- Application of the Water-gas Shift Reaction. III. Reduction of Oxidized Nitrogen Compounds with CO and H2O Catalyzed by (BPh4)2
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The ruthenium(II) complex, 4>(BPh4)2 (cod=1,5-cyclooctadiene, py=pyridine) has been shown to catalyze the reduction of oxidized nitrogen compounds with CO and H2O.In this reaction, primary, secondary, and tertiary nitroalkanes are converted into amides, ketones, and amines, respectively.Nitrosobenzene and picoline N-oxides are also reduciable to amines in good yields.
- Okano, Tamon,Fujiwara, Kensuke,Konishi, Hisatoshi,Kiji, Jitsuo
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- Selective Dehydrogenation of Alkylamines to Nitriles over Metal Oxide Catalysts
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Decompositions of alkylamines over ZrO2, SiO2-Al2O3, and MgO were examined in a closed recirculation reactor.ZrO2 showed the highest activities and selectevities for the formation of nitriles, especially in di- and trialkylamine decomposition.In contrast, SiO2-Al2O3 catalyzed dealkylation and deamination reactions exclusively.MgO exhibited high selectivity for the dehydrogenation of primary alkylamine.The high activity of ZrO2 is attributed to its acid-base bifunctional properties.
- Xu, Bo-Quing,Yamaguchi, Tsutomu,Tanabe, Kozo
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- Preparation of Highly Active Hydrogenation Catalyst by Immobilization of Polymer-Protected Colloidal Rhodium Particles
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Colloidal dispersion of rhodium protected by copolymer of mathyl acrylate and N-vinyl-2-pyrrolidone is treated with polyacrylamide gel having amino groups, resulting in immobilization of the rhodium particles onto the gel.The gel-immobilized rhodium particles exhibit 2-22 fold larger catalytic activities than a rhodium carbon catalyst for hydrogenation of olefins at 30 deg C under 1 atm.
- Hirai, Hidefumi,Ohtaki, Michitaka,Komiyama, Makoto
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- Calixarene-Catalyzed Generation of Dichlorocarbene and Its Application to Organic Reactions: The Catalytic Action of Octopus-Type Calixarene
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The dichlorocarbene generation reaction from CHCl3 and solid KOH in CH2Cl2 was catalyzed by the p-t-butylcalixarene derivative 1 which bears six 3,6,9-trioxadecyl substituents on the phenolic oxygens.Dichlorocarbene generated by this method reacted efficiently with alkenes and amides to give dichlorocyclopropane derivatives and nitriles, respectively, in high yields.The reaction with alkadiene having isolated double bonds gave mixtures of the mono- and bis-dichlorocarbene adducts, but the monoadduct formation always predominated.The catalytic action of the calixarene and the reactivity features of dichlorocarbene generated by the above procedure are discussed on the basis of kinetic measurements.They are also compared with those of the 18-crown-6-catalyzed reactions.
- Nomura, Eisaku,Taniguchi, Hisaji,Otsuji, Yoshio
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- Study on the conversion of glycerol to nitriles over a Fe 19.2K0.2/γ-Al2O3 catalyst
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An Fe19.2K0.2/γ-Al2O3 catalyst for the catalytic amination of glycerol to propionitrile was prepared. Acetonitrile as a major product was obtained over this catalyst from the amination of glycerol. Additionally, propionitrile, ethylene and propylene were also obtained. The parameters influencing the catalyst performance were studied thoroughly, and an optimised process for the amination of glycerol to acetonitrile and propionitrile over the catalyst was obtained. Under the optimised conditions, which were a reaction temperature of 525 °C, an atmospheric pressure with an ammonia/glycerol molar ratio of 8:1 and GHSV of 1338 h-1, the total yield of acetonitrile and propionitrile was 58.4%, and the converted amount of glycerol over one gram of catalyst reached 0.42 g h-1. The catalyst was characterised by XRD, XPS, TEM and IR of the adsorbed pyridine. The characterisation results indicated that the dehydration reaction in the tandem reaction mainly occurred on the Lewis acid sites and revealed that both Fe2O3 and Fe 3O4 are active species for the dehydrogenation of imines to nitriles, but the former is more active than the latter. It also revealed that the catalyst deactivation was due to carbon deposits, the transformation of Fe2O3 to the Fe3O4 phase, as well as agglomeration of the Fe2O3 or Fe3O 4 phase during the catalytic run and regeneration process.
- Zhang, Yuecheng,Ma, Tianqi,Zhao, Jiquan
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- Thermal decomposition of 4-methylpyrimidine. Experimental results and kinetic modeling
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The decomposition of 4-methylpyrimidine was studied behind reflected shock waves in a pressurized driver single-pulse shock tube at 1160-1330 K and overall densities of ～ 3 × 10-5 mole/cc. A plethora of decomposition products, both with and without nitrogen, (HCN, CH3CN, C2H3CN, CH4, C2H6, C2H4, etc.) was found in the post-shock mixtures. The attack of methyl radicals on the methyl group in 4-methylpyrimidine produced CH4, which was a major product among the species not containing nitrogen, leaving the radical 4-methylene pyrimidyl. The H atoms and methyl radicals initiated a chain mechanism by abstraction of an H atom from the methyl group and by dissociative attachment of an H atom and removal of a methyl group from the ring. The decomposition mechanism was discussed.
- Lifshitz, Assa,Suslensky, Aya,Tamburu, Carmen
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- Synergistic Effects of Superbasic Catalysts on the Selective Formation of Acrylonitrile via Oxidative Methylation of Acetonitrile with Methane
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The oxidative methylation of acetonitrile with methane to acrylonitrile occurs more actively and selectivelybialkali promoted CaO catalysts thanany monoalkali promoted system.The most effective catalytic systems are obtained with LiA + CsA, NaA + CsA, or KA + CsA (A = SO42- , OH-, Cl-, CH3COO-, CO32-, or NO3-) supported on CaO, containing total alkali loadings of 10 molpercent with equal molar amounts of both alkalis.At 750 deg C, under atmospheric pressure, at CH4 : O2 : CH3CN : He partial pressure ratios of 5.0 : 1.0 : 1.5 : 6.5, and at a space velocity of 15,000 cm3 g-1 h-1, the highest selectivity to acrylonitrile (70.0 molpercent) and yield (25 percent) are obtained(5 molpercent Na+ + 5 molpercent Cs+)/CaO (prepared from the sulfate precursors).Any bialkali-promoted system containing Rb was less effective, whereas the Li-containing systems, though active initially, gradually lost the activity due to its volatility.The performances of the effective bialkali systems, after an initial increase, remained almost unchanged for a period of 60 h.In contrast, the stability of any monoalkali promoted system with time-on-stream was very low and the maximum initial yield of acrylonitrile was only 11.5 percent under the aforementioned conditions.The synergistic increase in the catalytic performance of the bialkali promoted CaO is reflected in the synergistic increase of the surface basicity (leading to superbasicity) caused by the high enrichment of the surface layer with the alkali ions.The relationship between the catalytic performances and the physicochemical characteristics of the catalysts revealed by XPS, AAS, and basicity measurement is explored.
- Ruckenstein, Eli,Khan, Ashraf Z.
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- Selective Formation of Acrylonitrile via Oxidative Methylation of Acetonitrile with Methane over Superbasic Catalysts
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Promotion of CaO or MgO with various binary alkali metal compounds such as NaA + CsA, KA + CsA, LiA + CsA or LiA + NaA, where A = SO42-, OH-, Cl-, AcO-, CO32- or NO3-, leads to highly basic (superbasic) catalysts, which exhibit a noticeable synergistic effect compared with the effect produced by any monoalkali promoted system in the selective formation of acrylonitrile via oxidative methylation of acetonitrile with methane.
- Ruckenstein, Eli,Khan, Ashraf Z.
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- Synergy in N-Ethylformamide Dehydration by Mixtures of MoO3 and α-Sb2O4
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Mixtures of separately prepared MoO3 and α-Sb2O4 show a remarkable synergy in the dehydration of N-ethylformamide to propionitrile when a small amount of oxygen is fed together with the main reagent.The surface acidity of the samples was investigated by TPD of ammonia.ESR and XPS were used for investigating the behavior of the mixtures in reducing and oxidizing conditions.The acidity is attributed mainly to Bronsted sites situated on MoO3.Oxygen is neccessary to maintain these sites.The interpretation is that oxygen is provided, to the surface of MoO3, in the form of spillover oxygen, by α-Sb2O4.Such a mechanism corresponds to what has been called a remote control.
- Zhou, B.,Ceckiewicz, S.,Delmon, B.
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- Chemoselective hydrogenation of α,β-unsaturated nitriles
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The chemoselective hydrogenation of cinnamonitrile to 3-phenylallylamine proceeds with up to 80% selectivity at conversions of > 90% with Raney cobalt and up to 60% selectivity with Raney nickel catalysts. Best results were obtained with a doped Raney cobalt catalyst (RaCo/Cr/Ni/Fe 2724) in ammonia saturated methanol at 100°C and 80 bar. Major problems are the formation of hydrocinnamonitrile and of secondary amines, and overreduction to 3-phenylpropylamine. Important parameters are the catalyst type and composition, the solvent type and the presence and concentration of ammonia. The catalytic system tolerates functional groups like OH, OMe, Cl, C=O, but not aromatic nitro groups. Preliminary experiments indicate that other unsaturated nitriles with di- or trisubstituted C=C bonds are also suitable substrates.
- Kukula, Pavel,Studer, Martin,Blaser, Hans-Ulrich
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- Thermal Decomposition of 5-Methylisoxazole. Experimental and Modeling Study
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The thermal decomposition of 5-methylisoxazole was studied behind reflected shocks in a pressurized driver single-pulse shock tube over the temperature range 850-1075 K and overall densities of ca. 2.5 * 10-5 mol/cm3.Propionitrile and carbon monoxide are the major decomposition products, followed by ethane, methane, acetonitrile, and hydrogen cyanide.There is no effect of large quantities of toluene (/ ca. 10) on the concentrations of propionitrile and acetonitrile, indicating that no radical chains are involved in their production.It is suggested that the formation of C2H5CN and CO in 5-methylisoxazole involves an N-O bond cleavage in the 1,2-position, a methyl group shift from position 5 to 4, and a rupture of the C(4)-C(5) bond with the removal of carbon monoxide from the ring: 5,m-isox -> C2H5CN + CO (1).In contradiction to findings in isoxazole, this process requires a very large N-O bond stretch which results in a very loose transition state corresponding to a biradical mechanism.The rate constant for this reaction is k1 = 1017.76exp(-70 * 103/RT) s-1 where R is expressed in units of cal/(K mol).The presence of ethane and methane in the postshock mixtures indicates the presence of methyl radicals in the hot phase.It is suggested that the formation of methyl radicals involves the same N-O bond cleavage as in reaction 1 but without the methyl group shift: 5,m-isox -> CH2CN. + CH3CO. (2) followed by CH3CO. -> CH3. + CO (3).This is an endothermic reaction which proceeds at a lower rate than reaction 1 but at a much higher rate than a direct methyl group ejection from the ring.
- Lifshitz, Assa,Wohlfeiler, Dror
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- Studies on V2O5-TiO2 System. Part 1. -TiO2(rutile)-V2O5
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Mechanical mixtures of separately prepared V2O5 and TiO2(rutile) have been used as catalysts in the dehydration of N-ethylformamide (NEF) in the presence of oxygen.Catalytic activity has been measured as a function of the gas hourly space velocity (GHSV),
- Machej, T.,Remy, M.,Ruiz, P.,Delmon, B.
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- Intrinsic Barriers in Nucleophilic Displacements. A General Model for Intrinsic Nucleophilicity toward Methyl Centers
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The applicability of the Marcus rate-equilibrium formalism to the double-minimum potential energy surface for gas-phase SN2 reactions is proposed and used to develop a model for intrinsic nucleophilicity toward methyl centers.The key quantities in this model are the energy barriers to degenerate reactions of the form X(-*)CH3X -> XCH3(*)X(-), in which the reacting species are ion-molecule cluster intermediates.Available experimental and theoretical data corroborate several of the model's predictions.A new structure-nucleophilicity correlation is proposed, involving methyl cation affinities.The model suggests that delocalization effects do not greatly influence nucleophile reactivity.
- Pellerite, Mark J.,Brauman, John I.
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- The effect of solvent on the structure of the transition state for the SN2 reaction between cyanide ion and ethyl chloride in DMSO and THF probed with six different kinetic isotope effects
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The secondary α- and β-deuterium, the α-carbon, the nucleophile carbon, the nucleophile nitrogen, and the chlorine leaving group kinetic isotope effects for the SN2 reaction between cyanide ion and ethyl chloride were determined in the very slightly polar solvent THF at 30 °C. A comparison of these KIEs with those reported earlier for the same reaction in the polar solvent DMSO shows that the transition state in THF is only slightly tighter with very slightly shorter NC-Cα and Cα-Cl bonds. This minor change in transition state structure does not account for the different transition structures that were earlier suggested by interpreting the experimental KIEs and the gas-phase calculations, respectively. It therefore seems unlikely that the different transition states suggested by the two methods are due to the lack of appropriate solvent modeling in the theoretical calculations. Previously it was predicted that the transition state of SN2 reactions where the nucleophile and the leaving group have the same charge would be unaffected by a change in solvent. The experimental KIEs support this view.
- Fang, Yao-Ren,MacMillar, Susanna,Eriksson, Jonas,Kolodziejska-Huben, Magdalena,Dybala-Defratyka, Agnieszka,Paneth, Piotr,Matsson, Olle,Westaway, Kenneth Charles
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- CN-COMPOUNDS FORMATION OVER Al2O3 SUPPORTED Pt AND Rh CATALYSTS IN THE REDUCTION OF NO WITH PROPYLENE AND H2 - CO
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Large amounts of hydrogen cyanide (HCN), acetonitrile, acrylonitrile, and propionitrile were formed in the reduction of NO with propylene and H2 - CO over Al2O3 supported Pt and Rh catalysts.Rh was more active in both the reduction of NO and the formation of HCN and nitriles than Pt.Propylene employed as a reducing agent was more reactive in the conversion of NO into HCN than H2 - CO
- Mizuno, Koichi,Kamuki, Toru,Suzuki, Masaomi
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- An XRD, XPS, and EPR study of Li/MgO catalysts: Case of the oxidative methylation of acetonitrile to acrylonitrile with CH4
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The effects of the Mg and Li precursors and the catalyst surface properties on the catalytic performance in the oxidative methylation of acetonitrile were studied. The performance of the catalysts for the oxidative methylation of acetonitrile to acrylonitrile with CH4 was significantly affected by the Li precursor, where the catalysts prepared with LiCl and LiOH on MgO had the best performance for this reaction. Relatively high BET surface areas had a negative effect on the catalysts' performance by producing less acrylonitrile and more COx. XPS and XRD analyses of Li/MgO-based catalysts showed that the lithium salts used in the catalyst synthesis predominantly formed mixtures with MgO. The Li/Cl atomic ratio was 1:1 in catalysts prepared with LiCl, even after calcination at 650°C for 14 hr in air. The catalysts synthesized with LiCl and LiOH promoted the desired reaction, or equivalently associated with Li+O- species. The catalysts synthesized with LiNO3 showed superior thermal stability, even under severe calcination conditions.
- Bothe-Almquist, Catherine L.,Ettireddy, Reddy P.,Bobst, Albert,Smirniotis, Panagiotis G.
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- Thermal Decomposition of Isoxazole. Experimental and Modeling Study
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The thermal decomposition of isoxazole was studied behind reflected shocks in a pressurized-driver single-pulse shock tube over the temperature range 850-1100 K and overall densities of ca. 3*10 -5 mol/cm3.Acetonitrile and carbon monoxide are the major decomposition products, followed by hydrogen cyanide, acrylonitrile, propionitrile, and acetylene.Methane, ethylene, and ethane are produced in smaller quantities.There is no effect of large quantities of toluene (/ ca. 10) on the rate of formation of acetonitrile and carbon monoxide, indicating that the latter are formed in a unimolecular process.It is suggested that this reaction channel in the decomposition of isoxazole involves a simultaneous N-O bond cleavage in the 1-2 position, a hydrogen atom shift from position 5 to 4, and a rupture of the C(4)-C(5) bond with the removal of carbon monoxide from the ring: (1) C3H3ON -> CH3CN + CO.This process requires a very small N-O bond stretch which results in a very stiff transition structure.The rate constant for this reaction is k1 = 1011.94 exp(-44*103/RT)s-1.Since several products are formed by free-radical reactions, it is suggested that the initiation of free radicals involves the same reaction which proceeds at a much lower rate than reaction 1.
- Lifshitz, Assa,Wohlfeiler, Dror
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- Experimental and theoretical multiple kinetic isotope effects for an SN2 reaction. An attempt to determine transition-state structure and the ability of theoretical methods to predict experimental kinetic isotope effects
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The secondary α-deuterium, the secondary β-deuterium, the chlorine leaving-group, the nucleophile secondary nitrogen, the nucleophile 12C/13C carbon, and the 11C/14C α-carbon kinetic isotope effects (KIEs) and activation parameters have been measured for the SN2 reaction between tetrabutylammonium cyanide and ethyl chloride in DMSO at 30°C. Then, thirty-nine readily available different theoretical methods, both including and excluding solvent, were used to calculate the structure of the transition state, the activation energy, and the kinetic isotope effects for the reaction. A comparison of the experimental and theoretical results by using semiempirical, ab initio, and density functional theory methods has shown that the density functional methods are most successful in calculating the experimental isotope effects. With two exceptions, including solvent in the calculation does not improve the fit with the experimental KIEs. Finally, none of the transition states and force constants obtained from the theoretical methods was able to predict all six of the KIEs found by experiment. Moreover, none of the calculated transition structures, which are all early and loose, agree with the late (product-like) transition-state structure suggested by interpreting the experimental KIEs.
- Fang, Yao-ren,Gao, Ying,Ryberg, Per,Eriksson, Jonas,Kolodziejska-Huben, Magdalena,Dybala-Defratyka, Agnieszka,Madhavan,Danielsson, Rolf,Paneth, Piotr,Matsson, Olle,Westaway, Kenneth Charles
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- Vacancy-Rich Ni(OH)2 Drives the Electrooxidation of Amino C?N Bonds to Nitrile C≡N Bonds
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Electrochemical synthesis based on electrons as reagents provides a broad prospect for commodity chemical manufacturing. A direct one-step route for the electrooxidation of amino C?N bonds to nitrile C≡N bonds offers an alternative pathway for nitrile production. However, this route has not been fully explored with respect to either the chemical bond reforming process or the performance optimization. Proposed here is a model of vacancy-rich Ni(OH)2 atomic layers for studying the performance relationship with respect to structure. Theoretical calculations show the vacancy-induced local electropositive sites chemisorb the N atom with a lone pair of electrons and then attack the corresponding N(sp3)?H, thus accelerating amino C?N bond activation for dehydrogenation directly into the C≡N bond. Vacancy-rich nanosheets exhibit up to 96.5 % propionitrile selectivity at a moderate potential of 1.38 V. These findings can lead to a new pathway for facilitating catalytic reactions in the chemicals industry.
- Jiang, Zheng,Li, Huiqiao,Liu, Youwen,Wang, Wenbin,Wang, Yutang,Wen, Qunlei,Yang, Ruoou,Zhai, Tianyou
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- Synthesis of: N -unsubstituted cycloalkylimines containing a 4 to 8-membered ring
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Primary cycloalkylimines with a 4 to 8-membered ring were synthesized by dehydrocyanation of the corresponding α-aminonitriles on solid potassium hydroxide via a vacuum gas-solid reaction. Imine-enamine tautomerism has been demonstrated at room temperature for the most kinetically stable derivatives.
- Guillemin, Jean-Claude,Nasraoui, Wafa,Gazzeh, Houda
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- Molecular products from the thermal degradation of glutamic acid
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The thermal behavior of glutamic acid was investigated in N2 and 4% O2 in N2 under flow reactor conditions at a constant residence time of 0.2 s, within a total pyrolysis time of 3 min at 1 atm. The identification of the main pyrolysis products has been reported. Accordingly, the principal products for pyrolysis in order of decreasing abundance were succinimide, pyrrole, acetonitrile, and 2-pyrrolidone. For oxidative pyrolysis, the main products were succinimide, propiolactone, ethanol, and hydrogen cyanide. Whereas benzene, toluene, and a few low molecular weight hydrocarbons (propene, propane, 1-butene, and 2-butene) were detected during pyrolysis, no polycyclic aromatic hydrocarbons (PAHs) were detected. Oxidative pyrolysis yielded low molecular weight hydrocarbon products in trace amounts. The mechanistic channels describing the formation of the major product succinimide have been explored. The detection of succinimide (major product) and maleimide (minor product) from the thermal decomposition of glutamic acid has been reported for the first time in this study. Toxicological implications of some reaction products (HCN, acetonitrile, and acyrolnitrile), which are believed to form during heat treatment of food, tobacco burning, and drug processing, have been discussed in relation to the thermal degradation of glutamic acid.
- Kibet, Joshua K.,Khachatryan, Lavrent,Dellinger, Barry
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- Thermolytic synthesis of graphitic boron carbon nitride from an ionic liquid precursor: Mechanism, structure analysis and electronic properties
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Recent work has shown the potential of ionic liquids (ILs) as a precursor for porous networks and nitrogen doped carbon materials. The combination of liquid state and negligible vapour pressure represents almost ideal precursor properties and simplifies the processing drastically. Here, we extend this work to get a deeper insight into the solid formation mechanism and to synthesize a mixed boron carbon nitride species by the thermolysis of N,N′- ethylmethylimidazolium tetracyanoborate (EMIM-TCB), a well-known boron- and nitrogen-containing IL. In contrast to other molecule pyrolysis routes boron carbon nitride shows the average composition BC3N and like other IL-derived materials turns out to be distorted graphitic, but thermally and chemically very stable, and possesses favourable electrical properties. The detailed mechanistic investigation using TG-IR, FT-IR, solid-state NMR, Raman, WAXS, EELS, XPS and HRTEM also contributes to the general understanding of IL-based material formation mechanisms. The Royal Society of Chemistry 2012.
- Fellinger, Tim-Patrick,Su, Dang Sheng,Engenhorst, Markus,Gautam, Devendraprakash,Schloegl, Robert,Antonietti, Markus
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- High yield synthesis of nitriles by a new enzyme, phenylacetaldoxime dehydratase, from Bacillus sp. strain OxB-1.
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3-Phenylpropionitrile was synthesized from Z-3-phenylpropionaldoxime (0.75 M) in a quantitative yield (98 g/l) by the use of cells of Escherichia coli JM 109/pOxD-90F, a transformant harboring a gene for a new enzyme, phenylacetaldoxime dehydratase, from Bacillus sp. strain OxB-1. Other arylalkyl- and alkyl-nitriles were also synthesized in high yields from the corresponding aldoximes. Moreover, 3-phenylpropionitrile was successfully synthesized by the recombinant cells in 70 and 100% yields from 0.1 M unpurified E/Z-3-phenylpropionaldoxime, which is spontaneously formed from 3-phenylpropionaldehyde and hydroxylamine in a butyl acetate/water biphasic system and aqueous phase, respectively.
- Xie,Kato,Asano
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- Radical Mechanism for the Laser-Induced Explosion of Methyl Isocyanide
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The laser-induced isomerization of methyl isocyanide has previously been shown to exhibit a marked pressure dependence; large-scale isomerization occurs when threshold conditions have been exceeded.Recent investigations of this large-scale isomerization have shown that the threshold is not due to a thermal mechanism as previously believed.In this work, the characteristics of the threshold are examined and it is shown that the threshold is a result of a radical channel.
- Shultz, M. J.,Tricca, Robert E.,Berets, S. L.,Kostas, Christopher,Yam, Loretta M.
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- Studies on V2O5-TiO2 System. Part 3. -Monolayers of V2O5
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The catalytic behaviour of anatase- and rutile-vanadium monolayer-like ccatalysts has been studied in the dehydration of N-ethylformamide (NEF) in the presence of oxygen.The catalysts were prepared using two methods: grafting and impregnation.Physicochemi
- Machej, Tadeusz,Ruiz, Patricio,Delmon, Bernard
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- Infrared Laser-Induced Reaction of Ethyl Isocyanide: Comparison with Methyl Isocyanide
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Results from the infrared laser-induced reaction of ethyl isocyanide indicate the overall behaviour to be similar to that of methyl isocyanide with some significant differences.Similarities include the following: (1) both exhibit a dramatic dependence of nitrile yield on reactant pressure, including a threshold pressure above which massive isomerization occurs; (2) this threshold pressure is not due to a thermal explosion; (3) both contain a radical channel along with the isomerization channel.Major differences between the methyl isocyanide and ethyl isocyanide reactions are attributable to the nature of the radicals in the particular isocyanide system.
- Yam, L. M.,Shultz, M. J.,Rock, Elizabeth J.,Buchau, Susanne
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- LIGAND EFFECTS IN THE HYDROFORMYLATION OF ACRYLONITRILE BY COBALT CARBONYL
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The hydroformylation of acrylonitrile (VCN) using Co2(CO)8/L (L = HN(CH2CN)2, , Me2N(CH2)2NMeH, PPh3, and PCy3) has been examined in methanol solvent.Four reaction pathways are observed which are dependent on L.With no L or with L = HN(CH2CN)2, the reaction produces the desired acetal (MeO)2CHCH2CH2CN.For the more basic amines the reactin produces ca. 50percent yields of hydrodimerization products NCCHMe(CH2)2CN/NC(CH2)4CN in a 10/1 ratio and an ca. 30percent yield of the hydrogenation product CH3CH2CN.These reactions are shown to be metal catalyzed.The main reactionfor Co2(CO)8/PR3 catalyzed systems appears to be a classical Michael addition reaction of the solvent, methanol, with acrylonitrile to give MeOCH2CH2CN.Evidence is given to show that this reaction is catalyzed by phosphine which has dissociated under reaction conditions and not by a ligated cobalt complex.
- Dubois, R. A.,Garrou, P. E.
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- Vapor generation of inorganic anionic species after aqueous phase alkylation with trialkyloxonium tetrafluoroborates
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Aqueous phase reaction of trialkyloxonium tetrafluoroborates, R 3O+BF4- (R=Me, Et) has been tested in the alkylation of simple inorganic anionic substrates such as halogen ions, cyanide, thiocyanate, sulphide an
- D'Ulivo, Alessandro,Pagliano, Enea,Onor, Massimo,Pitzalis, Emanuela,Zamboni, Roberto
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- Synthesis of nitriles from acetonitrile and methanol in the presence of oxide catalysts
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The promoting effect of potassium included in Cr/MgO catalysts for the synthesis of nitriles from acetonitrile and methanol was found. The 5% Cr - 0.5% K/MgO catalyst exhibited the highest activity in the synthesis of nitriles.
- Lapidus,Tsapkina,Kravtsova,Gorlov
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- Amination of allyl alcohol to propionitrile over a Zn30Cr 4.5/γ-Al2O3 bimetallic catalyst via coupled dehydrogenation-hydrogenation reactions
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A Zn30Cr4.5/γ-Al2O3 bimetallic catalyst that can perform coupled dehydrogenation and hydrogenation reactions was prepared for the amination of allyl alcohol to propionitrile. During the catalysis, the hydrogen derived from the dehydrogenation of the alcohol and imine acted as an in situ source for the hydrogenation of the carbon-carbon double bond. The catalyst exhibited good performance for the reaction at atmospheric ammonia pressure. The parameters that affect the catalyst performance were studied thoroughly, and an optimized process for synthesizing propionitrile from allyl alcohol and ammonia over the catalyst was obtained. Under the optimized conditions, the propionitrile yield was greater than 65%. The characterization results indicated that the dehydrogenation reaction mainly occurred on the Lewis acid sites and revealed that ZnAl 2O4 is the active species for the coupled dehydrogenation-hydrogenation reactions. Chromium doping of the γ-Al 2O3-supported zinc catalyst Zn30/γ- Al2O3 resulted in a decrease in the size of the ZnAl 2O4 crystallites, which was favorable for the dehydrogenation-hydrogenation reactions. The characterization results also revealed that the catalyst deactivation was due to carbon deposition on the catalyst during the catalytic run. The catalyst could be reactivated by blowing air into the reactor at a high temperature.
- Zhang, Yuecheng,Wei, Tianyu,Pian, Yanjie,Zhao, Jiquan
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- SELECTIVE REDUCTION OF CONJUGATED DOUBLE BONDS WITH MOLECULAR HYDROGEN AND PALLADIUM(II) COMPLEXED TO FERROCENYLAMINE SULFIDE CATALYSTS
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Highly catalytic chemo- and regioselectivity have been achieved for the reduction of carbon-carbon double bonds conjugated to different unsaturated functional groups by molecular hydrogen and palladium(II) complexes of ferrocenylamine sulfides.Chemical yields and selectivities were more than 99percent in many cases.
- Ali, Hussein M.,Naiini, Ahmad A.,Brubaker, Carl H.
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- MALDI-TOF MS investigation of the unconventional termination of living polyoxazoline with ammonia
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Poly(2-oxazoline) (POx) based materials have experienced renewed interest, due to their biocompatibility and broad functional diversity. Although research pertaining to cationic ring opening polymerization (CROP) of 2-oxazoline derivatives spans upwards of 5 decades, modern characterization techniques, specifically Matrix Assisted Laser-Desorption Ionization—Time of Flight Mass Spectrometry (MALDI-TOF MS), were not available during early studies to aid in identifying polymer end-groups. Through careful synthesis and analytical characterization, evidence supports an alternative mode of nucleophilic attack during ammonia termination, with nucleophilic attack occurring at a different site on the terminal oxazolinium than where polymer propagation occurs. Furthermore, investigations employing targeted end-group modification, in conjunction with MALDI and NMR analysis, determined the structure of the resultant terminal group was a hydroxyethylamino end group. Based on the observed data, a mechanistic explanation for the observed 2-oxazoline ring-opening termination is proposed.
- Kosakowska, Karolina A.,Dimitrov, Philip,Panambur, Gangadhar,Grayson, Scott M.
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- Solid Base-catalysed Rearrangement of Methacrylonitrile to Crotononitrile
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MgO and CaO catalysts have shown high activity for the formation of crotonitrile (cis/trans=6/4) in the rearrangement of methacrylonitrile.
- Kurokawa, Hideki,Nakamura, Satoru,Ueda, Wataru,Morikawa, Yutaka,Moro-oka, Yoshihiko,Ikawa, Tuneo
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- Organic polymer composites as robust, non-covalent supports of metal salts
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A novel organic polymer composite for the encapsulation of metal catalysts and applications to synthesis are described here.
- Ng, Yeap Hung,Wang, Mian,Han, Hong,Chai, Christina L. L.
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- Direct synthesis of propionamide and propiononitrile from ethylene, carbon monoxide, and ammonia using supported Ru and Rh catalysts
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Propionamide and propiononitrile were formed by passing the mixture of ethylene, carbon monoxide, and ammonia under atmospheric pressure over silica-or zeolite-supported Ru ammine complex catalyst. Rh ammine complex also promoted the reaction but the catalytic activity was low. It is inferred that propionamide is formed primarily and is dehydrated successively on the acidic site of the support.
- Zhao, Shu-Ping,Sassa, Shu-Ichi,Inoue, Hideaki,Yamazaki, Masato,Mori, Tohru,Kobayashi, Masahiro,Morikawa, Yutaka
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- Studies on V2O5-TiO2 System. Part 2. -TiO2(anastase)-V2O5
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Mechanical mixtures of separately prepared V2O5, V6O13 and anatase have been used as catalysts in the dehydration of N-ethylformamide (NEF) in the presence of oxygen.Catalytic activity was measured as a function of the gas hourly space velocity (GHSV), th
- Machej, Tadeusz,Remy, Marc,Ruiz, Patricio,Delmon, Bernard
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Read Online
- Study of oxide-based catalysts for the oxidative transformation of acetonitrile to acrylonitrile with CH4
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Various oxides and metal-supported oxides were studied for the oxidative transformation of acetonitrile to acrylonitrile with methane in the range 550 to 730°C. This reaction requires the activation of both methane and the α-carbon of the acetonitrile. Surprisingly, it was found that the effective coupling of the reactants to acrylonitrile does not occur over all the catalysts that are effective for oxidative coupling of methane reactions. Among all the catalysts tested, only Li/MgO with nominal composition of lithium in the range 15 to 30 wt% was effective in forming acrylonitrile. This was probably due to the maximum concentration of [Li+O-] surface centers which catalyze the abstraction of hydrogen from the reactants and simultaneously disfavor the undesired oxidation of the nitriles. It was concluded that the efficiency of Li/MgO could not be attributed to its basicity characteristics. Other oxides such as Sm2O3, La2O3, Bi2O3, and CaO either individually or loaded with monometallic and/or bimetallic combinations of alkali metals are not effective catalysts and oxidize acetonitrile to CO and CO2. Individual magnesia and MgO-loaded with alkali metals (other than lithium) are not effective for the coupling of methane and acetonitrile to form acrylonitrile and propionitrile. We also found that the decrease in the acrylonitrile selectivity for extented periods of operation is associated with the loss of lithium from the Li/MgO catalysts. Undoped samaria and lanthana at elevated temperatures (> 680°C) oxidize acetonitrile completely to CO and CO2. For the latter oxides, if the oxygen fed into the reactor is the limiting reactant, then lattice oxygen is used for the complete oxidation of acetonitrile. The loading of samaria or lanthana with an alkali metal decreases the extent of oxidation reactions. This behavior is in versed when CaO is used as support. FT-IR and temperature-programmed desorption experiments indicate that the increase in the number and strength of the basic sites of the catalysts plays a negative role in the coupling of methane and acetonitrile to acrylonitrile.
- Zhang, Wenmin,Smirniotis, Panagiotis G.
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Read Online
- Reactions of Acetonitrile in a Radiofrequency Discharge
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Acetonitrile was flowed through an inductively coupled radiofrequency (rf) discharge.The products formed under various conditions of power and flow rate were isolated and quantitated by using gas chromatography.The major products were propionitrile, ethane, and hydrogen cyanide.Reaction of mixtures of acetonitrile and cyclohexane gave these three products and cyanocyclohexylmethane, methylcyclohexane, and cyclohexene.All six products can be rationalized by neutral radical reactions.Emission spectroscopy on acetonitrile plasmas showed the expected CN bands from the excited A2? and B2Σ+ states.Analysis of the peak intensities gave a vibrational temperature of ca. 5900K and a rotational temperature of ca. 735K for B2Σ+ state.Lower power, higher pressure, or added ethane diminished the emission intensity but did not change these temperatures.Added argon had no effect up to a mole fraction of argon of 0.8.The absence of cyanoalkanes from plasmas containing CN and alkyl radicals is noted.
- So, Ying-Hung,Bezuk, Steve J.,Miller, Lary L.
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Read Online
- Tail-to-Tail Dimerization of Acrylonitrile Catalyzed by Low-Valent Ruthenium Complexes
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Zero-valent ruthenium complexes, [Ru(cod)(cot)] and [Ru(cod)(benzene)], are effective catalyst precursors for the tail-to-tail dimerization of acrylonitrile. Hydrogen pressure is necessary for the catalytic reaction, and the turnover number for dimers is greatly improved in neat acrylonitrile. Under the conditions of 150 °C and 25 atm of H2 (initial pressure at room temperature), the conversion of acrylonitrile is 61% and the yield of tail-to-tail dimers is 42% (selectivity 69%) in 3 h. The turnover number for the dimers is 2060, which is much higher than those reported so far. From the results of a catalytic reaction under D2 pressure, a reaction mechanism is proposed, in which two successive insertions of acrylonitrile into dihydridoruthenium complex are involved. A fast and reversible insertion of the third acrylonitrile is responsible for the H-D exchange of acrylonitrile in the deuterium labeling experiment.
- Fukuoka, Atsushi,Nagano, Takeyuki,Furuta, Shuichi,Yoshizawa, Michito,Hirano, Masafumi,Komiya, Sanshiro
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Read Online
- NOVEL RHODIUM CLUSTER-CATALYZED REDUCTION OF NITROPROPANE TO PROPIONITRILE UNDER CO AND H2O
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Propionitrile is selectively formed by reduction of nitropropane using CO and H2O (8 atm of CO, 4O deg C).Rhodium carbonyls combined with bases show high catalytic activity.Amines with high pKa values as additives give high yields of propionitrile.
- Kaneda, Kiyotomi,Mori, Teruaki,Kobayashi, Masaya,Imanaka, Toshinobu,Teranishi, Shiichiro
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Read Online
- Ambient Hydrogenation and Deuteration of Alkenes Using a Nanostructured Ni-Core–Shell Catalyst
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A general protocol for the selective hydrogenation and deuteration of a variety of alkenes is presented. Key to success for these reactions is the use of a specific nickel-graphitic shell-based core–shell-structured catalyst, which is conveniently prepared by impregnation and subsequent calcination of nickel nitrate on carbon at 450 °C under argon. Applying this nanostructured catalyst, both terminal and internal alkenes, which are of industrial and commercial importance, were selectively hydrogenated and deuterated at ambient conditions (room temperature, using 1 bar hydrogen or 1 bar deuterium), giving access to the corresponding alkanes and deuterium-labeled alkanes in good to excellent yields. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated by gram-scale reactions as well as efficient catalyst recycling experiments.
- Beller, Matthias,Feng, Lu,Gao, Jie,Jackstell, Ralf,Jagadeesh, Rajenahally V.,Liu, Yuefeng,Ma, Rui
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supporting information
p. 18591 - 18598
(2021/06/28)
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- NHC-catalyzed silylative dehydration of primary amides to nitriles at room temperature
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Herein we report an abnormal N-heterocyclic carbene catalyzed dehydration of primary amides in the presence of a silane. This process bypasses the energy demanding 1,2-siloxane elimination step usually required for metal/silane catalyzed reactions. A detailed mechanistic cycle of this process has been proposed based on experimental evidence along with computational study.
- Ahmed, Jasimuddin,Hota, Pradip Kumar,Maji, Subir,Mandal, Swadhin K.,Rajendran, N. M.
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supporting information
p. 575 - 578
(2020/01/29)
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- A method of synthesizing fatty nitrile by the aliphatic aldehyde
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The invention relates to a method of synthesizing fatty nitrile by the aliphatic aldehyde. The method comprises the following steps: the aliphatic aldehyde, ionic liquid regenerating and ionic liquid in the reactor, to join the two toluene, stirring, of the reflux condensation, in the normal pressure, 90 - 120 °C reaction under 0.5 - 2 h, to obtain the product fatty nitrile; wherein said ionic liquid is 1 - sulfobutyl pyridine bisulphate ionic liquid; ion liquid hydroxylamine salt is 1 - sulfobutyl pyridine bisulphate ion liquid hydroxylamine salt. The invention in one reactor to achieve the fat [...] and fat aldoxime dehydration integrated two-step reaction, the process is simple, easy to operate; to ionic liquid as catalyst and a co-solvent, without the addition of metal salt catalyst and corrosive solvent, environment-friendly.
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Paragraph 0027; 0028; 0039; 0040
(2019/05/28)
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- Nitrilation of carboxylic acids with acetonitrile catalyzed by molybdenum and vanadium complexes
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Various carbonitriles were synthesized by reaction of the corresponding carboxylic acids with acetonitrile in carbon tetrachloride in the presence of VO(acac)2and Mo(CO)6in 6 h at 150–170°C.
- Khusnutdinov,Shchadneva,Bayguzina,Mayakova, Yu. Yu.
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p. 1282 - 1286
(2016/10/26)
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- 1,2,3-Triazolylidene ruthenium(ii)-cyclometalated complexes and olefin selective hydrogenation catalysis
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Silver(i) 1,2,3-triazol-5-ylidenes [(RCH2C2N2(NMe)Ph)2Ag][AgCl2] (R = Ph 3a, C6H2iPr33b, C6H2Me33c) and [(PhCH2C2N2(NMe)R)2Ag][AgCl2] (R = C6H4Me 3d, C6H4CF33e) were synthesized and subsequently treated with RuHCl(PPh3)3 and RuHCl(H2)(PCy3)2. The reaction of 3a with RuHCl(PPh3)3 gave RuHCl(PPh3)2(PhCH2C2N2(NMe)Ph) (4a1) as the minor product and the cyclometalated complex RuCl(PPh3)2(PhCH2C2N2(NMe)C6H4) (4a2) as the major product. However, similar reaction with 3b selectively formed the cyclometalated complex RuCl(PPh3)2((C6H2iPr3)CH2C2N2(NMe)C6H4) (4b2). Similarly the silver(i) triazolylidenes 3a and 3b were reacted with RuHCl(H2)(PCy3)2; gave RuHCl(PCy3)2(PhCH2C2N2(NMe)Ph) (5a1), RuCl(PCy3)2(PhCH2C2N2(NMe)C6H4) (5a2) and RuCl(PCy3)2((C6H2iPr3)CH2C2N2(NMe)C6H4) (5b2), respectively. Species 3c, 3d and 3e resulted in the cyclometalated complexes (5c2, 5d2 and 5e2) as the major products as well as the ruthenium-hydride complexes (5c1, 5d1 and 5e1) as the minor products. The cyclometalated species are derived from the ruthenium-hydride complexes via C(sp2)-H activation. These Ru-complexes were shown to act as hydrogenation catalyst precursors for olefinic substrates including those containing a variety of functional groups. This journal is
- Bagh, Bidraha,McKinty, Adam M.,Lough, Alan J.,Stephan, Douglas W.
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p. 2712 - 2723
(2015/02/19)
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- Half sandwich ruthenium(ii) hydrides: Hydrogenation of terminal, internal, cyclic and functionalized olefins
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Bis(1,2,3-triazolylidene) silver(i) complex 1a was reacted with [RuCl2(p-cymene)]2 to give the ruthenium complex [PhCH2N2(NMe)C2(C6H4CF3)]RuCl2(p-cymene) (2a) as major product in addition to the minor C(sp2)-H activated product [PhCH2N2(NMe)C2(C6H3CF3)]RuCl(p-cymene) (2a′). Similar ruthenium complexes 2b, 2c, 2d and 2e with general formula RuCl2(p-cymene)(NHC) (NHC = MesCH2N2(NMe)C2Ph 2b, PhCH2N2(NMe)C2Ph 2c, TripCH2N2(NMe)C2Ph 2d, IMes 2e) were also synthesized. Subsequent reaction of Me3SiOSO2CF3 with 2a and 2b resulted in cationic ruthenium species [(PhCH2N2(NMe)C2(C6H4CF3))RuCl(p-cymene)][OSO2CF3] (3a) and [(MesCH2N2(NMe)C2Ph)RuCl(p-cymene)][OSO2CF3] (3b), respectively. Complexes 3a and 3b dissolved in CD3CN to give [(PhCH2N2(NMe)C2(C6H4CF3))RuCl(CD3CN)(p-cymene)][OSO2CF3] (4a) and [(MesCH2N2(NMe)C2Ph)RuCl(CD3CN)(p-cymene)][OSO2CF3] (4b), respectively. Cationic ruthenium species 4a and 4b failed to show catalytic activity towards hydrogenation of olefins. Ruthenium(ii) complexes 2b-e with the general formula RuCl2(p-cymene)(NHC) were reacted with Et3SiH to generate a series of ruthenium(ii) hydrides 5b-e. These compounds 5b-e are effective catalysts for the hydrogenation of terminal, internal and cyclic and functionalized olefins.
- Bagh, Bidraha,Stephan, Douglas W.
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p. 15638 - 15645
(2015/01/08)
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- Facile access to 3,5-symmetrically disubstituted 1,2,4-thiadiazoles through phosphovanadomolybdic acid catalyzed aerobic oxidative dimerization of primary thioamides
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In the presence of Keggin-type phosphovanadomolybdic acids, e.g., H 6PV3Mo9O40, oxidative dimerization of various kinds of primary thioamides including aromatic, heterocyclic, and aliphatic ones efficiently proceeded to give the corresponding 3,5-disubstituted 1,2,4-thiadiazoles in excellent yields. This journal is the Partner Organisations 2014.
- Yajima, Kazuhisa,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information
p. 6748 - 6750
(2014/06/23)
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- SOCl 2/β-cyclodextrin: A new and efficient catalytic system for Beckmann rearrangement and dehydration of aldoximes under aqueous condition
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A rapid and efficient synthesis of amides via Beckmann rearrangement of ketoximes and dehydration of aldoximes to corresponding nitriles with good to excellent yields has been carried out in the presence of SOCl 2/β-cyclodextrin under aqueous conditions. The β-cyclodextrin has been recovered and reused. Copyright Taylor & Francis Group, LLC.
- Patil, Dipak,Dalal, Dipak
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p. 118 - 128
(2012/10/30)
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- Conversion of aldoximes into nitriles and amides under mild conditions
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A series of Pd(en)X2 salts were used as catalysts for the conversion of aldoximes into nitriles and amides. Highlights of this protocol include the use of inexpensive polar solvents, including water, and moderate reaction temperatures. A high degree of selectivity in the reaction outcome was observed when using aliphatic vs. aromatic/conjugated aldoximes. The Royal Society of Chemistry 2013.
- Tambara, Koujiro,Pantos, G. Dan
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supporting information
p. 2466 - 2472
(2013/06/05)
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- RUTHENIUM-BASED COMPLEX CATALYSTS
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The present invention provides novel Ruthenium-based transition metal complex catalysts comprising specific ligands, their preparation and their use in hydrogenation processes. Such complex catalysts are inexpensive, thermally robust, and olefin selective.
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Page/Page column 54; 64
(2013/03/26)
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- Rhodium-catalyzed hydrogenation of olefins in γ-valerolactone-based ionic liquids
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γ-Valerolactone-based ionic liquids were successfully used as the catalyst phase for [Rh(cod)2][BF4]/RP(C6H 4-m-SO3Na)2 (R = Me, Pr, Bu, Cp) catalyzed hydrogenation of different olefins. Compared to broadly used ionic liquids e.g. 1-butyl-3-methylimidazolium chloride [bmim][Cl], the turnover frequencies were significantly higher and the reaction was selective for the CC double bonds in the presence of carbonyl, cyano, and phenyl groups. The catalyst was recycled for ten consecutive runs under regular or biphasic conditions without loss of activity. The vapour pressure and viscosity of γ-valerolactone-based ionic liquids were determined as well.
- Stradi, Andrea,Molnar, Mark,Ovari, Mihaly,Dibo, Gabor,Richter, Frank U.,Mika, Laszlo T.
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p. 1857 - 1862
(2013/09/24)
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- One-pot synthesis of nitriles from aldehydes catalyzed by deep eutectic solvent
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The choline chloride-urea (1:2) based deep eutectic mixture as an efficient and ecofriendly catalyst for the one-pot synthesis of nitriles from aldehydes under solvent-free conditions under both conventional and microwave irradiation; the products were obtained in good to excellent yields. Georg Thieme Verlag Stuttgart New York.
- Patil, Umakant B.,Shendage, Suresh S.,Nagarkar, Jayashree M.
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p. 3295 - 3299
(2013/12/04)
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- Molecular iodine in aqueous ammonia: Oxidative fragmentation of oxiranes to nitriles
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Oxiranes undergo oxidative fragmentation, when treated with iodine in aqueous ammonia, to give nitriles. The reaction goes via formation of 1,2-amino alcohols as intermediates followed by CC bond cleavage. Advantages of the method are use of off-the-shelf nonexplosive, unlike previously used potentially explosive o-iodoxybenzoic acid, reagents, mild reaction conditions, and easy work-up procedure.
- Jadhav, Ravindra R.,Akamanchi, Krishnacharya G.
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p. 162 - 164
(2013/03/28)
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- Synthetic and mechanistic studies of metal-free transfer hydrogenations applying polarized olefins as hydrogen acceptors and amine borane adducts as hydrogen donors
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Metal-free transfer hydrogenation of polarized olefins (RR′ CCEE′: R, R′ = H or organyl, E, E′ = CN or CO2Me) using amine borane adducts RR′NH-BH3 (R = R′ = H, AB; R = Me, R′ = H, MAB; R = tBu, R′ = H, tBAB; R = R′ = Me, DMAB) as hydrogen donors, were studied by means of in situ NMR spectroscopy. Deuterium kinetic isotope effects and the traced hydroboration intermediate revealed that the double H transfer process occurred regio-specifically in two steps with hydride before proton transfer characteristics. Studies on substituent effects and Hammett correlation indicated that the rate determining step of the HN transfer is in agreement with a concerted transition state. The very reactive intermediate [NH2BH2] generated from AB was trapped by addition of cyclohexene into the reaction mixture forming Cy2BNH2. The final product borazine (BHNH)3 is assumed to be formed by dehydrocoupling of [NH2BH2] or its solvent stabilized derivative [NH2BH2]-(solvent), rather than by dehydrogenation of cyclotriborazane (BH2NH 2)3 which is the trimerization product of [NH 2BH2].
- Yang, Xianghua,Fox, Thomas,Berke, Heinz
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experimental part
p. 852 - 860
(2012/02/05)
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- A cis-bis-mixed-carbene ruthenium hydride complex: An olefin-selective hydrogenation catalyst
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The N-heterocyclic carbene C3H2N2(CH 2CH2OMe)2 (1; IOMe) reacts with RuHCl(PPh 3)3 to give RuClH(IOMe)(PPh3)2 (2), which reacts further with SIMes to give the cis-bis-mixed-carbene complex RuClH(IOMe)(SIMes)(PPh3) (3). This species has been shown to be a highly effective hydrogenation catalyst that tolerates the presence of a wide range of functional and donor groups.
- Lund, Clinton L.,Sgro, Michael J.,Cariou, Renan,Stephan, Douglas W.
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scheme or table
p. 802 - 805
(2012/04/17)
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- A substrate-driven approach to determine reactivities of α,β-unsaturated carboxylic esters towards asymmetric bioreduction
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The degree of C=C bond activation in the asymmetric bioreduction of α,β-unsaturated carboxylic esters by ene-reductases was studied, and general recommendations to render these "borderline-substrates" more reactive towards enzymatic reduction are proposed. The concept of "supported substrate activation" was developed. In general, an additional α-halogenated substituent proved to be beneficial for enzymatic activity, whereas β-alkyl or β-aryl substituents were detrimental for the reactivity of nonhalogenated substrates, and α-cyano groups showed little effect. The alcohol moiety of the ester functionality was found to have a strong influence on the reaction rate. Overall, activities were determined by both steric and electronic effects. Biotransformation: The asymmetric bioreduction of α,β-unsaturated carboxylic esters by ene-reductases could be tuned by varying the degree of C=C bond activation (see scheme). An additional α-halogenated substituent proved to be beneficial for enzymatic activity, whereas β-alkyl or β-aryl substituents were detrimental for the reactivity of nonhalogenated substrates. Copyright
- Tasnádi, Gábor,Winkler, Christoph K.,Clay, Dorina,Sultana, Nargis,Fabian, Walter M. F.,Hall, Mélanie,Ditrich, Klaus,Faber, Kurt
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experimental part
p. 10362 - 10367
(2012/10/08)
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- Facile synthesis of nitriles via manganese oxide promoted oxidative dehydrosulfurization of primary thioamides
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In the presence of manganese oxides, dehydrosulfurization of various kinds of primary thioamides including aromatic, heterocyclic, and aliphatic ones efficiently proceeded to give the corresponding nitriles in high yields. The observed catalysis was truly heterogeneous, and manganese oxides could be reused.
- Yamaguchi, Kazuya,Yajima, Kazuhisa,Mizuno, Noritaka
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supporting information
p. 11247 - 11249
(2013/01/15)
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- Characterization of covalent Ene adduct intermediates in "hydride equivalent" transfers in a dihydropyridine model for NADH reduction reactions
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A study of the reactions of an NADH model, 1,4-di(trimethylsilyl)-1,4- dihydropyridine, 7, with a series of α,β-unsaturated cyano and carbonyl compounds has produced the first direct evidence for an obligatory covalent adduct between a dihydropyridine and substrate in a reduction reaction. The reactions were monitored by NMR spectroscopy. In all reactions studied, the covalent adduct was the first new species detected and its decomposition to form products could be observed. Concentrations of adducts were sufficiently high at steady-state that their structures could be determined directly from NMR spectra of the reaction mixtures; adduct structures are those expected from an Ene reaction between 7 and the substrate. This first reaction step results in transfer of the C4 hydrogen nucleus of 7 to the substrate and formation of a covalent bond between C2 of the dihydropyridine ring and the substrate α-atom. Discovery of these Ene-adduct intermediates completes the spectrum of mechanisms observed in NADH model reactions to span those with free radical intermediates, no detectable intermediates and now covalent intermediates. The geometry of the transition state for formation of the Ene adduct is compared with those of theoretical transition state models and crystal structures of enzyme-substrate/inhibitor complexes to suggest a relative orientation for the dihydropyridine ring and the substrate in an initial cyclic transition state that is flexible enough to accommodate all observed mechanistic outcomes.
- Libby, R. Daniel,Mehl, Ryan A.
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experimental part
p. 57 - 66
(2012/03/26)
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- Reaction of triflyl-imidazole with aldoximes: Facile synthesis of nitriles and formation of novel aldoxime-bis(N-triflyl)-imidazole adducts
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The synthetic utility of N-triflylimidazole as an in situ reagent for facile, high yielding, synthesis of various aliphatic, aromatic, and heteroaromatic nitriles from the corresponding aldoximes has been demonstrated. With benzaldoximes, in the presence of certain substitutents (2-F; 2-OMe; 3-CF3; 2-Me-5-F) a different course of reaction was observed, leading instead to novel 1:1 aldoxime-bis(N-triflyl)imidazole covalent adducts, in which the aldoxime oxygen atom is bonded to the imidazole C-2 ring carbon. For these aldoximes, conversion to nitrile could be effected by reaction with Tf2O in the absence of imidazole. The molecular structure of the adduct formed from 2-methyl-5-fluoro-benzaldoxime was confirmed by X-ray analysis. Plausible mechanisms for the formation of 1:1 covalent adducts have been considered. Various attempts to isolate such adducts via the reaction of an authentic sample of bis(N-triflyl)imidazolium trifate with aldoxime were unsuccessful. Remarkably, whereas isolated benzaldoxime adducts undergo deprotonation/methylation with NaH/MeI, an authentic sample of bis(N-triflyl)imidazolium triflate did not undergo H/Me exchange under these conditions. These transformations are discussed.
- Kalkhambkar, Rajesh G.,Bunge, Scott D.,Laali, Kenneth K.
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supporting information; experimental part
p. 5184 - 5187
(2011/10/13)
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- UV laser photodeposition of nanomagnetic soot from gaseous benzene and acetonitrile-benzene mixture
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Megawatt KrF laser gas-phase photolysis of benzene and acetonitrile-benzene mixture was studied by using mass spectroscopy-gas-chromatography and Fourier transform infrared spectroscopy for analyses of volatile products, and by Fourier transform infrared, Raman and X-ray photoelectron spectroscopy, electron microscopy and magnetization measurements for analyses of solid products deposited from the gas-phase. The results are consistent with carbonization of benzene and decomposition of non-absorbing acetonitrile in carbonizing benzene through collisions with excited benzene and/or its fragments. The solid products from benzene and acetonitrile-benzene mixture have large surface area and are characterized as nanomagnetic amorphous carbonaceous soot containing unsaturated C centers prone to oxidation. The nanosoot from acetonitrile-benzene mixture incorporates CN groups, confirms reactions of benzene fragments with CN radical and has a potential for modification by reactions at the CN bonds.
- Pola, Josef,Ouchi, Akihiko,Mary?ko,Vorlí?ek,?ubrt, Jan,Bakardjieva,Bastl, Zdeněk
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experimental part
p. 188 - 194
(2012/02/02)
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- Dihydrogen reduction of nitroarmatics, alkenes, alkynes, benzaldehyde, and benzil by newly synthesized Rh(I) complexes in homogeneous phase
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Rh(I) complexes of S-triazines and azobenzene were found to be very efficient towards the catalytic hydrogenation of alkenes, alkynes at normal pressure, and at room temperature. Reduction of aromatic nitrocompounds, benzaldehyde, and benzil were observed in appreciable amounts only at high pressure and at high temperature. No diminished catalytic activity was observed even after 6-8 repeated catalytic runs. Profound effect was observed on the rate of reduction in presence of extra ligand without affecting the nature of yield, both under normal and high pressure conditions. Kinetics was studied. Mechanism has been proposed and rate equation has been derived. Copyright Taylor & Francis Group, LLC.
- Sagar, Priyanka,Rani, Varsha
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experimental part
p. 754 - 761
(2011/02/28)
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- Release and Recovery from Aliphatic Primary Amines or Di-Amines
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There is disclosed a process for hydrogen release and chemical storage by dehydrogenating low molecular weight aliphatic amines and di-amines to produce their corresponding nitriles in a reactor system containing a hydrogen fractionation membrane (or sweep gas) to quickly remove any and all hydrogen generated during the dehydrogenation reaction. This disclosure further provides a process for hydrogen recovery using bi- and tri-functional amines that produce corresponding nitriles and high density hydrogen release.
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Page/Page column 6-7
(2010/08/22)
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- Efficient conversion of aldoximes to nitriles using phosphoric acid diethyl ester 2-phenylbenzimidazol-1-yl ester
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Aromatic aldoximes were converted to the corresponding nitriles in good to excellent yields by employing phosphoric acid diethyl ester 2- phenylbenzimidazol-1-yl ester as reagent. The method was equally effective for oximes bearing electron-donating and electron-withdrawing substituents. Graphical Abstract: [Figure not available: see fulltext.]
- Kokare, Nagnnath D.,Shinde, Devanand B.
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experimental part
p. 185 - 188
(2010/03/26)
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- Selective oxidation of propylamine to propionitrile and propionaldehyde on oxygen-covered gold
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Oxidative dehydrogenation of amines using heterogeneous gold catalysts has unanticipated potential; chemisorbed atomic oxygen is used to activate propylamine, producing propionitrile and/or propionaldehyde on a single-crystal Au(111) surface. The Royal So
- Gong, Jinlong,Yan, Ting,Mullins, C. Buddie
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body text
p. 761 - 763
(2009/07/10)
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- Iodine/aqueous NH4OAc: An improved reaction system for direct oxidative conversion of aldehydes and alcohols into nitriles
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A convenient method for direct oxidative conversion of aldehydes and alcohols into nitriles has been developed by using the inexpensive and environmentally friendly reagent I2/aqueous NH4OAc. The aqueous NH4OAc as a non-toxic cyanide source is more eco-friendly than aqueous ammonia, because gaseous ammonia evaporates easily from aqueous ammonia but not from aqueous NH4OAc.
- Ren, Yi-Ming,Zhu, Yi-Zhong,Cai, Chun
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- A facile and high efficient synthesis of nitriles from aldoximes and primary amides with a mixture of triphenylphosphine/2, 3-dichloro-5, 6-dicyanobenzoquinone (PPh3DDQ) under neutral conditions
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Aldoximes are immediately converted to their corresponding nitriles with a mixture of triphenylphosphine and 2,3dichloro-5,6-dicyanobenzoquinone in dichloromethane under neutral conditions at room temperature., Nitriles are also formed from the reaction of primary amides with this reagent in refluxing acetonitrile under neutral conditions.
- Aghapour, Ghasem,Amirabadi, Marjan
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p. 649 - 652
(2008/09/18)
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- Organic reactions in water: Transformation of aldehydes to nitriles using NBS under mild conditions
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Aliphatic, aromatic, heterocyclic, conjugated, and polyhydroxy aldehydes gave corresponding nitriles in high yields at 0°C using NBS and ammonia in water. Copyright Taylor & Francis Group, LLC.
- Bandgar,Makone
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p. 1347 - 1352
(2007/10/03)
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- Rhodococcus nitrile hydratase
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The invention relates to a Rhodococcus polynucleotide cluster which contains nucleotide sequences which encode polypeptides having the activity of a nitrile hydratase, of an auxiliary protein P15K which activates this enzyme and of a cobalt transporter, to transformed microorganisms in which the nucleotide sequences encoding these proteins are present in increased quantity, and to the use of the transformed microorganisms for preparing amides from nitriles.
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- HIGH-PURITY ACETONITRILE AND PROCESS FOR PRODUCING THE SAME
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A process for producing high-purity acetonitrile having a low absorbance at a wavelength of 200 nm. It requires a reduced amount of energy for purification and the purification step is simple. It considerably diminishes the propionitrile contained in acetonitrile. The process for high-purity acetonitrile production is characterized by mixing hydrous crude acetonitrile with an alkali, separating the mixture into an acetonitrile phase and an aqueous phase, removing the aqueous phase, subjecting the resultant acetonitrile phase to a distillation step to obtain purified acetonitrile, and passing the resultant purified acetonitrile through an cation-exchange resin to obtain high-purity acetonitrile.
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Page/Page column 9-10
(2008/06/13)
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- Highly efficient conjugate reduction of α,β-unsaturated nitriles catalyzed by copper/xanthene-type bisphosphine complexes
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α,β-Unsaturated nitriles are chemoselectively reduced to the corresponding saturated nitriles in high yields using a copper-DPEphos or Xantphos complex as catalyst in the presence of polymethylhydrosiloxane (PMHS) as the stoichiometric reducing agent and t-butanol as additive. The Royal Society of Chemistry 2005.
- Kim, Daesung,Park, Bu-Mahn,Yun, Jaesook
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p. 1755 - 1757
(2007/10/03)
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- Regioselective HON-addition of bifunctional hydrazone oximes to Pt(IV)-bound nitriles
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Treatment of frans-[PtCl4(RCN)2] (R = Me, Et) with the hydrazone oximes MeC(=NOH)C(R′)=NNH2 (R′ = Me, Ph) at 45°C in CH2Cl2 led to the formation of trans-[PtCl4{NH=C(R)ON=C(Me)C(R′)=NNH2} 2] (R/R′ = Me/Ph 1, Et/ Me 2, Et/Ph 3) due to the regioselective OH-addition of the bifunctional MeC(=NOH)C(R′)=NNH 2 to the nitrile group. The reaction of 3 and Ph3P= CHCO2Me allows the formation of the Pt(II) complex trans-[PtCl 2{NH= C(Et)ON=C(Me)C(Ph)=NNH2}2] (4). In 4, the imine ligand was liberated by substitution with 2 equivalents of bis(1,2-diphenylphosphino)ethane (dppe) in CDCl3 to give, along with the free ligand, the solid [Pt(dppe)2]Cl2. The free iminoacyl hydrazone, having a restricted life-time, decomposes at 20-25°C in about 20 h to the parent organonitrile and the hydrazone oxime. The Schiff condensation of the free NH2 groups of 4 with aromatic aldehydes, i.e. 2-OH-5-NO2-benzaldehyde and 4-NO2-benzaldehyde, brings about the formation of the platinum(II) complexes trans-[PtCl 2{NH=C(Et)ON=C(Me)C(Ph)=NN=CH(C6H3-2-OH-5- NO2}2] (5) and trans-[PtCl2{NH= C(Et)ON=C(Me)C(Ph)=NN=CH(C6H4-4-NO2} 2] (6), respectively, containing functionalized remote peripherical groups. Metallization of 5, which can be considered as a novel type of metallaligand, was achieved by its reaction with M(OAc) 2·nH2O (M = Cu, n= 2; M = Co, n = 4) in a 1: 1 molar ratio furnishing solid heteronuclear compounds with composition [Pt]: [M] = 1: 1. The complexes were characterized by C, H, N elemental analyses, FAB - mass-spectrometry, IR, 1H, 13C{1H and 195Pt NMR spectroscopies; X-ray structures were determined for 3, 4 and 5.
- Garnovskii, Dmitrii A.,Pombeiro, Armando J.L.,Haukka, Matti,Sobota, Piotr,Kukushkin, Vadim Yu.
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p. 1097 - 1103
(2007/10/03)
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- RhCl3-catalyzed hydroboration of alkenyl nitriles
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RhCl3-promoted hydroboration-oxidation reactions of representative alkenyl nitriles have been carried out. Carbanion of acetonitrile is formed from the carbon-carbon heterolytic bond breaking in allyl cyanide during hydroboration. An unexpected process-trimerization of carbanion of acetonitrile has lead to the formation of 4-amino-2,6-dimethylpyrimidine.
- Buranov, Anvar U.,Morrill, Terence C.
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p. 6301 - 6304
(2007/10/03)
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- Organic reactions in water: Highly rapid CAN mediated one-pot synthesis of nitriles from aldehydes under mild conditions
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A variety of aliphatic and aromatic nitriles were prepared from the corresponding aldehydes in high yield in a direct one pot and rapid process using ceric ammonium nitrate (CAN) in amonia-water under mild conditions.
- Bandgar,Makone
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p. 262 - 264
(2007/10/03)
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- A rapid and facile conversion of primary amides and aldoximes to nitriles and ketoximes to amides with triphenylphosphine and N-chlorosuccinimide
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Primary amides and aldoximes are easily converted to their corresponding nitriles using a mixture of triphenylphosphine and N-chlorosuccinimide in dichloromethane at room temperature. The reaction of aldoximes occurs almost immediately and primary amides in 0.5h by this method. By this procedure secondary amides are produced by Beckmann rearrangement of ketoximes.
- Iranpoor,Firouzabadi,Aghapour
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p. 2535 - 2541
(2007/10/03)
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- Platinum(IV)-mediated coupling of dione monoximes and nitriles: A novel reactivity pattern of the classic oxime-based chelating ligands
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The reaction between dione monoximes and platinum(IV) nitrile complexes leads, instead of the conventional substitution, to metal-mediated coupling, giving iminoacylated species which, on being liberated, undergo disintegration to the nitrile and the oxime.
- Makarycheva-Mikhailova, Anastassiya V.,Haukka, Matti,Bokach, Nadezhda A.,Garnovskii, Dmitrii A.,Galanski, Markus,Keppler, Bernhard K.,Pombeiro, Armando J. L.,Kukushkin, Vadim Yu.
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p. 1085 - 1091
(2007/10/03)
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- Synthesis and pyrolysis of tetrahydro-1,4-oxazine-3,5-diones and tetrahydro-1,4-thiazine-3,5-diones
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The preparation and characterization of six 4-substituted tetrahydro-l,4-oxazine-3,5-diones and five 4-substituted tetrahydro-l,4-thiazine-3,5-diones is described. Upon flash vacuum pyrolysis at 700°C these give N-substituted acetamides and nitriles, and a mechanism for formation of these products is proposed.
- Aitken,Farrell,Kirton
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p. 1526 - 1531
(2007/10/03)
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