- Aminated Polystyrene-Bound Rhodium Carbonyl Clusters as a Catalyst for Deoxygenation of Various N-O Bonds
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Aminated polystyrene-bound rhodium carbonyl cluster complexes are prepared by treatment of Rh6(CO)16 with various aminated polystyrenes.The polymeric rhodium complexes show a catalytic activity for deoxygenation of nitro compounds, oximes, hydroxylamines, and N-oxides under the conditions using CO and H2O.The recovered rhodium complexes maintain the deoxygenation ability with a small loss of the selectivity.
- Kaneda, Kiyotomi,Takemoto, Tetsuya,Imanaka, Toshinobu
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- A practical and benign synthesis of amines through Pd@mpg-C 3N4 catalyzed reduction of nitriles
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Liquid phase hydrogenation of nitriles is an important method for the production of amines, which find a variety of applications as intermediates in chemical and pharmaceutical industry. In the present work, a highly efficient Pd@mpg-C3N4 catalytic system has been developed for chemoselective reduction of nitriles providing good to excellent conversion with remarkable chemoselectivity (up to 99%) without additives. Compared with homogeneous catalyst systems, the developed protocol is more advantageous due to the use of ambient hydrogen, solvent free and effective catalyst recyclability.
- Li, Yi,Gong, Yutong,Xu, Xuan,Zhang, Pengfei,Li, Haoran,Wang, Yong
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- The selective preparation of n-propylamines by the rhodium catalysed reaction of ethylene and syngas with alkylamines
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The aminoethylation of ethylene with a primary amine has been shown to provide a highly selective route to n-propylamines; the rhodium catalysed reaction of n-propylamine with ethylene and syngas (2/1, H2/CO) affords di-n-propylamine with 98percent selectivity (with respect to ethylene).The reaction of amines of the type RR1NH with the ethylene/syngas mixture and a rhodium catalyst provides a highly selective and general route to the n-propylamines RR1NPr (R=Pr, R1=H; R=t-Bu, R1=H; R=n-Bu, R1=H; R=C8H17, R1=H, R=R1=Pr; R=HOCH2Ch2, R1=H, and R=PhCH(OH)CH2, R1=H).
- Jones, M. D.
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- Alkyl substituent effect on the polarity of phenols-tri-n-alkylamine complexes
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The formation constants and the dipole moments of the H-bonded adducts of 1:1 and 2:1 stoichiometries formed between three different phenols (phenol, 2,4,6-trichlorophenol, and 2,4-dinitrophenol) and different tri-n-alkylamines are determined in solvents
- Pawelka, Zbigniew,Zeegers-Huyskens, Therese
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- Continuous Production of Dialkylamines by Selective Hydrogenation of Nitriles on a Nickel-Zeolite Catalyst
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Hydrogenation of aliphatic nitriles in the presence of nickel supported by NaX zeolite was studied. The data obtained were used to develop a continuous method for obtaining dialkylamines with the yield of the target product of up to 98%.
- Popov, Yu. V.,Mokhov,Latyshova,Panov,Pletneva, M. Yu.
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- Chemical modification of niobium layered oxide by tetraalkylammonium intercalation
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Chemical modification of the layered K4Nb6O 17 material was systematically investigated through the reaction of its proton-exchanged form (H2K2Nb6O 17) in alkaline solutions containing tetramethylammonium (tma +), tetraethylammonium (tea+) or tetrapropylammonium (tpa+) cations. The intercalated amount reaches 50percent (for tma +), 25percent (for tea+) and 15percent (for tpa+) of the H2K2Nb6O17 negative charge (concerning the exchange at interlayer I) due to the steric hindrance of larger cations. Hexaniobate samples present (020) basal reflections equal to 23.0, 26.3 and 26.5 A? once intercalated respectively with tma+, tea + and tpa+. When samples are heated above 200-250 °C, CO2 evolution is observed; Hofmann elimination reaction is also detected for hexaniobate-tpa+ samples. Scanning electron microscopy images show the predominance of plate-like particles; stick-like particles are also observed for samples containing bulky ions. The intercalation reaction is promoted in the order tma+ > tea+ > tpa+, while the formation of a dispersion of colloidal particles is facilitated in the inverse order.
- Shiguihara, Ana L.,Bizeto, Marcos A.,Constantino, Vera R. L.
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- The conversion of 1-propanamine on copper-containing MFI and BEA zeolites prepared by aqueous and vapor ion-exchange
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A process has been developed for exchanging one Cu atom per ion exchange site in an MFI zeolite. The material is synthesized by reaction of the acidic zeolite with CuCl vapor, followed by oxidation with oxygen, and conversion of the Cu2+ species to copper hydroxyl ions and copper hydroxyl dimers by reaction of the oxidized material with water upon exposure to humid air. This material, a similarly prepared BEA material, and copper-containing MFI and BEA zeolites prepared by conventional aqueous ion-exchange have been comparatively investigated for the conversion of 1-propanamine. Reaction products include C6 products such as dipropanamine and 1-propanamine, N-(1-propylidene). A bifunctional acid/metal reaction pathway is proposed to account for the observed products.
- Guidry, Trent F.,Price, Geoffrey L.
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- About selenidostannates. I: Synthesis, structure, and properties of [Sn2Se6]4-, [Sn4Se10]4-, and [Sn3Se7]2-
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The selenidostannates [(C4H9)2NH2]4Sn 2Se6·H2O (I), [(C4H9)2NH2]4Sn 4Se10·2H2O (II) und [(C3H7)3NH]2-Sn3Se 7 (III) were prepared by hydrothermal syntheses from the elements and the amines. I crystallizes in the monoclinic spacegroup P21/n (a = 1262.9(3) pm, b = 1851.3(4) pm, c = 2305.2(4) pm, β = 104.13(3)° and Z = 4). The [Sn2Se6]4- anion consists of two edge-sharing tetrahedra. II crystallizes in the orthorhombic spacegroup Pna21 (a = 2080.3(4) pm, b = 1308.2(3) pm, c = 2263.5(5) pm and Z = 4). The anion is formed from four SnSe4 tetrahedra which are joined by common corners to the adamantane cage [Sn4Se10]4-. III crystallizes in the orthorhombic spacegroup Pbcn (a = 1371.1(3) pm, b = 2285.4(5) pm, c = 2194.7(4) pm and Z = 8). The anion is a chain, built from edge-sharing [Sn3Se5Se4/2]2- units, in which two corner sharing tetrahedra are connected to a trigonal bipyramid by an edge of one and a corner of the other tetrahedron. The results of the TG/DSC measurements and of temperature dependent X-ray diffractograms reveal that I and II decompose at first by release of minor quantities of triethylammonium to compounds with layer structure and larger cell dimensions. At still higher temperature the rest of triethylammonium and H2Se is evolved, leaving SnSe2 and Se in the bulk. The former decomposes partially at the highest temperature to SnSe. In the measurements of III the complex intermediate compound was not observed. III decomposes directly to SnSe2. Wiley-VCH Verlag GmbH, 2001.
- Fehlker, Andreas,Blachnik, Roger
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- Protonation Dynamics of 2(μ-CO)(μ-C=CH2) and Decomposition Processes for 2(μ-CO)(μ-C=CH2)H(+) in the Gas Phase
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The proton affinity (PA) and site of protonation of 2(μ-CO)(μ-C=H2) (2), as well as the decomposition processes for 2(μ-CO)(μ-C=CH2)H(+) (7), are studied in the gas phase by using Fourier transform mass spectrometry (FTMS).The
- Jacobson, D. B.
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- A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
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The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
- García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
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supporting information
(2022/01/04)
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- Cyanidosilicates—Synthesis and Structure
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Starting from fluoridosilicate precursors in neat cyanotrimethylsilane, Me3Si?CN, a series of different ammonium salts [R3NMe]+ (R=Et, nPr, nBu) with the novel [SiF(CN)5]2? and [Si(CN)6]2? dianions was synthesized in facile, temperature controlled F?/CN? exchange reactions. Utilizing decomposable, non-innocent cations, such as [R3NH]+, it was possible to generate metal salts of the type M2[Si(CN)6] (M+=Li+, K+) via neutralization reactions with the corresponding metal hydroxides. The ionic liquid [BMIm]2[Si(CN)6] (m.p.=72 °C, BMIm=1-butyl-3-methylimidazolium) was obtained by a salt metathesis reaction. All the synthesized salts could be isolated in good yields and were fully characterized.
- Harloff, J?rg,Michalik, Dirk,Nier, Simon,Schulz, Axel,Stoer, Philip,Villinger, Alexander
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supporting information
p. 5452 - 5456
(2019/03/21)
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- Colloid and nanosized catalysts in organic synthesis: XVI.1 Continuous hydrogenation of carbonitriles catalyzed by nickel nanoparticles applied on a support
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Conversion of the starting nitriles and selectivity of the products formation during continuous hydrogenation of various nitriles catalyzed by Ni0/Ceokar-2 have been studied as functions of temperature. Performing the process at temperature 120–260°С has led to the formation of a mixture of products containing di- and trialkylamines as well as the corresponding imines and enamines.
- Popov, Yu. V.,Mokhov,Latyshova,Nebykov,Panov,Pletneva, M. Yu.
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p. 2276 - 2281
(2017/11/24)
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- Catalytic hydrogenation of amides to amines under mild conditions
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Under (not so much) pressure: A general method for the hydrogenation of tertiary and secondary amides to amines with excellent selectivity using a bimetallic Pd-Re catalyst has been developed. The reaction proceeds under low pressure and comparatively low temperature. This method provides organic chemists with a simple and reliable tool for the synthesis of amines. Copyright
- Stein, Mario,Breit, Bernhard
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supporting information
p. 2231 - 2234
(2013/03/28)
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- An efficient synthesis of tertiary amines from nitriles in aprotic solvents
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Tertiary amines are utilized extensively as non-nucleophilic proton scavengers for a number of organic transformations. Herein we report the efficient syntheses of tertiary alkyl amines from their corresponding alkyl nitriles in the presence of a heterogeneous palladium catalyst and a source of dihydrogen in aprotic solvents. The reaction is atom economic, the conditions are mild, and the isolated yields are virtually quantitative. The degree of amine alkylation shows some solvent dependency; in polar protic solvents such as ethanol or methanol, the reaction affords a mixture of products with the secondary alkyl amine as the major product.
- Shares, Jonathan,Yehl, Jenna,Kowalsick, Amanda,Byers, Philip,Haaf, Michael P.
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experimental part
p. 4426 - 4428
(2012/09/25)
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- PROCESS FOR PREPARING TRI-N-PROPYLAMINE (TPA)
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Process for preparing tri-n-propylamine (TPA), wherein di-n-propylamine (DPA) is reacted in the presence of hydrogen and a copper-comprising heterogeneous catalyst. An integrated process for preparing TPA, which comprises the following operations: I) reaction of n-propanol with ammonia in a reactor in the presence of an amination catalyst and optionally hydrogen to form a mixture of mono-n-propylamine, DPA and TPA,II) separation of unreacted ammonia, unreacted n-propanol and possibly hydrogen from the reaction product mixture and recirculation of at least the ammonia and propanol to the reactor in I) and also separation of the n-propylamine mixture by distillation and isolation of the TPA,III) reaction of the DPA obtained in the separation by distillation in II) in a reactor in the presence of hydrogen and a copper-comprising heterogeneous catalyst to form TPA andIV) feeding of the reactor output from III) to operation II).
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(2012/01/14)
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- PROCESS FOR THE PREPARATION OF ALKYLENE GLYCOL
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The invention provides a process for the preparation of an alkylene glycol from an alkylene oxide. Alkylene oxide reacts with carbon dioxide in the presence of a carboxylation catalyst to provide alkylene carbonate; alkylene carbonate reacts with water in the presence of a hydrolysis catalyst to provide alkylene glycol. An initial charge of the carboxylation catalyst and an initial charge of the hydrolysis catalyst are added, the degradation and activity of the hydrolysis catalyst are monitored, and when the activity of the hydrolysis catalyst has fallen below a minimum level, an additional charge of the hydrolysis catalyst is added.
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(2009/10/21)
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- Joint Synthesis of Tertiary Unsymmetrical and Symmetrical Aliphatic Amines
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Tertiary unsymmetrical and symmetrical aliphatic amines were prepared by reaction of higher (C8-C16) and lower (C2-C4) aliphatic alcohols with nitriles containing the same number of carbon atoms as the lower aliphatic alcohols. Reaction conditions ensuring nearly quantitative yields of tertiary amines were determined.
- Kozlov,Tereshko,Basalaeva,Tarasevich
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p. 1095 - 1098
(2007/10/03)
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- Selective Deoxygenation of Various N-O Bonds Catalyzed by Rhodium Carbonyl Clusters in the Presence of H2O and CO and Their Heterogenization Using Amino-Substituted Polystyrenes
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Catalytic deoxygenation of various N-O bonds using rhodium carbonyl compounds under a water gas shift reaction was studied.A catalyst system of Rh6(CO)16 and N,N,N',N'-tetramethyl-1,3-propanediamine was found to have high activities for the following deoxygenations: 1) conversion of nitrobenzenes to anilines, 2) aliphatic nitro compounds to nitriles, 3) oximes to nitriles, 4) hydroxylamines to amines, and 5) amine oxides to amines.The above-mentioned rhodium catalyst system was heterogenized by using amino-substituted polystyrenes.Rh6 and Rh14 carbonyl clusters of -, 2-, and 4-, were formed on the polymer surface.The characteristic features of the catalysis of the polymer-bound rhodium cluster complexes are described in relation to the corresponding homogenous ones.
- Kaneda, Kiyotomi,Fujita, Kazuo,Takemoto, Tetsuya,Imanaka, Toshinobu
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p. 602 - 612
(2007/10/02)
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- Entropy barriers to proton transfer
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Proton transfer between sterically hindered pyridines and amines proceeds through locked-rotor, low-entropy intermediates. The reactions exhibit slow kinetics (efficiencies of 0.1-0.0001) and large negative temperature coefficients (up to k = CT-8.7). The rates become slower and the temperature dependencies steeper with increasing steric hindrance. The observations are reproduced by a multiple complex-switching RRKM model that allows several alternative complexes to be rate controlling: a series of loose complexes, a locked-rotor tight complex that occurs before the formation of a hydrogen-bonded complex, and a complex located at the central barrier. The rate-limiting transition state shifts from the loose to the tight and central-barrier complexes with increasing temperature. The model suggests that at elevated temperatures, above 1000 K, ion-molecule reactions will become slow even for unhindered, small reactants. Ion kinetics may then become similar to neutral radical kinetics.
- Meot-Ner, Michael,Smith, Sean C.
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p. 862 - 869
(2007/10/02)
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- The effect of the nature of the amine leaving group on the nature of the E2 transition state for the reaction of 1-phenylethylammonium ions with sodium ethoxide in ethanol
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To investigate the effect of the leaving group on the elimination reaction of 1-phenylethylammonium ions with sodium ethoxide in ethanol at 60 deg C, the reaction of seven different quaternary ammonium salts and their β-deuterated analogues with trimethylamine, N-methylpiperidine, N-methyldiethylamine, triethylamine, N,N-dimethylbenzylamine, tripropylamine, and N,N-diethylbenzylamine as leaving groups has been studied.In all cases the elimination, which was shown to proceed via the concerted E2 process, was accompained by competing substitution reactions.Although a significant depedence of the rate of the elimination process on the nature of the leaving group was noted, there was not any linear correlation with the basicity of the amine leaving group.The primary hydrogen-deuterium kinetic isotope effect for the elimination process, (kH/kD)E, was found to increase initially with an increase of reaction rate, kHE, for substrates containing the leaving groups trimethylamine, N-methylpiperidine, N-methyldiethylamine, triethylamine, and N,N-dimethylbenzylamine; i.e., (kH/kD)E=5.03, 5.26, 5.40, 5.83, and 5.85, respectively.A further increase in rate, using substrates with tripropylamine and N,N-diethylbenzylamine as leaving groups resulted in a decrease of the magnitude of the hydrogen-deuterium isotope effect; i.e., (kH/kD)E= 5.42 and 4.67, respectively.It is concluded that steric effects mainly determine leaving group ability.As well, it is concluded that the leaving group ability of the amine determines the structure of the E2 transition state.For the reaction of the poorer leaving groups, trimethylamine, N-methylpiperidine, and N-methyldiethylamine, the proton is more than one-half transferred at the transition state while for reaction involving the two best leaving groups, tripropylamine and N,N-diethylbenzylamine, the Cβ-H bond is less than one-half broken at the transition state.The conclusions are considered in the light of the More O'Ferrall-Jencks potential energy surface diagram.Key words: elimination mechanism, transition state, isotope effects, leaving group, quaternary salts.
- Smith, Peter James,Amin, Md.
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p. 1457 - 1467
(2007/10/02)
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- 2,2-Dialkoxy-6-chlorocyclohexanones
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O-alkoxyphenols are produced from cyclohexanone or cyclohexanol by chlorination of cyclohexanone or cyclohexanol to trichlorocyclohexanone and reaction of the trichlorocyclohexanone with an aliphatic, monohydric alcohol having one to four carbon atoms and a base to form an intermediate compound or compounds which are further reacted to convert the intermediate compound or compounds to an o-alkoxyphenol.
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- Oxidation of thiols employing cobalt molybdate/triethylamine catalyst
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A thiol is oxidized to a corresponding disulfide employing a supported cobalt molybdate catalyst in combination with a liquid tertiary amine. 2-propanethiol is converted to diisopropyl disulfide with conversions of the order of 94% and selectivities of the order of 98%.
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- Production of o-alkoxyphenols
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O-alkoxyphenols are produced from cyclohexanone or cyclohexanol by chlorination of cyclohexanone or cyclohexanol to trichlorocyclohexanone and reaction of the trichlorocyclohexanone with an aliphatic, monohydric alcohol having one to four carbon atoms and a base to form an intermediate compound or compounds which are further reacted to convert the intermediate compound or compounds to an o-alkoxyphenol.
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