- Engineering Catalysts for Selective Ester Hydrogenation
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The development of efficient catalysts and processes for synthesizing functionalized (olefinic and/or chiral) primary alcohols and fluoral hemiacetals is currently needed. These are valuable building blocks for pharmaceuticals, agrochemicals, perfumes, and so forth. From an economic standpoint, bench-stable Takasago Int. Corp.'s Ru-PNP, more commonly known as Ru-MACHO, and Gusev's Ru-SNS complexes are arguably the most appealing molecular catalysts to access primary alcohols from esters and H2 (Waser, M. et al. Org. Proc. Res. Dev. 2018, 22, 862). This work introduces economically competitive Ru-SNP(O)z complexes (z = 0, 1), which combine key structural elements of both of these catalysts. In particular, the incorporation of SNP heteroatoms into the ligand skeleton was found to be crucial for the design of a more product-selective catalyst in the synthesis of fluoral hemiacetals under kinetically controlled conditions. Based on experimental observations and computational analysis, this paper further extends the current state-of-the-art understanding of the accelerative role of KO-t-C4H9 in ester hydrogenation. It attempts to explain why a maximum turnover is seen to occur starting at 25 mol % base, in contrast to only 10 mol % with ketones as substrates.
- Dub, Pavel A.,Batrice, Rami J.,Gordon, John C.,Scott, Brian L.,Minko, Yury,Schmidt, Jurgen G.,Williams, Robert F.
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p. 415 - 442
(2020/03/04)
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- SYNTHESIS OF FLUORO HEMIACETALS VIA TRANSITION METAL-CATALYZED FLUORO ESTER AND CARBOXAMIDE HYDROGENATION
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This application is directed to use of transition metal-ligand complexes to hydrogenate fluorinated esters and carboxamides into fluorinated hemiacetals. Methods for synthesis of certain ligands are also provided.
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Paragraph 0237-0238
(2020/11/24)
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- Ru-Catalyzed Transfer Hydrogenation of Nitriles, Aromatics, Olefins, Alkynes and Esters
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This paper reports the preparation of new ruthenium(II) complexes supported by a pyrazole-phosphine ligand and their application to transfer hydrogenation of various substrates. These Ru complexes were found to be efficient catalysts for the reduction of nitriles and olefins. Heterocyclic compounds undergo transfer hydrogenation with good to moderate yields, affording examples of unusual hydrogenation of all-carbon-rings. Internal alkynes with bulky substituents show selective reduction to olefins with the unusual E–selectivity. Esters with strong electron-withdrawing groups can be reduced to the corresponding alcohols, if ethanol is used as the solvent. Possible mechanisms of hydrogenation and olefin isomerization are suggested on the basis of kinetic studies and labelling experiments.
- Alshakova, Iryna D.,Gabidullin, Bulat,Nikonov, Georgii I.
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p. 4860 - 4869
(2018/10/02)
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- Preparation method of 2,2,3,3,3-pentafluoropropanol
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The invention discloses a preparation method of 2,2,3,3,3-pentafluoropropanol. In the presence of a load type precious metal composite catalyst, a solvent and an oxidizing agent, 1,1,1,2,2-perfluoropropane is catalytically oxidized by a one-step method to prepare the 2,2,3,3,3-pentafluoropropanol, wherein the mass ratio of the 1,1,1,2,2-perfluoropropane: the catalyst: the solvent: the oxidizing agent is 1: 0.01-0.1: 0.5-2: 0.05-0.5. The preparation method of the 2,2,3,3,3-pentafluoropropanol has the advantages of less reaction steps, simplicity in operation, cheap and easily obtained raw materials, high yield and gentle reaction conditions.
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Paragraph 0015; 0016; 0020-0045
(2018/04/27)
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- Method for preparing 2,2,3,3,3-pentafluoropropanol
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The invention discloses a method for preparing 2,2,3,3,3-pentafluoropropanol. According to the method, a metal phthalocyanine compound is taken as a catalyst, and 2,2,3,3,3-pentafluoropropanol is prepared through one-step catalytic oxidation of 1,1,1,2,2-pentafluoropropane in the presence of a solvent and an oxidizing agent, wherein the mass ratio of 1,1,1,2,2-pentafluoropropane, the catalyst, thesolvent and the oxidizing agent is 1:(0.01-0.1):(0.5-2):(0.05-0.5). The method for preparing 2,2,3,3,3-pentafluoropropanol has the advantages that the few reaction steps are used, operation is simple, raw materials are cheap and easy to obtain, the yield is high and the reaction condition is mild.
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Paragraph 0019-0046
(2018/05/16)
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- PROCESS FOR PRODUCING A-FLUOROALDEHYDES
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A production process of an α-fluoroaldehyde according to the present invention includes reaction of an α-fluoroester with hydrogen gas (H2) in the presence of a ruthenium complex. It is possible in the present invention to allow relatively easy industrial production of the α-fluoroaldehyde and to directly obtain, as stable synthetic equivalents of the α-fluoroaldehyde, not only a hydrate (as obtained by conventional techniques) but also a hemiacetal that is easy to purify and is of high value in synthetic applications. The present invention provides solutions to all problems in the conventional techniques and establishes the significantly useful process for production of the α-fluoroaldehyde.
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Paragraph 0058
(2014/06/24)
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- Practical selective hydrogenation of α-fluorinated esters with bifunctional pincer-type ruthenium(II) catalysts leading to fluorinated alcohols or fluoral hemiacetals
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Selective hydrogenation of fluorinated esters with pincer-type bifunctional catalysts RuHCl(CO)(dpa) 1a, trans-RuH2(CO)(dpa) 1b, and trans-RuCl2(CO)(dpa) 1c under mild conditions proceeds rapidly to give the corresponding fluorinated alcohols or hemiacetals in good to excellent yields. Under the optimized conditions, the hydrogenation of chiral (R)-2-fluoropropionate proceeds smoothly to give the corresponding chiral alcohol without any serious decrease of the ee value.
- Otsuka, Takashi,Ishii, Akihiro,Dub, Pavel A.,Ikariya, Takao
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supporting information
p. 9600 - 9603
(2013/07/26)
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- METHOD FOR PRODUCING OLEFIN
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The present invention provides a method for producing an olefin represented by General Formula (II): RfCF=CH2 (II) (wherein Rf is defined as below), wherein the method includes the step of contacting a fluorohalide represented by General Formula (I) : RfCF2CH2X (I) (wherein Rf is H(CF2)n (n = 1 to 8) or F(CF2)n (n = 1 to 8), and X is Br or I) with a metal in a reaction medium of a polar organic solvent, or a mixed solvent of water and a polar organic solvent to conduct a dehalogenation reaction. The production method of the present invention provides olefins in a highly selective manner at a low cost and high yield under relatively mild reaction conditions.
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Page/Page column 5-6
(2009/07/25)
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- Process for the manufacture of fluorinated alcohols
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Process for the manufacture of fluorinated alcohols having the formula ???????? CnFmH2n+1-mCH2OH?????(1) wherein n is 1 or 2; and m is an integer from 1 to 5, but not larger than 2n+1; by hydrogenating the corresponding fluorinated carboxylic acids and/or their derivates having the formula ???????? CnFmH2n+1-mCOR?????(2) wherein n and m have the above meanings and R represents OH, Cl, Br, F, and OR', wherein R' is a hydrocarbon rest, in the presence of a catalyst and of water but excluding the hydrogenation of trifluoroacetic acid to form trifluoroethanol.
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Page/Page column 3
(2008/06/13)
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- Spectrokinetic study of the reaction system of 2NO2?N 2O4 with some fluorinated derivatives of ethanol and propanols between 293-358 K in the gas phase
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The gas phase kinetics of the reversible reactions between nitrogen tetroxide and some fluorinated alcohols in the reaction system 2NO 2?N2O4 (1, 2) N2O4 + ROH?RONO+ + HNO3 (3, 4) have been studied by UV-Vis spectrophotometry to follow the NO2 decay. The products - RONO (R = CH2FCH2, CHF2CH2, CF 3CH2, CHF2CF2CH2, CF 3CF2CH2, CF3CHCF3) - were identified by their UV spectra and the values of the maxima UV absorption cross sections were determined in the range 320-400 nm. The rate constants for the forward reaction are 10-19k3av/cm 3molec-1s-1 9.7±1.5; 2.5±0.4; 1.8±0.3; 23±3.5, 2.3±0.3, 0.2±0.03 and for the reverse reaction 10-19k4av/cm 3molec-1s-1 4.6±0.7; 5.5±0.8; 4.9±0.7; 9.1±1.4; 7.7±1.2; 23±3.5 at 298 K for the reaction with 2-fluoroethanol, 2,2-difluoroethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol, 2,2,3,3,3-pentafluoro-1-propanol and 1,1,1,3,3,3-hexafluoro-2-propanol, respectively, were derived by the computer simulation of monitored NO2 decay profiles. The temperature dependence of the bimolecular rate constants k3 and k4 were studied in the temperature range 293-358 K and the activation energy for the forward E3 and for the reverse E4 reaction were derived. From the observed temperature dependence of the equilibrium constants K3,4, expressed in terms of the van't Hoff equation, the thermochemical parameters for all reactions studied were estimated.
- Wojcik-Pastuszka,Golonka,Ratajczak
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p. 1559 - 1574
(2008/02/04)
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