- Kinetics of the esterification of acetic acid with 2-propanol: Impact of different acidic cation exchange resins on reaction mechanism
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The kinetics of the esterification of acetic acid with the secondary alcohol, 2-propanol, catalyzed by the cation exchange resins, Dowex 50Wx8-400, Amberlite IR-120, and Amberlyst 15 has been studied at temperatures of 303, 323, and 343 K; acid to alcohol molar ratios of 0.5, 1, and 2; and catalyst loadings of 20, 40, and 60 g/L. The equilibrium constant was experimentally determined, and the reaction was found to be mildly exothermic. External and internal diffusion limitations were absent under the implemented experimental conditions. Systems catalyzed by gel-type resins (Dowex 50Wx8-400 and Amberlite IR-120) exhibit some similarities in their reaction kinetics. Increase in reaction temperature, acid to alcohol ratio, and catalyst loading is found to enhance reaction kinetics for the three catalysts. The pseudohomogeneous (PH), Eley Rideal (ER), Langmuir Hinshelwood (LH), modified Langmuir Hinshelwood (ML), and Poepken (PP) models were found to predict reaction kinetics with mean relative errors of less than 5.4%. However, the ML model was found to be better for predicting reaction kinetics in the systems catalyzed by gel-type resins, while the PP model was better for the system catalyzed by the macroreticular catalyst, Amberlyst 15. The Eact for the forward reaction is found to be 57.0, 59.0, and 64.0 kJ/mole for the systems catalyzed by Dowex 50Wx8-400, Amberlite IR-120, and Amberlyst 15, respectively. For these three catalysts, the adsorption equilibrium constants of the components present in the system increase in the same order as do the solubility parameters of the component. Nonideality in the system is successfully accounted for by the UNIFAC model.
- Ali, Sami H.,Merchant, Sabiha Q.
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- Synchrotron Photoionization Study of the Diisopropyl Ether Oxidation
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Scientific evidence has shown oxygenates help to reduce dangerous pollutants arising from burning fossil fuel in the automotive sector. For this reason, their use as additives has spread widely. The aim of this work consists in providing a comprehensive identification of the main primary oxidation products of diisopropyl ether (DIPE), one of the most promising among etheric oxygenates. The Cl-initiated oxidation of DIPE is examinated by using a vacuum ultraviolet (VUV) synchrotron radiation at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory (LBNL). Products are identified on the basis of their mass-to-charge ratio, shape of photoionization spectra, adiabatic ionization energies, and chemical kinetic profiles, at three different temperatures (298, 550, and 650 K). Acetone, propanal, propene, and isopropyl acetate have been identified as major reaction products. Acetone is the main primary product. Theoretical calculations using the composite CBS-QB3 method provided useful tools to validate the postulated reaction mechanisms leading to experimentally observed species. The formation of other species is also discussed.
- Giustini, Andrea,Meloni, Giovanni
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- Acetylation of alcohols catalyzed by dodeca-tungsto(molybdo)phosphoric acid
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Acetylation of primary, secondary, and tertiary alcohols was carried out in some refluxing alkyl acetates and in two carboxylic acids with the participation of catalytic amounts of H3PW12O 40, H3PMo12O40, and H 14P5W30O110 with good yields and high stereo(regio)specificity under mild reaction condition. H 3PW12O40 and H3PMo 12O40 have also shown excellent reactivity in the formylation of 1-butanol with ethyl formate at room temperature and in short reaction times. Heteropolyacid catalysts could be separated after a simple work up and reused for several times. Springer-Verlag 2006.
- Tayebee, Reza,Alizadeh, Mohammad H.
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- Reaction of the Nitrate Radical with Some Potential Automotive Fuel Additives. A Kinetic and Mechanistic Study
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Rate coefficients for the reaction of NO3 with ethyl tert-butyl ether (ETBE), diisopropyl ether (DIPE), and tert-amyl methyl ether (TAME) have been determined.Absolute rates were measured at temperatures between 257 and 367 K using the fast flow-discharge (FFD) technique.Relative rate experiments were also performed at 295 K in a reactor equipped with White optics and using FTIR spectroscopy to follow the reactions.Rate data from FFD experiments can be presented as follows: kETBE=(2.48 +/-0.78)E-12exp, kDIPE=(2.02 +/-0.35)E-12exp, and kTAME=(1.21 +/-0.22)E-12exp (in units of cm3 molecule-1 s-1).The rate coefficients at room temperature from the FFD experiments are in goog agreement with the corresponding rate coefficients from the relative experiments.Products from simulated atmospheric oxidation of the investigated ethers, initiated by the reaction with nitrate radical, were identified using FTIR spectroscopy.The degradation of ETBE results in tert-butyl formate, tert-butyl acetate, formaldehyde, and methyl nitrate, that of DIPE in acetone, isopropyl nitrate, isopropyl acetate, and formaldehyde, and that of TAME in tert-amyl formate, formaldehyde, and tert-amyl nitrate.
- Langer, Sarka,Ljundstroem, Evert
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- The heterogenation of melamine and its catalytic activity
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The immobilization of melamine (Mela) onto silica extracted from rice husk ash (RHA) has been done via 3-chloropropyltriethoxysiline (CPTES). The resulting catalyst was designated as RHAPrMela. The melamine loading on the silica was found to be ca. 65.74%. The 29Si MAS NMR showed the presence of T2, T3, Q3 and Q4 silicon centers. The 13C MAS NMR showed that RHAPrMela had three chemical shifts at 14.83, 31.17 and 52.24 ppm, consistent with the three carbon atoms, and two chemical shifts at 161.52 and 169.67 ppm with double spinning side bands, indicating that the three carbon atoms in melamine ring are not equivalent in RHAPrMela. The catalytic potential of RHAPrMela was tested for the esterification of acetic acid with several alcohols. A conversion of 73% was achieved with 100% selectivity for the respective esters. The catalyst was easily regenerated and could be reused many times without loss of catalytic activity.
- Adam, Farook,Hello, Kasim Mohammed,Osman, Hasnah
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- Efficient Baeyer-Villiger electro-oxidation of ketones with molecular oxygen using an activated carbon fiber electrode in ionic liquid [bmim][OTf]
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A new and efficient method for the synthesis of lactones and esters involving the application of an molecular oxygen-based electro-catalytic oxidation system and ionic liquid [bmim][OTf] as electrolyte has been developed. The reaction between various ketones with molecular oxygen proceeds in a three-electrode cell under constant current conditions in [bmim][OTf] at room temperature to give the corresponding esters and lactones in good to excellent isolated yield. Additionally, the possible mechanism of Baeyer-Villiger oxidation of ketones in the electro-catalytic system is proposed.
- Hu, Yu Lin,Xie, Yi Bi,Li, De Jiang
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- Alkali metal alkoxide clusters: Convenient catalysts for the synthesis of methylphosphonates
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Alkali metal alkoxides are good catalysts (1-8 mol %) for promoting the interchange reaction between carbonyl and phosphorus esters. This reactivity leads to convenient methodologies for the synthesis of symmetric and unsymmetric alkyl-substituted methylphosphonates from dimethyl methylphosphonate (DMMP). Reactions rates are high with initial turnover frequencies (N(t)) in excess of 1 x 106 h-1 observed and with KO(t)Bu > NaO(t)Bu > LiO(t)Bu. The reactions were sensitive to steric effects in the product methylphosphonates with reaction rates paralleling the size of the transferring alkoxide (n-alkyl > isoalkyl >> tert-alkyl). For the test reaction DMMP + isopropyl acetate, substitution kinetics were consistent with a scenario wherein each methoxide is replaced sequentially, and the substitution rate for the second displacement is substantially slower than the first. Kinetic studies on the first substitution process were indicative of a concentration dependent rate law; a scenario most easily accounted for by a coupled transesterification wherein alkoxide reversibly and independently adds to phosphonate and ester.
- Kissling, Rebecca M.,Gagne, Michel R.
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- Chemical Conversions using Sheet Silicates: Facile Ester Synthesis by Direct Addition of Acids to Alkenes
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Ethene and acetic acid react in the interlamellar regions of certain cation (e.g.Al3+)-exchanged montmorillonites to yield ethyl acetate as the sole product, and a variety of carboxylic acids readily add to C2-C8 alkenes at temperatures above 100 deg C to yield the corresponding esters in high and selective yields.
- Ballantine, James A.,Davies, Mary,Purnell, Howard,Rayanakorn, Mongkon,Thomas, John M.,Williams, Kevin J.
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- Multifunctional Zn(II) Complexes: Photophysical Properties and Catalytic Transesterification toward Biodiesel Synthesis
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Using 4-substituted derivatives of phenol-based compartmental Schiff-base hydroxyl-rich ligand, four multifunctional binuclear Zn(II) complexes have been synthesized and characterized. The photophysical properties of these complexes were explored in the solid state, in solutions, and in poly(methyl methacrylate) (PMMA) matrix, which revealed their good potential as tunable solid state emitters. Some of these complexes acted as efficient catalysts for the transesterification of esters and canola oil showing their potential in biodiesel generation. Mechanistic investigations using ESI-MS revealed that the transesterification catalyzed by these complexes proceeds through two types of acyl intermediates.
- Gupta, Abhishek Kumar,Dhir, Abhimanew,Pradeep, Chullikkattil P.
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- Hydroxide-promoted selective C(α)-C(β) bond activation of aliphatic ethers by rhodium(III) porphyrins
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The selective aliphatic C(α)-C(β) bond activation (CCA) of ethers by rhodium(III) porphyrin halides in the presence of KOH was achieved to give Rh-C(β) alkyls up to 88% yield. The addition of H2O and a phase transfer agent Ph4PBr improved the homogeneity of the reaction mixture and significantly brought down the reaction temperature to 60 °C. At this mild temperature, the C(α) co-product was oxidized to the corresponding esters in up to 89% yield. KOH promotes the bond activation by transferring the hydroxyl group to rhodium porphyrin to generate the key intermediate RhIII(ttp)OH (ttp = 5,10,15,20-tetratolylporphyrinate dianion).
- Lee, Siu Yin,Lai, Tsz Ho,Hui, Ying Ying,Chan, Kin Shing
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- Homogeneous Metal-Complex Catalyst Systems in the Partial Oxidation of Propane with Oxygen
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Abstract: The effect of copper compounds and phosphorus–molybdenum–vanadium heteropoly acids (HPAs) H5PMo10V2O40 and H7PMo8V4O40 used as cocatalysts in the cooxidation
- Chepaikin, E. G.,Menchikova, G. N.,Pomogailo, S. I.
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- Rasta resin-TBD as a reusable catalyst for transesterification reactions
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Rasta resin-TBD has been synthesized and used to catalyze a wide range of transesterification reactions, including biodiesel synthesis and ring-opening polymerizations. It was found to be a more efficient heterogeneous catalyst than a related polystyrene-based analogue based on the Merrifield resin architecture involving divinylbenzene cross-linking. In the reactions studied rasta resin-TBD was separated from the desired products simply by filtration, and it could be regenerated and reused numerous times without significant loss of catalytic activity. Georg Thieme Verlag Stuttgart · New York.
- Yang, Yun-Chin,Leung, Dennis Y.C.,Toy, Patrick H.
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- Direct catalytic oxidation of lower alkanes in ionic liquid media
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Immobilization of rhodium (palladium)-copper-chloride catalytic systems in ionic liquids as high-boiling-point solvents affects the distribution of propane oxidation products: the acetone yield increases and the yield of alcohols decreases. Propane is oxidized to acetone, bypassing the isopropanol formation step. Methane is oxidized under more severe conditions than propane, giving methyl trifluoroacetate as the main product. Mechanisms of action of the catalytic systems based on rhodium and palladium are close to each other and likely include oxo or peroxo complexes as intermediates.
- Chepaikin,Bezruchko,Menchikova,Moiseeva,Gekhman
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- Esterification processes based on functionalized mesoporous solids
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The abilities of niobium and manganese to enhance oxidation of thiol groups in (3-mercaptopropyl)trimethoxysilane (MPTMS) used for functionalization of SBA-15 and MCF materials, by hydrogen peroxide in order to form catalysts with acidic properties were evaluated. Materials obtained were characterized by: N2 adsorption, XRD, XRF, elemental and thermal analyses and titration of acid sites. The highest concentration of acidic sites was found for SBA-15 structure modified with niobium. The catalytic activities of materials obtained were examined in esterification of acetic acid with ethanol and 2-propanol. Both niobium containing samples (MP-NbSBA-15 and MP-NbMCF) showed high yields of ethyl and 2-propyl acetate. The amount of 2-propyl acetate formed was found to linearly depend on the number of acid sites on the catalyst surface. The reuse tests proved that the drop in the catalyst activity in consecutive catalytic cycles is not too high, which suggests possible application of the materials obtained after further optimization.
- Trejda, Maciej,Pokora, Beata,Ziolek, Maria
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- A potential “green” organotin: Bis-(methylthiopropyl)tin dichloride, [MeS (CH2)3]2SnCl2
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The tetravalent organotin compound [MeS(CH2)3]2SnCl2, 1, has been synthesized in high yield and structurally characterized as being hexa-coordinate at tin with two intramolecular Sn-S bonds. The specific structure has been shown by theoretical calculations to be the low energy geometric structure available, and the differences associated with the experimental and calculated Sn-S bond lengths ascribed to crystal packing issues. The intramolecular Sn-S bonding produces a benign organotin compound with respect to its interactions with human natural killer cells; however, this blocking of coordination sites at Sn does not reduce its capacity to act as an efficient esterification catalyst.
- Vargas, Diana Gabriela,Metta-Maga?a, Alejandro,Sharma, Hemant K.,Whalen, Margaret M.,Gilbert, Thomas M.,Pannell, Keith H.
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- A new simplified method for esterification of secondary and tertiary alcohols
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Esters of secondary and tertiary alcohols have been synthetized in the absence of solvent and catalyst and only under the effect of temperature with high yields.
- Kammoun,Le Bigot,Delmas,Boutevin
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- Counterion-directed regioselective acetylation of octyl β-D-glucopyranoside
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(Equation presented) The DMAP-catalyzed acetylation of octyl β-D-glucopyranoside with a series of acetylating agents has been investigated. The nature of the counterion of the catalytic DMAP-acetyl complex dramatically influences the outcome of the reaction, indicating that the deprotonation of the transition state is controlling the reaction. Noncovalent interactions of the acetate ion with the substrate seem to direct the acetylation toward secondary hydroxyl groups.
- Kattnig, Egmont,Albert, Martin
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- Commercial zinc oxide (Zn2+) as an efficient and environmentally benign catalyst for homogeneous benzoylation of hydroxyl functional groups
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The solvent-free O-acylation of some alcohols with benzoyl chloride was carried out to the corresponding benzoylated products in good to excellent yields by the mediation of a catalytic amount (5 mol%) of the commercially available and inexpensive zinc oxide in short reaction times. This methodology represents an eco-friendly and simple catalytic alternative for benzoylation of primary, secondary, tertiary, and benzylic alcohols with ZnO. This catalytic system was homogeneous because of high solubility of zinc oxide in the reaction medium. Findings showed that ZnO was dissolved in hydrochloric acid, created in situ, after a few minutes. Although, others argued on the catalytic role of solid phase zinc oxide under a heterogeneous condition, it is not surprising to emphasize on the catalytic function of Zn2+ in the benzoylation of alcohols under homogeneous reaction conditions. Zinc oxide served as pre-catalyst to form Zn2+, as the catalytically active species.
- Tayebee, Reza,Cheravi, Fatemeh,Mirzaee, Mehdi,Amini, Mojtaba M.
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- The Baeyer-Villiger oxidation of ketones with Oxone in the presence of ionic liquids as solvents
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Cyclic and linear ketones were readily oxidised with Oxone at 40 °C in ionic liquids as solvents and short times (2.5-20 h), affording their corresponding lactones and esters in high yields (65-95%). Both, aprotic and protic ionic liquids were used. The best conversion of ketones and the highest yields of products were obtained with 1-buty-3-methylimidazolium tetrafluoroborate and 1-methylimidazolium acetate as solvents. These ionic liquids were also efficiently recycled in the Baeyer-Villiger reaction without significant loss of activity. Several factors, such as the partial solubility of KHSO5 in the ionic liquid, its viscosity and the presence of a proton in protic ionic liquids, have an influence on the course of the reaction.
- Chrobok, Anna
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- Green, efficient and economical coal fly ash based phosphomolybdic acid catalysts: preparation, characterization and application
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Abstract: Cost-effective, efficient and green solid acid catalysts have been synthesized by incipient wetness impregnation of various weight fractions of phosphomolybdic acid (5, 10, 15 and 25 wt. %) on mechanically and thermally activated coal fly ash. N2 adsorption–desorption, XRD, FT-IR, SEM, SEM–EDX, TEM, TGA, UV–Vis DRS, solid state 31P MAS NMR were used for characterization of as synthesized catalysts. Catalytic active sites were developed on inert surface of coal fly ash by using various activation techniques whose performance was assessed over a series of acylation of various aliphatic alcohols. For rapid and higher catalytic activity, reactions were conducted in microwave heating mode. Impregnation of phosphomolybdic acid generates Lewis acidic sites on coal fly ash surface as inferred by pyridine adsorbed FT-IR studies which were then utilized in acylation reactions. Various reaction parameters like weight fraction of catalysts, molar ratio of reactants, time, temperature, etc. were optimized for attaining highest conversion %. The catalyst with 15 wt. % of phosphomolybdic acid was found to be more efficient and could be recycled up to five reaction cycles with analogous conversion %. Negligible leaching of catalyst was confirmed by hot filtration test. This work suggests an alternative approach for valorisation of industrial solid waste, coal fly ash in development of innovative, economical solid catalysts. Graphic abstract: [Figure not available: see fulltext.].
- Malpani, Sakshi Kabra,Goyal, Deepti,Katara, Stuti,Rani, Ashu
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- Diverse zinc(ii) coordination assemblies built on divergent 4,2′:6′,4′′-terpyridine derivatives: Syntheses, structures and catalytic properties
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A series of metal-organic architectures (compounds 1-5) based on zinc salts and four 4′-substituted 4,2′:6′,4′′-tpys including two new ligands have been synthesized and structurally characterized. The ligands L1-L4 with various 4′-substituents on 4,2′:6′,4′′-tpy react with Zn(OAc)2·2H2O to yield assemblies 1-4 containing either 1-D polymeric chains (1-3) or a discrete dinuclear complex (4). X-ray structural analysis revealed that although similar 1-D polymeric chains were observed in both 1 and 3, the 3-D packing modes were essentially different. The chains in 1 were stacked to form a network structure with microporous channels that were not present in 3. In contrast, 4 was a discrete dinuclear complex containing a paddle-wheel {Zn2(μ-OAc)4} motif, although another minor component possibly coexists in the bulk sample as revealed by the PXRD studies. Crystals of 5 were prepared from the reaction between L4 and ZnI2 and its X-ray structure revealed a 1-D polymeric chain with a wave-like structure. Phase-pure compounds 1-3 and 5 were tested for the catalytic transesterification of phenyl acetate with alcohols, and the results indicated that 1 was the most active catalyst for this reaction, affording the new ester product in 95% yield at 50 °C under neat conditions, while other catalysts also catalysed the reaction with modest yields. Several different alcohols were examined as substrates for 1-catalysed transesterification and it was found that the size of substrates has important influence on the catalytic efficiency. In addition, amine additives were found to remarkably promote the catalytic efficiency of the less active catalyst 3. The structure-catalytic activity relationship was discussed in detail based on the catalytic data obtained. This journal is
- Zhang, Guoqi,Jia, Yi-Xia,Chen, Wenbo,Lo, Wen-Feng,Brathwaite, Nyeisha,Golen, James A.,Rheingold, Arnold L.
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- Acetic Anhydride as an Oxygen Donor in the Non-Hydrolytic Sol–Gel Synthesis of Mesoporous TiO2 with High Electrochemical Lithium Storage Performances
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An original, halide-free non-hydrolytic sol–gel route to mesoporous anatase TiO2 with hierarchical porosity and high specific surface area is reported. This route is based on the reaction at 200 °C of titanium(IV) isopropoxide with acetic anhydride, in the absence of a catalyst or solvent. NMR spectroscopic studies indicate that this method provides an efficient, truly non-hydrolytic and aprotic route to TiO2. Formation of the oxide involves successive acetoxylation and condensation reactions, both with ester elimination. The resulting TiO2 materials were nanocrystalline, even before calcination. Small (about 10 nm) anatase nanocrystals spontaneously aggregated to form mesoporous micron-sized particles with high specific surface area (240 m2 g?1 before calcination). Evaluation of the lithium storage performances shows a high reversible specific capacity, particularly for the non-calcined sample with the highest specific surface area favouring pseudo-capacitive storage: 253 mAh g?1 at 0.1 C and 218 mAh g?1 at 1 C (C=336 mA g?1). This sample also shows good cyclability (92 % retention after 200 cycles at 336 mA g?1) with a high coulombic efficiency (99.8 %). Synthesis in the presence of a solvent (toluene or squalane) offers the possibility to tune the morphology and texture of the TiO2 nanomaterials.
- Wang, Yanhui,Kim, Sanghoon,Louvain, Nicolas,Alauzun, Johan G.,Mutin, P. Hubert
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- A unique annulation of 7-azaindoles with alkenyl esters to produce π-conjugated 7-azaindole derivatives
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Rhodium(iii)-catalyzed N-directed ortho C-H activation and subsequent roll-over C-H activation represents an important strategy to synthesize fused polycyclic compounds. Herein, the novel methodology broadens the scope of the coupling partner to alkenes, which working smoothly with 7-azaindoles has been proven to be an efficient and atom-economical strategy to access complex π-conjugated 7-azaindole derivatives.
- Li, Shuai-Shuai,Liu, Chen-Fei,Xia, Ying-Qi,Li, Wei-Huan,Zhang, Guo-Tai,Zhang, Xiao-Mei,Dong, Lin
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- Pseudo-homogeneous kinetic model for esterification of acetic acid with propanol isomers over dodecatungstophosphoric acid supported on montmorillonite k10
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Esterification of acetic acid with propanol isomers such as isopropanol and n-propanol was carried out over dodecatungstophosphoric acid (DTPA), dodecamolybdophosphoric acid ammonium salt hydrate, and sodium tungstate hydrated purified supported on montmorillonite K10, which were characterized by powder X-ray diffraction, Brunauer-Emmett-Teller, and temperature programmed ammonia desorption. A pseudo-homogeneous (P-H) kinetic model was established for esterification of acetic acid with propanol isomers over DTPA supported on montmorillonite K10. Effects of various parameters such as reaction time, speed of agitation, particle size, temperature, percent catalyst loading, molar ratio and mixture of propanol isomer were investigated in detail. The 20% (w/w) DTPA/K10 was found to be an optimum solid catalyst with 82% n-propanol and 53% isopropanol conversion with 100% selectivity toward propyl acetate. The 20% (w/w) DTPA/K10 catalyst was found to be reusable for three cycles. The reaction follows second-order kinetics with activation energies of 25.53-kJ-mol -1 and 28.15-kJ-mol-1 for isopropanol and n-propanol, respectively. Pseudo-homogeneous kinetic model fitted with R2 value of trend line 0.999. This implies that esterification reaction is kinetically controlled owing to high activation energy. Copyright
- Gurav, Hanumant R.,Nandiwale, Kakasaheb Y.,Bokade, Vijay V.
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- Substituent and Solvent Effects in the Kinetics of N-Alkylimidazole-Catalyzed Reaction of Acetic Anhydride with Isopropyl Alcohol
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The overall rate of the N-alkylimidazole-catalyzed reaction of acetic anhydride with isopropyl alcohol is rather insensitive to solvent polarity.Of the nine solvents studied, N,N-dimethylformamide is the best for analytical use.A series of N-alkyl substituted imidazoles was investigated as catalysts in this reaction.The most effective catalyst was N-n-pentylimidazole, which is about 60percent more reactive than N-methylimidazole.
- Pandit, Nivedita K.,Obaseki, Andrew O.,Connors, Kenneth A.
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- A Pyridine-Acetylene-Aniline Oligomer: Saccharide Recognition and Influence of this Recognition Array on the Activity as Acylation Catalyst
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In order to create new functions of foldamer-type hosts, various kinds of recognition arrays are expected to be developed. Here, a pyridine-acetylene-aniline unit is presented as a new class of a saccharide recognition array. The conformational stabilities of this array were analyzed by DFT calculation, and suggested that a pyridine-acetylene-aniline oligomer tends to form a helical structure. An oligomer of this array was synthesized, and its association for octyl β-D-glucopyranoside was confirmed by 1H NMR measurements. UV/Vis, circular dichroism, and fluorescence titration experiments revealed its high affinity for octyl glycosides in apolar solvents (Ka=104 to 105 M?1). This oligomer was relatively stable under basic conditions, and therefore this array was expected to be applied to the derivatization of saccharides. A 4-(dialkylamino)pyridine attached pyridine-acetylene-aniline oligomer proved to catalyze the acylation of the octyl glucoside.
- Ohishi, Yuki,Takata, Toshikazu,Inouye, Masahiko
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- Non-aqueous routes to metal oxide thin films by atomic layer deposition
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(Figure Presented) Controlled growth: A non-aqueous approach inspired from sol-gel chemistry and adapted to the formation of metal oxide thin films by means of atomic layer deposition is presented. The process is based on the reaction of a carboxylic acid with an alkoxide. Growth of metal oxides is achieved at temperatures as low as 50°C on various supports including carbon nanotubes (see TEM picture). The as-grown films show excellent uniformity and possess good dielectric properties.
- Rauwel, Erwan,Clavel, Guylhaine,Willinger, Marc-Georg,Rauwel, Protima,Pinna, Nicola
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- Synthesis, Characterisation, and Determination of Physical Properties of New Two-Protonic Acid Ionic Liquid and its Catalytic Application in the Esterification
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A new ionic liquid was synthesised, and its chemical structure was elucidated by FT-IR, 1D NMR, 2D NMR, and mass analyses. Some physical properties, thermal behaviour, and thermal stability of this ionic liquid were investigated. The formation of a two-protonic acid salt namely 4,4′-trimethylene-N,N′-dipiperidinium sulfate instead of 4,4′-trimethylene-N,N′-dipiperidinium hydrogensulfate was evidenced by NMR analyses. The catalytic activity of this ionic liquid was demonstrated in the esterification reaction of n-butanol and glacial acetic acid under different conditions. The desired acetate was obtained in 62-88 % yield without using a Dean-Stark apparatus under optimal conditions of 10 mol-% of the ionic liquid, an alcohol to glacial acetic acid mole ratio of 1.3: 1.0, a temperature of 75-100°C, and a reaction time of 4 h. α-Tocopherol (α-TCP), a highly efficient form of vitamin E, was also treated with glacial acetic acid in the presence of the ionic liquid, and O-acetyl-α-tocopherol (Ac-TCP) was obtained in 88.4 % yield. The separation of esters was conducted during workup without the utilisation of high-cost column chromatography. The residue and ionic liquid were used in subsequent runs after the extraction of desired products. The ionic liquid exhibited high catalytic activity even after five runs with no significant change in its chemical structure and catalytic efficiency.
- Shahnavaz, Zohreh,Zaharani, Lia,Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie
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p. 165 - 172
(2020/10/26)
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- Oxidation of Propane: Influence of the Nature of Catalyst, Cocatalyst, and Coreductant
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Abstract: Variation of the nature of the components of the catalytic systems comprisinga catalyst [Pd/C, Pd(α,α-bipy)Cl2,RhCl3] and a cocatalyst(FeSO4, CuSO4), as well as acoreductant (H2, CO), allows exerting some control overthe selectivity of the process of propane oxidation with oxygen. In particular,the yield of carbonyl compounds such as acetone and propanal in the presence ofthe Pd/C–FeSO4–H2catalytic systemreached 90%, and that of propyl esters in the presence ofRhCl3–CuSO4–CO catalyticsystem was 64.5%. These differences are supposedly attributable to the changesin the process mechanism depending on the composition of the catalyticsystems. [Figure not available: see fulltext.]
- Chepaikin, E. G.,Menchikova, G. N.,Pomogailo, S. I.
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p. 781 - 786
(2021/08/03)
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- Scalable green approach toward fragrant acetates
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The advantageous properties of ethylene glycol diacetate (EGDA) qualify it as a useful substitute for glycerol triacetate (GTA) for various green applications. We scrutinised the lipase-mediated acetylation of structurally diverse alcohols in neat EGDA furnishing the range of naturally occurring fragrant acetates. We found that such enzymatic system exhibits high reactivity and selectivity towards activated (homo) allylic and non-activated primary/secondary alcohols. This feature was utilised in the scalable multigram synthesis of fragrant (Z)-hex-3-en-1-yl acetate in 70percent yield. In addition, the Lipozyme 435/EGDA system was also found to be applicable for the chemo-selective acetylation of (hydroxyalkyl) phenols as well as for the kinetic resolution of chiral secondary alcohols. Lastly, its discrimination power was demonstrated in competitive experiments of equimolar mixtures of two isomeric alcohols. This enabled the practical synthesis of 1-pentyl acetate isolated as a single product in 68percent yield from the equimolar mixture of 1-pentanol and 3-pentanol.
- Puchl'Ová, Eva,Szolcsányi, Peter
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- ALCOHOL STABLE ENZYMES
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The present disclosure provides enzyme-polymer conjugates stable to denaturing action of alcohols and methods for using enzyme-polymer conjugates in biocatalysis.
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Paragraph 0038-0040; 0107-0108
(2020/11/24)
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- Magnetically recoverable AlFe/Te nanocomposite as a new catalyst for the facile esterification reaction under neat conditions
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In this work, a new Fe3O4/AlFe/Te nanocomposite was synthesized by a one-step sol–gel method. The Fe3O4 magnetic nanoparticles (MNPs) were prepared and then mixed with aluminum telluride (Al2Te3) in an alkali medium to produce the desired catalyst. After characterization of the Fe3O4/AlFe/Te nanocomposite by SEM, TEM, EDS, XRD, and ICP analyses, it was used in the esterification reaction. This heterogeneous catalyst showed high catalytic activity in the esterification of commercially available carboxylic acids with various alcohols to produce the desired esters at high conversions under neat conditions. The Fe3O4/AlFe/Te nanocomposites were separated from the reaction mixture via an external magnet and re-used 8 times without significant loss of catalytic activity.
- Alavi, Seyed Jamal,Sadeghian, Hamid,Seyedi, Seyed Mohammad,Eshghi, Hossein,Salimi, Alireza
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- α-Tetrasubstituted Aldehydes through Electronic and Strain-Controlled Branch-Selective Stereoselective Hydroformylation
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Hydroformylation utilizes dihydrogen, carbon monoxide, and a catalyst to transform alkenes into aldehydes. This work applies chiral bisdiazaphospholane (BDP)- and bisphospholanoethane-ligated rhodium complexes to the hydroformylation of a variety of alkenes to produce chiral tetrasubstituted aldehydes. 1,1′-Disubstituted acrylates bearing electron-withdrawing substituents undergo hydroformylation under mild conditions (1 mol % of catalyst/BDP ligand, 150 psig gas, 60 °C) with high conversions and yields of tetrasubstituted aldehydes (e.g., 13:1 regioselectivity, 85% ee, and 99% regioselectivity and >19:1 diastereoselectivity to tetrasubstituted aldehydes at rates >50 catalyst turnovers/hour. NMR studies of the noncatalytic reaction of HRh(BDP)(CO)2 with methyl 1-fluoroacrylate enable interception of tertiary alkylrhodium intermediates, demonstrating migratory insertion to acyl species is slower than formation of secondary and primary alkylrhodium intermediates. Overall, these investigations reveal how the interplay of sterics, electronics, and ring strain are harnessed to provide access to valuable α-tetrasubstituted aldehyde synthetic building blocks by promoting branched-selective hydroformylation.
- Eshon, Josephine,Foarta, Floriana,Landis, Clark R.,Schomaker, Jennifer M.
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p. 10207 - 10220
(2018/09/06)
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- Method and device for preparing sec butanol
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The present invention provides a method and a device for preparing sec butanol, and the method is as follows: (1) sec-butyl acetate is introduced into a first-stage catalytic distillation column, excessive C1-C3 alcohols are added simultaneously for ester exchange, the sec butanol as a product falls into a tower kettle to collect, and the unreacted C1-C3 alcohols and reaction product acetic acid C1-C3 esters partly are sent into a second-stage catalytic distillation column for further reaction separation; (2) excessive sec-butyl acetate is added into the second-stage catalytic distillation column, the acetic acid C1-C3 esters are distilled off from the top of the column, and then congealed to partly reflux to the top of the second-stage catalytic distillation column and partly use as a product to collect; and (3) the sec butanol obtained by the step (2) and the unreacted sec-butyl acetate are returned to the first-stage catalytic distillation column for further reaction separation. The purity of the sec butanol obtained by the method is high above 99.9%, the purity of the separated acetic acid C1-C3 esters is more than 99%, at the same time, the method has the advantages of simple process and easy operation, compared with the process of butylene hydration for preparing the sec butanol, energy consumption is greatly reduced, and cost is saved.
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Paragraph 0047-0048
(2017/05/18)
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- Enantiomeric two-fold interpenetrated 3D zinc(ii) coordination networks as a catalytic platform: significant difference between water within the cage and trace water in transesterification
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Self-assembly of Zn(ClO4)2 with 1,1,2,2-tetramethyl-1,2-di(pyridin-3-yl)disilane (L) as a bidentate N-donor gives rise to 3D coordination networks, [Zn(μ-OH)(L)]3(ClO4)3·5H2O (1·5H2O), of unique, 103-a srs net topology. An important feature is that two enantiomeric 3D frameworks, 41- and 43-[Zn(μ-OH)(L)]3(ClO4)3·5H2O, are interpenetrated to form a racemic two-fold 3D network with cages occupied by two water molecules. Another structural characteristic is a C3-symmetric planar Zn3(μ-OH)3 6-membered ring with tetrahedral Zn(ii) ions. The steric hindrance of substrates and trace water effects on transesterification catalysis using the network have been scrutinized. The coordination network acts as a remarkable heterogeneous transesterification catalytic system that shows both the significant steric effects of substrate alcohols and momentous water effects. The substrate activity is in the order ethanol > n-propanol > n-butanol > iso-propanol > 2-butanol > tert-butanol. For the reaction system, solvate water molecules within the cages of the interpenetrated 3D frameworks do not decrease the transesterification activity, whereas the trace water molecules in the substrate alcohols act as obvious obstacles to the reaction.
- Choi, Eunkyung,Ryu, Minjoo,Lee, Haeri,Jung, Ok-Sang
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supporting information
p. 4595 - 4601
(2017/04/11)
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- Deep eutectic solvent choline chloride·2CrCl3·6H2O: An efficient catalyst for esterification of formic and acetic acid at room temperature
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A highly efficient and selective method for esterification of formic and acetic acid with alcohols has been achieved at room temperature, with the choline chloride (ChCl)/chromium(iii) chloride hexahydrate (CrCl3·6H2O) deep eutectic solvent as a catalyst. High yields and good selectivities of organic esters are obtained using DES [ChCl][CrCl3·6H2O]2 with the molar ratio 5:1 (carboxylic acids:alcohols) at room temperature in 24 h. The ease of recovery and reusability of DES with high catalytic activity makes this method efficient and practical.
- Cao, Jin,Qi, Bin,Liu, Jun,Shang, Yuhan,Liu, Huiwen,Wang, Wenjing,Lv, Jia,Chen, Zhiyan,Zhang, Haibo,Zhou, Xiaohai
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p. 21612 - 21616
(2016/03/08)
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- A reaction-reaction strengthening method of synthesizing acetic acid isopropyl ester
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The invention belongs to the technical field of reaction reinforcement, relates to synthesis of isopropyl acetate, and particularly relates to a method for synthesizing isopropyl acetate by means of reaction-reaction reinforcement. The method comprises the following steps that: acetic acid, concentrated sulfuric acid and isopropyl alcohol are added into a homogeneous phase reaction kettle, the acetic acid and the isopropyl alcohol in the homogeneous phase reaction kettle react under the action of the concentrated sulfuric acid and produce isopropyl acetate and water; in a fixed bed reactor, the isopropyl alcohol reacting incompletely continues to react with acetic acid steam and the internally flowing-back acetic acid under the action of a catalyst to produce isopropyl acetate and water, and azeotrope of isopropyl acetate and water is conveyed into a cooler for condensation; and synthetic product is conveyed into an water-oil separator, water phase product is conveyed into a waste water tank, oil phase product is conveyed into a raw product tank, and then, raw isopropyl acetate is obtained for further purification and refining. With the preparation method provided by the invention, raw material conversion rate is high, products are easy to separate, the adopted concentrated sulfuric acid catalyst and alumina supported sulfonated polystyrene resin catalyst serve long time and can be recycled for reuse, the technology is simple, operations are safe and steady, and system energy consumption is low.
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-
Paragraph 0027-0036
(2017/03/17)
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- A reaction with acetic acid from propylene of preparing acetic acid isopropyl ester method and device for
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The invention discloses a method for preparing isopropyl acetate through reaction of propylene and acetic acid. The method is characterized by comprising the following steps: (A) mixing an inert component with propylene and acetic acid, and feeding into a fixed bed reactor for reaction; (B) feeding the reacted mixture into a heavy component removal tower for removing heavy components; (C) condensing the tower top product of the heavy component removal tower, feeding into a light component removal tower for further separation, condensing the tower top product of the light component removal tower, feeding back a part of the condensed product to the tower top for backflow, feeding back a part of the condensed part to a reaction system for recycling and reuse, and discharging out an isopropyl acetate product from a side line of the column bottom. By adopting the method, the reaction acid-alkene ratio is reduced, the operation pressure of the reaction system is reduced, the treatment capacity of the heavy component removal tower is increased, the energy consumption is reduced, conventional processes and equipment can be used, propylene which is discharged out at present can be effectively recycled, the material consumption is reduced, the influence caused by discharged propylene to the environment is reduced, the potential safety hazard is eliminated, the separation process procedures are shortened, and the equipment investment is reduced.
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-
Paragraph 0054; 0055
(2017/05/26)
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- Reaction monitoring using online vs tube NMR spectroscopy: Seriously different results
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We report findings from the qualitative evaluation of nuclear magnetic resonance (NMR) reaction monitoring techniques of how each relates to the kinetic profile of a reaction process. The study highlights key reaction rate differences observed between the various NMR reaction monitoring methods investigated: online NMR, static NMR tubes, and periodic inversion of NMR tubes. The analysis of three reaction processes reveals that rates derived from NMR analysis are highly dependent on monitoring method. These findings indicate that users must be aware of the effect of their monitoring method upon the kinetic rate data derived from NMR analysis.
- Foley, David A.,Dunn, Anna L.,Zell, Mark T.
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p. 451 - 456
(2016/05/24)
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- NOVEL CATALYST FOR ESTER EXCHANGE REACTION AND METHOD FOR PRODUCING ESTER COMPOUND USING THE SAME
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PROBLEM TO BE SOLVED: To provide a catalyst that makes an ester exchange reaction proceed on a mild condition and gives a target product at a high reaction yield, and provide a method for producing an ester compound on a mild condition. SOLUTION: The present invention provides a catalyst for ester exchange reaction comprising a dianionic zinc ate complex represented by General Formula (1) and a method for producing an ester compound using the complex (where n is an integer of 1-4 and when n is 1 or 2, Rs may be the same or different to represent a C1-C8 alkyl group, alkenyl group, aryl group, or arylalkyl group, M is lithium or magnesium, and m is 1 or 2). SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0043
(2017/02/24)
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- Doping of copper (I) oxide onto a solid support as a recyclable catalyst for acetylation of amines/alcohols/phenols and synthesis of trisubstituted imidazole
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A study of copper-mediated C-heteroatom especially C-N and C-O bond formations using simpler methodologies has been carried out. In the present work, acetylation of various substrates such as amines, phenols and alcohols; synthesis of 2,4,5-trisubstituted imidazole is done using simple and easily available starting materials. Copper (I) oxide was synthesized in situ by the reduction of Fehling's solution with glucose followed by its anchoring onto different supports like silica, HAP, basic alumina and cellulose. Comparison and contrasts between the reactivity of copper (I) oxide supported onto different supports for these reactions are made. The reactivity of copper (I) oxide seems to be largely dependent on the nature of support and the most active catalyst for a particular reaction was further characterized by different spectroscopic techniques such as FTIR, XRD, TGA, XPS, SEM, TEM and AAS. The catalysts were found to be stable, easily recyclable without any significant loss in activity. Graphical abstract: Applications of solid supported copper (I) oxides (where solid support is silica, HAP, cellulose and basic alumina) are studied for various organic transformations with special emphasis on C-N and C-O bond formation reactions.[Figure not available: see fulltext.]
- Gupta, Manjulla,Gupta, Monika
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p. 231 - 241
(2016/01/09)
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- A catalytic conversion method for preparing pyruvate ester of lactic acid (by machine translation)
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A method for preparing pyruvate through catalytic conversion of lactic acid is provided; according to the method, with oxygen or air as an oxidant, alcohol as a solvent, and molybdovanadophosphoric heteropoly acid and/or tungstovanadophosphoric heteropoly acid as a catalyst, and by coupling of a catalytic oxidation reaction and an esterification reaction, lactic acid is converted into pyruvate by one step. The method directly adopts oxygen or air as the oxidant and is green and safe; the used raw material lactic acid is obtained directly from conversion of biomass resources, moreover, the reaction conditions are mild, and the method has important application prospects.
- -
-
Paragraph 0022
(2016/10/10)
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- Efficient acylation and transesterification catalyzed by dilithium tetra-tert-butylzincate at low temperatures
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The acylation and transesterification of alcohols with vinyl acetate and carboxylic esters were investigated in the presence of a catalytic amount (1-10 mol %) of dilithium tetra-tert-butylzincate (TBZL) as a catalyst. The acylation proceeded quantitatively at 0 °C within 1 h. The transesterification occurred for a wide range of combinations of esters and alcohols at 0 to -40 °C. To the best of our knowledge, this is the first successful transesterification at such low temperatures. The time-conversion plots for the transesterification show that the reaction reached equilibrium within 5 min at 0 °C. The reaction proceeded quantitatively by addition of molecular sieves 4A. In addition, the transesterification proceeded even in the presence of H2O and amines.
- Oshimura, Miyuki,Oda, Yuki,Kondoh, Keita,Hirano, Tomohiro,Ute, Koichi
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p. 2070 - 2073
(2016/04/26)
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- Efficient approach for the chemoselective acetylation of alcohols catalyzed by a novel metal oxide nanocatalyst CuO-ZnO
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A new method has been developed for the chemoselective acetylation of alcohols with acetic anhydride in the presence of phenols using a novel, recyclable CuO-ZnO nanocatalyst. The catalyst was synthesized using the co-precipitation method and characterized by N2 adsorption-desorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersion scanning analyses. Furthermore, this catalyst could be recycled up to six times without significant loss in its activity.
- Albadi, Jalal,Alihosseinzadeh, Amir,Mardani, Mehdi
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p. 308 - 313
(2015/09/28)
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- Efficient and convenient oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4]
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A simple, efficient, and eco-friendly procedure for the oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4] has been developed. This atom-economical protocol affords the target products in good to high yields. The products can be separated by a simple extraction with organic solvent, and the catalytic system can be recycled and reused without loss of catalytic activity. Additionally, the possible mechanism of oxidation in the catalytic system is proposed. This journal is
- Hu, Yu-Lin,Li, De-Jiang,Li, Dong-Sheng
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p. 24936 - 24943
(2015/03/30)
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- CAL-B-Catalyzed Enantioselective Deacetylation of Some Benzylic Acetate Derivatives Via Alcoholysis in Non-aqueous Media
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Enantioselective deacetylation of a set of benzylic acetates via alcoholysis catalyzed by Lipase B from Candida antarctica (CAL-B), under mild conditions is described. A systematic study allows to determine the appropriate combination nucleophile/organic solvent and also to explain the influence of these parameters on the enzymatic catalytic reaction. In all cases, (R)-alcohols are obtained with high ee (up to >99 %) at conversion 36 % 500. The enzymatic reactivity is influenced by the hydrophobicity of solvent and the structure/nature of the nucleophile. Furthermore, CAL-B allows enantio-complementary between transesterifications in non-aqueous media: alcoholysis and acetylation.
- Zadi, Amna,Merabet-Khelassi, Mounia,Aribi-Zouioueche, Louisa
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p. 1054 - 1061
(2015/02/05)
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- Transfer hydrogenation of ketones, nitriles, and esters catalyzed by a half-sandwich complex of ruthenium
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Half-sandwich complexes [Cp(PiPr3)Ru(CH3CN)2]PF6 (1; Cp = cyclopentadienyl) and [Cp(phen)Ru(CH3CN)]PF6 (2; Cp = pentamethylcyclopentadienyl, phen = phenanthroline) catalyse the transfer hydrogenation of ketones to alcohols, aldimines to amines, and nitriles to imines under mild conditions. In the latter process, the imine products come from the coupling of the amines formed initially with acetone derived from the reducing solvent (isopropanol). Among functionally substituted nitriles, the aldo and keto groups are reduced concomitantly with the cyano group, whereas ester and amido groups are tolerated. Amides and alkyl esters are not reduced under these conditions even upon heating to 70°C. However, phenylbenzoates and trifluoroacetates are reduced to alcohols. Kinetic studies on the reduction of acetophenone in isopropanol established that the reaction is first order in both the substrate and the alcohol. Stoichiometric mechanistic studies showed the formation of a hydride species. A hydride mechanism was proposed to account for these observations.
- Lee, Sun-Hwa,Nikonov, Georgii I.
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p. 107 - 113
(2015/01/30)
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- Comparison of the performance of commercial immobilized lipases in the synthesis of different flavor esters
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In this work, it is compared the performance of three commercial lipase preparations (Novozym 435, Lipozyme TL-IM, and Lipozyme RM-IM) in the synthesis of flavor esters obtained by esterification of acetic, propionic, and butyric acids using ethanol, isopropyl alcohol, butanol, or pentanol. A comprehensive comparison was performed verifying activities of these three enzyme preparations versus the different couples of substrates, checking the obtained yields. In general, the longer the acid chain, the higher the reaction yields. Novozym 435 was the most efficient enzyme in most cases, and only Lipozyme RM-IM offered better results than Novozym 435 in the production of ethyl butyrate. Reactions with butyric acid showed the highest conversion rates using all biocatalysts. Using optimal substrates, the reactions catalyzed by the three enzymes were optimized using the response surface methodology, and the catalytic performance of the biocatalysts in repeated batches was assessed. After optimization, yields higher than 90% were obtained for all three enzymes, but Lipozyme TL-IM needed four-times more biocatalyst content than the other two preparations. Novozym 435 kept over 80% of its activity when reused in 9 successive batches, whereas Lipozyme RM-IM can be reused 5 times and Lipozyme TL-IM only 3 times. In general, Novozym 435 showed to be more suitable for these reactions than the other two enzyme preparations.
- Martins, Andrea B.,Da Silva, Alexandre M.,Schein, Mirela F.,Garcia-Galan, Cristina,Zachia Ayub, Marco A.,Fernandez-Lafuente, Roberto,Rodrigues, Rafael C.
-
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- Metal-free amidation of ether sp3 C-H bonds with sulfonamides using PhI(OAc)2
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A selective protocol for the metal-free α-C-H amidation of ethers using sulfonamides and hypervalent iodine oxidants has been developed. The absence of precious metals and the conditions employed make the method environmentally attractive. A number of cyclic and acyclic, linear and branched ethers have been successfully amidated, and a broad sulfonamide scope has been demonstrated. Two unusual reactions, namely the amidation of an unactivated tert-butyl group and a tandem C-C coupling reaction, are also described. This journal is
- Campos, Jess,Goforth, Sarah K.,Crabtree, Robert H.,Gunnoe, T. Brent
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p. 47951 - 47957
(2014/12/10)
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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
-
-
- Carbodeoxygenation of biomass: The carbonylation of glycerol and higher polyols to monocarboxylic acids
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Glycerol is converted to a mixture of butyric and isobutyric acid by rhodium- or iridium-catalysed carbonylation using HI as the co-catalyst. The initial reaction of glycerol with HI results in several intermediates that lead to isopropyl iodide, which upon carbonylation forms butyric and isobutyric acid. At low HI concentration, the intermediate allyl iodide undergoes carbonylation to give vinyl acetic acid and crotonic acid. Higher polyols CnH n+2(OH)n are carbonylated to the corresponding C n+1 mono-carboxylic acids. Copyright
- Coskun, Timur,Conifer, Christopher M.,Stevenson, Laura C.,Britovsek, George J. P.
-
supporting information
p. 6840 - 6844
(2013/07/05)
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- A mild and clean Baeyer-Villiger oxidation of ketones using sodium peroxydisulfate as oxidant catalyzed by silica-supported aluminum chloride
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Sodium peroxydisulfate was used as the oxidant for Baeyer-Villiger oxidation of a variety of cyclic and acyclic ketones at room temperature in the presence of Silica-supported aluminum chloride (silica-AlCl3) as catalyst. The catalyst was prepared by a simple procedure, which exhibited high catalytic activity for the Baeyer- Villiger oxidation of ketones using environmental friendly sodium peroxydisulfate as oxidizing agent. Iranian Chemical Society 2012.
- Mahmoodi, Nosrat Ollah,Heirati, Seyedeh Zahra Dalil,Ekhlasi-Kazaj, Kamel
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p. 521 - 528
(2013/02/22)
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- Sulfonic groups functionalized preoxidated polyacrylonitrile nanofibers and its catalytic applications
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A SO3H-bearing nanofiber mat was synthesized and investigated as a novel heterogeneous acid catalyst. Preoxidated polyacrylonitrile nanofiber mat was prepared via electrospinning and heat treatment, and then reacted with chlorosulfuric acid to introduce the sulfonic groups. The nanofiber mat owned high acidity of 2.99 mmol/g. The preoxidation and sulfonation were examined by FT-IR spectroscopy, elemental analysis and X-ray diffraction spectroscopy (XRD). The fiber morphologies were characterized by scanning electron microscopy (SEM). The catalytic activities and reuse of the prepared nanofiber mat solid acid catalyst have been evaluated for the acetalization and esterification. The regular fiber mat structure could significantly facilitate the recovery and reuse of the catalyst. The excellent catalytic performance and easy recycling made the novel fiber mat solid acid hold great potential for the green chemical processes.
- Shao, Linjun,Xing, Guiying,He, Luyao,Chen, Ji,Xie, Hangqing,Liang, Xuezheng,Qi, Chenze
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p. 133 - 137
(2015/04/15)
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- Polystyrene-supported GaCl3: A new, highly efficient and recyclable heterogeneous Lewis acid catalyst for acetylation and benzoylation of alcohols and phenols
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A new, simple and highly chemoselective method for both acetylation and benzoylation of alcohols and phenols with acetic anhydride in the presence of polystyrene-supported gallium trichloride (PS/GaCl3) as a highly active and reusable heterogeneous Lewis acid catalyst is presented. In this catalytic system, primary, secondary and tertiary alcohols as well as phenols were converted to the corresponding acetates and benzoates with high yields. The heterogenized catalyst is of high reusability and stability in the acetylation reactions and was recovered several times with negligible loss in its activity or a negligible catalyst leaching, and also there is no need for regeneration. Remarkably, a selective mono-acetylation of symmetrical diols can be achieved chemoselectively by employing the same catalyst.
- Rahmatpour, Ali
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p. 1048 - 1054
(2013/02/22)
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- Novel double-SO3h functionalized ionic liquid for acetylation
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Novel double-SO3H functionalized ionic liquid (DFIL) was synthesized and its catalytic activities for acetylation studied. The result showed that the DFIL possess high acidity and was very efficient for the acetylation of alcohols, amines and phenols with good to excellent yields in short reaction times. Operational simplicity, stability to water and air, small amounts needed, low cost, high yields, high acidity, applicability to large-scale reactions and reusability are the key features of the DFIL, which indicated promising applications of DFIL in green chemical processes. Pleiades Publishing, Ltd., 2012.
- Zhu, Lili,Liang, Xuezheng
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p. 684 - 688
(2013/02/23)
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- METHOD AND APPARATUS FOR PREPARING MULTIPLE ESTERS
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Disclosed is a method and an apparatus for manufacturing at least two esters. The method includes steps of: (a) reacting an acid and an alcohol mixture in a reactive distillation (RD) column to generate an alcohol-ester-water azeotrope, wherein the alcohol mixture includes at least two alcohols; (b) separating the alcohol-ester-water azeotrope as the organic mixture and water in a decanter; (c) purifying the organic mixture to generate the ester mixture in a stripper; and (d) performing the ester-ester separation on the ester mixture to generate at least two esters in a distillation column, wherein the number of at least two esters is the same with that of at least two alcohols. The unpurified ester mixture carrying heat can be refluxed into stripper for saving energy and enhancing the efficiency of purification.
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Page/Page column 3-4
(2012/04/11)
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- Highly efficient and versatile acetylation of alcohols, phenols and amines catalyzed by methylenediphosphonic acid (MDP) under solvent-free conditions
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Methylenediphosphonic Acid (MDP) was found to be a simple, cheap and reusable heterogeneous catalyst for the acetylation of structurally diverse alcohols, phenols and amines with acetic anhydride under solvent-free conditions at room temperature. This method showed preferential selectivity for the acetylation of the amino group in the presence of hydroxyl group. The method is very mild and the yields were in excellent.
- Xie, Minhao,Wang, Hongyong,Wu, Jun,He, Yongjun,Liu, Yaling,Zou, Pei
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experimental part
p. 884 - 886
(2012/04/23)
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- Room-temperature selective aliphatic carbon-carbon bond activation and functionalization of ethers by rhodium(II) porphyrin
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Selective aliphatic carbon(α)-carbon(β) bond activation of ethers by (5,10,15,20-tetramesitylporphyrinato)rhodium(II) (Rh(tmp) (1)) was achieved at room temperature to yield corresponding rhodium porphyrin alkyls and the functionalized esters. Rh(tmp)OH was the proposed intermediate responsible for cleaving the C(α)-C(β) bond. The reaction is general for both straight- and branch-chain ethers.
- Lee, Siu Yin,Lai, Tsz Ho,Choi, Kwong Shing,Chan, Kin Shing
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scheme or table
p. 3691 - 3693
(2011/09/20)
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- PROCESS INCLUDING HYDROGENOLYSIS OF BIOMASS FOLLOWED BY DEHYDROGENATION AND ALDOL CONDENSATION FOR PRODUCING ALKANES
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A method comprises providing a bio-based feedstock; contacting the bio-based feedstock with a solvent in a hydrolysis reaction to form an intermediate stream comprising carbohydrates; contacting the intermediate stream with an aqueous phase reforming catalyst to form a plurality of oxygenated intermediates, wherein a first portion of the oxygenated intermediates are recycled to form the solvent; and contacting at least a second portion of the oxygenated intermediates with a condensation catalyst comprising a base functionality to form a fuel blend.
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Page/Page column 34-37
(2011/12/02)
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- NOVEL METHOD FOR THE CONVERSION OF CELLULOSE AND RELATED CARBOHYDRATE MATERIALS TO LOW-MOLECULAR-WEIGHT COMPOUNDS
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Methods of converting cellulose or related biorenewable carbohydrate materials into high-value chemical compounds. The methods provide a means of converting low-cost materials such as cellulose and biomass into high yields of compounds such as ethylene glycol, propylene glycol, glycerin, methanol, hydroxyacetone, glycolaldehyde and dihydroxyacetone.
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Page/Page column 9
(2011/06/24)
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- Effect of protecting agent concentration, catalyst (mol %) and temperature on the protection of 2-propanol catalyzed by dodeca-tungstophosphoric acid
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Protection of various alcohols with carboxylic acids catalyzed by heteropolyacids is realized as an efficient method among different familiar reaction pathways. Herein, effective reaction parameters such as temperature, alcohol:protecting agent mole ratio and catalyst (mol %) were investigated on the acetylation and formylation of 2-propanol with acetic acid, formic acid and ethyl formate, as acetylating agents, in the presence of dodeca- tungstophosphoric acid, H3PW12O40. Findings showed that efficiency of the protection system was increased by enhancing temperature, using higher amounts of catalyst and increasing concentration of the protecting agent. Obviously, enhancing concentration of the protecting agent was more effective than elevation of temperature on the reaction progress.
- Tayebee, Reza,Cheravi, Fatemeh
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scheme or table
p. 5567 - 5574
(2012/07/31)
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- Molecular iodine in ionic liquid: A green catalytic system for esterification and transesterification
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Esterification of carboxylic acids and transesterification of-ketoesters with alcohols have been developed using a catalytic amount of iodine in polyethylene glycol (PEG) ionic liquid (IL 1000) to afford the corresponding esters in good yields. By simple separation of the ionic-liquid phase containing the iodine, the system of I2/IL 1000 can be reused several times. Copyright
- Ren, Yiming,Cai, Chun
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scheme or table
p. 1670 - 1676
(2010/08/03)
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