513-86-0Relevant articles and documents
Vapor-phase catalytic dehydration of 2,3-butanediol to 3-buten-2-ol over ZrO2 modified with alkaline earth metal oxides
Duan, Hailing,Yamada, Yasuhiro,Kubo, Shingo,Sato, Satoshi
, p. 66 - 74 (2017)
Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) to produce 3-buten-2-ol (3B2OL) was investigated over several monoclinic ZrO2 (m-ZrO2) catalysts modified with alkaline earth metal oxides (MOs), such as SrO, BaO, and MgO, to compare with the previously reported CaO/m-ZrO2. It was found that these modifiers enhanced the 3B2OL formation to the same level as CaO did by loading an appropriate MO content. Among all the tested catalysts, the BaO/m-ZrO2 calcined at 800?°C with a low BaO content (molar ratio of BaO/ZrO2?=?0.0452) shows the highest 2,3-BDO conversion (72.4%) and 3B2OL selectivity (74.4%) in the initial stage of 5?h at 350?°C. In order to characterize those catalysts, their catalytic activities, crystal structures, and basic properties were studied in detail. In X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) experiment, it was elucidated that highly dispersed M-O-Zr (M?=?Ca, Sr, and Ba) hetero-linkages were formed on the surface by loading these MOs onto m-ZrO2 with an appropriate content and then calcining at 800?°C. It can be concluded that the M-O-Zr hetero-linkages generate the proper base-acid balance for the efficient formation of 3B2OL from 2,3-BDO.
Kinetics and Mechanisms of Oxidations by Metal Ions. V. Oxidation of 4-Oxopentanoic Acid by the Aquavanadium(V) Ion
Mehrotra, Raj Narain
, p. 2389 - 2394 (1985)
The outer sphere oxidation of 4-oxopentanoic acid (4-OPA), studied at 50 deg C by aquavanadium (V) ion, is H(1+)-catalyzed reaction.The reaction has a first-order dependence on each of , , and .The H(1+) catalysis can not be ascribed to keto enol equilibrium because of the knowledge that a γ-keto acid is the least enolized amongst keto acids.Hence V(OH)3(2+)(aq) ion is the active oxidant.The proposed mechanism, assumed to involve the initial decarboxylation, is supported by the spot test characterization of acetoin as the intermediate oxidation product.Acetoin is further oxidized to two moles of acetic acid which is the final oxidation product.The overall energy of activation (ΔH1=26+/-3 kJ mol-1) is lower than the normal value (84 kJ mol-1) and therefore the highly negative value of the overall entropy of activation (ΔS1=-268+/-8 JK-1 mol-1) is considered to be responsible for the observed slowrate of oxidation.
Influence of Br- Concentration on (Br)+-Mediated Indirect Electrooxidation of Alcohols to the Corresponding Carbonyl Compounds
Takiguchi, Tsuyoshi,Nonaka, Tsutomu
, p. 3137 - 3142 (1987)
Current efficiency for the (Br)+ (positive bromine species)-mediated indirect electrooxidation of alcohols to the corresponding carbonyl compounds decreased with increase in Br- concentration in dichloromethane and aqueous acidic solutions, while no concentration dependence was observed in an aqueous neutral solution.These facts suggested a general practical guideline for the indirect electrooxidation, i.e. low Br- concentration is favorable in an electrolytic solution of low nucleophilicity.It was also found that the kind of (Br)+ species formed anodically in the absence of the alcohols in dichloromethane celarly depended on charge(Q) passed as follows:Br3- at Q-1 (1F = 96480 C), Brn- (n>3) at 2/3-1, and Br2 at Q = 1F mol-1.Among these species, Br3- and Br2 seemed to be the weakest and strongest oxidizing agents, respectively.Lower efficiency for the direct electrooxidation in higher Br- concentration was rationalized as due to more predominant formation of Br3- and/or Brn- with smaller n values.
A highly efficient thiazolylidene catalyzed acetoin formation: Reaction, tolerance and catalyst recycling
Gu, Liuqun,Lu, Ting,Li, Xiukai,Zhang, Yugen
, p. 12308 - 12310 (2014)
An efficient formation of acetoin from acetaldehyde was achieved under thiazolylidene catalysis. High yields and TON were achieved. Its sufficient tolerance toward ethanol and moisture renders it a practical key step of the ethanol upgrading process. A new type of solid supported thiazolylidene catalyst was designed to make catalyst recycling achievable. This journal is
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Loeb,Pulvermacher
, p. 12 (1910)
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Selective hydrogenation by novel composite supported Pd egg-shell catalysts
Carrara,Badano,Betti,Lederhos,Rintoul,Coloma-Pascual,Vera,Quiroga
, p. 72 - 77 (2015)
Two organic-inorganic mixed phase supports were prepared, comprising an alumina filler and polymers of different chemical nature. Four low loaded Pd catalysts were prepared. Good activities and selectivities were obtained during the hydrogenations of styrene, 1-heptyne and 2,3-butanedione. The catalysts were found to have excellent mechanical properties and could be used in applications needing high attrition resistance and crushing strength. In this sense, processes for fine chemicals using slurry reactors or processes for commodities using long packed beds could advantageously use them.
Vapor-phase catalytic dehydration of 2,3-butanediol into 3-buten-2-ol over Sc2O3
Duan, Hailing,Yamada, Yasuhiro,Sato, Satoshi
, p. 1773 - 1775 (2014)
Vapor-phase catalytic dehydration of 2,3-butanediol (2,3-BDO) was investigated over rare earth oxide (REO) catalysts as well as In2O3. In the dehydration of 2,3-BDO, 3-buten-2-ol (3B2OL) was produced together with 3-hydroxy-2-butanone (3H2BO), butanone (MEK), 2-methylpropanal (IBA), 2-methyl-1-propanol (IBO), etc. Sc2O3 and In2O3 showed hi gher 3B2OL select ivities than other REOs. In particular, Sc2O3 converted 2,3-BDO into 3B2OL with an excellent selectivity of 85.0% at 99.9% conversion.
N-PEGylated Thiazolium Salt: A Green and Reusable Homogenous Organocatalyst for the Synthesis of Benzoins and Acyloins
Haghighi, Ali Javaheri,Mokhtari, Javad,Karimian, Khashayar
, p. 1646 - 1652 (2020/10/19)
N-PEGylated-thiazolium salt is used as efficient catalyst for the benzoin condensation. The catalyst was synthesized by reaction of activated polyethylene glycol 10,000 (PEG-10000) with 4-methyl-5-thiazoleethanol (sulfurol). Reaction mixture undergoes temperature-assisted phase transition and catalyst separated by simple filtration. After reaction course, catalyst can be recycled and reused without any apparent loss of activity which makes this process cost effective and hence ecofriendly. Synthesized benzoins and acyloins by this method have been characterized on the basis of melting point and 1H-NMR spectral studies. Graphic Abstract: [Figure not available: see fulltext.]
carba Nicotinamide Adenine Dinucleotide Phosphate: Robust Cofactor for Redox Biocatalysis
D?ring, Manuel,Sieber, Volker,Simon, Robert C.,Tafertshofer, Georg,Zachos, Ioannis
supporting information, p. 14701 - 14706 (2021/05/13)
Here we report a new robust nicotinamide dinucleotide phosphate cofactor analog (carba-NADP+) and its acceptance by many enzymes in the class of oxidoreductases. Replacing one ribose oxygen with a methylene group of the natural NADP+ was found to enhance stability dramatically. Decomposition experiments at moderate and high temperatures with the cofactors showed a drastic increase in half-life time at elevated temperatures since it significantly disfavors hydrolysis of the pyridinium-N?glycoside bond. Overall, more than 27 different oxidoreductases were successfully tested, and a thorough analytical characterization and comparison is given. The cofactor carba-NADP+ opens up the field of redox-biocatalysis under harsh conditions.
Selective Hydrogenation of Diketones on Supported Transition Metal Catalysts
Carrara,Badano,Vailard,Vera,Quiroga
, p. 461 - 470 (2019/11/13)
Abstract: The hydrogenation of α-diketones yields α-hydroxyketones or vic-diols, both compounds of great interest in fine chemistry. The reaction tests were the liquid phase hydrogenation of 2,3-butanedione and 2,3-pentanedione at mild conditions. The objectives of this work were evaluating the effect over the activity and selectivity of: (a) different transition metallic phase based catalysts supported on activated carbon, (b) the symmetry of the reactants and (c) solvents. The physicochemical characterization of the catalysts was carried out by ICP, XRD, TEM, N2 adsorption and XPS. The keto-enol equilibrium of diketones was studied by 1H-NMR. All the catalysts were active in both reactions. In terms of activity, Pt and Rh were the best active phases. For both reactants the highest selectivity towards hydroxyketones were achieved with Pd, while Ru was the most selective towards the diol. Both the activity and selectivity followed similar patterns in the hydrogenation of both diketones. The greater activity of Pt was attributed to the high dispersion of the active metal phase in this catalyst and the high efficiency of Pt for C = O bond reduction. The high selectivity of the Pd catalysts towards the intermediate product was attributed to many effects: (i) a lower interaction of the hydroxyketone with the active site as compared to the diketone, (ii) the easy reducibility of the C = C double bond on Pd, provided by the keto-enol tautomerism of diketones.