- Characterization of HNbMoO6, HNbWO6 and HTiNbO 5 as solid acids and their catalytic properties for esterification reaction
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HTiNbO5, HNbMoO6·H2O and HNbWO 6·1.5H2O were prepared by proton-exchange of the precursors KTiNbO5, LiNbMoO6 and LiNbWO6, respectively, which were synthesized by a solid-state reaction method. The morphology and the micro-structure were characterized by means of scanning electron microscope (SEM), transmission electron microscope (TEM), powder X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). NH 3 temperature-programmed desorption (NH3-TPD) was used to measure the acidic properties of the samples. The Sanderson electronegativity and Kataoka′s bond strength theory were also applied to investigate the acid properties of the as-prepared samples. Finally, their catalytic activities were evaluated through catalyzing the liquid-phase esterification reaction of acetic acid and n-butanol to form n-butyl acetate. It has been revealed that H+ ions existed in different forms and interaction modes with MO bond in the solid acids. The acid strength for these as-prepared samples follows the order HNbMoO6·H2O > HNbWO6·1. 5H2O > HTiNbO5. In this work, HNbMoO 6·H2O presents an excellent catalytic activity for the esterification reaction, while HNbWO6·1.5H2O and HTiNbO5 have little catalytic activity. The result suggested that the catalytic activity of the layered solid acid for the esterification reaction was mainly controlled by gallery height.
- He,Li,Tang,Yang,Li,Li,Li
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- A facile synthesis of vanadium phosphate: An efficient catalyst for solvent free esterification of acetic acid
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This paper reports the facile synthesis of vanadium phosphate (VPO) by the decomposition of VOHPO4?0.5H2O which was prepared by reduction of dihydrate VOPO4?2H2O with isobutanol. The material was promoted with aluminum by impregnation method. The catalysts were unambiguously characterized by N2 adsorption-desorption, XRD, FT-IR techniques, UV-Vis DRS and the total amount of the acidity of the catalysts was estimated by NH3-TPD. The catalytic activities were checked in the heterogeneous catalytic esterification of acetic acid with 1° alcohol (n-butanol) in a solvent free medium. The optimization of reaction was carried out by varying temperature from 75 to 150 °C, molar ratio (butanol:acetic acid) from 1:1 to 1:4. Under optimum conditions, the catalytic esterification runs revealed a significant effect of the VPO giving 62% conversion with 100% selectivity to butyl acetate.
- Parida,Behera, Gobinda Chandra
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- PHASE TRANSFER CATALYSTS POLYETHYLENE GLYCOLS IMMOBILIZED ONTO METAL OXIDE SURFACES
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Catalysts prepared by reacting polyethylene glycol and polyethylene glycol monomethyl ether with both alumina and silica gel were found to be effective phase transfer agents in displacement and oxidation reactions.
- Sawicki, Robert A.
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- Facile synthesis of dodecatungstophosphoric acid @ TiO2 pillared montmorillonite and its effectual exploitation towards solvent free esterification of acetic acid with n-butanol
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An acid activated montmorillonite, treated with organic cationic surfactant, i.e. cetyltrimethylammonium bromide (CTAB), was used as a template to prepare TiO2 pillared montmorillonite taking titanium ethoxide as titania precursor in hydrochloric acid environment. The pillared montmorillonite was further promoted by dodecatungstophosphoric acid impregnation. The as prepared materials were characterized by various spectroscopic and analytical characterization techniques. The catalyst was employed towards a solvent free esterification of acetic acid with n-butanol. The catalyst showed excellent results with 88% conversion and 100% butyl acetate selectivity. It can be recovered and reused readily, making product isolation and catalyst reuse simple.
- Bishwa Bidita Varadwaj,Parida
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- Modulation of starch nanoparticle surface characteristics for the facile construction of recyclable Pickering interfacial enzymatic catalysis
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In this work, maize starch (MS) was successively modified via an esterification reaction with acetic anhydride (AA) and phthalic anhydride (PTA). Combined with the gelatinization-precipitation process, the formed starch nanoparticles at an AA/PTA ratio of 2 (MS-AP (2)) and 3 (MS-AP (3)) had similar regular spheres but distinct surface characteristics. In order to enhance the activity of lipase B from Candida antarctica (CALB) in an organic solvent, we designed an oil-in-water (o/w) and a water-in-oil (w/o) Pickering interfacial catalytic system simultaneously by utilizing MS-AP (2) and MS-AP (3) as robust Pickering emulsion stabilizers. Impressively, during the esterification of 1-butanol and vinyl acetate, the specific activity of CALB in the o/w (0.0843 U μL-1) or w/o (0.0724 U μL-1) Pickering interfacial catalytic system was much higher than that of free enzymes in the monophasic (0.0198 U μL-1) and biphasic (0.0282 U μL-1) system. Moreover, after preliminarily elaborating mass transfer discrepancies between the o/w and w/o Pickering interfacial catalytic systems and calculating their mass transfer resistance, we clarified the effects of the location of these two phases on the catalytic capacity of the Pickering emulsion. Impressively, both Pickering interfacial catalytic systems exhibited high effectiveness in product separation. It was found that the w/o Pickering emulsion enabled the organic product to be facilely isolated through a simple decantation, while the o/w Pickering emulsion achieved similar results after adjusting the system temperature. The bio-based nanomaterials and simple protocol, in conjunction with the stability to simultaneously achieve high catalysis efficiency and excellent recyclability, makes us believe that this starch nanoparticle-based Pickering interfacial catalytic system is a promising system for meeting the requirements of green and sustainable chemistry.
- Qi, Liang,Luo, Zhigang,Lu, Xuanxuan
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- Esterification of acetic acid with n-Butanol using vanadium oxides supported on γ-alumina
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Esterification of acetic acid with n-Butanol has been studied in a heterogeneous reaction system using two γ-alumina-supported vanadium oxide catalysts with different V loadings, which were prepared by the impregnation of a precipitated alumina. The alumina support and the supported catalysts were characterized using X-ray diffraction, N2 adsorption, EDX analysis and NH3-TPD techniques. The effects of the reaction time, of the molar ratio of the reactants, of the speed of agitation and of the mass fraction of the catalyst on the catalytic properties were studied. In the presence of the supported catalyst containing 10 wt % V2O5 (10V-Al2O3 sample) the conversion reached 87.7% after 210 min of reaction at 100 °C with an n-Butanol-to-acetic acid mole ratio equal to one. The conversion as well as the total acidity measured by TPD of NH 3 increased in the following order: Al2O3 2O3 (5 wt % V2O5/Al 2O3) 2O3. In all cases the reaction was completely selective to n-butyl acetate. Nevertheless, a loss in catalytic activity after three reaction cycles with 10 V2O 5-Al2O3 catalyst was observed.
- Mitran, Gheorghita,Makó, éva,Rédey, ákos,Marcu, Ioan-Cezar
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- Polymers as reagents and catalysts. Part 28. The effect of polymer catalyst structure on the esterification of acids
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Crosslinked sulphonated polystyrene (Dowex 20 M) and various salts of crosslinked co-poly[styrene-4-vinylpyridine] with hydrogen halides were used as solid catalysts in investigations of the conversion of acids to esters. The role of the structure of the acid (acetic acid, benzoic acid), solvent (n-octane, toluene, n-butanol) and reaction temperature in the presence of polymer supported catalyst was tested in the reaction with n-butanol. Sulphonated crosslinked polystyrene (3a) was the most active catalys, similar activity was found with crosslinked co-poly[styrene-4-vinyl(pyridinium chloride)], while catalysts bearing a fluoride (3b) and iodide (3e) function were almost unreactive. The important role of co-solvents was also established.
- Zupan,Segatin
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- One-step synthesis of a novel carbon-based strong acid catalyst through hydrothermal carbonization
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A novel carbon-based strong acid catalyst was synthesized through the one-step hydrothermal carbonization of furaldehyde and p-toluenesulfonic acid (PTSA) in aqueous solution at 180 °C for only 4 h. The novel carbonbased solid acid possessed high acidity, and the catalytic activities were investigated by esterification and oxathioketalization. The results showed that the novel catalyst demonstrated much greater activity than the traditional solid acids and was comparable to sulfuric acid. The onestep method provides an efficient procedure for the synthesis of various functionalized carbons by one-step hydrothermal carbonization. Springer-Verlag 2010.
- Xiao, Huiquan,Guo, Yingxue,Liang, Xuezheng,Qi, Chenze
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- A Convenient Synthesis of Isotopically Labelled Anthraquinones, Chrysophanol, Islandicin, and Emodin. Incorporation of Chrysophanol into Tajixanthone in Aspergillus variecolor
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Cycloaddition reactions of labelled 6-methoxy-3-methyl-2-pyrone (1) with naphthoquinones provide the common fungal anthraquinones, chrysophanol (2), islandicin (3), and emodin (4) suitably labelled for biosynthetic studies, as demonstrated by synthesis and incorporation of chrysophanol into the xanthone metabolite, tajixanthone (17) in Aspergillus variecolor.
- Ahmed, Salman A.,Bardshiri, Esfandiar,Simpson, Thomas J.
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- Tailoring ionic liquid catalysts: Structure, acidity and catalytic activity of protonic ionic liquids based on anionic clusters, [(HSO4)(H 2SO4)x]- (x = 0, 1, or 2)
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Aiming at inexpensive Bronsted-acidic ionic liquids, suitable for industrial-scale catalysis, a family of protonic ionic liquids based on nitrogen bases and sulfuric acid has been developed. Variation of the molar ratio of sulfuric acid, ?H2SO4, was used to tune acidity. The liquid structure was studied using 1H NMR and IR spectroscopies, revealing the existence of hydrogen-bonded clusters, [(HSO4)(H2SO4)]?, for ?H2SO4 0.50. Acidity, quantified by Gutmann Acceptor Number (AN), was found to be closely related to the liquid structure. The ionic liquids were employed as acid catalysts in a model reaction; Fischer esterification of acetic acid with 1-butanol. The reaction rate depended on two factors; for ?H2SO4 0.50, the key parameter was acidity (expressed as AN value), while for ?H2SO4 0.50 it was the mass transport (solubility of starting materials in the ionic liquid phase). Building on this insight, the ionic liquid catalyst and reaction conditions have been chosen. Conversion values of over 95% were achieved under exceptionally mild conditions, and using an inexpensive ionic liquid, which could be recycled up to eight times without diminution in conversion or selectivity. It has been demonstrated how structural studies can underpin rational design and development of an ionic liquid catalyst, and in turn lead to a both greener and economically viable process.
- Matuszek, Karolina,Chrobok, Anna,Coleman, Fergal,Seddon, Kenneth R.,Swadzba-Kwasny, Malgorzata
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- Magnetic MOF microreactors for recyclable size-selective biocatalysis
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In this contribution we report a synthetic strategy for the encapsulation of functional biomolecules within MOF-based microcapsules. We employ an agarose hydrogel droplet Pickering-stabilised by UiO-66 and magnetite nanoparticles as a template around which to deposit a hierarchically structured ZIF-8 shell. The resulting microcapsules are robust, highly microporous and readily attracted to a magnet, where the hydrogel core provides a facile means to encapsulate enzymes for recyclable size-selective biocatalysis.
- Huo, Jia,Aguilera-Sigalat, Jordi,El-Hankari, Samir,Bradshaw, Darren
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- Preparation of fibrous sulfated zirconia (SO4 2-/ZrO2) solid acid catalyst using collagen fiber as the template and its application in esterification
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A novel fibrous sulfated ZrO2 (SO4 2-/ZrO2) solid acid catalyst was prepared using collagen fiber as the template. The surface morphology of the as-prepared catalyst was observed by scanning electron microscopy (SEM), and the corresponding crystalline properties were determined by X-ray diffraction (XRD). To collect the structural properties of the SO42-/ZrO2 catalyst, N2 adsorption/desorption method was carried out. Temperature-programmed decomposition (TPD) of ammonia was conducted to determine the acid strength of the catalyst. It was found that the SO4 2-/ZrO2 catalyst had well-defined fibrous morphology and porous structure, which contained both medium strong acidic sites and strong acidic sites. Subsequently, the esterification of acetic acid with n-butanol was carried out to evaluate the catalytic activity and reusability of the SO 42-/ZrO2 catalyst. The SO4 2-/ZrO2 catalyst exhibited high catalytic activity as compared with other solid acid catalysts. Furthermore, the catalyst can be reused 6 times without significant loss of catalytic activity, suggesting a satisfied reusability.
- Liao, Yang,Huang, Xin,Liao, Xuepin,Shi, Bi
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- Zr-La doped sulfated titania with a by far better catalytic activity and stability than pure sulfated titania in the esterification of acetic acid and n-butanol
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A novel solid superacid catalyst TiO2-Zr-La/SO4 2- was prepared by doping Zr and La to the bulk of TiO2. The modified TiO2-Zr-La/SO4 2- and the unmodified TiO2/SO4 2- were used to catalyze the esterification of acetic acid and n-butanol, in which these two catalysts were systematically compared in a lost of aspects such as catalytic activity and stability and so on. When a small amount of Zr and La were co-doped into the bulk of TiO2, the modified catalyst obtained a by far better catalytic activity and stability than the unmodified, showing that the modified is more resistive to deactivation than the unmodified. Under the set reaction conditions, the average conversion (of acetic acid) and the 20th-cycle conversion (of acetic acid) are 88.83 and 77.35 % for the modified, 80.83 and 46.15 % for the unmodified, respectively. The two catalysts were characterized by means of FTIR, XRD, BET, SEM, TG, and NH3-TPD methods to find the possible reasons for the superiority of the modified catalyst to the unmodified one. The characteristic results indicated that the incorporation of a small amount of Zr and La into the catalyst was beneficial to the modified catalyst: (1) improving its water-tolerance; (2) increasing its surface sulfate group content; (3) decreasing its crystallinity after calcination by retarding its crystallization from amorphous TiO2 to anatase TiO2; (4) increasing its specific surface area; (5) increasing its acidity including the concentration and acid strength of the surface acidic sites of it. All the above advantageous effects arisen from the two-element-doping are to be responsible for the substantially-improved catalytic performances of the modified catalyst.
- Shi, Wenping
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- Sulfated graphene as an efficient solid catalyst for acid-catalyzed liquid reactions
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Graphene with its two-dimensional sheet of sp2-hybridized carbon is a hot topic in the fields of materials and chemistry due to its unique features. Herein, we demonstrate that sulfated graphene is an efficient solid catalyst for acid-catalyzed liquid reactions. The sulfated graphene was synthesized from a facile hydrothermal sulfonation of reduced graphene oxide with fuming sulfuric acid at 180 °C. Combined characterizations of XRD, Raman, and AFM techniques show that G-SO3H has a sheet structure (1-4 layers). IR spectroscopy shows that G-SO3H has a S = O bond, and the XPS technique confirms the presence of an S element in G-SO3H. Acid-base titration indicates that the acidic concentration of sulfonic groups in the sulfated graphene is 1.2 mmol g-1. TG curves shows that the decomposition temperature (268 °C) of the sulfonic groups on the sulfated graphene is much higher than that of conventional SO3H-functionalized ordered mesoporous carbon (237 °C). Catalytic tests of the esterification of acetic acid with cyclohexanol, the esterification of acetic acid with 1-butanol, the Peckmann reaction of resorcinol with ethyl acetoacetate, and the hydration of propylene oxide show that sulfated graphene is much more active than the conventional solid acid catalysts of Amberlyst 15, OMC-SO3H, SO3H-functionalized ordered mesoporous silica (SBA-15-SO 3H), graphene oxide, and reduced graphene oxide, which is attributed to the fact that the sulfated graphene almost has no limitation of mass transfer due to its unique sheet structure. Very importantly, the sulfated graphene has extraordinary recyclability in these reactions, which is attributed to the stable sulfonic groups on the sulfated graphene. The advantages, including high activities and good recyclability as well as simple preparation, are potentially important for industrial applications of the sulfated graphene as an efficient heterogeneous solid acid catalyst in the future. The Royal Society of Chemistry 2012.
- Liu, Fujian,Sun, Jing,Zhu, Longfeng,Meng, Xiangju,Qi, Chenze,Xiao, Feng-Shou
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- Production of aroma esters by immobilized Candida rugosa and porcine pancreatic lipase into calcium alginate gel
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Candida rugosa lipase (CRL) and porcine pancreatic lipase (PPL) were immobilized into calcium alginate (Ca-Alg) gel beads by means of entrapment and were used to produce three industrially important flavour esters, namely isoamyl acetate (banana flavour), ethyl valerate (green apple flavour) and butyl acetate (pineapple flavour). Immobilization conditions were optimized in terms of sodium alginate (Na-Alg) and CaCl2 concentrations by determination of the entrapped enzyme amount as well as by esterification of 4-nitrophenol and acetic acid. The best results were obtained at 2.5% Na-Alg and 2.5 M CaCl2 for CRL while at 2.5% Na-Alg and 2.0 M CaCl2 for PPL. On carrying out flavour syntheses in solvent-free medium and also in hexane medium, higher ester yields were obtained in hexane medium for all esters and both types of lipases. Ester esterification efficiency increased in parallel with both enzyme concentrations at immobilization medium and the immobilized lipase amount in esterification medium. Maximum ester production was observed between 40 and 50 °C for CRL and PPL. Besides, the effect of substrate concentrations on ester conversion was remarkable. The best ester yield was obtained for isoamyl acetate when immobilized PPL was used.
- Ozyilmaz, Gul,Gezer, Esra
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- An improved esterification of carboxylic acids using phase transfer conditions without solvents
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Esterification of sodium salt of carboxilic acids were performed with alkyl bromide in phase-transfer conditions without solvent.
- Vinczer,Novak,Szantay
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- Cholinium-based deep eutectic solvents and ionic liquids for lipase-catalyzed synthesis of butyl acetate
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The aim of this study was to analyze the advantages and limitations of cholinium-based ionic liquids (ILs) and deep eutectic solvents (DESs) used as green solvents for immobilized Candida antarctica lipase B-catalyzed synthesis. The reaction of acetic anhydride with 1-butanol to give short chain ester butyl acetate was chosen as a model reaction. Results showed that selected ILs (choline glycinate, choline alaninate, choline asparaginate, choline malate) and DESs (choline chloride mixtures with glycerol Gly, ethylene glycol EG, and urea U as hydrogen bond donors in molar ratio 1:2) are poor media for tested reaction if applied as pure solvents (yield 50 >5 mM) for both cell lines. Obtained results suggest that DESs are promising candidates for green biocatalysis.
- Cvjetko Bubalo, Marina,Jurinjak Tu?ek, Ana,Vinkovi?, Marijana,Rado?evi?, Kristina,Gaurina Sr?ek, Vi?nja,Radoj?i? Redovnikovi?, Ivana
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- Process optimization by response surface methodology for transesterification of renewable ethyl acetate to butyl acetate biofuel additive over borated USY zeolite
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Butyl acetate, a renewable biofuel additive was synthesized by transesterification of butanol with ethyl acetate via a renewable and sustainable route. Use of fermentation derived bio-butanol and bio-ethyl acetate for synthesis of butyl acetate would be a more advantageous route over conventional Fischer Esterification. For the first time, a heterogeneous zeolite catalyst such as Ultra Stable Y (USY) and its modified versions obtained by borating on parent USY were used for the synthesis of butyl acetate. Response surface methodology (RSM) was employed to optimize the process parameters for transesterification of butanol with ethyl acetate over a 4% (w/w) B-USY catalyst. The influence of three crucial process variables such as catalyst loading, molar ratio, and reaction temperature on yield of butyl acetate were addressed by Box-Behnken experimental design (BBD). 4% (w/w) B-USY was proved to be a potential catalyst with 96% yield of butyl acetate at optimum process parameters. The 4% (w/w) B-USY catalyst was found to be reusable for 6 catalytic cycles. This journal is
- Nandiwale, Kakasaheb Y.,Galande, Nitish D.,Bokade, Vijay V.
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- Molybdena-vanadia supported on alumina: Effective catalysts for the esterification reaction of acetic acid with n-butanol
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The paper describes the preparation of alumina-supported molybdena-vanadia catalysts, their structural and textural characterization using XRD, N 2 adsorption, UV-vis and NH3-TPD techniques as well as their catalytic properties in the esterification reaction of acetic acid with n-butanol. The effects of esterification conditions including reaction time, catalyst loading and acid-to-alcohol mole ratio and of reactant pre-adsorption on the conversion were investigated. The catalytic activity correlated well with the number of strong acid sites which increased by increasing the vanadia content. In optimized conditions, conversions higher than 85% with 100% selectivity for n-butyl acetate can be obtained. Reactant pre-adsorption experiments suggested that the reaction follows the Langmuir-Hinshelwood mechanism. A good reusability of the catalysts after three reaction cycles was observed. A local interaction between molybdenum and vanadium on the catalyst surface has been evidenced.
- Mitran, Gheorghita,Pavel, Octavian-Dumitru,Marcu, Ioan-Cezar
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- Hydrogenation of ethyl acetate to ethanol over Ni-based catalysts obtained from Ni/Al hydrotalcite-like compounds
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A series of Ni-based catalysts were prepared using hydrogen reduction of Ni/Al hydrotalcite-like compounds (Ni/Al HTlcs) synthesized by coprecipitation. The physicochemical properties of Ni/Al hydrotalcite-like compounds and the corresponding Ni-based catalysts were characterized using inductively coupled plasma (ICP), BET surface areas, Xray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. The results indicated that Ni/Al HTlcs with layered structures could be successfully prepared by the coprecipitation method, and the characteristic HTlcs reflections were also observed in the XRD analysis. The NiO and Ni 0 phases were identified in all Ni-based catalysts, which displayed randomly interconnected pores and no layer structures. In addition, the studies also found the Ni/Al HTlcs and Nibased catalysts had high specific surface areas, low pore volumes and low pore diameters. The catalytic hydrogenation of ethyl acetate to ethanol with Ni-based catalysts was also investigated. Among the studied catalysts, RE1NASH-110-3 showed the highest selectivity and yield of ethyl acetate to ethanol, which were 68.2% and 61.7%, respectively. At thesame time, a major by-product, butyl acetate, was formed due to an ester-exchange reaction. A proposed hydrogenation pathway for ethyl acetate over Ni-based catalysts was suggested.
- Zhang, Beixiao,Lin, Lu,Zhuang, Junping,Liu, Ying,Peng, Lincai,Jiang, Longfei
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- One-step synthesis of novel biacidic carbon via hydrothermal carbonization
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The novel biacidic carbon has been synthesized via one-step hydrothermal carbonization of glucose, citric acid, and hydroxyethylsulfonic acid at 180 °C for only 4 h. The novel carbon had an acidity of 1.7 mmol/g with the carbonyl to sulfonic acid groups molar ratio of 1:3, which was confirmed by IR, XPS, TPD, SEM, and BET analyses. The catalytic activities of the carbon were investigated through esterification and oxathioketalization. The results showed that the carbon owned the comparable activities to sulfuric acid, which indicated that the carbon holds great potential for the green processes.
- Xiao, Huiquan,Guo, Yingxue,Liang, Xuezheng,Qi, Chenze
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- Kinetic study of transesterification of methyl acetate with n-butanol catalyzed by NKC-9
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The transesterification of methyl, acetate and n-butanol catalyzed by cation-exchange resin, NKC-9, was studied in this work to obtain the reaction kinetics. The experiments were carried out in a stirred batch reactor at different temperatures (328.15, 33
- Baoyun, Xu,Weijiang, Zhang,Xuemei, Zhang,Cuifang, Zhou
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- Towards acid MOFs-catalytic performance of sulfonic acid functionalized architectures
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In this work, the inclusion of free sulfonic acid groups in highly stable MOFs is explored. The synthesized catalysts have been applied in a model esterification reaction. Two metal organic frameworks bearing sulfonic acid moieties are investigated: HSO3-MIL-101(Cr) synthesized following different approaches and a new structure based on HSO3-bdc and Zr. The acidic properties, catalytic performance, deactivation and stability of the different structures are critically evaluated. In the case of MIL-101(Cr), deactivation of the sulfonic groups via formation of butanol sulfonic esters has been observed. Due to the strong interaction between -SO3 - and the Cr open metal site where usually fluorine (F-) is located in the structure, the HSO3-MIL-101(Cr) catalysts are not stable under acidic regeneration conditions. When using Zr as a metal node, a new and stable sulfonic acid containing porous structure was synthesized. This structure showed high activity and full re-usability in the esterification of n-butanol with acetic acid. In this case, deactivation of the catalyst due to sulfonic ester formation could be reversed by reactivation under acidic conditions. The Royal Society of Chemistry 2013.
- Juan-Alcaniz, Jana,Gielisse, Robin,Lago, Ana B.,Ramos-Fernandez, Enrique V.,Serra-Crespo, Pablo,Devic, Thomas,Guillou, Nathalie,Serre, Christian,Kapteijn, Freek,Gascon, Jorge
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- Surface, textural and catalytic properties of pyridinium hydrogen sulfate ionic liquid heterogenized on activated carbon carrier
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Pyridinium hydrogen sulfate ionic liquid (PHS) heterogenized on activated carbon (AC) is investigated for the first time in the current paper. For that purpose, the xPHS/AC (x = 8, 17, 33 and 66 wt%) samples are analyzed by a number of physicochemical methods such as N2 adsorption–desorption measurements, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Catalytic activity and reusability of xPHS/AC are evaluated in the reaction of butyl acetate synthesis. Effect of the reaction temperature and catalyst loading on the butyl acetate yield are examined in this work as well. Important thermodynamic parameters such as equilibrium constant, activation energy, Gibbs free energy and activation energy barrier for the reaction of butyl acetate synthesis in the presence of xPHS/AC are determined. Textural characterization revealed the that xPHS/AC are mixed micro-mesoporous materials. The PHS heterogenization on AC affects both ionic liquid and support phases due to a surface PHS–AC interaction. FT-IR and XPS showed that this interaction is: (i) manly expressed as a close contact between the pyridinium cation and the functional groups on the AC surface and (ii) electrostatic in nature. The existence of a PHS–AC interaction is found to be responsible for the formation of surface PHS particles of various size. However, the catalytic activity of xPHS/AC is established to be affected by the surface active phase amount, but not the PHS particle size.
- Avdeev, Georgi,Kolev, Hristo,Tankov, Ivaylo
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- Nonisothermal calorimetry for fast thermokinetic reaction analysis: Solvent-free esterification of n -butanol by acetic anhydride
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An enhanced small-scale reaction calorimeter has been built for nonisothermal applications. Its unique design, combining compensation heater and heat flow sensors together with a solid intermediate thermostat is particularly suited for data oriented process development (determination of chemical reaction parameters, i.e. rate constants, reaction enthalpies, and reaction monitoring with optional in situ devices) in a wide range of applications in chemical and life-science oriented industries. The performance of the calorimeter is successfully demonstrated for kinetic investigation under nonisothermal conditions. Three different methods for determining the time-resolved reaction heat have been tested. The first is based on the traditional heat balance, the second on the twin principle, while the third is a novel method based on a rigourous heat flow modelling using mathematical finite methods. As a case study, we investigated the esterification of n-butanol with acetic anhydride catalysed by tetramethylguanidine using a temperature ramp from 30 to 80 °C. Each method accounts differently for the dynamics and the heat accumulation in the system. However, all three methods show minor differences in the resulting kinetic parameters and reaction enthalpies. In this temperature range, kinetic and mechanistic analysis resolved two competitive parallel catalytic and noncatalytic steps.
- Richner, Gilles,Neuhold, Yorck-Michael,Hungerbuehler, Konrad
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- Zinc oxide as a solid acid catalyst for esterification reaction
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Zinc oxide and its composites with Hβ zeolite were produced under different synthesis conditions. The synthesized catalysts were evaluated for performance in esterification of n-butanol with acetic acid. BET surface area, XRD, and acidity (using NH3 and pyridine as probe molecules) were measured to correlate the activity with the structural features of the catalysts.
- Nagvenkar, Anjani,Naik, Sajo,Fernandes, Julio
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- Crosslinked Polyvinylpyridine Hydrochloride as Mild Polymeric Catalyst for Acetalization of Carbonyl Compounds and Esterification of Carboxylic Acids
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Crosslinked poly(4-vinylpyridine) hydrochloride was found to be an effective catalyst for acetalization of carbonyl compounds and esterification of carboxylic acids.The polymeric catalyst was inert to some acid sensitive functional groups which cannot tolerate under the influence of a strong acid cation exchange resin.
- Yoshida, Jun-ichi,Hashimoto, Jiro,Kawabata, Nariyoshi
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- High-temperature synthesis of magnetically active and SO 3H-functionalized ordered mesoporous carbon with good catalytic performance
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Magnetically active and SO3H-functionalized ordered mesoporous resin and carbon (MOMR-SO3H, MOMC-SO3H) were successfully prepared by high-temperature hydrothermal synthesis from resol, copolymer surfactant, and iron cations at 180 °C, followed by sulfonation from sulfuric acid fuming. X-ray diffraction patterns show that MOMR-SO3H and MOMC-SO3H have ordered hexagonal mesoporous symmetry. N 2 isotherms indicate that these samples have uniform and opened mesopores, high surface areas (335-591 m2/g), and large pore volumes (0.34-0.35 cm3/g). Transmission electron microscopy shows that iron nanoparticles, which are superparamagnetic in nature, are highly dispersed in MOMC-SO3H sample. Catalytic tests show that MOMC-SO3H is highly active and excellently recyclable in esterification of acetic acid with butanol, esterification of acetic acid with cyclohexanol, and condensation of benzaldehyde with ethylene glycol. More interestingly, MOMC-SO3H catalyst is magnetically active, showing potential applications for separating catalysts by a magnetic field in the future.
- Liu, Fujian,Sun, Jing,Sun, Qi,Zhu, Longfeng,Wang, Liang,Meng, Xiangju,Qi, Chenze,Xiao, Feng-Shou
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- Application of a sodalite membrane reactor in esterification - Coupling reaction and separation
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A tubular hydroxy sodalite (SOD) membrane was successfully applied in the esterification of acetic acid with ethanol and acetic acid with 1-butanol, to selectively remove water by pervaporation and to overcome the thermodynamic equilibrium limitation of the esterification. The reactions were carried out using equimolar solutions of acetic acid with the appropriate organic alcohol at 363 K using Amberlyst 15 as acid catalyst. The hybrid process drove the esterification reactions almost to completion. The special feature of the SOD-membrane is that it showed absolute selectivity towards water and retained its stability under the reaction conditions. The membrane exhibited a stable water pervaporation performance at pH values above 2.9 for acetic acid-water mixtures.
- Khajavi, Sheida,Jansen, Jacobus C.,Kapteijn, Freek
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- Studies on a Synthesis of (RS)-Mevalonic Acid Lactone
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Full details of a high yielding synthesis of mevalonic acid lactone (1) which is of particular value in the preparation of 3- and/or 3'-labelled compounds are described.The key step, conversion of 3-hydroxy-3-methylpentane-1,5-dioic acid (3) into 3-hydroxy-3-methylpentane-1,5-dioic anhydride (4) using acetic anhydride, has been fully investigated, and an additional method using acetyl chloride and triethylamine is described.
- Bardshiri, Esfandiar,Simpson, Thomas J.,Scott, A. Ian,Shishido, Kozo
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- Ultrasound-assisted butyl acetate synthesis catalyzed by Novozym 435: Enhanced activity and operational stability
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The influence of low-frequency ultrasound (40 kHz) in the esterification reaction between acetic acid and butanol for flavor ester synthesis catalyzed by the commercial immobilized lipase B from Candida antarctica (Novozym 435) was evaluated. A central composite design and the response surface methodology were used to analyze the effects of the reaction parameters (temperature, substrate molar ratio, enzyme content and added water) and their response (yields of conversion in 2.5 h of reaction). The reaction was carried out using n-hexane as solvent. The optimal conditions for ultrasound-assisted butyl acetate synthesis were found to be: temperature of 46 °C; substrate molar ratio of 3.6:1 butanol:acetic acid; enzyme content of 7%; added water of 0.25%, conditions that are slightly different from those found using mechanical mixing. Over 94% of conversion was obtained in 2.5 h under these conditions. The optimal acid concentration for the reaction was determined to be 2.0 M, compared to 0.3 M without ultrasound treatment. Enzyme productivity was significantly improved to around 7.5-fold for each batch when comparing ultrasound and standard mechanical agitation. The biocatalyst could be directly reused for 14 reactions cycles keeping around 70% of its original activity, while activity was virtually zeroed in the third cycle using the standard mixing system. Thus, compared to the traditional mechanical agitation, ultrasound technology not only improves the process productivity, but also enhances enzyme recycling and stability in the presence of acetic acid, being a powerful tool to improve biocatalyst performance in this type of reaction.
- Martins, Andréa B.,Schein, Mirela F.,Friedrich, John L.R.,Fernandez-Lafuente, Roberto,Ayub, Marco A.Z.,Rodrigues, Rafael C.
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- Calibration-free estimates of batch process yields and detection of process upsets using in situ spectroscopic measurements and nonisothermal kinetic models: 4-(Dimethylamino)pyridine-catalyzed esterification of butanol
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The use of an near-IR fiber-optic spectrometer with a high-speed diode array for calibration-free monitoring and modeling of the reaction of acetic anhydride with butanol using the catalyst 4-(dimethylamino)pyridine in a microscale batch reactor was presented. Nonlinear fitting of a first-principles model directly to the reaction spectra gave calibration-free estimates of time-dependent concentration profiles and pure component spectra. Real-time modeling of a batch reaction could be achieved by augmenting prerun batch data with recently acquired spectral data followed by fitting of a multiway kinetic model. In real-time applications, accurate initial guesses of the parameter estimates from prerun data can be used to facilitate rapid convergence of the iterative nonlinear fitting process.
- Gemperline, Paul,Puxty, Graeme,Maeder, Marcel,Walker, Dwight,Tarczynski, Frank,Bosserman, Mary
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- Study of the esterification reaction of acetic acid with n-butanol over supported WO3 catalysts
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The liquid-phase esterification of acetic acid with n-butanol has been studied over tungsten oxide supported on alumina, silica and silica-alumina containing two different W loadings. They were prepared by the impregnation of precipitated supports and characterized using X-ray diffraction, N2 adsorption, SEM-EDX and NH3-TPD techniques. The effects of esterification conditions including the reaction time and temperature, the acid-to-alcohol mole ratio, the amount of catalyst and the catalyst reusability as well as the effect of reactant pre-adsorption on the reaction conversion were investigated. The best catalytic performance was obtained with WO3 supported on silica-alumina with a silica-to-alumina mole ratio of 0.4 (10W-Si(0.4)Al sample). The activity of the different catalysts ranged as follows (the conversion of acetic acid at 120 min reaction time in parenthesis): 10W-Si(0.4)Al (95.5) > 10W-Al (86.2) > 10W-Si(1.0)Al (82.1) > 10W-Si(2.5)Al (79.8) > 5W-Al (77.5) > 10W-Si (75.9) > 5W-Si (70.6). The catalytic activity correlated well with the total number of acid sites determined by NH3-TPD. In all cases the reaction was completely selective to n-butyl acetate. Reactant pre-adsorption experiments suggested that the reaction follows the Langmuir-Hinshelwood mechanism. A good reusability of the 10W-Si(0.4)Al catalyst after three reaction cycles was observed.
- Mitran, Gheorghi?a,Yuzhakova, Tatiana,Popescu, Ionel,Marcu, Ioan-Cezar
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- Efficient synthesis of vitamin e intermediate by lipase-catalyzed regioselective transesterification
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Trimethylhydroquinone-1-monoacetate (TMHQ-1-MA) is a valuable synthetic intermediate for vitamin E acetate. Immobilized Lipozyme RM IM from Mucor miehei was shown to be the best biocatalyst for the production of TMHQ-1-MA through regioselective transesterification between trimethylhydroquinone diacetate (TMHQ-DA) and alcohol. The effects of lipase-catalyzed reaction conditions including solvent, acyl receptor, substrate mole ratio, reaction temperature and agitation speed were investigated. The optimum conditions for Lipozyme RM IM catalyzed regioselective transesterification were achieved at a substrate mole ratio of 1:1, an agitation of 200 rpm at 50 °C in MTBE/n-hexane (3:7). Under the above conditions, Lipozyme RM IM exhibited high substrate tolerance (substrate concentrations of 1.06 M). Recycling experiments demonstrated that Lipozyme RM IM was quite steady under the reaction conditions. The analysis of kinetic experiment showed that the enzymatic reaction obeys the Ping-Pong bi-bi mechanism with n-butanol inhibition.
- Wei, Chun,Fu, Xian-Feng,Wang, Zhao,Yu, Xin-Jun,Zhang, Yin-Jun,Zheng, Jian-Yong
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- Characterization of titanium dioxide nanoparticles dispersed in organic ligand solutions by using a diffusion-ordered spectroscopy-based strategy
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Diffusion-ordered NMR spectroscopy (DOSY NMR) is presented as a tool for the determination of the diffusion coefficients of organic ligands in suspensions of titanium dioxide nanoparticles. The nanoparticles were prepared by a sol-gel process by hydrolysis and condensation reactions of titanium tetra-n-butoxide in the presence of pentane-2,4-dione (acacH: acetylacetone), as well as para-toluenesulfonic acid (pTsA) and n-butanol (nBuOH). NMR spectroscopic studies were performed in various deuterated solvents, on both dispersed xerosols and diluted sols. The bipolar-pulsed field gradient longitudinal eddy-current delay (LED) pulse sequence was used for data acquisition. The data were processed by inverse Laplace transformation (ILT), by using a maximum entropy algorithm, to afford 2D DOSY spectra. Different diffusion regimes for organic ligands in the bound and unbound states were successfully discriminated, more particularly in [D3]acetonitrile, thus allowing assessment of their interactions with the nanoparticles.
- Van Lokeren, Luk,Maheut, Geraldine,Ribot, Francois,Escax, Virginie,Verbruggen, Ingrid,Sanchez, Clement,Martins, Jose C.,Biesemans, Monique,Willem, Rudolph
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- New insights into the encapsulation and stabilization of heteropolyacids inside the pore walls of mesostructured silica materials
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A method of synthesizing stable and reactive modified mesoporous hybrid materials with intact heteropolyacid (HPA) Keggin units is reported. The materials were synthesized by a one-pot method using a mixture of structure directing agents (CTAB and Pluronic 123). The key to obtaining stable HPA containing materials was the sequential calcination and extraction steps, and the authors present a working hypothesis for this phenomenon. Studies of several other key factors concerning synthetic parameters are also reported. All materials were characterized by a wide variety of physical and spectroscopic methods at each step of the synthesis. The kinetics of the esterification of acetic acid by butanol mediated by several of the materials and relevant homogeneous acid catalysts showed that the HPA containing hybrid material was a highly effective catalyst.
- Dufaud, Veronique,Lefebvre, Frederic,Niccolai, Gerald P.,Aouine, Mimoun
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- Esterification of acetic acid with butanol over sulfonic acid-functionalized hybrid silicas
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Sulfonic acid-functionalized hybrid silicas with different loading of organic moieties were synthesized by grafting and co-condensation followed by oxidation of the precursor thiol groups with hydrogen peroxide or by in situ oxidation methods involving the oxidation by hydrogen peroxide during the condensation reaction. As determined by photoelectron spectroscopy (XPS) complete oxidation of the thiol groups in the differently prepared materials was achieved at room temperature. In the esterification reaction of acetic acid with butanol the samples prepared by the in situ oxidation method exhibited the best catalytic activity. During recycling test with a selected sample, in spite of some sulfur leaching, stable activity was observed.
- Testa, Maria Luisa,La Parola, Valeria,Venezia, Anna Maria
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- Liquid phase esterification of acetic acid over WO3 promoted β-SiC in a solvent free system
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A series of tungstate promoted β-SiC catalysts was synthesized by a wetness impregnation method. The as synthesized catalysts were unambiguously characterized by XRD, Raman, FTIR, XPS, UV-Vis DRS, TEM, BET surface areas and FE-SEM, and simultaneously the total amount of the acidity of the catalysts was estimated by NH3-TPD. The catalytic activities of the synthesized materials were tested in the liquid phase esterification of acetic acid with n-butanol in a solvent free medium. The reaction parameters were optimized to a temperature of 120 °C, molar ratio of butanol and acetic acid of 1:2 and a reaction time of 6 h after performing a number of experiments. Under the optimum conditions, the catalytic esterification revealed a significant effect of 88% conversion with 100% selectivity to butyl acetate in 20 wt% WO 3/β-SiC. This is the first report on the effective utilization of β-SiC as a catalyst support for liquid phase esterification of acetic acid.
- Mishra, Gopa,Behera, Gobinda C.,Singh,Parida
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- Alkyl substituted 4-N-oxazadisilinane cations: A new family of Si protic ionic liquids and its application on esterification reactions
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A series of oxazadisilinane compounds were prepared and used as Br?nsted bases to form a series of 21 siloxane protic ionic liquids (Si-PILs) with four different acids. This new family of Si-PILs were well characterized and examined to catalyze esterification reactions.
- Alhaddad, Maha,Chakraborty, Priyanka,Hu, Jinsong,Huang, Kuo-Wei
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- Highly effective continuous-flow monolithic silica microreactors for acid catalyzed processes
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This work reports the performance of a new monolithic silica microreactor, activated with sulphonic acid groups in the continuous-flow synthesis of n-butyl acetate and n-butyl lactate. A reactive core of the reactor was made of a single silica rod with bi-continuous structure, containing flow-through pores with diameter in the range of 20-50 μm and mesopores of ca. 20 nm localized in silica struts. This structure resulted in low pressure drop, even at flow rates large enough to eliminate external mass transfer effect on the reaction kinetics. The microreactor functionalized with 0.65mmol/g of-SO3H groups showed high activity and productivity in both esterification reactions carried out in temperatures up to 140 °C. Structural and catalytic stability of the microreactor was confirmed to demonstrate its process viability.
- Koreniuk,Maresz,Odrozek,Jarz?bski,Mrowiec-Bia?oń
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- Thermodynamics of phase and chemical equilibrium in a strongly nonideal esterification system
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In this study, the reaction equilibrium of the reversible esterification of acetic acid with 1-butanol giving 1-butyl acetate and water was investigated. The entire composition space including the miscibility gap was covered at temperatures relevant for technical processes (353.15 K to 393.15 K). The experiments were carried out in a multiphase batch reactor with online gas chromatography and in a batch reactor with quantitative 1H NMR spectroscopy, respectively. The thermophysical database available in the literature was complemented by measurements of liquid-liquid and vapor-liquid equilibria. On the basis of that comprehensive data, thermodynamically consistent models of the reaction equilibrium were developed which predict the concentration dependence of the mass action law pseudoequilibrium constant, Kx. The following different modeling approaches are compared: the GE models NRTL and UNIQUAC as well as the PC-SAFT equation of state and the COSMO-RS model. All of them can successfully be used, the COSMO-RS model, however, has the highest predictive power.
- Grob, Sascha,Hasse, Hans
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- Esterification of acetic acid with n-butanol using molybdenum oxides supported on γ-alumina
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Two γ-alumina-supported molybdenum oxide catalysts with different Mo loadings were prepared by the impregnation of a precipitated alumina. The alumina support and the supported catalysts were characterized using X-ray diffraction, N2 adsorption and NH3-TPD techniques and tested in the liquid-phase esterification of acetic acid with n-butanol. The effects of the reaction time, of the molar ratio of the reactants, of the speed of agitation and of the mass fraction of the catalyst on the catalytic properties were studied. After only 120 min of reaction at 100 °C with an n-butanol to acetic acid mole ratio equal to 3 the conversion reached 81% in the presence of the supported catalyst containing 10 wt% MoO3 (10Mo-Al2O3 sample). The conversion as well as the total NH3-TPD acidity increased in the following order: Al 2O3 2O3 (5 wt% MoO 3/Al2O3) 2O3. The selectivity of n-butyl acetate was, in all cases, 100%. No loss in catalytic activity and product selectivity after three cycles with 10Mo-Al 2O3 catalyst was observed. Graphical Abstract: [Figure not available: see fulltext.]
- Mitran, Gheorghita,Mako, Eva,Redey, Akos,Marcu, Ioan-Cezar
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- Transesterification between Ethyl Acetate and n-Butanol in Compressed CO2 in the Critical Region of the Reaction System
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The phase behavior (KT) and the equilibrium constant (Kx) of the reaction system for the transesterification between ethyl acetate and n-butanol in compressed CO2 were studied systematically. The Kx was very sensitive to pressure as the reaction mixture approached the critical point (CP), bubble point (BP), and dew point (DP) in the critical region. The Kx increased significantly as the pressure approached the DP and CP, while it decreased as the pressure approached the BP, i.e., pressure had the opposite effect on the Kx in the subcritical region and in the supercritical region. The Peng-Robinson EOS could predict the Kx far from the critical region satisfactorily. However, the difference of the predicted results and the experimental data became larger as the reaction system approached the CP, BP, and DP in the critical region. The reaction could be carried out in the critical region with a suitable amount of CO2, whereas this was impossible without the solvent. Thus, the clean solvent could also be used as a green solvent to adjust the critical point and phase behaviors of the reaction system, so that the reaction could take place in the critical region, and the reaction could be tuned effectively by pressure.
- Gao, Liang,Wu, Weize,Hou, Zhenshan,Jiang, Tao,Han, Buxing,Liu, Jun,Liu, Zhimin
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- A novel solid acid catalyst synthesized from ZnAl2O4 spinel and its application in the esterification of acetic acid and n-butyl alcohol
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A new spinel-style S2O82-/ZnAl2O4 solid acid catalyst was prepared by sol-gel method. The catalytic performance was evaluated by the esterification of n-butyl acetate. The structure, morphology and acidity of the samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Field emission scanning electron microscopy (FE-SEM), N2 physisorption, X-ray photoelectron spectroscopy (XPS) and NH3 temperature programmed desorption (NH3-TPD). The results showed that the catalytic performances were significantly affected by the calcination temperature. S2O82-/ZnAl2O4-600 exhibited the highest catalytic activity of 91.7% under the optimum reaction conditions. The characterization showed that the mesoporous structure S2O82-/ZnAl2O4-600 maintained the well crystallinity of spinel as well as the spinel-style carrier in the sulfidation and recycling. This journal is
- Wang, An-Qi,Wu, Xiu-Ling,Wang, Jun-Xia,Pan, Hui,Tian, Xiao-Yun,Xing, Yu-Lin
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- Characterization and catalytic performance of basaltic dust as an efficient catalyst in the liquid-phase esterification of acetic acid with n-butanol
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Three natural basaltic samples were collected and used as efficient catalysts for the liquid-phase synthesis of n-butyl acetate. The samples were characterized by X-ray fluorescence analysis (XRF), X-ray diffraction (XRD), thermogravimetry (TG), differential thermal analysis (DTA), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), and N2 sorption. The acidity of the samples was determined using isopropanol dehydration, and the strength of the acid sites was measured using chemisorption of basic probes. The catalytic activity of the samples towards the esterification of acetic acid with n-butanol was extensively examined. The influence of different parameters, such as the reaction refluxing time, molar ratio, catalyst loading, reusability, and calcination temperature, on the esterification reaction was studied in detail. The results revealed that all samples had high catalytic activity with a selectivity of 100% to n-butyl acetate formation. In addition, the sample obtained from the top hill of Volcano had the highest activity with a 80% yield of n-butyl acetate. Moreover, the significant catalytic performances were well correlated with the acidity of the samples and to the reaction rate constants.
- Said, Abd El-Aziz A.,Heikal, Mohamed Th. S.,Goda, Mohamed N.
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- Preparation of sulfated alumina supported on mesoporous MCM-41 silica and its application in esterification
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New types of mesoporous SA/MCM-41 solid acid catalysts were prepared by loading sulfated alumina (SA) on MCM-41. The prepared catalysts were characterized by XRD, IR, N2 physisorption, elemental analysis, FT-IR of adsorbed pyridine and NH3-TPD. The esterification of acetic acid with n-butanol and citric acid with n-butanol were used as model reactions to test the catalytic activities and reusability of the SA/MCM-41 solid acid catalysts. Compared with SA catalyst, SA/MCM-41 catalysts exhibited higher catalytic performances, which were attributed to their high BET surface area and large pore volume. Moreover, 20SA/MCM-41 solid acid catalyst showed excellent reusability in both esterifications.
- Pan, Hui,Wang, Junxia,Chen, Long,Su, Guanghui,Cui, Jiameng,Meng, Dawei,Wu, Xiuling
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- Dehydrogenative ester synthesis from enol ethers and water with a ruthenium complex catalyzing two reactions in synergy
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We report the dehydrogenative synthesis of esters from enol ethers using water as the formal oxidant, catalyzed by a newly developed ruthenium acridine-based PNP(Ph)-type complex. Mechanistic experiments and density functional theory (DFT) studies suggest that an inner-sphere stepwise coupled reaction pathway is operational instead of a more intuitive outer-sphere tandem hydration-dehydrogenation pathway.
- Ben-David, Yehoshoa,Diskin-Posner, Yael,Kar, Sayan,Luo, Jie,Milstein, David,Rauch, Michael
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supporting information
p. 1481 - 1487
(2022/03/07)
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- Alcohol-Activated Vanadium-Containing Polyoxometalate Complexes in Homogeneous Glucose Oxidation Identified with 51V-NMR and EPR Spectroscopy
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Alcoholic solvents, especially methanol, show an activating affect for heteropolyacids in homogenously catalysed glucose transformation reactions. In detail, they manipulate the polyoxometalate-based catalyst in a way that thermodynamically favoured total oxidation to CO2 can be completely supressed. This allows a nearly 100 % carbon efficiency in the transformation reaction of glucose to methyl formate in methanolic solution at mild reaction conditions of 90 °C and 20 bar oxygen pressure. By using powerful spectroscopic tools like 51V-NMR and continuous wave EPR we could unambiguously prove that the vanadate-methanol-complex[VO(OMe)3]n is responsible for the selectivity shift in methanolic solution compared to the aqueous reference system.
- Wesinger, Stefanie,Mendt, Matthias,Albert, Jakob
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p. 3662 - 3670
(2021/06/18)
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- Evaluation of gem-Diacetates as Alternative Reagents for Enzymatic Regio-and Stereoselective Acylation of Alcohols
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Geminal diacetates have been used as sustainable acyl donors for enzymatic acylation of chiral and nonchiral alcohols. Especially, it was revealed that geminal diacetates showed higher reactivity than vinyl acetate for hydrolases that are sensitive to acetaldehyde. Under optimized conditions for enzymatic acylation, several synthetically relevant saturated and unsaturated acetates of various primary alcohols were obtained in very high yields up to 98% without E/Z isomerization of the double bond. Subsequently, the acyl donor was recreated from the resulting aldehyde and reused constantly in acylation. Therefore, the developed process is characterized by high atomic efficiency. Moreover, it was shown that acylation using geminal diacetates resulted in remarkable regioselectivity by discriminating among the primary and secondary hydroxyl groups in 1-phenyl-1,3-propanediol providing exclusively 3-acetoxy-1-phenyl-propan-1-ol in good yield. Further, enzymatic kinetic resolution (EKR) and chemoenzymatic dynamic kinetic resolution (DKR) protocols were developed using geminal diacetate as an acylating agent, resulting in chiral acetates in high yields up to 94% with enantiomeric excesses exceeding 99%.
- Koszelewski, Dominik,Brodzka, Anna,Madej, Arleta,Trzepizur, Damian,Ostaszewski, Ryszard
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p. 6331 - 6342
(2021/05/06)
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- Photo-on-Demand Synthesis of Vilsmeier Reagents with Chloroform and Their Applications to One-Pot Organic Syntheses
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The Vilsmeier reagent (VR), first reported a century ago, is a versatile reagent in a variety of organic reactions. It is used extensively in formylation reactions. However, the synthesis of VR generally requires highly toxic and corrosive reagents such as POCl3, SOCl2, or COCl2. In this study, we found that VR is readily obtained from a CHCl3 solution containing N,N-dimethylformamide or N,N-dimethylacetamide upon photo-irradiation under O2 bubbling. The corresponding Vilsmeier reagents were obtained in high yields with the generation of gaseous HCl and CO2 as byproducts to allow their isolations as crystalline solid products amenable to analysis by X-ray crystallography. With the advantage of using CHCl3, which bifunctionally serves as a reactant and a solvent, this photo-on-demand VR synthesis is available for one-pot syntheses of aldehydes, acid chlorides, formates, ketones, esters, and amides.
- Liang, Fengying,Eda, Kazuo,Okazoe, Takashi,Wada, Akihiro,Mori, Nobuaki,Konishi, Katsuhiko,Tsuda, Akihiko
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p. 6504 - 6517
(2021/05/06)
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- A rings-in-pores net: Crown ether-based covalent organic frameworks for phase-transfer catalysis
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We herein present a new family of crown ether-based covalent organic frameworks (CE-COFs) for the first time. The CE-COFs show excellent phase-transfer catalytic performance in various nucleophilic substitution reactions.
- Guo, Wen-Di,Hu, Bingwen,Jiang, Wei-Ling,Lou, Xiaobing,Ma, De-Li,Qi, Qiao-Yan,Shen, Ji-Chuang,Shen, Ming,Yang, Hai-Bo,Zhao, Xin
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supporting information
p. 595 - 598
(2020/01/29)
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- Cascade conversion of furancarboxylic acid to butanediol diacetate over Pd/C and La(OTf)3 catalytic system
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The conversion of biomass to a high value-added product 1, 4-butanediol (BDO) and its derivatives is of great economic significance. In this work, furancarboxylic acid (FCA) was adopted as the raw material to prepare BDO. The one-pot synthesis of 1, 4-butanediol diacetate (BDA) has been successfully prepared from FCA with metal triflates and Pd/C catalysts. The effect of reaction conditions was investigated and the reaction routes was systematically studied by 1H-NMR and GC. The tandem catalytic process from FCA to BDA mainly underwent three stages. Firstly, FCA was hydrogenated to tetrahydrofurfuric acid (THFCA) by Pd/C. Afterwards, THFCA was decarbonylated to form oxonium ions with metal triflates. Then the oxonium ions was rapidly hydrogenated to form tetrahydrofuran (THF) by Pd/C. Ultimately, THF was ring-opening esterified to BDA by metal triflates. This novel synthesis method of BDO from FCA provides a promising protocol for broadening the application of common biomass substrates.
- Deng, Jin,Fu, Yao,Gong, Baoxiang,Zhou, Gongyu,Zhu, Rui
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- Enhancement of Acid-Catalyzed Esterification by the Addition of Base
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General acid-catalyzed reaction can be enhanced by the addition of base. Self-catalyzed esterification of benzoic acid and octan-1-ol was enhanced by the addition of certain base such as imidazole. The rate of the esterification was accelerated as the concentration of imidazole increased. Trans-esterification of 4-nitrophenyl acetate was promoted in chloroform by the mixture of benzoic acid and imidazole, but not by benzoic acid or imidazole alone.
- Kihara, Nobuhiro,Matsumoto, Yasuhiro,Tsukamoto, Shunsuke
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- A sulfonic acid type double-nuclear ionic liquid in catalytic synthesis of carboxylic acid butyl ester in application and method
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The invention relates to the field of organic synthetic technology, in particular discloses a sulfonic acid type double-nuclear ionic liquid in catalytic synthesis of carboxylic acid butyl ester in application and method, the sulfonic acid type can absorb almost double-nuclear ionic liquid as Wherein m=3 - 4 ,n=3 - 4 ,X- For the HSO4- . The carboxylic acid of the n-butyl synthetic method is the double-nuclear ionic liquid the states the sulfonic acid, carboxylic acid and normal butanol added into the reactor, heating to reflux the reaction is carried out, after the reaction is finished layered, recovery of the lower sulfonic acid type double-nuclear ionic liquid catalyst, the upper layer to obtain the product carboxylic acid is n-butyl. The invention selected ionic liquid environment friendly, easy to recycle, to the carboxylic acid esterification reaction of high catalytic efficiency.
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Paragraph 0018; 0019; 0022; 0023; 0026; 0027; 0032; 0033
(2019/06/13)
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- Epoxide as precatalyst for metal-free catalytic transesterification
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Transesterification of methyl esters was accelerated by an in situ-generated metal-free catalyst comprising a quaternary alkylammonium salt and an epoxide. The combination of a quaternary alkylammonium acetate and glycidol is optimal, and various esters were synthesized from methyl esters with alcohols in good to excellent yield. Analysis of the catalyst solution revealed that basic species are generated by the ring-opening reaction of epoxide.
- Tanaka, Shinji,Nakashima, Takuya,Satou,Oono, Hiromi,Kon, Yoshihiro,Tamura, Masanori,Sato, Kazuhiko
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p. 2009 - 2013
(2019/07/03)
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- Ionic liquid, preparation method and application
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The invention relates to an ionic liquid. Cations of the ionic liquid contain hexafluoroisopropyl sulfonic acid groups. According to the ionic liquid provided by the invention, the hexafluoroisopropylsulfonic acid groups are introduced into the cation part of the ionic liquid to give a super acid center to the ionic liquid, through changing anion types, the ionic liquid of which the acidity is greater than that of 98% concentrated sulfuric acid is obtained, and the highest level of the hamlet acidity (H0) in the obtained ionic liquid can reach -14.13.
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Paragraph 0226; 0227; 0228; 0229
(2018/03/28)
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- SEPARATION OF ORGANIC ACIDS FROM MIXTURES CONTAINING AMMONIUM SALTS OF ORGANIC ACIDS
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The invention relates to a process for separation of organic acids from mixture of ammonium salts of one or more organic acids and other compounds via an integrated process. The process involves suspending mixture of ammonium salts of one or more organic acids and other compounds in dry hydrocarbon solvent/s or mixtures thereof; wherein the selected hydrocarbon solvent/s or mixtures thereof have boiling point more than 100° C. and forms an azeotrope with water. The reaction mixture thus obtained is dehydrated azeotropically followed by esterification of basic salt of the organic acids by addition of alcohol in presence of metal or metal salt; thereafter the individual esters formed are separated by distillation and hydrolysed to obtain corresponding organic acids having more than 98% purity.
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Paragraph 0069
(2018/06/30)
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- Fe-catalyzed esterification of amides via C-N bond activation
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An efficient Fe-catalyzed esterification of primary, secondary, and tertiary amides with various alcohols for the preparation of esters was performed. The esterification process was accomplished with FeCl3$6H2O, which is a stable, inexpensive, environmentally friendly catalyst with high functional group tolerance.
- Chen, Xiuling,Hu, Siying,Chen, Rongxing,Wang, Jian,Wu, Minghu,Guo, Haibin,Sun, Shaofa
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p. 4571 - 4576
(2018/02/09)
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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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- DBU-Based Dicationic Ionic Liquids Promoted Esterification Reaction of Carboxylic Acid with Primary Chloroalkane Under Mild Conditions
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Abstract: A series of DBU-based (DBU = 1, 8-diazabicyclo [5.4.0] undec-7-ene) dicationic ionic liquids with different anions were successfully synthesized by the reaction of DBU and 1, 6-dichlorohexane. Therein, the dicationic ionic liquid 1, 1′-(hexane-1, 6-diyl)bis(1, 8-diazabicyclo [5.4.0]undec-7-enium) dichlorine (IL-1) was successfully employed as an efficient catalyst in esterification reaction of carboxylic acids with primary chloroalkanes under mild conditions without any additional basic reagents. Moreover, the optimum catalyst could be efficiently reused for five times without any significant change on the catalytic effect. The improved protocol is not only efficient, but also green and pollution-free.
- Liu, Yang,Mao, Guijie,Zhao, Hongyan,Song, Jinyi,Han, Huatao,Li, Zhuofei,Chu, Wenyi,Sun, Zhizhong
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p. 2764 - 2771
(2017/09/14)
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- Iron-catalyzed C[sbnd]C bond activation/C[sbnd]O bond formation: Direct conversion of ketones to esters
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The iron-catalyzed oxidative activation of the (O)C[sbnd]C bond in ketones has been developed. This method enables direct synthesis of esters by the reaction between ketones and alcohols via conversion of the (O)C[sbnd]C bond to the (O)C[sbnd]O bond. The
- Arzumanyan, Ashot V.
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supporting information
p. 4667 - 4671
(2017/11/21)
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- Effective management of polyethers through depolymerization to symmetric and unsymmetric glycol diesters using a proton-exchanged montmorillonite catalyst
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From the standpoint of green sustainable chemistry, it is very important to build a resource recycling system. Herein, an efficient and practical method for catalytic depolymerization of polyethers to glycol diesters was developed using proton-exchanged montmorillonite (H-mont). H-mont uniquely exhibited high catalytic activity for the depolymerization of polyethers with benzoic anhydride to symmetric glycol dibenzoates under mild reaction conditions. Various symmetric and unsymmetric glycol diesters were obtained from the reaction of diverse polyethers with carboxylic acid derivatives. The high catalytic efficiency for this depolymerization of H-mont is interpreted by its character, in which the montmorillonite layers act as an effective two-dimensional macroligand to form the intercalated complex with polyethers. Furthermore, a new protocol for the utilization of waste polyethers in water was developed based on the catalytic and adsorption abilities of H-mont.
- Maeno, Zen,Yamada, Shota,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro
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p. 2612 - 2619
(2017/07/17)
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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.
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Paragraph 0019
(2016/10/10)
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- PRODUCTION OF TWO ESTERS USING HOMOGENEOUS CATALYST
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Disclosed is a process for preparing two esters by reacting an aldehyde with an alcohol in the presence of a ruthenium complex compound as a catalyst. The process is particularly useful for preparing ethyl acetate and n-butyl acetate, isobutyl acetate, or 2-ethylhexyl acetate in high yield by coupling acetaldehyde with n-butanol, i-butanol, or 2-ethylhexanol.
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Paragraph 0048
(2016/10/31)
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- Conversion of ethanol into linear primary alcohols on gold, nickel, and gold–nickel catalysts
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The direct conversion of ethanol into the linear primary alcohols CnH2n+1OH (n = 4, 6, and 8) in the presence of the original mono- and bimetallic catalysts Au/Al2O3, Ni/Al2O3, and Au–Ni/Al2O3 was studied. It was established that the rate and selectivity of the reaction performed under the conditions of a supercritical state of ethanol sharply increased in the presence of Au–Ni/Al2O3. The yield of target products on the bimetallic catalyst was higher by a factor of 2–3 than that reached on the monometallic analogs. Differences in the catalytic behaviors of the Au, Ni, and Au–Ni systems were discussed with consideration for their structure peculiarities and reaction mechanisms.
- Chistyakov,Zharova,Tsodikov,Nikolaev,Krotova,Ezzhelenko
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p. 803 - 811
(2016/12/07)
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- Method for preparing acetic ester by adopting acid-resistant molecular sieve membrane reactor
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The invention relates to a method for preparing acetic ester by adopting an acid-resistant molecular sieve membrane reactor. According to the method, an esterification reaction stock solution with excess acetic acid is utilized, concentrated sulfuric acid is utilized as a catalyst, an acid-resistant MOR-type molecular sieve membrane reactor prepared from a reaction stock solution which is not added with an organic template agent is in full contact with the reaction stock solution at a certain working pressure and temperature, so that the relatively reaction energy loss and dosage of catalysts of the esterification reaction are achieved, the conversion rates of ethanol and butanol are increased, and the continuous production of acetic ester can be realized. The method has the advantages of high efficiency, environmental friendliness, high selectivity, low equipment requirement, simple operation, and the like; the beneficial basis is provided for the industrial continuous production of acetic ester, furthermore, the method can be broadened to be applied to other organic reaction systems such as esterification of inorganic oxyacid and alcohol, intramolecular dehydration of alcohol, intermolecular dehydration of alcohol, aldol condensation, and dehydration condensation of amino acid.
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Paragraph 0011; 0019
(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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- ZINC COMPLEX
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A zinc complex characterized in exhibiting an octahedral structure and being configured from repeating units represented by general formula (I): wherein L represents a linker region, and R1 represents a C1-4 alkyl group, which can have a halogen atom.
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Paragraph 0177-0178
(2016/05/19)
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- Ag-Cu nanoparticles as efficient catalysts for transesterification of β-keto esters under acid/base-free conditions
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Transesterification of β-keto esters and alcohols are traditionally catalyzed by acid or basic catalysts. However, these traditional catalysts do not always meet the requirements of modern synthetic chemistry which need to be highly efficient, selective, and environmentally friendly. In this work, Ag-Cu metal sites were first introduced as transesterification catalysts. The effect of the support, Ag:Cu molar ratio, and reaction conditions were investigated. The Ag-Cu metal sites were proved to be active in the β-ketoester transesterification with various alcohols, having yields comparable to the conventional acid- or base-catalysts.
- Yue, Hongmei,Yu, Hao,Liu, Sheng,Xu, Chunli
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p. 19041 - 19051
(2016/03/01)
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- A SINGLE STEP PROCESS FOR THE PREPARATION OF BUTYL ACETATE
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The present invention discloses a single step, environmentally and economical viable process for the preparation of butyl acetate from ethyl acetate and n-butanol with high yield using boron loaded zeolite catalyst.
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Page/Page column 13;14
(2016/04/20)
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- Paracetamol and method for the co-production of acetic acid n-butyl
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The invention provides a co-production method for paracetamol and butyl acetate. Para-aminophenol and acetic acid are subjected to an acylation reaction in a reflux state and paracetamol is synthesized. The dilute acetic acid steam generated from the reaction is directly introduced to a reactor containing n-butanol, and the two materials are subjected to an esterification reaction and butyl acetate is generated. For the first time, in the method, co-production of butyl acetate is carried out by utilization of dilute acetic acid steamed out from the acylation reaction, and the production flow is subjected to scientific and reasonable design. Through re-utilization of dilute acetic acid, the esterification reaction of butyl acetate is achieved with lowest energy consumption. The whole flow forms a closed loop effect and no "three wastes (waste gas, waste water and industrial residue)" are discharged.
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Paragraph 0022; 0026-0027
(2017/01/23)
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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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- Kinetic analysis and process modeling for cellulose valorization in cooperative ionic liquid pairs
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Studies on kinetic analysis and process modeling are important and necessary for the development of novel and efficient technology for cellulose utilization. In this study, a kinetic model for the batch reactor was described for catalytic cellulose degradation in cooperative ionic liquid pairs based on an intensive analysis of the experimental parameters. Our fitting results show that the proposed model agrees well with the experimental data. The kinetic parameters obtained from the above model were subsequently applied to the continuous stirred tank reactor (CSTR) by constructing a mathematical process model for the continuous operation of cellulose degradation combined with product separation. The effects of reaction temperature, retention time, extract flow rate and distribution coefficients were intensively investigated. The numerical results demonstrate that relatively high temperature and larger retention time are favorable in cellulose conversion, whereas the product distribution coefficient and extract flow rate mainly affect the concentration of the hexane-soluble fraction (volatile chemicals). The findings presented in this work will serve as a beneficial reference for further biomass transformation of industrial purpose.
- Liu, Sijie,Tang, Luo,Long, Jinxing,Guan, Jianyu,Li, Xuehui
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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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p. 7492 - 7500
(2016/08/09)
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- PRODUCTION OF BUTYL ACETATE FROM ETHANOL
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A reactive distillation method comprises introducing a feed stream to a reactive distillation column, wherein the feed stream comprises ethanol, contacting the feed stream with one or more catalysts in the reactive distillation column during a distillation, and removing butyl acetate during the distillation from the reactive distillation column as a bottoms stream. The feed stream reacts in the presence of the one or more catalysts to produce a reaction product comprising ethyl acetate, butanol, and water, wherein the butanol and the ethyl acetate react to produce a reaction product comprising the butyl acetate.
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Paragraph 00135
(2015/06/18)
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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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- Carboxyl activation of 2-mercapto-4,6-dimethylpyrimidine through n-acyl-4,6-dimethylpyrimidine-2-thione: A chemical and spectrophotometric investigation
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2-Mercapto-4,6-dimethylpyrimidine, as effective carboxyl activating group, has been successfully proved by converting it into respective acyl derivatives and the subsequent conversion to the amides and esters respectively using amines, amino alcohols and alcohols. The aminolysis and esterification were monitored chemically and spectrophotometrically. This paved way to establish that the above mercaptopyrimidine derivative is an efficient carboxyl activating group applicable in solid phase peptide synthesis.
- Rajan
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p. 287 - 291
(2015/01/30)
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- Esterification of carboxylic acids with alkyl halides using imidazolium based dicationic ionic liquids containing bis-trifluoromethane sulfonimide anions at room temperature
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Task-specific room temperature ionic liquids (RTILs) composed of symmetrical N-methylimidazolium rings linked with a short oligo (ethylene glycol) chain (cationic part) and bis-trifluoromethane sulfonimide (NTf2, anionic part) were successfully synthesized, and their physicochemical properties were determined by various modern analytical techniques. The catalytic activity of the synthesized RTILs was evaluated in the esterification reaction of acids with alkyl halides in solvent-free conditions at room temperature. From the screening test, all the synthesized RTILs showed a high yield with significant selectivity for respective esters in a very short reaction time. Especially, 0.1 equimolar of RTIL-1 ([tetraEG(mim)2][NTf2]2) was found to be, the most efficient and reusable catalyst for this reaction. As a result, 100% conversion and up to a 94% yield of the respective ester product was obtained in a 30 min reaction time. This might be due to their synergetic effect of Lewis acidity, wide liquid range, and high miscibility compared to the other homogeneous and heterogeneous catalysts. Beside this, RTIL was easily separated from the reaction mixture and reused several times without any significant loss of catalytic activity and structural property. The present dicationic ionic liquids (ILs) under a solvent-free catalytic system were found to be kinetically fast, naturally benign, and achieved good yields for esterification of carboxylic acids with alkyl halides.
- Jadhav, Arvind H.,Lee, Kyuyoung,Koo, Sangho,Seo, Jeong Gil
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p. 26197 - 26208
(2015/10/20)
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- Synthesis of lipase nano-bio-conjugates as an efficient biocatalyst: Characterization and activity-stability studies with potential biocatalytic applications
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In the present study, we have synthesized lipase-nano-bio-conjugates via immobilization of various lipases on multiwall carbon nano-tubes (MCNT), in order to construct an efficient and recyclable biocatalytic system. In a screening study lipase Pseudomonas fluorescens (PFL) acted as an efficient biocatalyst (lipase-nano-bio-conjugates) which showed higher retention of lipase activity and protein loading. Consequently the immobilization support : lipase (MCNT : PFL) composition was screened in which MCNT : PFL (2 : 1) was calculated as a robust biocatalyst composition which showed higher activity retention and protein loading. This nano-bio-conjugate was then characterized in detail with physical and biochemical techniques using SEM, TEM, FTIR, Km, Vmax, catalytic efficiency and (%) water content analysis. This developed biocatalyst was further used for practical biocatalytic applications such as O-acylation reactions. Various reaction parameters were optimized in detail like reactant molar ratio (2 : 3.5), solvent, MCNT : PFL biocatalyst amount (36 mg), temperature (50°C) etc. The developed biocatalytic protocol was then extended to synthesize several (twenty-two) industrially important acylated moieties with an excellent yield, these products are well characterized by 1HNMR, 13CNMR and GCMS analysis. Moreover in the present study, we have reviewed the potential industrial applications of various synthesized compounds. Also, we have studied the thermodynamic aspect which demonstrated more feasibility of use of immobilized MCNT : PFL lipase over free lipase. Interestingly, immobilized MCNT : PFL lipase showed 2.3 fold higher catalytic activity than free PFL. Besides this, the biocatalyst was efficiently recycled for up to five cycles. Thus the present protocol demonstrated, (i) synthesis of nano-bio-conjugates as a bio-catalyst, (ii) detailed physical-biochemical characterization of nano-bio-conjugates, (iii) optimization of the biocatalytic protocol (iv) practical biocatalytic applications along with a mechanistic study (v) a thermodynamic feasibility study and (vi) recyclability study. 2015
- Badgujar, Kirtikumar Chandulal,Sasaki, Takehiko,Bhanage, Bhalchandra Mahadeo
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p. 55238 - 55251
(2015/07/07)
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- Continuous flow Fischer esterifications harnessing vibrational-coupled thin film fluidics
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Rapid Fischer esterification reactions occur under solventless, continuous flow conditions in dynamic thin films. This methodology uses limited catalyst, require no additional heat input and occurs within the confinements of an inexpensive vortex fluidic device (VFD). The associated mechanoenergy is primarily delivered from two types of vibration, which are manifested in sharp increases in the yield of the reactions. These vibrations promote the existence of Faraday waves that alter the instantaneous shear rates of the reactants within the rotating tube. Tuning the rotational speed of the device allows harmonic vibrations to be utilized in the synthesis of alkyl-based esters within both a high and low contact angle NMR tube. This journal is
- Britton, Joshua,Dalziel, Stuart B.,Raston, Colin L.
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p. 1655 - 1660
(2015/02/02)
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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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- Magnetically separable γ-Fe2O3 nanoparticles: An efficient catalyst for acylation of alcohols, phenols, and amines using sonication energy under solvent free condition
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This paper reports a facile synthesis of magnetically separable iron oxide (γ-Fe2O3) nanoparticles using thermolysis method. The structural and morphological study of the synthesized γ-Fe2O3 nanoparticles was carried out using X-ray diffraction (XRD), field emission gun-scanning electron microscopy (FEG-SEM), energy dispersive X-ray spectrum (EDS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) techniques. The electron microscopy reveals that the γ-Fe2O3 nanoparticles have spherical morphology with a particle size in the range of 40-100 nm. The XPS study confirmed the Fe is in +3 oxidation state. The synthesized γ-Fe2O3 nanoparticles have been used as an efficient heterogeneous catalyst for the organic transformation between phenols, alcohols, and amines with acetic anhydride under sonication using mild reaction conditions. Various electrons withdrawing and electrons donating substrates show an excellent yield of desired products with the advantage of magnetic separation and reusability of γ-Fe2O3 nanocatalyst.
- Bhosale, Manohar A.,Ummineni, Divya,Sasaki, Takehiko,Nishio-Hamane, Daisuke,Bhanage, Bhalchandra M.
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- Acid-catalyzed oxidation of levulinate derivatives to succinates under mild conditions
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Levulinate derivatives are an attractive platform for the production of renewable chemicals. Here we report on the oxidation of methyl levulinate into dimethyl succinate with peroxides under mild conditions using Br?nsted and Lewis acid catalysts. Selectivities to succinate and acetate derivatives of approximately 60 and 40 %, respectively, were obtained with strong Br?nsted acids in methanol. Although the molecular structure (i.e., carbon-chain length and branching around the C=O group) and the oxidant type affect the product distribution, solvent choice has the strongest impact on changing the location of oxygen insertion into the carbon backbone. Specifically, switching the solvent from methanol to heptane resulted in a decrease in the succinate/acetate ratio from 1.6 to 0.3. In contrast to Br?nsted acids, we demonstrate that the nature of the metal cation is responsible for changing the reaction selectivity of water-tolerant Lewis acidic triflate salts.
- Wang, Yuran,Vogelgsang, Ferdinand,Román-Leshkov, Yuriy
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p. 916 - 920
(2015/03/18)
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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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p. 15870 - 15879
(2015/03/04)
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