- Kinetics and Mechanistic Study of the Methanol Homologation with Cobalt-Ruthenium mixed Catalyst
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The role of each catalyst was examined in detail in the methanol homologation with cobalt-ruthenium miwed catalyst.Cobalt catalyst showed much higher activity for the hydrocarbonylation of methanol than ruthenium.On the other hand, the hydrogenation of acetaldehyde proceeded much more rapidly by ruthenium catalyst.The rate of methanol homologation in 1,4-dioxane with cobalt-ruthenium mixed catalyst system was found to be of the first order with respect to the partial pressure of CO.The in situ IR spectra indicated that (1-) was an active species for the hydrocarbonylation of methanol and that existed under the reaction conditions.On the basis of both the kinetic studies and in situ IR spectral observations, the reaction mechanism of methanol homologation was fully discussed.
- Watanabe, Kazuhiro,Kudo, Kiyoshi,Sugita, Nobuyuki
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- High activity cobalt based catalysts for the carbonylation of methanol
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[Cp(*)Co(CO)2] in the presence of PEt3 and Mel catalyses the carbonylation of methanol with initial rates up to 44 mol dm-3 h-1 before decaying to a second catalytic phase with rates of 3 mol dm-3 h-1; [CoI(CO)2(PEt3)2], which is trigonal bipyramidal with axial PEt3 ligands, has been isolated from the final reaction solution.
- Marr, Andrew C.,Ditzel, Evert J.,Benyei, Attila C.,Lightfoot,Cole-Hamilton, David J.
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- FLASH VACUUM THERMOLYSIS OF 2-BROMOETHANOL. FORMATION OF &α-BROMOETHYLETHERS VIA 1-BROMOETHANOL.
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Flash Vacuum Thermolysis of 2-bromoethanol (2) leads to the quantitative formation of 1-bromo-1-(1-bromoethoxy)ethane (5, di-α-bromoethylether).Low temperature IR spectroscopy shows that 5 arises from the dimerization of 1-bromoethanol (3), which is observed below -100 deg C as the primary product.
- Jenneskens, Leonardus W.,Wiersum, Ulfert E.,Ripoll, Jean-Louis
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- Gas-Phase NMR Studies of Chemical Equilibria. 1. Methodology
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Methods for obtaining 1H NMR spectra of gases are discussed.Particular attention is paid to the nature of the tube and to the use of 'second sample' field/frequency locking.The question of the chemical shift reference is examined, and some results for tetramethylsilane gas are presented.Representative spectra are shown for three types of organic equilibria in the gas phase: keto-enol tautomerism, addition of methanol to acetaldehyde and Z-E isomerism of acetaldoxime.
- Harris, Robin K.,Rao, Renee C.
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- Functional methacryloyoxy acetals: II. Electophilic addition of alcohols to vinyloxyalkyl methacrylates
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Alcohols of various structures, in particular, ethylene, acetylene, fluorocontaining alcohols, add regio-and chemoselectively to the vinyloxy group of vinyloxyalkyl methacrylates at 20-40°C in the presence of catalytic quantities of trifluoroacetic acid a
- Gorelova,Oparina,Parshina,Gusarova,Trofimov
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- Catalytic Hydromethoxylation of Acetylene over Pre-Activated K2PdCl4
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Abstract: The catalytic addition of methanol to the triple bond of acetylene occurred on the surface of mechanically pre-activated K2PdCl4 and formed dimethylacetal and the vinyl chloride by-product. The addition of alcohol occurs regioselectively in accordance with the Markovnikov rule. The stereoselectivity of acetylene hydrochlorination corresponds to the trans-addition of H and Cl to the C≡C triple bond of acetylene. The effective activation energies of reaction routes were determined. A possible mechanism of formation of H3C–CH(OCH3)2 and H2C=CHCl was proposed.
- Khazipov, O. V.,Krasnyakova, T. V.,Mitchenko, S. A.,Nikitenko, D. V.
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p. 879 - 885
(2020/12/30)
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- Tetrachloromethane Hydrodechlorination over Palladium-Containing Nanodiamonds
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Abstract: Using nanodiamonds of the UDD-STP brand 1 wt % palladium-containing nanodiamonds are obtained and tested as catalysts of tetrachloromethane hydrodechlorination under mild conditions (solvents, ethanol and methanol; Т = 298–318 K; PH2 = 0.1 MPa). The catalytic properties of the obtained material and a palladium-containing analog based on activated carbon are compared. It is shown that the hydrodechlorination reaction occurs in a stepwise manner via two pathways: to form products with a smaller content of chlorine, for example, chloroform, and to yield oxygen-containing products, for example, diethyl carbonate. The qualitative and quantitative compositions of reaction products are determined by gas chromatography/mass spectrometry.
- Belkina, E. G.,Gruzdev, M. S.,Kalmykov, P. A.,Klyuev, M. V.,Lysenok, A. A.,Magdalinova, N. A.
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p. 1148 - 1153
(2020/10/14)
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- Photocatalytic decarboxylation of lactic acid by Pt/TiO2
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A photocatalytic route for the conversion of lactic acid to acetaldehyde in water is demonstrated. Direct UV photolysis of lactic acid yields CO2 and ethanol via a radical mechanism. Pt/TiO2 considerably increases the rate of lactic acid decarboxylation with acetaldehyde, H2 and CO2 as the main products. A concerted photodecarboxylation/dehydrogenation mechanism is proposed.
- Liu, Kaituo,Litke, Anton,Su, Yaqiong,Van Campenhout, Bart G.,Pidko, Evgeny A.,Hensen, Emiel J. M.
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p. 11634 - 11637
(2016/10/04)
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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 0017
(2016/10/10)
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- Conversion of alcohols to longer chain aldehydes or alcohols
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Processes are provided for contacting at least one Cn alcohol equivalent having n carbon atoms and at least one Cn+1 alcohol equivalent having (n+1) carbon atoms with a Guerbet catalyst to form a product composition comprising a product compound having the structure: wherein: C is a carbon atom; H is a hydrogen atom; Q is an alcohol or aldehyde group having one carbon; R is a linear alkyl group having n carbon atoms; and T is an alkyl group having (n?1) carbon atoms, except that when n=1, T is methyl.
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Page/Page column 34-36
(2016/04/20)
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- A highly reducing metal-free photoredox catalyst: Design and application in radical dehalogenations
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Here we report the use of 10-phenylphenothiazine (PTH) as an inexpensive, highly reducing metal-free photocatalyst for the reduction of carbon-halogen bonds via the trapping of carbon-centered radical intermediates with a mild hydrogen atom donor. Dehalogenations were carried out on various substrates with excellent yields at room temperature in the presence of air.
- Discekici, Emre H.,Treat, Nicolas J.,Poelma, Saemi O.,Mattson, Kaila M.,Hudson, Zachary M.,Luo, Yingdong,Hawker, Craig J.,De Alaniz, Javier Read
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supporting information
p. 11705 - 11708
(2015/07/15)
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- Efficient synthesis of 1,1-diethoxyethane via sequential ethanol reactions on silica-supported copper and H-Y zeolite catalysts
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1,1-Diethoxyethane (DEE) is an important chemical with versatile applications. Here, we report the efficient synthesis of DEE via two-sequential reactions of ethanol including the selective dehydrogenation of ethanol to acetaldehyde and the subsequent acetalization of acetaldehyde with ethanol to DEE. The ethanol dehydrogenation was examined on Cu catalysts supported on SiO2, Al2O3, ZrO2 and TiO 2 supports with similar Cu dispersions, and Cu/SiO2 was more selective to acetaldehyde with 99.0% selectivity at 493 K, due to the inert surface of SiO2, compared to the other three oxide supports with stronger acidity and basicity facilitating the side reactions of acetaldehyde. For the equilibrium-limited acetalization reaction, comparison of representative solid acids (e.g. SO42-/ZrO2, Amberlyst 15, H-Y zeolite and AlCl3/SiO2) showed that while they offered nearly 100% DEE selectivities, the Br?nsted acid sites were more active than the Lewis acid sites. This was confirmed by the higher activities (normalized per acid site) for the H-Y zeolites with higher factions of the Br?nsted acid sites obtained by calcination at lower temperatures in the range 773-1073 K. Combination of the ethanol dehydrogenation on Cu/SiO 2 at 493 K and the acetalization reaction on H-Y (calcined at 773 K) at 293 K in the two-sequential flow microreactors led to the steady conversion of ethanol to DEE in a yield of as high as 35.0%. This yield could be further improved, for example, to 70.5%, the highest yield from ethanol reported to date, after removal of water in the acetalization reactor by 3A zeolite. Such two-sequential reactor configuration also applied to the efficient synthesis of other important acetals, and as an example, dimethoxymethane was synthesized directly from methanol in a yield of 84.1% on iron molybdate and H-ZSM-5 catalysts.
- He, Xiaohui,Liu, Haichao
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p. 133 - 139
(2014/07/07)
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- METHANOL HOMOLOGATION
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Embodiments include homologation of methanol in the presence of a rhodium catalyst. The rhodium catalyst can include rhodium diphosphene di-iodide.
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Paragraph 37-38
(2013/07/05)
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- Chemo-and regioselective reaction of vinyl furfuryl ethers with alcohols
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Furfuryl and tetrahydrofurfuryl vinyl ethers reacted with various alcohols under mild conditions (20-25°C, 1-3 h, 1 wt % of CF3COOH) with high chemo- and regioselectivity to give the corresponding Markovnikov adducts at the vinyl group in up to 93% yield.
- Oparina,Vysotskaya,Stepanov,Gusarova,Trofimov
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p. 1162 - 1167
(2013/01/15)
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- Promoters for Pd-catalyzed methoxycarbonylation of vinyl acetate
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A study on the influence of acidic and non-acidic promoters for Pd(PPh 3)-catalyzed methoxycarbonylation of vinyl acetate was conducted in order to find an efficient protocol for the synthesis of methyl O-acetyl lactate. Besides known promoters also some new catalytic systems were tested. Aluminium triflate is the most active additive. ARKAT-USA, Inc.
- Shuklov, Ivan A.,Dubrovina, Natalia V.,Schulze, Joachim,Tietz, Wolfgang,Kuehlein, Klaus,Boerner, Armin
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experimental part
p. 66 - 75
(2012/03/11)
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- METHOD FOR PRODUCING POLYOXYMETHYLENE DIMETHYL ETHERS
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The invention relates to a method for producing a polyoxymethylene dimethyl ether of formula H3CO(CH2O)nCH3, in which n = 2 - 10. According to said method, methylal and trioxane are fed to a reactor and are reac
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(2008/06/13)
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- TRIOXANE PRODUCTION METHOD WHEREIN A SIDE AQUEOUS FLOW IS DEDUCTED AT A FIRST DISTILLATION STAGE
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The invention relates to a trioxane production method comprising the following stages: catalysed reaction in an acid medium of an aqueous highly concentrated formaldehyde solution (1) in a reactor (R) for obtaining a trioxane/formaldehyde/water mixture (2) (stage I); distillation of said trioxane/formaldehyde/water mixture (2) of the stage I for obtaining a raw trioxane as a head flow (3) (stage II), distillation treatment of the raw dioxane of the stage II in one or several stages for obtaining a pure dioxane (8), wherein a side aqueous flow (4) is deducted during the stage II.
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Page/Page column 4-7
(2008/06/13)
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- Microwave-assisted preparation of 1-butyl-3-methylimidazolium tetrachlorogallate and its catalytic use in acetal formation under mild conditions
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1-Butyl-3-methylimidazolium tetrachlorogallate, [bmim][GaCl4], prepared via microwave-assisted protocol, is found to be an active catalyst for the efficient acetalization of aldehydes under mild conditions.
- Yong, Jin Kim,Varma, Rajender S.
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p. 7447 - 7449
(2007/10/03)
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- Alkylation and acetal formation using supercritical alcohol without catalyst
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The aromatic ring alkylation of phenols, N-alkylation of aniline, O-alkylation of phenols and acetal formation from acetaldehyde or acetone were examined using supercritical (SC) alcohol without any catalyst. Highly selective syntheses of monoalkylated compounds were achieved for the aromatic ring alkylation and N-alkylation. The O-alkylation proceeded more preferentially than the aromatic ring alkylation for phenols which have a deactivating group. The acetal formation went on in more than 96% selectivity.
- Horikawa, Yoshiteru,Uchino, Yuki,Sako, Takeshi
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p. 232 - 233
(2007/10/03)
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- Process for preparing 1,3-alkanediol from epoxide derivative
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A process for preparing an 1,3-alkanediol through carbonylation of an epoxide derivative includes the steps of (a) reacting an epoxide derivative with alcohol and carbon monoxide in a solvent at a temperature from about 30 to about 150° C. and at a pressure from about 50 to about 3000 psig in the presence of a catalyst system including an effective amount of a cobalt catalyst and an effective amount of a promoter to afford a reaction mixture including a 3-hydroxyester or derivative thereof in an amount of from 2 to about 95% by weight, (b) separating the reaction product and solvent from the catalyst and promoter, (c) reacting said reaction product and solvent with hydrogen at a temperature from about 30 to about 350° C. and at a pressure from about 50 to about 5000 psig in the presence of a catalyst system for hydrogenation to prepare a hydrogenation product mixture including a 1,3-alkanediol, and (d) recovering the 1,3-alkanediol from the hydrogenation product mixture. Catalyst systems for carrying out the inventive processes are also provided.
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(2008/06/13)
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- Method for producing enol ethers
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Enol ethers of the formula I where R1is an aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic radical which may carry further substituents which do not react with acetylenes or allenes, and the radicals R, independently of one another, are hydrogen or aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic radicals, which may be bonded to one another to form a ring, and m is 0 or 1, are prepared by reacting an acetal or ketal of the formula II with an acetylene or allene of the formula III or IV where R and R1have the abovementioned meanings, in the gas phase at elevated temperatures in the presence of a zinc- or cadmium- and silicon- and oxygen-containing heterogeneous catalyst.
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- Palladium-catalysed mild transformation of non-activated terminal alkynes into acetals 1
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Pd(pp2) (O3SCF3)2 (pp2 = bis(2-diphenylphosphinoethyl)phenylphosphine) catalyses the transformation of non-activated terminal alkynes into acetals. The reaction proceeds fast, without the addition of heat and in quantitative yield. σ-Alkynyl-palladium complexes have been identified as intermediates.
- Scheffknecht, Christoph,Peringer, Paul
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- Prins Reaction of 2-Oxabicyclooct-6-en-3-one and Related Derivatives
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Reaction of formaldehyde with the title olefinic lactone in acetic acid affords diacetate of 1,3-diol (2a) as the main product in 50-60percent yield via regioselective trans-addition.Less favourable results were obtained with related bicyclic derivatives.
- Toemoeskoezi, Istvan,Gruber, Lajos,Baitz-Gacs, Eszter
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p. 10345 - 10352
(2007/10/02)
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- Kinetische Untersuchungen zur Methanolyse von Acetalen
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It has been shown that the acid-catalyzed methanolysis of the diethylacetales RCH(OEt)2 of acetaldehyde (R=CH3), propionaldehyde (R = C2H5), butyraldehyde (R = C3H7) and caprylaldehyde (R = C7H15) at temperatures between 283 and 318 K proceeds as a consecutive reaction involving a reversible second step.The pseudo first order rate constants of the three reaction steps, their activation parameters and equilibrium constants were estimated by measuring the concentration-time-curves of starting product, intermediate and final product and using a large excess of methanol.There is a linear dependence be tween rate constants of methanolysis and concentration of the catalyst.
- Claus, P.,Berndt, T.,Scherzer, K.
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p. 1205 - 1216
(2007/10/02)
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- Photosensitized (electron transfer) carbon-carbon bond cleavage of radical cations: the 2-phenylethyl ether and acetal systems
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The scope of the photosensitized (electron transfer) carbon-carbon bond cleavage involving radical cations has been defined for 2-phenylethyl ethers and acetals.The thresholds for reactivity of the monophenylethyl and gem-diphenylethyl derivatives are compared.While the radical cation of methyl 2,2-diphenylethyl ether (7) cleaves to give ultimately diphenylmethane (2) and dimethoxymethane (8), the radical cation of methyl 2-phenylethyl ether (9) was stable under these conditions.In contrast to the lack of reactivity of the radical cation of 9, the radical cations of methyl 2-phenyl-2-propyl ether (11), methyl 2-phenylcyclopentyl ether (13), and 2-phenylmethyl-1,3-dioxolane (16) cleave.Cleavage in the monophenylethyl series is limited to formation of a carbocation at least as stable as the secondary α-oxyalkyl or di-α-oxyalkyl.The basis for predicting this type of reactivity of radical cations is defined.The rate of carbon-carbon bond cleavage is increased the oxidation potential of the molecule, by decreasing the carbon-carbon bond strength, and (or) by decreasing the oxidation potential of that fragment that will become the carbocation.The results obtained from the reactions of 2-diphenylmethyl-1,3-dioxolane (14) and 2-phenylmethyl-1,3-dioxolane (16) cast doubt on the published oxidation potential for the 1,3-dioxolan-2-yl radical.Key words: photochemistry, radical cation, electron transfer, bond cleavage, radical.
- Arnold, Donald R.,Lamont, Laurie J.
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p. 2119 - 2127
(2007/10/02)
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- Neuartige basische Liganden fur die homogenkatalytische Methanolcarbonylierung XVII. Dioxanylmethyldiorganylphosphane als Steuerliganden bei der Methanol(hydro)carbonylierung zu Acetaldehyd und Essigsaure
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The (ether-phosphane) ligands R2PCH2(1,4-diox) (1a-c) (R=Ph (a), Mess (b), Cy (c); diox=dioxane residue) and Ph2PCH2(1,3-diox) (2a) are obtained from the corresponding phosphides LiPR2 and 2-chloromethyl-1,4-dioxane and -1,3-dioxane, respectively, at -40 oC in ether.High pressure experiments can provide useful information on conversion and selectivity in the (hydro)carbonylation of methanol, if parameters like educt/catalyst ratio, effect of substituents of the ligands 1a-c, 2a, directed application of cobalt complexes, and composition of catalyst and synthesis gas are varied.The possibility that there is a cobalt-catalyzed (hydro)carbonylation of methanol to acetaldehyde and acetic acid cycle is explored.
- Lindner, Ekkehard,Sickinger, Anselm,Wegner, Peter
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- Novel Basic Ligands for the Homogeneous Catalytic Methanol Carbonylation, XI. Ether Phosphane Cobalt Complexes in the Catalytic Hydrocarbonylation of Methanol to Acetaldehyde
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PhP(CH2C4H7O2)2 (1) and D>2 (3a-c) are obtained by reaction of Li2PPh and Na(Ph)PD with ClCH2C4H7O2 and ClCH2CH2Cl, respectively. 1 and 3a, b give rise to high selectivities and conversions in the cobalt catalyzed hydrocarbonylation of methanol to acetaldehyde.Model complexes of cobalt which are of importance in the catalytic cycle are synthesized.Complexes of the type X2Co(Ph2PD)2 (6az, 6bx-bz, 6cx-cz), especially those with X = I, obtained from CoX2 and the ether phosphan es Ph2PD (5a-c), are regarded as precursors of the catalytically active species.With K they are reduced to the cobalt(I) complexes XCo(Ph2PD)(Ph2PD) (7az, 7bx-bz, 7cx-cz).Trapping reactions with CO, PPh3 or 5b, c lead to the compounds XCo(CO)2(Ph2PD)2 (8az, 8bx-bz, 8cx-cz), XCoPPh3(Ph2PD)2 (9bx-bz), and XCo(Ph2PD)3 (10bz, cz), respectively, with cleavage of a Co-O bond.The reduction of X2Co(PPh3)2 (11x, z) with K represents a simple method for the preparation of the complexes XCo(CO)2(PPh3)2 (13x, z) which are formed from the intermediates XCo(PPh3)2*THF (12x, z) in the presence of CO. - Keywords: Ether Phosphane Ligands, Methanol Hydrocarbonylation, Acetaldehyde, Cobalt Complexes
- Lindner, Ekkehard,Schober, Uwe,Glaser, Erhard,Norz, Hubert,Wegner, Peter
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p. 1527 - 1536
(2007/10/02)
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- Method for preparation of acetals
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A method of preparation for acetals utilizing saturated or unsaturated aldehydes, in particular, the preparation of dimethylacetals of acetaldehyde, acrolein and methacrolein. The production of the acetal takes place in a liquid phase in the presence of a solid acid catalyst, such as a strongly acidic ion exchange resin or zeolite. The conversion mixture is extracted by means of water and by means of water insoluble organic solvents. There is obtained not only the desired acetals, but in addition also the unconverted initial quantities of the starting materials by a simple method and with very good yields.
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- Process for homologating alcohols through the intermediate production of ketals with cobalt carbonyl complexes as catalysts
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Process for the homologation of an alcohol wherein a ketal of the alcohol is reacted with hydrogen and carbon monoxide in the presence of a cobalt carbonyl complex and the resultant product is hydrolyzed to yield the aldehyde with one more carbon atom.
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- Process for producing an acetal
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An acetal is produced at a high yield and a high selectivity by contacting an olefin and an alcohol with each other in the presence of (a) a nitrite, (b) a platinum group metal or the salts thereof and (c) a halide at a high reaction rate without requirement of any troublesome operations for the separation, recovery and regeneration of the catalyst.
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- Kinetik der homogenen, katalytischen Hydrierung von Acetaldehyd mit Ru-Komplexen und Synthesegas
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The homogeneous hydrogenation of acetaldehyde with synthesis-gas CO/H2 = 1/3 and catalyst RuCl2(CO)2(P(C6H5)3)2, dissolved in methanol can be described by the kinetic equation:
- Strohmeier, W.,Hoecker, H.
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p. 924 - 926
(2007/10/02)
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- Etude de la composition de solutions aqueuses d'acide glyoxylique en RMN de 13C
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In order to determine the composition of aqueous solutions of glyoxylic acid, we studied the 13C nmr spectra of variously concentrated solutions (20 to 60 percent).The two well-separated regions (acids and esters on one side, acetals, hemiacetals and hydrates on the other) display not directly related intensities owing to the relaxation times of carbonyl carbons.Nevertheless, by plotting the relative intensity of each line in its own region, we were able to associate signals coming from the same species.Aside from the two prominent lines of monomeric hydrate, we identified two other pairs with intensity increasing with total concentration.Apart from a small line due to glyoxal and some other very small lines, we observed four lines of equal and slightly increasing intensity, three of acetal type and one of acid or ester type.In order to establish the structures of the species present, we determined the chemical shifts of a series of related molecules to be used as models (reported on table 2): first esters, acids, acetals, hemiacetals and hydrates of monomeric strukture, then dimers and trimers of acetaldehyde, ethyl glyoxylate and glyoxal.We were thus able to establish increments and correlations which allowed us to estimate the values of chemical shifts for possible dimers and trimers of glyoxylic acid: it was easy to see that two of the entities present in the solution are dimeric hemiacetals-acids, the erythro and threo isomers (figure 3).The fourth species is necessarily a combination of acid with glyoxal and the inspection of models led us to identify it as dihydroxy-4,5 dioxolan-1,3 carboxylic acid (figure 4).Its concentration was shown to increase with that of glyoxal in glyoxylic acid, and furthermore, some of its derivatives could be isolated.The acetalization and esterification of glyoxylic acid by ethanol in acidic medium, effected with remowal of water, provided a mixture of esters-acetals which was analysed by coupled VPC-mass spectrometry and VPC-chemical ionization (with ammonia).The analysis confirmed the existence of the above monomer and dimers in proportions related to the composition of the aqueous solution; moreover a small amount of a cyclic dimer is observed.No more than 5 percent of higher oligomers was evidenced.As for the combinations between glyoxal and glyoxylic acid, the principal one can be accompanied by many others, of various stoechiometries, when more glyoxal is initially present in the glyoxylic acid solution.Thus it is shown that glyoxylic acid in aqueous solution is mostly in the form of monomeric hydrate (69 to 88 percent)) and dimeric hemiacetals-acids (2,5 to 12 percent).Higher oligomers never exceed 5 percent in concentrated solutions, but glyoxal, if present, easily combines with glyoxylic acid, to form various compounds, the major one accounting for up to 12 percent of the material in some concentrated mixture of glyoxal and glyoxylic acid.
- Chastrette, Francine,Bracoud, Corinne,Chastrette, Maurice,Mattioda, Georges,Christidis, Yani
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- REACTIONS CO/H2 EN PHASE LIQUIDE. SYNTHESE DE PRECURSEURS DE L'ETHANOL PAR HOMOLOGATION DU METHANOL. I. INFLUENCES DE LA TEMPERATURE ET DE LA PRESSION
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The CO/H2 homologation of methanol to acetaldehyde and subsequently to its dimethyl acetal in the presence of cobalt acetate promoted by iodine was examined under various conditions.Temperature and pressure were found as critical parameters.High pressures (140 MPa) and low temperatures (160-170 deg C) give optimal yields and selectivity to acetaldehyde.According to pressure, temperature, contact time, gas ratio and ligand/catalyst ratio, the reaction is oriented towards acetaldehyde, its dimethyl acetal or methyl acetate.
- Andrianary, Philippe,Jenner, Gerard,Kiennemann, Alain
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p. 209 - 220
(2007/10/02)
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- Solvent Effects on Equilibria of Addition of Nucleophiles to Acetaldehyde and the Hydrophilic Character of Diols
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Equilibria of addition of water, methanol, methanethiol, ammonia, methylamine, nitromethane, and ethylene glycol to acetaldehyde have been compared in water and in chloroform, and the partition coefficients of reactants and products between the two solvents have been estimated by direct and indirect methods.Single additions of oxygen nucleophiles were found to proceed equally favorably in either solvent, whereas single additions of sulfur, nitrogen, and carbon nucleophiles proceeded much further toward completion in water than in chloroform.Equilibria of acetal formation, involving methanol or ethylene glycol, were somewhat more favorable in chloroform than in water.Reexamination of the vapor pressures of ethylene glycol and related compounds over water indicated that their hydrophilic character was greater than had been supposed.
- Bone, Roger,Cullis, Paul,Wolfenden, Richard
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p. 1339 - 1343
(2007/10/02)
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- Process for the production of acetaldehyde dimethyl acetal
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Improved process for the production of acetaldehyde dimethyl acetal by reacting methanol with carbon monoxide and hydrogen in the presence of a cobalt-containing catalyst, halogen or a halide as promoter and a 3-valent phosphorus compound as ligand using a nickel compound as a co-catalyst.
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- PROMOTION BY PHOSPHORUS COMPOUNDS OF RUTHENIUM-CATALYZED METHYL FORMATE HOMOLOGATION
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Trivalent phosphorus compounds are promoters for methyl formate homologation to ethanol and ethyl formate catalyzed by ruthenium compounds in the presence of iodide at 220 deg C and 27 MPa of synthesis gas.Under these conditions the phosphines are quaternized, but decomposition of phosphonium salts occurs during the reaction.Promotion is also observed for methyltriphenylphosphonium bromide and triphenylphosphine sulfide, but benzyltrimethylammonium bromide, triphenylarsine, and triphenylantimony are not effective.The major ruthenium species present is Ru(CO)3I3 but with triphenylantimony a trimethylantimony complex, Ru(CO)2(Sb(CH3)3)2I2, can be isolated in high yield.
- Keister, Jerome B.,Gentile, Robert
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p. 143 - 154
(2007/10/02)
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- SYNTHESIS OF UNSYMMETRICAL 1,1-DIALKOXYALKANES AND THEIR SULFUR-CONTAINING ANALOGS
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Acyclic acetals and 1,1-di(alkylthio)alkanes enter into exchange reactions in the presence of aprotic acids and of the KU-2 cation-exchange resin with the formation of the unsymmetric acetals and 1-alkoxy-1-alkylthioalkanes.In reaction with ethylal di(ethylthio)methane forms 3,5,7-trioxanonane in addition to ethylthioethoxymethane. 2-Methyl-4-thia-2-hexene was found in the products from the reaction of 1,1-di(ethylthio)-2-methylpropane with methylal.
- Gazizova, L. B.,Imashev, U. B.,Musavirov, R. S.,Kantor, E. A.,Zlotskii, S. S.,et al.
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p. 226 - 231
(2007/10/02)
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- HOMOLOGATION OF METHANOL CATALYZED BY MIXED TRANSITION METAL CLUSTERS CONTAINING COBALT
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Syntheses of mixed transition metal clusters containing cobalt and their catalytic activities for homologation of methanol were investigated.The reaction of RuCl3 with Na gave a reddish brown complex Na.The cluster easily underwent a cation exchange to give the Cs+ and + salts.These clusters showed a remarkable catalytic activity for homologation of methanol.The selectivity of ethanol was increased up to 51 percent in ca. 40 percent conversion in case of + salt.Catalytic activities of some other mixed metal clusters were also examined.
- Hidai, Masanobu,Orisaku, Masami,Ue, Makoto,Uchida, Yasuzo,Yasufuku, Katsutoshi,Yamazaki, Hiroshi
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p. 143 - 146
(2007/10/02)
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- THE HOMOLOGATION OF METHANOL. THE MODIFICATION OF COBALT CATALYST BY DIPHOSPHINES
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Cobalt iodide modified by α,ω-bis(diphenylphosphino)alkane (PCnP; n=1-6) efficiently catalyzes the homologation of methanol to ethanol.The ethanol selectivity as high as 89percent was achieved by using PC6P as the ligand.
- Sugi, Yoshihiro,Bando, Ken-ichiro,Takami, Yasuo
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- Preparation of ascorbic acid intermediates
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A synthetic route to ascorbic acid is provided in which a 3,5:4,6-protected derivative of gulonic acid is prepared from gulono-1,4-lactone. Oxidation of the derivative and hydrolysis of the resulting product affords 2-ketogulonic acid or ester thereof which can be readily converted to ascorbic acid by known methods.
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- FRAGMENTATION OF LINEAR ACETALS IN HOMOLYTIC LIQUID-PHASE TRANSFORMATIONS
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The kinetics of the accumulation of the products formed by fragmentation of linear acetals in free-radical liquid-phase reactions initiated by thermal decomposition of tert-butyl peroxide were investigated.The products from the transformation of 1,1-dimethoxyethane are methyl acetate and methane, whereas ethanal, pentanal, and 1-ethoxypentane are formed in addition to amyl acetate and pentane in the case of 1,1-dipentyloxyethane, and ethanal, hexanal, and 1-ethoxyethane are formed in addition to hexyl acetate and hexane from 1,1-dihexyloxyethane.The initial formation rate of pentane and hexane was measured for the first time, and it was shown that the sum of the accumlation rate of the alkane and the initiation rate is close to the accumlation rate of the ester.A scheme which takes account of all the products is proposed for the fragmentation of linear acetals.The C1-H bond in the linear acetals is an order of magnitude more reactive than the other C-H bonds.The difference in the activation energies for the cleavage of the active C-H bonds was evaluated, and the lenght of the chains, the activation energies for decomposition of tert-butyl peroxide in the acetals, and the kinetic parameters of the homolytic liquid-phase reactions of the acetals were determined.
- Kalashnikov, S. M.,Imashev, U. B.,Zlotskii, S. S.,Rakhmankulov, D. L.
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p. 783 - 786
(2007/10/02)
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- THE SYNTHESIS OF METHYL TETROSIDES AND THEIR METHYL ESTERS
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Methyl α- and β-D-threofuranosides (I and II) and methyl α- and β-D-erythrofuranosides (VII and VIII) were prepared in modified manner.For the preparation of monomethyl ethers of compounds I and II 1,2-isopropylidene-β-D-threofuranose (IV) was prepared as the starting compound.For the synthesis of monomethyl ethers of compounds VII and VIII partial methylation of these diols was made of use.
- Jary, Jiri,Marek, Miroslav
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p. 3571 - 3582
(2007/10/02)
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