- Effect of functional groups in organic chlorides on radical reduction with hydrostannane under microwave irradiation
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The effect of functional groups on the activation of molecules by microwave irradiation in the reduction of organic chlorides by Bu3SnH was investigated. The reactivity of a substrate with a hydroxy group increased under microwave heating conditions in comparison with conventional heating.
- Nishimoto, Yoshihiro,Yazawa, Satoshi,Kiyokawa, Kensuke,Kajiki, Takahito,Tsukahara, Yasunori,Yamauchi, Tomohisa,Wada, Yuji,Baba, Akio,Yasuda, Makoto
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- Efficient method for oxidation of ketones to esters with 4-aminoperoxybenzoic acid supported on silica gel
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4-Aminoperoxybenzoic acid supported on silica gel was found to be a versatile and efficient oxidant for the oxidation of ketones to esters. Copyright Taylor & Francis Group, LLC.
- Ghazanfari, Dadkhoda,Hashemi, Mohammed M.,Shahidi-Zandi, Mehdi
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- High density monolayer of diisocyanide on gold surface as a platform of supported Rh-catalyst for selective 1,4-hydrogenation of α,β- unsaturated carbonyl compounds
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A high density monolayer of diisocyanide on gold surface was utilized as a platform of supported Rh catalyst for selective 1,4-hydrogenation of α,β-unsaturated carbonyl compounds. The catalyst exhibited high turnover numbers in a range of 50-000 to 150-000 per Rh atom and showed steady catalyst performance over six recycle usages.
- Jagtap,Kaji,Fukuoka,Hara
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- Mechanisms of the homogeneous, unimolecular gas-phase elimination kinetics of triethyl orthoacetate and triethyl orthopropionate
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Triethyl orthoacetate and triethyl orthopropionate were pyrolyzed in a static system over the temperature range of 291-351°C and pressure range of 80-170 Torr. The elimination reactions of these orthoesters in seasoned vessels are homogeneous, unimolecular, and follow a first-order rate law. The reaction products are ethanol, ethylene and the corresponding ethyl ester. The Arrhenius expressions of these eliminations were found as follow: for triethyl orthoacetate, log k1 (s-1) = (13.76 ± 0.09) - (187.6 ± 1.1) KJ mol-1 (2.303 RT)-1 (r = 0.9993), and for triethyl orthopropionate, log k1 (s-1) = (13.63 ± 0.07) - (193.3 ± 1.8) kJ mol-1 (2.303 RT) -1 (r = 0.9992). A reasonable mechanism of these elimination is to consider that the C-OCH2CH3 bond, as Cδ+. ..δ+ OCH2CH3 in the TS, is the rate-determining step. The nucleophilicity of the oxygen atom of OCH 2CH3 may abstract the hydrogen of the adjacent C-H bond for a four-membered cyclic structure to give the corresponding unsaturated ketal. The unstable ketal intermediate decomposes, in a six-membered cyclic transition state, into ethylene and the corresponding ethyl ester. Copyright
- Marquez, Edgar,Tosta, Maria,Dominguez, Rosa M.,Herize, Armando,Chuchani, Gabriel
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- Magnetically recoverable AlFe/Te nanocomposite as a new catalyst for the facile esterification reaction under neat conditions
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In this work, a new Fe3O4/AlFe/Te nanocomposite was synthesized by a one-step sol–gel method. The Fe3O4 magnetic nanoparticles (MNPs) were prepared and then mixed with aluminum telluride (Al2Te3) in an alkali medium to produce the desired catalyst. After characterization of the Fe3O4/AlFe/Te nanocomposite by SEM, TEM, EDS, XRD, and ICP analyses, it was used in the esterification reaction. This heterogeneous catalyst showed high catalytic activity in the esterification of commercially available carboxylic acids with various alcohols to produce the desired esters at high conversions under neat conditions. The Fe3O4/AlFe/Te nanocomposites were separated from the reaction mixture via an external magnet and re-used 8 times without significant loss of catalytic activity.
- Alavi, Seyed Jamal,Sadeghian, Hamid,Seyedi, Seyed Mohammad,Eshghi, Hossein,Salimi, Alireza
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- Catalytic Reaction of Methanol with a Series of Ruthenium(II) Complexes and the Mechanism of the Formation of Acetic Acid from Methanol Alone
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The catalytic abilities of a series of ruthenium(II) complexes containing zero, one and two SnCl3(1-) ligands, 4> 1, 4> 2 and 3> 3, have been compared in the reaction of methanol to form acetic acid (and/or methyl acetate due to esterification), as well as their reactions with the possible intermediates (formaldehyde, methyl formate) in the overall reaction.It was found that the formation of acetic acid from methanol occured only with 3, which also converted paraformaldehyde or methyl formate into acetic acid.Complex 1 showed only a catalytic activity for the Tischenko-type dimerization (2 HCHO -> HCO2Me), and 2 exhibited an intermediate character, being able to catalyse the two reactions (2 HCHO -> HCO2Me, HCO2Me -> MeCO2H) but unable to react with methanol.Based on kinetic results for the reaction of methanol with 3, a possible reaction pathway is proposed where methyl formate and acetic acid are formed from formaldehyde competitively sharing a common reaction path.For the isomerization of methyl formate as a substrate a separate reaction path is suggested, where the Ru(II)-Sn(II) bimetallic centre of 2 and 3 converts the co-ordinated HCO2Me into a five-membered acetate bridge.
- Yamakawa, Tetsu,Hiroi, Masayuki,Shinoda, Sumio
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- Reduction of conjugate double bonds with trichlorosilane
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A variety of α,β-unsaturated esters and cyclic ketones underwent smooth reduction of the carbon-carbon double bond with a combination of inexpensive and readily available trichlorosilane and CoCl2. The reactions are performed under very mild conditions and products are obtained in high yields.
- Chauhan, Moni,Boudjouk, Philip
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- Efficient palladium and ruthenium nanocatalysts stabilized by phosphine functionalized ionic liquid for selective hydrogenation
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Pd and Ru nanoparticles were synthesized in ionic liquid by using tri(m-sulfonyl)triphenyl phosphine 1-butyl-2,3-dimethyl-imidazolium salt ([BMMIM]3[tppt]) as a stabilizing agent. The well-dispersed Pd and Ru NPs with mean diameters of 2.4 nm and 1.7 nm were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It was demonstrated that [BMMIM]3[tppt] stabilized Pd and Ru NPs displayed high activity and excellent selectivity in the hydrogenation of functionalized olefins, aromatic nitro compounds and aromatic aldehydes. The Pd and Ru NPs showed better catalytic performance than corresponding commercially available Pd/C and Ru/C catalysts. The present catalytic system could be easily reused at least six times without significant decrease in activity and selectivity.
- Wu, Zhifeng,Jiang, Heyan
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- Kinetics of catalytic esterification of propionic acid with different alcohols over amberlyst 15
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The kinetics of the esterification reaction between propionic acid and methanol, ethanol, and 1-butanol over the ion exchange resin, Amberlyst 15, was investigated. Experiments were conducted using a fixed-bed plug flow reactor over the temperature range of 298-328 K. Acid to alcohol molar ratios of 3:1, 1:1, and 1:3 were employed. For each esterification system, the equilibrium conversion of propionic acid was found to increase with increasing reaction temperature. Several kinetic models were tested to correlate the collected data under kinetically controlled conditions; the pseudo-homogeneous (P-H), Eley-Rideal (E-R), Langmuir-Hinshelwood (L-H), and Poepken (P-P) models. In all cases, the activity coefficients were estimated using the UNIFAC model to account for the nonideal thermodynamic behavior of the reactants and products. The P-P model was found to best represent the kinetic data of the investigated esterification systems with a total average error of less than 3%. The increase of alcohol chain length had a negative impact on the conversion of propionic acid due to steric hindrance. The activation energy of the esterification reaction is influenced by the chain length of the alcohol used. The adsorption equilibrium constants estimated by the P-P model and the solubility parameters reported by AICHE DIPPER followed the same trend; ester acid alcohol water.
- Ali, Sami H.
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- Oxidative functionalization of methane in the presence of a homogeneous rhodium-copper-chloride catalytic system: Transformation of acetic and propionic acids as solvent components
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The oxidative functionalization of methane (O2, CO, 95°C, Rh III/CuI, II/Cl- catalytic system) was studied in an aqueous acetic or propionic acid medium. It was shown that oxidative decarbonylation of carboxylic acids takes place along with methanol and methyl carboxylate formation.
- Chepaikin,Bezruchenko,Menchikova,Moiseeva,Gekhman,Moiseev
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- CATHODIC ESTERIFICATION OF CARBOXYLIC ACIDS
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A cathodic method for the esterification of carboxylic acids under mild conditions was found.The esterification proceeded smoothly at room temperature by the reaction of alkylating with quaternary ammonium carboxylates formed in a cathode chamber.
- Awata, Takeshi,Baizer, Manuel M.,Nonaka, Tsutomu,Fuchigami, Toshio
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- Enolate Anions. 2. Reaction between Potassium Solutions Containing Crown Ethers and β-Lactones
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A novel fission of the α carbon to β carbon by the treatment of β-lactones with potassium solutions containing crown ether is reported.The enolate carbanion formed, upon subsequent treatment with HCl or methyl iodide yielded respective esters.
- Jedlinski, Z.,Misiolek, A.,Kurcok, P.
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- Direct syntheses of sulfonated mesoporous SiO2-TiO 2-SO3H materials as solid acid catalysts
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A facile one-step approach for a mesoporous solid acid catalyst SiO 2-TiO2-SO3H network was developed by the simple chelation of a benzene disulfonate compound to the Ti ion. The resulting catalyst showed excellent catalytic performance for esterification.
- Ryoo, Hyang Im,Hong, Lan Young,Jung, Sang Hee,Kim, Dong-Pyo
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- Rapid degradation of cyclic peroxides by titanium and antimony chlorides
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First responders face extraordinary risks when dealing with organic peroxides such as TATP due to the extreme sensitivity of this class of explosives, and to a lack of a robust chemical means of safe and rapid neutralisation. The Lewis acids TiCl4 and SbCl3 have been found to demonstrate a novel degradation mechanism, with TiCl4 degrading a model cyclic peroxide in minutes when used in a two-fold excess, or ～3 hours at half equivalence. The products cannot re-form peroxide compounds as is the case with acid degradation, suggesting the two mechanisms are fundamentally different. The Lewis acids mediate a rearrangement reaction in the cyclic peroxide backbone leading to relatively innocuous products through deactivation of oxidising O. Sub-stoichiometric TiCl4 reactions highlight a secondary reaction pathway that also leads to some oxidative chlorination products, possibly mediated by an unconfirmed titanium-oxychloride species. SbCl3 was found to exhibit similar reactivity to TiCl4, although at a slower rate. A mechanism is proposed, consistent with the observations for both stoichiometric and sub-stoichiometric quantities of TiCl4.
- Bali, Mark S.,Armitt, David,Wallace, Lynne,Day, Anthony I.
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- Hydrogen induced polarization-nuclear-spin hyperpolarization in catalytic hydrogenations without the enrichment of para- or orthohydrogen
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During the last 40 years, Prof. Dr. Joachim Bargon, to whom several articles in this issue are dedicated, has contributed more than 90 scientific publications to the understanding of NMR hyperpolarization phenomena such as chemically induced dynamic nucle
- Jonischkeit, Thorsten,Woelk, Klaus
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- EQUILIBRIA BETWEEN MexSiCl4-x, x = 3,2,1,0 AND ALKYL CARBOXYLATE ESTERS
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At 150 deg C equilibria are established between chlorosilanes and alkyl esters according to the equation: MexSiCl4-x + RCOOR' MexSi(O0.5)y(OOCR)z-yCl4-x-y-z + yRCOCl + zR'Cl.When x = 3, y = 0, z = 0.56; when x = 2, y = 0.26, z = 0.98.When x = 1, y = z = 0.56; when x = 0, y = z = 0.53.Lewis acid salts such as ZnCl2 or FeCl3 are effective catalysts for the reactions leading to mixtures of these compounds.
- Mbah, Godfrey C.,Speier, John L.
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- Highly active Cu/SiO2 catalysts for hydrogenation of diethyl malonate to 1,3-propanediol
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Cu/SiO2 catalysts prepared by the ammonia evaporation method were applied to hydrogenation of diethyl malonate to 1,3-propanediol. The calcination temperature played an important role in the structural evolution and catalytic performance of the Cu/SiO2 catalysts, which were systematically characterized by N2 adsorption-desorption, inductively coupled plasma-atomic emission spectroscopy, N2O chemisorption, X-ray diffraction, Fourier transform infrared spectroscopy, H2 temperature-programmed reduction, transmission electron microscopy, and X-ray photoelectron spectroscopy. When the Cu/SiO2 catalyst was calcined at 723 K, 90.7% conversion of diethyl malonate and 32.3% selectivity of 1,3-propanediol were achieved. Compared with Cu/SiO2 catalysts calcined at other temperatures, the enhanced catalytic performance of the Cu/SiO2 catalyst calcined at 723 K can be attributed to better dispersion of copper species, larger cupreous surface area and greater amount of copper phyllosilicate, which results in a higher ratio of Cu+/Cu0. The synergetic effect of Cu0 and Cu+ is suggested to be responsible for the optimum activity.
- Ding, Tongmei,Tian, Hengshui,Liu, Jichang,Wu, Wenbin,Yu, Jintao
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- Relative Bond Dissociation Energies for Two-Ligand Complexes of Cu+ with Organic Molecules in the Gas Phase
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Ralative two-ligand dissociation enthalpies, δD(Cu+-2L), for Cu+ with 43 organic molecules are determined.A pulsed-laser volatilization/ionization sourse is used to generate Cu+ which reacts with EtCl and/or other molecules to give Cu(ligand)2+ species.Equilibrium constants are measured for the ligand-exchange reactions which occur when pairs of ligand molecules are present.Free energies for two-ligand exchange are obtained from the equilibrium constant for the reaction Cu(A)2+ + 2B ->/+ + 2A.The free-energiy differences are added to give a scale of relative free energies for ligand exchange.These are converted to enthalpies to give δD(Cu+-2L) scale with the assumption that enthropy changes are small and can be neglected except for symmetry corrections which are made in appropriate cases.Dependence of δD(Cu+-2L) on functional group and substituent effects is analyzed.These results for Cu+ are compared to available results for other reference acids: H+, Al+, Mn+, Li+, and CpNi+.These comparisons show that Cu+ is a softer acid than the other reference acids.This is apparent from the relative preference of Cu+ for mercaptans and HCN compared to alcohols and other oxygen bases.
- Jones, Roger W.,Staley, Ralph H.
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- Hydrocarbonylation of ethyl orthoformate in the presence of rhodium catalysts
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The reaction of ethyl orthoformate with a mixture of CO and H2 (P 8 MPa) in the presence of various rhodium carbonyl catalysts with and without iodide promoters at temperatures of 150-170 deg C has been studied.The -/CH3I systems mainly catalyze the hydrogenation of ethyl orthoformate to diethoxymethane without any subsequent hydrogenation to methyl derivatives and methane.Carbonylation and hydrocarbonylation products of the ethyl moiety, i.e. ethyl propionate and 1,1-diethoxypropane together with diethyl carbonate coming from carbonylation of the ethoxy group, are produced, with a maximum selectivity of 12percent.Chlorocarbonylrhodium systems without iodide promoters are active in the hydrogenation and hydrocarbonylation of the substrate, whereas carbonylrhodium derivatives without halide ligands and promoters only catalyze the hydrogenation to diethoxymethane.IR spectroscopic studies show that the rhodium species produced under the reaction conditions are in all cases anionic halocarbonyl or carbonyl complexes, and the course of the reaction seems to depend on the hydrido character of the parent derivative.
- Raspolli Galletti, A.M.,Braca, G.,Sbrana, G.
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- Predicting the Solvent Effect on Esterification Kinetics
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It is well known that solvents influence reaction kinetics. The classical concentration-based kinetic modeling is unable to describe these effects. In this work, the reaction kinetics was studied for the esterifications of acetic acid and propionic acid with ethanol at 303.15 K. It was found that the reactant ratio as well as the applied solvents (acetonitrile, tetrahydrofurane, dimethylformamide) significantly affect the reaction rate. The thermodynamic model PC-SAFT was applied to account for the interactions between the reacting species and the solvents via activity coefficients. This allowed the identification of solvent-independent kinetic constants and the prediction of the solvent effect on reaction kinetics in almost quantitative agreement with experimental data. The presented approach shows the importance of taking into account thermodynamic non-idealities and significantly reduces experimental effort for finding the best solvent candidate for a given target reaction.
- Lemberg, Max,Sadowski, Gabriele
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- Uncommon oxidative transformations of acetic and propionic acids
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The oxidative decarbonylation of acetic and propionic acids with the formation of the corresponding alcohol and alkyl carboxylate is observed in the RhIII/CuI,II/Cl- catalytic system in the presence of O2 and CO. The decarbonylation of propionic acid in a deuterated solvent results in the substitution of hydrogen atoms by deuterium in the alkyl part of the products to form CH2DCOOD (CHD 2COOH) and CHD2COOD (CD3COOH). The subsequent decarbonylation of deuterated acetic acids affords the corresponding deuteromethanols detected as esters with propionic and deuteroacetic acids. The substitution of the hydrogen atom by deuterium in the alkyl part of molecules of the products of oxidative decarbonylation of propionic acid, when the reaction is carried out in a deuterated solvent, indicates that propionic acid behaves as saturated hydrocarbon and blocks the oxidation of poorly soluble methane. Unlike propionic acid, acetic acid enters only the oxidative decarbonylation reaction and does not block methane oxidation.
- Chepaikin,Bezruchenko,Menchikova,Moiseeva,Gekhman,Moiseev
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- Highly conserved progesterone 5β-reductase genes (P5βR) from 5β-cardenolide-free and 5β-cardenolide-producing angiosperms
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Most cardenolides used in the therapy of cardiac insufficiency are 5β-configured and thus the stereo-specific reduction of the Δ4,5-double bond of a steroid precursor is a crucial step in their biosynthesis. This step is thought to be catalysed by progesterone 5β-reductases. We report here on the isolation of 11 progesterone 5β-reductase (P5βR) orthologues from 5β-cardenolide-free and 5β-cardenolide-producing plant species belonging to five different angiosperm orders (Brassicales, Gentianales, Lamiales, Malvales and Solanales). Amino acid sequences of the P5βR described here were highly conserved. They all contain certain motifs qualifying them as members of a class of stereo-selective enone reductases capable of reducing activated CC double bonds by a 1,4-addition mechanism. Protein modeling revealed seven conserved amino acids in the substrate-binding/catalytic site of these enzymes which are all supposed to exhibit low substrate specificity. Eight P5βR genes isolated were expressed in Escherichia coli. Recombinant enzymes reduced progesterone stereo-specifically to 5β-pregane-3,20-dione. The progesterone 5β-reductases from Digitalis canariensis and Arabidopsis thaliana reduced activated CC double bonds of molecules much smaller than progesterone. The specific role of progesterone 5β-reductases of P5βRs in cardenolide metabolism is challenged because this class of enone reductases is widespread in higher plants, and they accept a wide range of enone substrates.
- Bauer, Peter,Munkert, Jennifer,Brydziun, Margareta,Burda, Edyta,Müller-Uri, Frieder,Gr?ger, Harald,Muller, Yves A.,Kreis, Wolfgang
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- Comparison of the performance of commercial immobilized lipases in the synthesis of different flavor esters
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In this work, it is compared the performance of three commercial lipase preparations (Novozym 435, Lipozyme TL-IM, and Lipozyme RM-IM) in the synthesis of flavor esters obtained by esterification of acetic, propionic, and butyric acids using ethanol, isopropyl alcohol, butanol, or pentanol. A comprehensive comparison was performed verifying activities of these three enzyme preparations versus the different couples of substrates, checking the obtained yields. In general, the longer the acid chain, the higher the reaction yields. Novozym 435 was the most efficient enzyme in most cases, and only Lipozyme RM-IM offered better results than Novozym 435 in the production of ethyl butyrate. Reactions with butyric acid showed the highest conversion rates using all biocatalysts. Using optimal substrates, the reactions catalyzed by the three enzymes were optimized using the response surface methodology, and the catalytic performance of the biocatalysts in repeated batches was assessed. After optimization, yields higher than 90% were obtained for all three enzymes, but Lipozyme TL-IM needed four-times more biocatalyst content than the other two preparations. Novozym 435 kept over 80% of its activity when reused in 9 successive batches, whereas Lipozyme RM-IM can be reused 5 times and Lipozyme TL-IM only 3 times. In general, Novozym 435 showed to be more suitable for these reactions than the other two enzyme preparations.
- Martins, Andrea B.,Da Silva, Alexandre M.,Schein, Mirela F.,Garcia-Galan, Cristina,Zachia Ayub, Marco A.,Fernandez-Lafuente, Roberto,Rodrigues, Rafael C.
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- Synthesis of mesoporous iridium nanosponge: A highly active, thermally stable and efficient olefin hydrogenation catalyst
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Three dimensional porous structures offer high specific surface areas and large pore volumes, which enhance substrate diffusion within the porous structures and provide a large number of surface active sites. Such types of structures find applications in catalysis. Herein, we report a simple synthetic strategy for the preparation of iridium nanosponges by the capping agent dissolution method. An Ir@BNHx nanocomposite was prepared starting from different iridium precursors by a solid state reduction method using ammonia borane wherein iridium(0) nanoparticles are embedded in a BNHx polymer. Capping agent (here, the BNHx polymer) dissolution using water under ambient conditions resulted in the formation of a mesoporous iridium nanosponge. This iridium nanosponge exhibits a surface area of 33.5 m2 g-1. The iridium nanosponge was found to be catalytically active for hydrogenation of a variety of olefinic substrates including linear and cyclic alkenes and α,β-unsaturated esters under relatively mild conditions and exhibits high turnover frequencies. It was also found to exhibit much better catalytic activity as compared to other iridium based heterogeneous catalysts for olefin hydrogenation reactions. Additionally, catalyst recovery was achieved via simple filtration from the hydrogenation reaction mixture. The catalytically active surface area of iridium nanosponge was estimated using H2-temperature programmed desorption (TPD) experiments. Moreover, the catalyst was found to be thermally quite robust. The catalyst was recyclable over seven cycles of styrene hydrogenation and was found to be capable of hydrogenating 99% of styrene to ethyl benzene after seven cycles.
- Ghosh, Sourav,Jagirdar, Balaji R.
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- Dehalogenation of α-Halo Carbonyl Compounds by a New Efficient Reagent, Triphenylphosphonium Iodide
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Triphenylphosphonium iodide, Ph3PHI, was found to be an efficient reagent for the dehalogenation of α-halo carbonyl compounds. α-Halo esters, which were difficult to be reduced with Me3SiCl/NaI reagent, was smoothly debromiated by Ph3PHI.Treatment of α-halocarbonyl compounds with Ph3PDI produced the corresponding α-deuterated compounds.
- Kamiya, Naoshi,Tanmatu, Hiroshi,Ishii, Yasutaka
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- Methane functionalization in water with micellar catalysis
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The functionalization of methane in water as the reaction medium (where it is nearly insoluble) at room temperature using micellar catalysis is described. Aggregates are formed from surfactant molecules and act as methane concentrators, also trapping the catalyst (a silver-based complex) and the diazo reagent (ethyl diazoacetate, EDA), providing yields of ethyl propionate up to 14% (referred to as EDA). This is the first example of methane being functionalized in water at room temperature.
- Gava, Riccardo,Ballestín, Pilar,Prieto, Auxiliadora,Caballero, Ana,Pérez, Pedro J.
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- HOMOLOGATION WITH CO+H2 OF ETHYL ORTHOFORMATE IN THE PRESENCE OF RUTHENIUM CATALYSTS: A STEPWISE HYDROGENATION AND CARBONYLATION REACTION
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The reaction of ethyl orthoformate with CO+H2 (P 10-15 MPa) in the presence of ruthenium carbonyl iodide catalysts at temperatures of 130-200 deg C has been studied.Products of hydrogenation, carbonylation and homologation of the CH, Et and EtO moieties of the ester are formed, indicating that the catalyst can activate the substrate in three ways.Diethoxymethane was the main product at lower temperatures, whereas methyl ethyl ether, methanol, and ethyl propionate predominate at higher temperatures.The formation of significant amounts of diethyl carbonate and diethoxyethane indicates the intermediate formation of EtO-Ru derivatives.Results of experiments with CO+D2 suggest a step-wise process of hydrogenation and carbonylation of the substrate, and shed new light on the mechanism of activation of esters by ruthenium carbonyl iodide catalysts.
- Braca, G.,Galletti, A. M. Raspolli,Sbrana, G.,Lazzaroni, R.
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- Synthesis, characterization and catalytic performance of a novel picolinic acid-12-molybdophosphoric acid hybrid catalyst
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A novel 12-molybdophosphoric acid (HPM)-based complex (H2 PI)2(H 3 O)[PMo12O 40] [Mo2 O5 (H2 O)2 (PI)2 ]?11H2 O (PI-HPM) was prepared by modification with picolinic acid (HPI) and characterized by the methods of Fourier transform infrared (FTIR) spectroscopy, thermogravimetry (TG), X-ray powder and single crystal diffraction. The complex retained the classical Keggin structure of bulk HPM, there were some strong hydrogen bonds existing between the [PMo12 O40 ]3- polyanion, the [Mo2 O5 (H2 O)2 (PI)2 ] coordination moiety, the protonated HPI and the lattice water molecules. Then PI-HPM was employed as heterogeneous catalyst for esterification reaction to evaluate its acid-catalytic activity. The complex exhibited high activity and good durability in reaction mixtures, indicating that it was a promising heterogeneous acid catalyst for esterification that including the conversion of oleic acid to oleates.
- Liu, Lijun,Wang, Honghong,Gong, Shuwen,Lu, Jing,Zhang, Qian
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- ZrOCl2·8H2O: An efficient, cheap and reusable catalyst for the esterification of acrylic acid and other carboxylic acids with equimolar amounts of alcohols
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Esterifications of carboxylic acids with equimolar amount of alcohols could be efficiently catalyzed by ZrOCl2·8H2O. Acrylate esters were obtained in good yields under solvent-free conditions at ambient temperature. The esterification of other carboxylic acids with alcohols also proceeded at ambient temperature or at 50°C to afford esters in high yields. If the esterification was performed in toluene under azeotropic reflux conditions to remove water, both the catalytic activity of ZrOCl 2·8H2O and the rate of esterification could be increased greatly. Furthermore, in the present catalytic system, the esters could be easily separated from the reaction mixtures and the catalyst could be easily recovered and reused.
- Sun, Hong-Bin,Hua, Ruimao,Yin, Yingwu
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- Thermal decomposition of diethylketone cyclic triperoxide in polar solvents
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The thermolysis of diethylketone cyclic triperoxide (3,3,6,6,9,9-hexaethyl- 1,2,4,5,7,8-hexaoxacyclononane, DEKTP) was studied in different polar solvents (ethanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, and acetonitrile). The rate constant values (kd) are higher for reactions performed in secondary alcohols probably because of the possibility to form a cyclic adduct with the participation of the hydrogen atom bonded to the secondary carbon. The kinetic parameters were correlated with the physicochemical properties of the selected solvents. The products of the DEKTP thermal decomposition in different polar solvents support a radical-based decomposition mechanism. CSIRO 2014.
- Barreto, Gaston P.,Alvarez, Elida E.,Eyler, Gladys N.,Canizo, Adriana I.,Allegretti, Patricia E.
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- Carbonylation of alcohols in the Pd(OAc)2/TsOH/molten salt system
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A non-phosphine catalytic system, Pd(OAc)2/TsOH/NBu 4Br, is suggested for the synthesis of acids by the carbonylation of alcohols.
- Eliseev, Oleg L.,Bondarenko, Tatyana N.,Stepin, Nikolai N.,Lapidus, Albert L.
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- Quaternary phosphonium polymer-supported dual-ionically bound [Rh(CO)I3]2– catalyst for heterogeneous ethanol carbonylation
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A single-Rh-site catalyst (Rh-TPISP) that was ionically-embedded on a P(V) quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation. The [Rh(CO)I3]2– unit was proposed to be the active center of Rh-TPISP for the carbonylation reaction based on detailed Rh L3-edge X-ray absorption near edge structure (XANES), X-ray photoelectron spectroscopy (XPS), and Rh extended X-ray absorption fine structure (EXAFS) analyses. As the highlight of this study, Rh-TPISP displayed distinctly higher activity for heterogeneous ethanol carbonylation than the reported catalytic systems in which [Rh(CO)2I2]? is the traditional active center. A TOF of 350 h?1 was obtained for the reaction over [Rh(CO)I3]2–, with >95% propionyl selectivity at 3.5 MPa and 468 K. No deactivation was detected during a near 1000 h running test. The more electron-rich Rh center was thought to be crucial for explaining the superior activity and selectivity of Rh-TPISP, and the formation of two ionic bonds between [Rh(CO)I3]2– and the cationic P(V) framework ([P]+) of the polymer was suggested to play a key role in firmly immobilizing the active species to prevent Rh leaching.
- Ding, Yunjie,Jiang, Zheng,Liu, Yang,Lyu, Yuan,Ren, Zhou,Song, Xiangen,Zheng, Changyong
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- The Double Carbonylation of Diiodomethane Catalysed by Rhodium Complexes
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In alcohols, ROH, in the presence of and optionally also in the presence of a tertiary phosphorus ligand PR'3, CH2I2 reacts with CO to give CH2(CO2R)2, CH2(OR)2 and RI.
- Weston, William S.,Gash, Rosslyn C.,Cole-Hamilton, David J.
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- HOMOLOGATION OF CARBOXYLIC METHYL ESTERS VIA REDUCTIVE CARBONYLATION CATALYZED BY A COBALT-RUTHENIUM MIXED CATALYST
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Mixtures of cobalt acetate and ruthenium acetylacetonate promote the homologation of carboxylic methyl esters to the corresponding ethyl esters by CO-H2.The reaction of methyl formate is considered separately because of its tendency to decarboxylate.The behavior of five other methyl esters is considered as a function of the length and the size of the acyl group.In each case reductive carbonylation of the methyl ester gives methanol, ethanol, the carboxylic acid, and the ethyl ester.The formation of the last product is enhanced by the mixture of Co and Ru complexes. The mechanism is thought to be essentially the same as that previously proposed for homologation of methyl acetate.
- Kheradmand, Houchang,Kiennemann, Alain,Jenner, Gerard
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- Efficient Palladium-Catalyzed Alkoxycarbonylation of Bulk Industrial Olefins Using Ferrocenyl Phosphine Ligands
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The development of ligands plays a key role and provides important innovations in homogeneous catalysis. In this context, we report a novel class of ferrocenyl phosphines for the alkoxycarbonylation of industrially important alkenes. A basic feature of our ligands is the combination of sterically hindered and amphoteric moieties on the P atoms, which leads to improved activity and productivity for alkoxycarbonylation reactions compared to the current industrial state-of-the-art ligand 1,2-bis((di-tert-butylphosphino)methyl)benzene). Advantageously, palladium catalysts with these novel ligands also enable such transformations without additional acid under milder reaction conditions. The practicability of the optimized ligand was demonstrated by preparation on >10 g scale and its use in palladium-catalyzed carbonylations on kilogram scale.
- Dong, Kaiwu,Sang, Rui,Fang, Xianjie,Franke, Robert,Spannenberg, Anke,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
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- A HIGH YIELD ROUTE TO ETHYL ESTERS OF CARBOXYLIC ACIDS
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Diethyl trichloromethylphosphonate reacts with carboxylic acids to yield their ethyl esters, via transesterification; even the hindered mesitoic acid is esterified in high yield.
- Downie, Ian M.,Wynne, Neil,Harrison, Stephen
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- Silver-catalyzed C-C bond formation between methane and ethyl diazoacetate in supercritical CO2
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Even in the context of hydrocarbons' general resistance to selective functionalization, methane's volatility and strong bonds pose a particular challenge. We report here that silver complexes bearing perfluorinated indazolylborate ligands catalyze the reaction of methane (CH4) with ethyl diazoacetate (N2CHCO2Et) to yield ethyl propionate (CH3CH2CO2Et). The use of supercritical carbon dioxide (scCO2) as the solvent is key to the reaction's success. Although the catalyst is only sparingly soluble in CH4/CO2 mixtures, optimized conditions presently result in a 19% yield of ethyl propionate (based on starting quantity of the diazoester) at 40°C over 14 hours.
- Caballero, Ana,Despagnet-Ayoub, Emmanuelle,Diaz-Requejo, M. Mar,Diaz-Rodriguez, Alba,Gonzalez-Nunez, Maria Elena,Mello, Rossella,Munoz, Bianca K.,Ojo, Wilfried-Solo,Asensio, Gregorio,Etienne, Michel,Perez, Pedro J.
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- Vapor-phase ethanol carbonylation with heteropolyacid-supported Rh
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Ethanol carbonylation is a potential route to valuable C3 products. Here, Rh supported on porous, Cs-exchanged heteropolyacid Cs3PW12O40, is demonstrated as an effective catalyst for vapor-phase ethanol carbonylation, with higher selectivity and conversion to propionates than existing catalysts. Residual acidity or a Mo polyatom was strongly detrimental to yields. Propionate selectivity was maximized at 96% at 170 °C and with added H2O. The catalyst displayed stable selectivity over 30 h on stream and up to 77% conversion. Ethyl iodide is a required co-catalyst but at levels as low as 2% relative to ethanol. XPS and in situ XANES indicate partial Rh reduction, consistent with the formation of low-valent reactive intermediates and slow deactivation through formation of Rh nanoparticles. With further optimization and understanding, these Rh/heteropolyacid catalysts may lead to stable and selective catalysts for the production of propionates through ethanol carbonylation.
- Yacob, Sara,Park, Sunyoung,Kilos, Beata A.,Barton, David G.,Notestein, Justin M.
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- Effects of a Tridentate Pincer Ligand on Parahydrogen Induced Polarization
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The role of ligands in rhodium- and iridium-catalyzed Parahydrogen Induced Polarization (PHIP) and SABRE (signal amplification by reversible exchange) chemistry has been studied in the benchmark systems, [Rh(diene)(diphos)]+ and [Ir(NHC)(sub)3(H)2]+, and shown to have a great impact on the degree of hyperpolarization observed. Here, we examine the role of the flanking moieties in the electron-rich monoanionic bis(carbene) aryl pincer ligand, ArCCC (Ar=Dipp, 2,6-diisopropyl or Mes, 2,4,6-trimethylphenyl) on the cobalt-catalyzed PHIP and PHIP-IE (PHIP via Insertion and Elimination) chemistry that we have previously reported. The mesityl groups were exchanged for diisopropylphenyl groups to generate the (DippCCC)Co(N2) catalyst, which resulted in faster hydrogenation and up to 390-fold 1H signal enhancements, larger than that of the (MesCCC)Co-py (py=pyridine) catalyst. Additionally, the synthesis of the (DippCCC)Rh(N2) complex is reported and applied towards the hydrogenation of ethyl acrylate with parahydrogen to generate modest signal enhancements of both 1H and 13C nuclei. Lastly, the generation of two (MesCCC)Ir complexes is presented and applied towards SABRE and PHIP-IE chemistry to only yield small 1H signal enhancements of the partially hydrogenated product (PHIP) with no SABRE hyperpolarization.
- Muhammad, Safiyah R.,Nugent, Joseph W.,Greer, Rianna B.,Lee, Brian C.,Mahmoud, Jumanah,Ramirez, Steven B.,Goodson, Boyd. M.,Fout, Alison R.
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- Ionic liquid immobilized nickel(0) nanoparticles as stable and highly efficient catalysts for selective hydrogenation in the aqueous phase
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Nickel nanoparticles (NPs) well-dispersed in the aqueous phase were conveniently prepared by reducing nickel(II) salt with hydrazine in the presence of the functionalized ionic liquid 1-(3-aminopropyl)-2,3-dimethylimidazolium bromide. UV/Vis spectros-copy, elemental analysis, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) show the presence of a weak interaction of the functionalized ionic liquid with Ni11 and Ni 0 complexes. The face-centered cubic structure of the Ni0 NPs was confirmed by X-ray diffraction (XRD) characterization. Transmission electron microscopy (TEM) images reveal that smaller Ni0 particles of approximately 6-7 nm average diameter assemble to give larger, blackberry-shaped particles with an average diameter of around 35 nm. The Ni NPs were employed as highly efficient catalysts for the selective hydrogenation of C=C double bonds in the aqueous phase under mild reaction conditions (40-90°C at 1.0- 3.0 MPa), and the Ni0 nanocatalysts in the aqueous phase are stable enough to be reused at least seven times without significant loss of catalytic activity during subsequent reuse cycles. 2010 Wiley-VCH Verlag GmbH Co. KGaA, Weinheim.
- Hu, Yu,Yu, Yinyin,Hou, Zhenshan,Yang, Hanming,Feng, Bo,Li, Huan,Qiao, Yunxiang,Wang, Xiangrui,Hua, Li,Pan, Zhenyan,Zhao, Xiuge
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- Controlling the Lewis Acidity and Polymerizing Effectively Prevent Frustrated Lewis Pairs from Deactivation in the Hydrogenation of Terminal Alkynes
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Two strategies were reported to prevent the deactivation of Frustrated Lewis pairs (FLPs) in the hydrogenation of terminal alkynes: reducing the Lewis acidity and polymerizing the Lewis acid. A polymeric Lewis acid (P-BPh3) with high stability was designed and synthesized. Excellent conversion (up to 99%) and selectivity can be achieved in the hydrogenation of terminal alkynes catalyzed by P-BPh3. This catalytic system works quite well for different substrates. In addition, the P-BPh3 can be easily recycled.
- Geng, Jiao,Hu, Xingbang,Liu, Qiang,Wu, Youting,Yang, Liu,Yao, Chenfei
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p. 3685 - 3690
(2021/05/31)
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- Design, Synthesis, and Study of the Insecticidal Activity of Novel Steroidal 1,3,4-Oxadiazoles
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A series of novel steroidal derivatives with a substituted 1,3,4-oxadiazole structure was designed and synthesized, and the target compounds were evaluated for their insecticidal activity against five aphid species. Most of the tested compounds exhibited potent insecticidal activity against Eriosoma lanigerum (Hausmann), Myzus persicae, and Aphis citricola. Compounds 20g and 24g displayed the highest activity against E. lanigerum, showing LC50 values of 27.6 and 30.4 μg/mL, respectively. Ultrastructural changes in the midgut cells of E. lanigerum were detected by transmission electron microscopy, indicating that these steroidal oxazole derivatives might exert their insecticidal activity by destroying the mitochondria and nuclear membranes in insect midgut cells. Furthermore, a field trial showed that compound 20g exhibited effects similar to those of the positive controls chlorpyrifos and thiamethoxam against E. lanigerum, reaching a control rate of 89.5% at a dose of 200 μg/mL after 21 days. We also investigated the hydrolysis and metabolism of the target compounds in E. lanigerum by assaying the activities of three insecticide-detoxifying enzymes. Compound 20g at 50 μg/mL exhibited inhibitory action on carboxylesterase similar to the known inhibitor triphenyl phosphate. The above results demonstrate the potential of these steroidal oxazole derivatives to be developed as novel pesticides.
- Bai, Hangyu,Jiang, Weiqi,Li, Qi,Li, Tian,Ma, Shichuang,Shi, Baojun,Wu, Wenjun
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p. 11572 - 11581
(2021/10/12)
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- Manganese-Mediated C-C Bond Formation: Alkoxycarbonylation of Organoboranes
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Alkoxycarbonylations are important and versatile reactions that result in the formation of a new C-C bond. Herein, we report on a new and halide-free alkoxycarbonylation reaction that does not require the application of an external carbon monoxide atmosphere. Instead, manganese carbonyl complexes and organo(alkoxy)borate salts react to form an ester product containing the target C-C bond. The required organo(alkoxy)borate salts are conveniently generated from the stoichiometric reaction of an organoborane and an alkoxide salt and can be telescoped without purification. The protocol leads to the formation of both aromatic and aliphatic esters and gives complete control over the ester's substitution (e.g., OMe, OtBu, OPh). A reaction mechanism was proposed on the basis of stoichiometric reactivity studies, spectroscopy, and DFT calculations. The new chemistry is particularly relevant for the field of Mn(I) catalysis and clearly points to a potential pathway toward irreversible catalyst deactivation.
- Van Putten, Robbert,Filonenko, Georgy A.,Krieger, Annika M.,Lutz, Martin,Pidko, Evgeny A.
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supporting information
p. 674 - 681
(2021/04/02)
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- Genome mining reveals new bacterial type I Baeyer-Villiger monooxygenases with (bio)synthetic potential
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Baeyer-Villiger monooxygenases (BVMOs) are oxidorreductases that catalyze the oxidation of ketones in a very selective manner. By genome mining we detected seven putative type I BVMOs in Bradyrhizobium diazoefficiens USDA 110. As we established the phylogenetic relationships among them and with other type I BVMOs, we found out that they belong to different clades of the phylogenetic tree. Thus, we decided to clone and heterologously express five of them. Three of them, each one from a divergent phylogenetic group, were obtained as soluble proteins, allowing us to proceed with their biocatalytic assessment and enzymatic characterization. As to substrate scope and selectivity, we observed a complementary behavior among the three BVMOs. BVMO2 was the more versatile biocatalyst in whole-cell systems while BVMO4 and BVMO5 showed a narrow substrate profile with preference for linear ketones and particular regioselectivity for (±)-cis-bicyclo[3.2.0]hept-2-en-6-one.
- Bianchi, Dario A.,Carabajal, María Ayelén,Ceccoli, Romina D.,Rial, Daniela V.
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- Method for preparing organic carboxylic ester through combined catalysis of aryl bidentate phosphine ligand
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The invention discloses a method for preparing organic carboxylic ester by combined catalysis of an aryl bidentate phosphine ligand. The method comprises the following steps: under the action of a palladium compound/aryl bidentate phosphine ligand/acidic additive combined catalyst, carrying out a hydrogen esterification reaction on terminal olefin, carbon monoxide and alcohol so as to generate theorganic carboxylic ester with one more carbon than olefin. According to the invention, by adoption of the palladium compound/aryl bidentate phosphine ligand/acidic additive combined catalyst, good catalytic activity and selectivity for the hydrogen esterification reaction of the olefin are achieved, and olefin carbonylation to synthesize organic carboxylic ester can be efficiently catalyzed. Thearyl bidentate phosphine ligand has a rigid skeleton structure of a rigid ligand and the flexibility of a flexible ligand, so the aryl bidentate phosphine ligand has proper flexibility due to the characteristic that the aryl bidentate phosphine ligand is soft and rigid, and a most favorable coordination mode and a stable active structure in space are favorably formed. In addition, the aryl bidentate phosphine ligand has the advantages of high stability, simple and convenient synthesis method and the like; and a novel industrial technology is provided for production of organic carboxylate compounds.
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Paragraph 0036
(2020/05/29)
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- Reduction of Activated Alkenes by PIII/PV Redox Cycling Catalysis
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The carbon–carbon double bond of unsaturated carbonyl compounds was readily reduced by using a phosphetane oxide catalyst in the presence of a simple organosilane as the terminal reductant and water as the hydrogen source. Quantitative hydrogenation was observed when 1.0 mol % of a methyl-substituted phosphetane oxide was employed as the catalyst. The procedure is highly selective towards activated double bonds, tolerating a variety of functional groups that are usually prone to reduction. In total, 25 alkenes and two alkynes were hydrogenated to the corresponding alkanes in excellent yields of up to 99 %. Notably, less active poly(methylhydrosiloxane) could also be utilized as the terminal reductant. Mechanistic investigations revealed the phosphane as the catalyst resting state and a protonation/deprotonation sequence as the crucial step in the catalytic cycle.
- Longwitz, Lars,Werner, Thomas
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supporting information
p. 2760 - 2763
(2020/02/05)
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- Oxidative Esterification of Aldehydes and Alcohols Catalyzed by Camphor-Based Imidazolium Salts
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Abstract: Sixteen new camphor-based imidazolium salts have been synthesized with renewable camphorsulfonic acid as the starting material. The chemical shifts of the characteristic proton of C2 on the imidazolium ring (N?C=N) were discussed thoroughly and all of these imidazolium salts exhibit good thermal stability. Furthermore, the excellent catalytic performance of the synthesized imidazolium salts were observed in the oxidative esterification between aromatic or aliphatic aldehydes containing electron-withdrawing or electron-donating groups on aromatic ring and primary or secondary alcohol by air as the sole oxidant. Graphic Abstract: [Figure not available: see fulltext.].
- Bian, Tiancen,Feng, Li,Li, Danfeng,Huang, Jiaxin,Zhao, Yuxun,Xu, Xu,Yang, Yiqin,Wang, Shifa
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p. 1812 - 1820
(2020/01/11)
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- Preparation method of ramelteon
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The invention relates to the technical field of insomnia drugs, and discloses a preparation method of ramelteon. The method comprises the following step of: 1) adding triethyl phosphonoacetate and 400-600 ml of tetrahydrofuran into a 2L three-necked bottle and carrying out ice-water bath below 40 DEG C. According to the preparation method of ramelteon, ethyl acrylate and chloroform are stirred anddissolved, bromine is dropwise added at a normal temperature, bromine is dropwise added again after reaction is carried out for 1 hour, reaction is carried out for 2 hours, a water layer is extractedby concentrated hydrochloric acid, washing is carried out with water, saturated sodium hydrogen sulfite solution and saline water in sequence, anhydrous sodium sulfate is dried and filtered, and thefiltrate is decompressed and steamed to remove a solvent and then decompressed and dried below 60 DEG C so as to ensure that the reaction can be completely carried out, the purity of the prepared ramelteon is greatly improved, and the problems that the manufacture process is long in time, the ratio of the ramelteon in the extract is low, the preparation efficiency of the ramelteon is low and the preparation cost of the ramelteon is greatly increased are avoided.
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Paragraph 0021; 0023; 0026; 0028; 0031; 0033
(2019/01/17)
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- Electronic Ligand Modifications on Cobalt Complexes and Their Application toward the Semi-Hydrogenation of Alkynes and Para-Hydrogenation of Alkenes
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The effect of the electronic modification of a bis(carbene) pincer ligand, (MesCCCR), on cobalt catalysis has been investigated. The pincer ligand was modified in the para position of the aryl backbone with a tert-butyl and trifluoromethyl moiety to yield the electronic variants that were applied toward the synthesis and characterization of several cobalt complexes, (MesCCCR)Co. The application of the (MesCCCR)CoI(N2)PPh3 complexes toward the semihydrogenation of alkynes revealed that while the tert-butyl group does not impact reactivity, the loss of electron density at the metal center, by the installation of the CF3 group, does affect product ratios. Further inspection of the proposed mechanism suggested that the installation of the trifluoromethyl group slows down olefin hydrogenation. This finding was further supported in the application of the (MesCCCR)CoI-py (py = pyridine) complexes toward the parahydrogenation of ethyl acrylate, which demonstrated that the electron-withdrawing ligand variant produced less polarization.
- Muhammad, Safiyah R.,Nugent, Joseph W.,Tokmic, Kenan,Zhu, Lingyang,Mahmoud, Jumanah,Fout, Alison R.
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supporting information
p. 3132 - 3138
(2019/08/26)
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- Method for synthesizing propionate through ester-ester exchange path
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The invention provides a method for synthesizing propionate through an ester-ester exchange path and relates to a method for synthesizing the propionate. According to the method, reaction raw materials include, but are not limited to ethyl formate, propyl formate, butyl formate, ethyl acetate, propyl acetate, butyl acetate and the like; the method for synthesizing the propionate through an ester exchange one-step method is adopted. A catalyst comprises alkaline materials including ionic liquid, soluble strong base, solid base and the like respectively; the catalyst has the advantages of high catalysis efficiency and no pollution. By taking methyl propionate and ethyl acetate reaction as an example, KOH is used as the catalyst, the mol ratio of the raw materials is 1 to 1, the reaction temperature is 60 DEG C and the reaction time is 5 min; the conversion ratios of the methyl propionate and the ethyl acetate can reach 70 percent or more; products comprise ethyl propionate and the methylacetate. The whole reaction path has the characteristics of short synthetic route, simple technological flow and high yield and the catalyst is stable, does not become inactive and can be repeatedlyutilized.
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Paragraph 0030-0031
(2019/04/04)
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- Camphoryl imidazole type ionic liquid and preparation method and application thereof
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The invention discloses a camphoryl imidazole type ionic liquid and a preparation method and application thereof. According to the preparation method, a derivative camphorsulfonic acid of a natural renewable resource camphor is taken as a raw material to prepare 10-iodocamphor; then the 10-iodocamphor and aryl imidazole are subjected to a quaterisation reaction to prepare camphoryl imidazole iodide; then the camphoryl imidazole iodide and sodium hexafluorophosphate, sodium tetrafluoroborate, bis(trifluorosulfonimide)lithium and the like are subjected to ion exchange to prepare camphoryl imidazole hexafluorophosphate, camphoryl imidazole tetrafluoroborate, camphoryl imidazole bis(trifluorosulfonimide)salt and other ionic liquids. The camphoryl imidazole type ionic liquid shows good catalytic activity for an oxidation esterification reaction of aldehyde-alcohol, has the advantages of short reaction time, good reaction selectivity and high product yield, and has a good application prospect.
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Paragraph 0060; 0074
(2019/10/05)
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- Method for preparing propionate by ester alcohol exchange
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The invention discloses a method for preparing propionate by ester alcohol exchange, and relates to a method for preparing propionate. According to the invention, the method for synthesizing propionate by ester alcohol exchange of methyl propionate and various alcohols (including monohydric alcohols such as ethanol, propanol, butanol, tert-butanol, isopropanol, cyclohexanol, allyl alcohol and thelike, dihydric alcohols such as 1,3-propylene glycol and the like, glycerol and the like) is adopted, and methyl propionate and the alcohols are used as raw materials to carry out a reaction under catalysis of alkaline ionic liquid, soluble strong alkali or solid alkali to prepare higher propionate and methanol. According to the method, the synthetic route is short, and the reaction product is taken out through azeotropic extraction of the methyl propionate and methanol, so that the reaction is more thorough, and the target product is directly obtained by one step. The product obtained by thereaction only contains propionate and methanol, the whole reaction process is concise and efficient and is free of pollution, no byproducts are generated, and great significance is achieved for large-scale and low-cost production of propionate.
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Paragraph 0034-0045
(2019/07/04)
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- 13C NMR Signal Enhancement Using Parahydrogen-Induced Polarization Mediated by a Cobalt Hydrogenation Catalyst
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The use of a cobalt-based catalyst for the generation of hyperpolarized 13C NMR resonances by parahydrogenation of ethyl acrylate is presented herein. Comparisons of the carboxylate 13C NMR signal enhancement factor of ethyl propionate between using (MesCCC)Co-py and a commonly utilized cationic diphosphine rhodium complex demonstrates that the cobalt system is a viable PHIP catalyst alternative. Furthermore, the operative hydrogenation mechanism of the cobalt system was examined by using 1H, 13C, and parahydrogen-induced polarization NMR spectroscopies to elucidate reaction intermediates affiliated with the observed 1H and 13C NMR signal enhancements in ethyl propionate.
- Tokmic, Kenan,Greer, Rianna B.,Zhu, Lingyang,Fout, Alison R.
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supporting information
p. 14844 - 14850
(2018/11/20)
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- Iron-mediated coupling of carbon dioxide and ethylene: Macrocyclic metallalactones enable access to various carboxylates
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Treatment of (iPrPDI)Fe(N2)2 (iPrPDI, 2,6-(2,6-iPr2C6H3Na? CMe)2C5H3N) with CO2 and ethylene resulted in the formation of a homologous series of saturated and unsaturated iron carboxylate products, (iPrPDI)Fe(O2CR), the distribution of which depends on the ratio of the reagents. The solid-state and electronic structures of a saturated product, (iPrPDI)Fe(O2CC2H5), were elucidated. Product distributions, deuterium labeling studies, and stoichiometric experiments support initial formation of a five-membered metallalactone intermediate, which undergoes subsequent ethylene insertions to generate macrocyclic metallalactones. Competitive β-hydride elimination, CO2 insertion, or reaction with H2 determines the fate of the metallalactone, the latter accounting for formation of iron complexes with saturated carboxylates. Similar reactivity was observed upon addition of propiolactone and ethylene to (iPrPDI)Fe(N2)2, supporting C-O oxidative addition and C-C bond formation through metallacycle intermediates.
- Rummelt, Stephan M.,Zhong, Hongyu,Korobkov, Ilia,Chirik, Paul J.
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supporting information
p. 11589 - 11593
(2018/09/29)
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- Photo-selective chain end transformation of polyacrylate-iodide using cysteamine and its application to facile single-step preparation of patterned polymer brushes
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Cysteamine, which is an inexpensive and non-toxic aminothiol, was successfully employed as a photo-selective chain end transformation agent of iodo-terminated polymer chains (polymer-I). Polymer-I was selectively transformed to hydrogen-terminated (polymer-H) and thiol-terminated (polymer-SH) polymers with and without UV irradiation, respectively. This method is applicable to acrylate polymers. This photo-selective reaction offered a single-step preparation of patterned polymer brushes with SH and H chain end functionalities as a unique application.
- Chen, Chen,Wang, Chen-Gang,Xiao, Longqiang,Goto, Atsushi
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supporting information
p. 13738 - 13741
(2019/01/03)
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- Hydrogenation of Ketones and Esters Catalyzed by Pd/C?SiO2
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Hydrogenation of unsaturated ketones and esters with molecular hydrogen on the 5%Pd/C?SiO2 heterogeneous catalyst has been studied. The reaction direction and yield are determined by the starting compounds structure. Hydrogenation of unsaturated ketones containing phenyl group at the double carbon–carbon atom is accompanied by the reduction of the ketone group into the alcohol one. Hydrogenation of unsaturated esters is accompanied by transesterification.
- Akchurin,Baibulatov,Dokichev
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p. 195 - 198
(2018/03/26)
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- Selective Hydrodeoxygenation of Alkyl Lactates to Alkyl Propionates with Fe-based Bimetallic Supported Catalysts
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Hydrodeoxygenation (HDO) of methyl lactate (ML) to methyl propionate (MP) was performed with various base-metal supported catalysts. A high yield of 77 % MP was obtained with bimetallic Fe–Ni/ZrO2 in methanol at 220 °C and 50 bar H2. A synergistic effect of Ni increased the yield of MP significantly when using Fe–Ni/ZrO2 instead of Fe/ZrO2 alone. Moreover, the ZrO2 support contributed to improve the yield as a phase transition of ZrO2 from tetragonal to monoclinic occurred after metal doping giving rise to fine dispersion of the Fe and Ni on the ZrO2, resulting in a higher catalytic activity of the material. Interestingly, it was observed that Fe–Ni/ZrO2 also effectively catalyzed methanol reforming to produce H2 in situ, followed by HDO of ML, yielding 60 % MP at 220 °C with 50 bar N2 instead of H2. Fe–Ni/ZrO2 also catalyzed HDO of other short-chain alkyl lactates to the corresponding alkyl propionates in high yields around 70 %. No loss of activity of Fe–Ni/ZrO2 occurred in five consecutive reaction runs demonstrating the high durability of the catalyst system.
- Khokarale, Santosh Govind,He, Jian,Schill, Leonhard,Yang, Song,Riisager, Anders,Saravanamurugan, Shunmugavel
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p. 681 - 687
(2018/02/13)
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- PROCESS FOR HYDROGENOLYSIS OF ALPHA-HYDROXY ESTERS OR ACIDS USING A HETEROGENEOUS CATALYST
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The present invention relates to a method for hydrogenolysis of alpha-hydroxy esters or acids, comprising reacting the alpha-hydroxy ester or acid in the presence of a heterogeneous catalyst. The present invention also relates to a method for producing propionic acid ester, and the use of any of the methods for the production of propionic acid esters, such as alkyl propionate.
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Page/Page column 26
(2017/01/31)
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- Tin-containing catalyst is used for a method of producing a calbonyl compd.
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PROBLEM TO BE SOLVED: To provide a reaction catalyst having a high reaction selectivity and being recyclable in a peroxidation reaction using a carbonyl compound, and to provide a method for highly efficiently producing, for example, ester, lactone and formyloxy compounds or derivatives thereof by subjecting a carbonyl compound to a peroxidation reaction using the reaction catalyst.SOLUTION: A specific tin-containing catalyst can be used for a peroxidation reaction of a carbonyl compound, and a recyclable specific tin-containing catalyst is reusable for the reaction. A method for producing an oxide carries out a peroxidation reaction of a carbonyl compound in the presence of the tin-containing catalyst or the tin-containing recyclable catalyst.
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Paragraph 0147
(2017/03/25)
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- Process for the preparation of propionic acid methyl ester
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The invention relates to a preparation method of propionate, belonging to the technical field of preparation of organic substances. Propanoic acid and monobasic alcohol are subjected to esterification reaction under the action of a gel-type strong-acid ion exchange resin catalyst to generate the propionate. The gel-type strong-acid ion exchange resin is a hydrogen-type styrene-stilbene copolymer with sulfonate group, and the pore size of the resin is less than 8nm. The preparation method provided by the invention uses the catalyst to effectively adsorb the reaction impurities and enhance the product purity; and the catalyst has the advantages of favorable catalytic effect and low corrosivity, and can be easily separated from the product.
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Paragraph 0034; 0035; 0036; 0037; 0038; 0039
(2016/12/22)
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- By using low-temperature co- melt solvent a method of catalytic ester (by machine translation)
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The invention discloses a method of utilizing low-temperature co- melt solvent catalytic ester method, will be 0.05-0.5 mole of sharemelt solvent of low-temperature co-preprocessing, 1-5 mole of share alcohol and 1-10 mole of share of acid in the reaction vessel, stirring and heating, 25-200 ° C reaction under 2-96h, then the reaction fluid settlement , liquid, organic is accepted after passing an examination the level , get the esterification reaction products of the; reaction after the treatment and recovery of low-temperature co- melt solvent the preprocessing, can be reused. This invention utilizes the easy preparation of low-temperature co- melt solvent the preprocessing of catalytic esterification reaction, the reaction front is homogeneous, can be formed after the reaction of the two-phase reaction in the process of direct dehydration, without adding other dehydrating agent, has the advantages of simple operation, the reaction efficiency is high, corrosion of small equipment, less side reactions, the product quality is good, no pollution to the environment, and the like, it has broad application prospects. (by machine translation)
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Paragraph 0040; 0041
(2017/01/17)
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- Vapor phase ethanol carbonylation over Rh supported on zeolite 13X
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While methanol carbonylation has been extensively studied, higher alcohol carbonylation has received relatively little attention, even though, for example, ethanol carbonylation could be a useful route for the production of propionates. Here we use Rh/Na13X to investigate the vapor phase carbonylation of ethanol with an ethyl iodide co-feed. In the base case, the catalyst is ～40% selective to propionates, with the remainder forming ethylene and diethyl ether. Deposition of additional alkali can increase selectivities to ～60%. Isotopic labeling of ethyl iodide demonstrates reversible formation of ethyl iodide from ethanol, and that preferential incorporation of ethyl iodide initiates the Rh-catalyzed carbonylation cycle. XPS and in situ X-ray absorption spectroscopy are consistent an active anionic RhI iodide species at a zeolite exchange site. This proposed structure and the attendant catalytic reaction network are directly analogous to those of classic solution-phase Rh catalysts and other supported Rh catalysts. However, important differences are noted in the reaction orders and apparent activation barrier, which suggest that the rate of ethyl iodide formation is overall rate limiting under these conditions and for this catalyst.
- Yacob, Sara,Kilos, Beata A.,Barton, David G.,Notestein, Justin M.
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p. 122 - 131
(2016/05/09)
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- Baeyer-Villiger oxidation of cyclohexanone by molecular oxygen with Fe-Sn-O mixed oxides as catalysts
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Fe-Sn-O mixed oxides were synthesized and used as catalysts for Baeyer-Villiger oxidation of cyclohexanone, which showed both high catalytic activity and selectivity. X-ray powder diffraction and scanning electron microscopy suggested that the Fe-Sn-O catalysts had a tetragonal structure with a grain size of 29.3 nm. An ε-caprolactone yield as high as 98.8% was obtained in a small-scale experiment (5 mmol of cyclohexanone). In a scale-up test (20 mmol of cyclohexanone), the cyclohexanone conversion and ε-caprolactone yield were 96.7 and 96.5%, respectively. In addition, the catalysts can be reused five times without any major decline in catalytic activity.
- Ma, Yongli,Liang, Zhengyong,Feng, Shuxiao,Zhang, Yadong
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p. 450 - 455
(2015/06/30)
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- An improved solvent-free system for the microwave-assisted decarboxylation of malonate derivatives based on the use of imidazole
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A comparative study of the thermal and microwave-assisted decarboxylation of a series of mono- and disubstituted monohydrolyzed malonate derivatives has been carried out. It has been found out that in both circumstances the use of imidazole has a profound effect on the success of the reaction. In general terms the assistance of microwave irradiation accelerates the decarboxylation process significantly and, at the same time, permits the use of minored temperatures with respect to the thermal via. It has been also found that both the thermal and the microwave-assisted transformation can be developed under solvent-free conditions.
- Tellitu, Imanol,Beitia, Itziar,Díaz, Marta,Alonso, Argi?e,Moreno, Isabel,Domínguez, Esther
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p. 8251 - 8255
(2015/10/05)
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- Synthesis of 3-hydroxyindanones via potassium salt of amino acid catalyzed regioselective intramolecular aldolization of ortho-diacylbenzenes
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First organocatalytic intramolecular aldolization of ortho-diacylbenzenes to construct highly functionalized 3-hydroxyindanones is described. In this transformation a high trans-selectivity is achieved by the use of metal salt of amino acid. This method allows an easy access to the strained spirocyclic 3-hydroxyindanones related to a number of natural product frameworks. Synthesis of a new class of indole skeleton substituted by 3-hydroxyindanones added an extra essence to this new protocol.
- Chanda, Tanmoy,Chowdhury, Sushobhan,Anand, Namrata,Koley, Suvajit,Gupta, Ashutosh,Singh, Maya Shankar
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supporting information
p. 981 - 985
(2015/03/04)
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- Why are organotin hydride reductions of organic halides so frequently retarded? kinetic studies, analyses, and a few remedies
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Kinetic data for reduction of organic halides (RX) by tri-n-butylstannane (SnH) reveal a serious flaw in the current view of the kinetic radical chain: the tacit but unproven assumption that the speed of reaction is determined by the slowest propagation step. Our results show this is rarely true for reductive chains and that the observed rate is in fact controlled by unseen side-reactions of propagating R? and Sn? radicals with the solvent (notably, benzene!) or solvent impurities (e.g., trace benzophenone dryness indicator in THF) or, crucially, with allylic-CH and conjugated unsaturated groups in substrates and products. Most R? and/or Sn? radicals are therefore converted into relatively inert delocalized species A? and/or B? that inhibit the chain. Retardation in the degraded chain is given by a simple sum of terms, each being the ratio of the chain-transfer rate divided by the rate of chain-return. The model kinetic equation is linear and easy to ratify, interpret, and apply: to calculate retarding rate constants, optimize reaction conditions, and identify additives or "remedies" that repair the chain and accelerate reaction. The present work is thus expected to have a helpful impact on the practice and design of SnH radical chain based (and related) syntheses.
- Ingold,Bowry, Vincent W.
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p. 1321 - 1331
(2015/02/19)
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- Complete Switch of Selectivity in the C-H Alkenylation and Hydroarylation Catalyzed by Iridium: The Role of Directing Groups
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A complete switch in the CpIr(III)-catalyzed paths between C-H olefination and hydroarylation was found to be crucially dependent on the type of directing groups. This dichotomy in product distribution was correlated to the efficiency in attaining syn-coplanarity of olefin-inserted 7-membered iridacycles. Theoretical studies support our hypothesis that the degree of flexibility of this key intermediate modulates the β-H elimination, which ultimately affords the observed chemoselectivity.
- Kim, Jiyu,Park, Sung-Woo,Baik, Mu-Hyun,Chang, Sukbok
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supporting information
p. 13448 - 13451
(2015/11/09)
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- Study on the one-pot oxidative esterification of glycerol with MOF supported polyoxometalates as catalyst
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In this work, glycerol was treated under green and mild conditions (water solvent, H2O2 oxidant, 40°C) in an attempt to utilise its additional value. With a metal organic framework (MOF) supported polyoxometallate (POM) as a catalyst, esters were generated as one of the major products which could be useful for various industrial applications. The selectivity of esters formation reached 34.5% in this one-pot oxidative esterification process. Benefiting from the pore limitation effect of the MOF, diffusion was restricted and the original products could be further transformed into esters with the existence of the POM. No other reagents were needed during this process, and all of the intermediates were produced from glycerol itself. The oxidative esterification reaction was studied in detail including the role of the MOF, the influence of pH and the POM type, the mechanism and so on. It was concluded that the POM served as the active site for this oxidative esterification process and H2O2 provided weak acidity in addition to the source of oxygen. Too stronger acidity and oxidizability were unfavourable to the generation of esters. Also, the catalysts could be recovered after reaction, exhibiting good stability and reusability.
- Zhu, Jie,Wang, Peng-Cheng,Lu, Ming
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p. 3383 - 3393
(2015/06/08)
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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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- Rhodium(iii)-catalyzed C-H allylation of electron-deficient alkenes with allyl acetates
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Rhodium-catalyzed C-H allylation of acrylamides with allyl acetates is reported. The use of weakly coordinating directing group resulted in high reaction efficiency, broad functionality tolerance and excellent γ-selectivity, which opens a new synthetic pathway for the access of 1,4-diene skeletons.
- Feng, Chao,Feng, Daming,Loh, Teck-Peng
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supporting information
p. 342 - 345
(2015/01/09)
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- MONOMER, POLYMER, RESIST COMPOSITION, AND PATTERNING PROCESS
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A polymer comprising recurring units derived from a (meth)acrylate monomer of tertiary ester type having branched alkyl on alicycle is used to form a resist composition. When subjected to exposure, PEB and organic solvent development, the resist composition is improved in dissolution contrast.
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- B12-TiO2 Hybrid Catalyst for Light-Driven Hydrogen Production and Hydrogenation of C-C Multiple Bonds
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The B12-TiO2 hybrid catalyst mediates H2O reduction to form hydrogen under UV irradiation (turnover number of one per hour). The catalyst also mediates reductions of alkenes such as styrene derivatives and alkylacrylates (maximum turnover number of 100 per hour) under mild conditions of room temperature, ordinary pressure, and water or alcohol as solvent.
- Shimakoshi, Hisashi,Hisaeda, Yoshio
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p. 1250 - 1253
(2016/02/18)
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- Immobilization of palladium catalyst on magnetically separable polyurea nanosupport
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This work describes a method for preparing magnetic polyurea nanoparticles (PU NPs) and their utilization as a catalyst support. The method is based on entrapment of hydrophilic magnetic nanoparticles within the polyurea matrix. The synthetic process of these magnetic polyurea nanoparticles is based on oil-in-oil nanoemulsification of an organic polar phase comprised of N,N-dimethylacetamide (DMAc), 2,6-diaminopyridine and ionic liquid modified magnetite nanoparticles (MNPs-IL), in heptane containing a suitable surfactant. This was followed by interfacial polycondensation reaction between an isocyanate monomer, polymethylenepolyphenyl isocyanate (PAPI 27), and the amine monomer producing magnetically separable polyurea nanoparticles. Subsequently, these particles were employed as a catalyst nanosupport. Two catalytic systems based on the encapsulation of Pd(OAc)2 within magnetic PU NPs or their adsorption on the surface of these particles were produced and subjected to hydrogenation reactions and selective hydrogenations of α,β-unsaturated compounds. Pd(OAc)2 adsorbed on the surface of the magnetic PU NPs demonstrated high catalytic activity and selectivity, which was superior to the conventional catalyst Pd/C or palladium nanoparticles supported directly on the surface of magnetite nanoparticles. The catalyst was easily recovered from the reaction mixture by applying an external magnetic field and recycled over five times without observing any significant loss in its catalytic efficiency. This journal is
- Natour, Suzana,Abu-Reziq, Raed
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p. 48299 - 48309
(2014/12/10)
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- Polymer-supported sulfonated magnetic resin: An efficient reagent for esterification of O-alkyl alkylphosphonic-and carboxylic-acids
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A mild and efficient synthetic method has been developed for the esterification of O-alkyl alkylphosphonic-and carboxylic-acids using polymer-supported sulfonated magnetic resins. Polymer-supported resins are recovered using an external magnet and reused several times.
- Purohit, Ajay Kumar,Kumar, Ajeet,Singh, Varoon,Goud D, Raghavender,Jain, Rajiv,Dubey
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supporting information
p. 6844 - 6846
(2015/01/09)
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