A novel fluorous DMAP quaternary ammonium iodide salt organocatalyst was prepared. This fluorous organocatalyst was successfully employed to the acylation reaction at room temperature without the use of a stoichiometric amount of external base. It could be recovered 3 times from the reaction mixture by simple precipitation with excellent purity for direct reuse.
- Yi, Wen-Bin,Zhu, Yi-Wei,Cai, Chun
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- Esterification of carboxylate-based ionic liquids with alkyl halides
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A facile reaction of 1-ethyl-3-methylimidazolium acetate ([EMIm]Ac) with dichloromethane at room temperature was observed with esters among the products. This esterification can be exploited for mild solvent-free esterification with a range of other carboxylate-based ionic liquids and alkyl halides. The Royal Society of Chemistry.
- Zhao, Bin,Greiner, Lasse,Leitner, Walter
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scheme or table
p. 2973 - 2975
(2011/04/24)
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- Enhanced Pd-catalyzed hydrogenation of olefins within polymeric microreactors under organic/aqueous biphasic conditions
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A microreactor of a water-soluble hollow polymeric microsphere with Pd nanoparticles immobilized in the wall was proposed for the hydrogenation of olefins under organic and aqueous biphasic conditions. It was found that the microreactor was stable and was used in practical application for continuous hydrogenation of olefins on a technical scale without deactivation in activity. It was composed of three parts, such as the outer corona of polyacrylamide (PAM), the cross-linked and hydrophobic wall of poly[styrene-co-2-(acetoacetoxy) -ethylmethacrylate] (PS-co-PAEMA), and 3.9 mm Pd nanoparticles. Hollow microspheres were constructed using several procedures of seed polymerization along with removal of the seed for the synthesis of the microreactor. It was observed that the microreactor dispersed easily in aqueous phase due to the presence of the hydrophilic PAM corona. The hydrogenation of CA with H 2 was also evaluated to investigate hydrogenation of olefins within the microreactor.
- Lan, Yang,Zhang, Minchao,Zhang, Wangqing,Yang, Li
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scheme or table
p. 3670 - 3673
(2009/12/05)
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- DEGRADATION OF POLYCYCLIC AROMATIC HYDROCARBONS TO RENDER THEM AVAILABLE FOR BIODEGRADATION
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A method for the degradation of polycyclic aromatic compounds is disclosed that involves dissolving ozone in a bipolar solvent comprising a non-polar solvent in which is of sufficiently non-polar character to solubilized the polycyclic aromatic compounds, and a polar-water-compatible solvent which is fully miscible with the non-polar solvent to form a single phase with the non-polar solvent. The bipolar solvent with dissolved ozone is contacted with the polycyclic aromatic compounds to solubilize the polycyclic aromatic compounds and react the dissolved polycyclic aromatic compounds with the ozone to degrade the dissolved polycyclic aromatic compounds to oxygenated intermediates. The bipolar solvent is then mixed with sufficient water to form separate non-polar and polar phases, the non-polar phase comprising the non-polar solvent and the polar phase comprising the non-polar solvent and the oxygenated intermediates. The polar phase is then diluted and incubated with bacteria to biodegrade the oxygenated intermediates.
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Page/Page column 5-8; 15-16
(2008/12/07)
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- Structure-function correlation in lipase catalysed esterification reactions of short and medium carbon chain length alcohols and acids
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An attempt has been made to correlate the carbon chain lengths of acids and alcohols to the extent of esterification in the Rhizomucor miehei lipase catalyzed esterification reactions involving acids of carbon chain length C2-C5 and alcohols of carbon chain length C1-C8.
- Divakar, Soundar
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p. 1919 - 1922
(2007/10/03)
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- Kinetics and mechanism of oxidation of aliphatic acetals with peroxomonosulphate
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The oxidation of fifteen aliphatic acetals of normal aliphatic aldehydes and substituted aliphatic aldehydes with aliphatic and substituted aliphatic as well as with aromatic alcohols by peroxomonosulphate in aqueous acetic acid medium is first order each in [oxidant] and [acetal] and yields the corresponding esters as the main product. The oxidation reaction is independent of change in dielectric constant of the medium. The activation enthalpies and entropies of the reactions are linearly related. A mechanism involving hydride ion shift is proposed.
- Janakiram,Venkataraman,Basheer Ahamed
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p. 339 - 341
(2007/10/03)
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- Novel Template Effects of Distannoxane Catalysts in Highly Efficient Transesterification and Esterification
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The transesterification of carboxylic esters and the esterification of carboxylic acids are effected under mild conditions under catalysis by 1,3-disubstituted tetraalkyldistannoxanes 1.Various functional groups remain unaffected and otherwise difficult to obtain esters are accessible.An ester bearing a tertiary butyl group in the carboxylic acid moiety remained unchanged in competition experiments with a less bulky ester, which undergoes transesterification quantitatively.The unique features of the reactions are attributable to the template effects of the dimeric structure of 1.The facility with which compounds 1 can be converted into alkoxystannoxanes 2 and the synergistic effect of the proximate tin atoms of 2 play key roles in permitting smooth reactions and high selectivity.Another notable feature of compounds 1 is their unusually high solubility in organic solvents, even though the compounds have a metaloxane core as a major skeletal part.The double-layered structure of 1, in which the inorganic moiety is surrounded by eight alkyl groups, permits esterification to be driven to completion simply by heating a mixture of the carboxylic acid and the alcohol.The distannoxane-catalyzed esterification is irreversible, and thus, no hydrolysis of the product esters occurs when compounds 1 are used as catalysts.
- Otera, Junzo,Dan-oh, Nobushisa,Nozaki, Hitosi
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p. 5307 - 5311
(2007/10/02)
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- CATALYSED LIQUID PHASE OXIDATION OF ACETALS BY MOLECULAR OXYGEN
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Nine different acetals have been oxidized in the presence of Co(OOCCH3)2*4H2O under isobaric conditions (0.1 - 0.2 MPa O2) while following the uptake of molecular oxygen.The reactivity of acetals was expressed by the rate constants of the autocatalytic model of oxidation.The main product of the oxidation are alcohols, esters and acids.The distribution of products and the total reactivity of acetals are controlled by the structure of both parts of acetal molecule.The dominant effects of the course of the reaction exerts the type of carbon atoms on which radicals are formed.The oxidation is accompanied by consecutive and co-oxidation reactions, by deactivation of the catalysts and by decarbonylation of intermediate products.The effect of oxygen pressure is reported and the more detailed radical mechanism of the oxidation is proposed.
- Vcelak, Jaroslav,Klimova, Miroslava,Chvalovsky, Vaclav
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p. 847 - 866
(2007/10/02)
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- Quarternary Ammonium Salts for Butylation and Mass Spectral Identification of Volatile Organic Acids
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The esterification method described by Greeley (J.Chromatogr. 1974, 88, 229) was modified to overcome the problem of volatile acid evaporation during sample workup procedures.After solvent extraction from an aqueous sample, the acids were converted to their butyl ester derivatives in a two step process.Firstly, an involatile quarternary ammonium salts was formed which allowed concentration by solvent evaporation without loss of volatile acids.The acid salts were then converted to butyl esters by heating in the presence of n-butyl bromide and the esters were separated on a support- coated open tabular (SCOT) OV17 capillary column.The recovery and butylation yield were shown to be quantitative for isobutyric acid and the linearities and limits of detection are given for the five C4-C5 aliphatic acids.The mass spectra of butyl esters contain abundant rearrangement ions not present in methyl, ethyl, trimethylsilyl, or aryl esters which enable their rapid identification.The method was applied to the analysis of volatile urinary acids from a patient with Maple Syrup Urine Disease and showed conclusively the presence of both 2-methylbutyric and isovaleric acids.
- Burke, Daniel G.,Halpern, Berthold
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p. 822 - 826
(2007/10/02)
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- Selective Dimerization of Aldehydes to Esters Catalyzed by Hydridoruthenium Complexes
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RuH2(PPh3)4 and other hydridoruthenium complexes catalyze selective conversion of aldehydes into esters in high yields.The method is applicable to most aliphatic aldehydes as well as to aromatic aldehydes.The purity of aldehydes is critical for achieving high conversions, since the presence of carboxylic acid completely inhibits the reaction and alcohol and triphenylphosphine reduce the yields of esters.RuH2(PPh3)4 is converted into Ru(CO)3(PPh3)2 through the reaction indicating the occurrence of decarbonylation of aldehyde.A mechanism involving the acyl-H cleavageof aldehyde is proposed to account for the catalysis and formation of compounds accompanying the reaction.The mechanism is compared with an alternative one which comprises of consecutive insertions of two aldehyde molecules into Ru-H bond followed by β-hydrogen abstraction from an alkoxo intermediate formed.Addition of water changes the reaction course togive carboxylato carbonyl complexes Ru(OCOR)2(CO)m(PPh3)2 (m = 1 and 2).Cross esterification studies showed the reactivity order of RCHO as R = Et > Me > n-Pr > i-Pr >> Ph.
- Ito, Takashi,Horino, Hiroshi,Koshiro, Yoshitaka,Yamamoto, Akio
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p. 504 - 512
(2007/10/02)
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- Reaction of Lithium Dialkylcuprates with S-2-Pyridiyl Thioates in the Presence of Oxygen. A Carboxylic Ester Synthesis
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Reaction of lithium dialkylcuprates with S-2-pyridyl thioates in the presence of oxygen affords carboxylic esters in high yields, whereas under nitrogen it affords ketones.
- Kim, Sunggak,Lee, Jae In,Chung, Bong Young
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p. 1231 - 1232
(2007/10/02)
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