- Ammoxidation of Ethanol to Acetonitrile over Molecular Sieves
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For the first time, we report the ammoxidation of ethanol over crystalline, microporous silica-aluminophosphate and Y zeolite with >99.0 and 40.0percent m/m yields of acetonitrile respectively.
- Kulkarni, S. J.,Rao, R. Ramachandra,Subrahmanyam, M.,Rao, A. V. Rama
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- Vibrational Overtone Activation of the Isomerization of Methyl Isocyanide
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The photoisomerization of methyl isocyanide to form acetonitrile induced by excitation into the fourth (ca. 1 kcal/mol above the activation barrier) and fith (ca. 8 kcal/mol above the barrier) C-H stretch vibrational overtones is reported.The ratio of the collisional deactivation rate constant to be unimolecular rate coefficient, k(ε), was determined by a Stern-Volmer analysis plotting the inverse apparent rate constant against the total pressure.The unimolecular rate coefficients increase monotonically with increasing excitation energies across the rotational band contours.The experimental k(ε) agree with RRKM calculated values.The Stern-Volmer plots are nonlinear at low pressure: the fourth overtone excitation shows negative curvature (decreasing slope with increasing pressure) and the fifth overtone shows positive curvature (increasing slope with increasing pressure).The magnitude and direction of this curvature agree well with the calculated Stern-Volmer plots in earlier work using a master equation simulation.In these vibrational overtone activation studies, the collisional deactivation efficiency of argon is 0.3 of that of the self-collider.
- Hassoon, Salah,Rajapakse, Nandani,Snavely, Deanne L.
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- Cationic Titanium(IV) Complexes via Halide Abstraction from : Crystal and Molecular Structure of 3*2MeCN
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Treatment of (cp=η5-C5H5) with SbCl5 as chloride abstractor in acetonitrile provided hexachloroantimonate(V) salts of (1+), (2+) and (3+) respectively.With 1:1 stoichiometry red-brown crystals of 1 are obtained and with 1:2 stoichiometry light blue crystals of 2 2.Complete removal of chloride ion from requires a six-fold excess of SbCl5 when purple-blue crystals of 3 3 can be isolated.These products were characterised by analytical and spectroscopic (IR, 1H NMR) data and, in the case of 3, by a crystal structure determination.Proton NMR studies indicate the presence of intermediate halide-bridged species in solution during the sequential halide abstractions 1 --> 2 --> 3.Crystals of complex 3, obtained as the bis(solvate) from recrystallisation in acetonitrile, are monoclinic and X-ray structural analysis confirmed the formulation.The crystal structure a=19.650(4), b=19.182(4), c=12.958(3) Angstroem, β=91.612(3) deg, Z=4, R=0.0386, R'=0.0406> shows discrete cations and anions and a pseudo-octahedral co-ordination sphere for the Ti(IV).A significant trans influence of the cyclopentadienyl ligand affects Ti-N bond lengths in the complex.
- Willey, Gerald R.,Butcher, Mark L.,McPartlin, Mary,Scowen, Ian J.
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- Structure, stability, and generation of CH3CNS
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The unstable acetonitrile N-sulfide molecule CH3CNS has been photolytically generated in inert solid argon matrix from 3,4-dimethyl-1,2,5- thiadiazole by 254-nm UV irradiation, and studied by ultraviolet spectroscopy and mid-infrared spectroscopy. The molecule is stable in the matrix to 254-nm UV irradiation, but decomposes to CH3CN and a sulfur atom when broad-band UV irradiation is used. Chemiluminescence due to S2 formation from triplet sulfur atoms was detected on warming the matrix to ~20-25K. The ground-state structure and potential uni- and bimolecular reactions of CH3CNS are investigated using B3LYP, CCSD(T), and MR-AQCC quantum-chemical methods. CH3CNS is demonstrated to be stable under isolated conditions at room temperature, i.e. in the dilute gas phase or in an inert solid matrix, but unstable owing to bimolecular reactions, i.e. in the condensed phase. CSIRO 2010.
- Krebsz, Melinda,Hajgato, Balazs,Bazso, Gabor,Tarczay, Gyoergy,Pasinszki, Tibor
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- An unusual coordination mode of acetylide ligands: synthesis of tetranuclear copper(I) complexes containing μ3-η1acetylide ridging ligands. Crystal structure of 3-η1-CCPh)-(Ph2Ppy-P)>4 (Ph2Ppy=2-(diphenylphosphine)pyridine)
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The preparation and properties of novel tetranuclear copper(I) complexes of the type CR)(L-L)4 (L-L = 2-(diphenylphosphine)pyridine (Ph2Ppy) R = tBu, Ph; L-L = bis(diphenylphosphino)methane (dppm), R = Ph are described.The crystal structure of 3-η1-CCPh)(Ph2Ppy-P)>4 has been determined by X-ray diffraction.Crystals are monoclinic, space group C2/c with Z=4 in a unit cell of dimensions a 14.859(3), b 24.405(4), c 23.279(4) Angstroem and β 95.35(2) deg; refinement gave R = 0.056 for 3586 reflections with I>=2.5?(I).The molecule consists of a tetrahedral cluster of copper atoms bearing four μ3-η1 phenylacetylide and four monodentate P-bonded 2-(diphenylphosphine)pyridine ligands (Ph2Ppy-P).IR, 1H and 31P-NMR data are discussed.
- Gamasa, Pilar M.,Gimeno, Jose,Lastra, Elena,Solans, Xavier
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- Ground-state rotational spectrum of CH3NC...HCN and the nature of hydrogen bonds involving triply-bonded carbon
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The ground state rotational spectra of the hydrogen-bonded species CH3NC...HCN and CH3NC...DCN have been studied using the technique of pulsed-nozzle Fourier-transform microwave spectroscopy.The spectra were of the symmetric top type and their analysis led to the rotational constants B0 = 969.0435(4) MHz and 964.7530(5) MHz for the parent and deuterated molecule, respectively.The centrifugal distortion constants, DJ and DJK, were established to be 0.369(7) kHz for CH3NC...HCN, and 0.356(8) kHz and 39.4(2) kHz for the deuterium species, while the corresponding (14)N-nuclear coupling constants were χ(14N) = -4.23(11) MHz and -4.5(1) MHz.Analysis of the centrifugal constants DJ using a model of C3v symmetry with the atoms arranged in the order H3CNC...HCN gave the quadratic force constant associated with stretching of the hydrogen bond as 9.3(1) N m-1 and 9.7(1) N m-1 in CH3NC...HCN and CH3NC...DCN, respectively.The distances in these isotopomers between the carbon nuclei adjacent to the hydrogen bond r(C...C), were found to be 3.433(3) Angstroem and 3.420(3) Angstroem, when using a model that compensates for the contributions of the intermolecular bending modes to the zero-point motion.
- Legon, A. C.,Thorn, J. C.
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- Ammoxidation of ethylene over low and over-exchanged Cr-ZSM-5 catalysts
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Catalytic performances of Cr-ZSM-5 catalysts (5 wt.% of Cr, Si/Al = 26), prepared by solid-state reaction and aqueous exchange, from Cr nitrate and Cr acetate precursors, were evaluated in the selective ammoxidation of ethylene into acetonitrile in the temperature range 425.500 °C. Catalysts were characterized by chemical and thermal analysis, XRD, N2 physisorption, 27Al MAS NMR, TEM, UV-vis DRS, Raman, DRIFTS and H2-TPR. Characterization results shown that solid-state exchange was favorable for Cr2O3 formation, while exchanging chromium in aqueous phase led, essentially, to Cr(VI) species. Catalysts were actives and selectives in the studied reaction, and among them, those, prepared from aqueous exchange, exhibited the highest acetonitrile yields (23±0.5%, at 500 °C). Improved catalytic properties can be correlated with the chromium species nature. In fact, mono/di-chromates and/or polychromate species, sited in the charge compensation positions, were definitively shown, as being, the active sites. Furthermore, during solid-state reaction, the agglomeration of Cr2O3 oxide should be avoided since these species inhibit the catalyst activity.
- Ayari,Mhamdi,álvarez-Rodríguez,Guerrero Ruiz,Delahay,Ghorbel
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- A double decker type complex: Copper(I) iodide complexation with mixed donor macrocycles via [1:1] and [2:2] cyclisations
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19-membered and a 38-membered macrocycles obtained as a mixture via respective [1:1] and [2:2] cyclisations were separated and their coordination behaviours with copper(I) iodide were investigated. One of the notable products isolated is a tetranuclear bis(macrocycle) complex with the larger macrocycle adopting a double decker type structure. Furthermore, removal of the lattice solvent molecules in the above complex in air motivates the displacement of the double decker units along the a-axis by sliding in a single-crystal-to-single-crystal manner.
- Kang, Yunji,Park, In-Hyeok,Ikeda, Mari,Habata, Yoichi,Lee, Shim Sung
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- Synthesis and ligand-based mixed valency of cis- and trans-CrIII(X4SQ)(X4Cat)(L)n (X = Cl and Br, n = 1 or 2) complexes: Effects of solvent media on intramolecular charge distribution and ligand dissociation of CrIII(X4SQ)3
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The treatment of CrIII(X4SQ)3 (SQ = o-semiquinonate; X = Cl and Br) with acetonitrile affords trans CrIII(X4SQ)- (X4Cat)(CH3CN)2 (X = Cl (1) and Br (2)). In the presence of 2,2′-bipyridine (bpy) or 3,4,7,8-tetramethyl-1,10-phenanthrene (tmphen), the reaction affords CrIII(X4SQ)(X4Cat)(bpy) ·nCH3CN (X = Cl, n = 1 (3); X = Br, n = 0.5 (4)) or CrIII(X4SQ)(X4Cat)(tmphen) (X = Cl (5) and Br (6)), respectively. All of the complexes show a ligand-based mixed-valence (LBMV) state with SQ and Cat ligands. The LBMV state was confirmed by the presence of the interligand intervalence charge-transfer band. Spectroscopic studies in several solvent media demonstrate that the ligand dissociation included in the conversion of CrIII(X4SQ)3 to 1-6 occurs only in solvents with relatively high polarity. On the basis of these results, the effects of solvent media were examined and an equilibrium, CrIII(X4SQ)3 ? CrIII(X4BQ)(X4SQ)(X4Cat) (BQ = o-benzoquinone), is proposed by assuming an interligand electron transfer induced by solvent polarity.
- Chang, Ho-Chol,Mochizuki, Katsunori,Kitagawa, Susumu
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- Picosecond Kinetics by Exchange Broadening in the Infrared and Raman. 3. CH3CN.IBr
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Spectra of the ν2 and ν3+ν4 bands of CH3CN in the presence of IBr and in CCl4 solution were measured over a range of temperatures.The spectra could be analyzed to reveal the kinetics of the CH3CN + IBr CH3CN.IBr reaction, in the picosecond range.Association and dissociation rate constants were determined and, from them, activation energies and entropies.
- Cohen, Benyamin,Weiss, Shmuel
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- A reaction pathway for the ammoxidation of ethane and ethylene over Co-ZSM-5 catalyst
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The ammoxidation of ethane and ethylene to acetonitrile was studied over a Co-ZSM-5 catalyst with an emphasis on the reaction pathway. We found that the adsorption of ammonia on Co-ZSM-5 is stronger than that on H-ZSM-5. CzH4 adsorption is weak and readily desorbs below 300°C. While the adsorption of C2H3N (a reaction product) is very strong in He, its desorption is accelerated with the presence of NH3. With a specially designed temperature programmed experiment (reaction between the adsorbed NH3 and gaseous C2H4/O2/He mixture), we observed C2H5NH2 as a reactive intermediate, and this intermediate was demonstrated to be readily converted to C2H3N under the ammoxidation reaction conditions. A detailed pathway is offered, whereby C2H4 is thought to add on an adsorbed NH3, forming an adsorbed ethylamine which is subsequently dehydrogenated to form C2H3N. We further speculate that an oxidative environment N2 comes from N-N pairing between the adsorbed NH3 and an amine (both on a single Co2+ site).
- Li, Yuejin,Armor, John N.
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- ENERGY TRANSFER IN THE INFRARED LASER-INDUCED REACTION OF METHYL ISOCYANIDE
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Experimental results are presented for the infrared laser-induced isomerization of methyl isocyanide to acetonitrile in the presence of several bath gases: Ar, O2, CO2, CH4, C2H6, C2H5CN, C2H5NC, and di-tert-butyl peroxide (DTBP).For all addends except DTBP, increasing the bath gas pressure results in a decrease in acetonitrile yield due to collosional deactivation of the methyl isocyanide.The efficiency of this collosional deactivation is related to the heat capacity and to the vibrational mode distribution of the buffer gas.Ethyl isocyanide as a buffer gas shows an enhanced suppression of the acetonitrile yield due to moderation of the radical channel for the reaction.DTBP, on the other hand, increases the acetonitrile yield and lowers the threshold for massive isomerization due to its generation of methyl radicals.
- Shultz, M. J.,Yam, L. M.,Tricca, Robert E.
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- Effect of phosphorus-oxygen compounds on structural, acidic, and catalytic properties of γ-alumina in the acetic acid ammonolysis reaction
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The effect of a promoter on the acidic and catalytic properties of aluminum oxide in the reaction of acetic acid ammonolysis has been studied. It has been shown that the promotion of γ-Al2O3 with phosphorus-oxygen compounds results in a change in the porous structure, an increase in the concentration of acid sites, and site strength redistribution, thereby enhancing the activity and selectivity of the catalyst. The change in the acid properties of γ-Al2O3 surface has a significant effect on the second stage of the process, the dehydration of acetamide.
- Galanov,Sidorova
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- Acetonitrile Formation from Ethylene and Ammonia over Zn2+ and Cd2+ Exchanged Y-zeolites
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Zn2+ and Cd2+ exchanged Y-zeolites are found to be active for acetonitrile formation from ethylene and ammonia.Their catalytic activities are much higher than that on Al2O3, which has been known to be an active catalyst for this reaction.
- Takahashi, Nobuo,Minoshima, Hiroshi,Iwadera, Hiroyuki
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- Interdependence of Fluence and Pressure in the Laser-Induced Isomerization of Methyl Isocyanide
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The infrared 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.In this work the wavelength and fluence dependence of the pressure threshold have been investigated.It has been determined that threshold conditions reflect a balance between the average level of excitation and the sample pressure.The multiphoton spectrum and the treshold as a function of wavelength have been determined and both reflect the structure of the linear absorption spectrum, indicating that the effective anharmonicity is small.In addition, the earlier conclusion that the threshold is not due to a laser-triggered, thermal explosion is corroborated.
- Shultz, M. J.,Tricca, Robert E.,Yam, Loretta M.
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- Laser photochemistry and transient Raman spectroscopy of silyl-substituted Fischer-type carbene complexes
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Pulsed laser irradiation of the silyl-substituted carbene complexes (CO)5W=C(XR)SiPh3 (XR = NC4H8 (1); = OEt (2)) in various solvents has been investigated using transient absorbance and time-resolved resonance Raman scattering as monitoring techniques. Irradiation of (1) in noncoordinating or weakly-coordinating solvents at 355 nm within the ligand field absorption band results in the rapid formation, within the laser pulse duration, of a permanent photoproduct. Saturation of the irradiated solution with CO results in regeneration of the starting complex 1. IR and Raman spectral data suggest that the photoproduct is the internally stabilized 16-electron species (CO)4W=C(NC4H8)SiPh3. The observations are discussed in relation to the previously reported formation of the same 16-electron species by thermolysis of 1. When the irradiation is carried out in CH3CN as solvent, UV-visible evidence suggests formation of the photosubstituted species (CO)4(CH3CN)W=C(NC4H8)SiPh 3. No photoactivity, either transient or permanent, is seen in any solvent when the irradiation is carried out at 416 nm, a wavelength which falls within the MLCT absorption region of 1. When the ethoxy-substituted carbene complex 2 is irradiated in either the LF or MLCT absorption regions a transient species forms rapidly, within the laser pulse duration, and decays on a time scale of several μs, with a lifetime dependent on solvent polarity but independent of CO concentration in solution. Time-resolved resonance Raman studies in which the sample is photolyzed at 355 nm and probed by means of a delayed pulse at 406 nm show the formation and decay of a transient consistent with the flash photolysis results. The data are interpreted in terms of photoinduced anti-syn isomerization of 2 about the Ccarbene-O bond.
- Rooney, A. Denise,McGarvey, John J.,Gordon, Keith C.,McNicholl, Ruth-Anne,Schubert, Ulrich,Hepp, Wolfgang
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- Radiolytic Studies of Ruthenium Oxo-Acetato Trinuclear Complexes in Acetonitrile
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Redox reactions of the ruthenium(III,III,III) and ruthenium(III,III,II) trinuclear cluster complexes PF6 and Ru3(μ3-O)(μ-CH3COO)6(py)3, (Ru(333) and Ru(332), respectively) in acetontrile were studied by pulse radiolysis.Irradiation of deaerated Ru(333) acetonitrile solutions induced one-electron reduction of the trinuclear Ru(333) center by the acetonitrile radical anion, CH3CN(*-), to Ru(332).When Ru(332) was used as a parent complex, irradiation afforded Ru(322).The yield of CH3CN(*-) was evaluated to be 0.21 μmol J-1.In aerated solutions, Ru(333) was competitively reduced by CH3CN(*-) with a rate constant of 6.1 x 1010 M-1 s-1 and the superoxide ion, O2(-), with a rate constant of 3.5 x 109 M-1 s-1 at 14 deg C.Ru(332) once produced decayed to regenerate Ru(333) in 100-300 μs after the electron-pulse irradiation.Oxidation of Ru(332) by the peroxyl radical, (*)OCH2CN, to Ru(333) with a rate constant of 2.7 x 109 M-1 s-1 was confirmed.The whole reaction scheme for the radiation-induced processes is discussed.
- Imamura, Taira,Sumiyoshi, Takashi,Takahashi, Kenta,Sasaki, Yoichi
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- Experimental and ab Initio Theoretical Study of the Kinetics of Rearrangement of Ketene Imine to Acetonitrile
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When heated by reflected shock waves to temperatures between 1400 and 1700 K at pressures of approximately 12-15 atm, mixtures of acetonitrile in argon (0.4-7 mol percent) exhibit strong banded absorption in the ultraviolet region between 320 and 250 nm.The carrier of the absorption spectrum is ketene imine, H2C=C=NH.Time-resolved spectra of ketene imine have been recorded with exposure times between 100 and 200 μs using a charge-coupled device (CCD) with an imaging spectrograph.Through the use of the technique of pixel binning, temporal profiles of formation and equilibration of ketene imine have been obtained with a time resolution of 24 μs.The rearrangement of ketene imine acetonitrile has been studied using ab initio quantum chemical techniques.The calculations predict the rate-determining step in the rearrangement process to be the 1,2-hydrogen transfer of the imine hydrogen to the adjacent carbon atom to produce vinyl nitrene.With the aid of the ab initio results, the experimental rate data for the reaction ketene imine -> acetonitrile have been extrapolated to the high-pressure limit, yielding the rate constant expression k = 1013.4(+/-0.5) exp(-294(+/-14) kJ mol-1/RT) s-1.
- Doughty, Alan,Bacskay, George B.,Mackie, John C.
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- Structural characterization of tris(pyrazolyl)hydroborato and tris(2-pyridylthio)methyl lithium compounds: Lithium in uncommon trigonal pyramidal and trigonal monopyramidal coordination environments
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X-ray diffraction reveals that the molecular structures of the tris(pyrazolyl)hydroborato and tris(2-pyridylthio) methyl lithium compounds, [TpBut, R]Li (R = H, Me) and [κ4-Tptm]Li, respectively exhibit threecoordinate trigonal pyram
- Chakrabarti, Neena,Sattler, Wesley,Parkin, Gerard
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- One Step Synthesis of Acetonitrile from Ethanol via Ammoxidation over Sb-V-P-O/Al2O3 Catalyst
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Selective synthesis of acetonitrile in one step from ethanol by ammoxidation is reported, for the first time, using alumina supported and antimony promoted vanadium phosphorus oxide catalyst.
- Reddy, Benjaram M.,Manohar, Basude
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- Thermal Explosions of Methyl Isocyanide in Spherical Vessels
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An improved set of measurements, including a wide variety of consistency tests, on the thermal explosion of methyl isocyanide in spherical vessels from 0.3 to 12.6 L at 350 deg C is presented.We also report an accidental explosion which took place with liquid methyl isocyanide at room temperature.
- Clothier, P. Q. E.,Glionna, M. T. J.,Pritchard, H. O.
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- Mild temperature palladium-catalyzed ammoxidation of ethanol to acetonitrile
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The ammoxidation of ethanol is investigated as a renewable process for the production of acetonitrile from a bio-feedstock. Palladium catalysts are shown to be active and very selective (>99%) to this reaction at moderate to low temperatures (150-240 °C), with acetonitrile yields considered a function of Pd morphology. Further investigations reveal that the stability of these catalysts is influenced by an unselective product, and that any deactivation observed is reversible. Interpretation of this deactivation allows operating conditions to be defined for the stable, high yielding production of acetonitrile from ethanol.
- Hamill, Conor,Driss, Hafedh,Goguet, Alex,Burch, Robbie,Petrov, Lachezar,Daous, Muhammad,Rooney, David
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- Conversion of methane to acetonitrile over GaN catalysts derived from gallium nitrate hydrate co-pyrolyzed with melamine, melem, or g-C3N4: the influence of nitrogen precursors
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Co-pyrolyzing gallium nitrate hydrate and melamine, melem, or g-C3N4 generates gallium nitride (GaN) for the conversion of methane to acetonitrile (AcCN). The solid-state-pyrolysis-made GaN catalysts exhibited better activity than commercial GaN. Among the as-prepared catalysts, GaN made by using g-C3N4 with a N/Ga ratio of 2 (i.e., GaN-(C3N4)-(2)) was the most attractive: a high initial methane conversion (28.2%), a high initial AcCN productivity (151 μmol gcat?1 min?1), and a 6 h accumulated AcCN yield (5816 μmol gcat?1) were obtained at 700 °C with a space time of 3000 mLCH4?gcat?1?h?1. GaN-(C3N4)-(2) had finely dispersed GaN crystals and enriched amorphous CN species (e.g., sp2 N and C N groups), and both are important in promoting the methane conversion rate. GaN agglomeration, coke deposition, and depleted CN species contributed to the deactivation of the catalyst, and a nitridation–activation process could rejuvenate the activity partially. The analysis of the structure–activity correlation revealed that the accumulated AcCN yield had an inverse trend with respect to the crystallite size of GaN and the sp3/sp2 ratio of the N environment.
- Chen, Chi-Liang,Chen, Chin-Han,Huang, Ai-Lin,Lee, Jyh-Fu,Lin, Yu-Chuan,Trangwachirachai, Korawich
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p. 320 - 331
(2022/01/19)
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- Product selectivity controlled by manganese oxide crystals in catalytic ammoxidation
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The performances of heterogeneous catalysts can be effectively tuned by changing the catalyst structures. Here we report a controllable nitrile synthesis from alcohol ammoxidation, where the nitrile hydration side reaction could be efficiently prevented by changing the manganese oxide catalysts. α-Mn2O3 based catalysts are highly selective for nitrile synthesis, but MnO2-based catalysts including α, β, γ, and δ phases favour the amide production from tandem ammoxidation and hydration steps. Multiple structural, kinetic, and spectroscopic investigations reveal that water decomposition is hindered on α-Mn2O3, thus to switch off the nitrile hydration. In addition, the selectivity-control feature of manganese oxide catalysts is mainly related to their crystalline nature rather than oxide morphology, although the morphological issue is usually regarded as a crucial factor in many reactions.
- Hui, Yu,Luo, Qingsong,Qin, Yucai,Song, Lijuan,Wang, Hai,Wang, Liang,Xiao, Feng-Shou
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p. 2164 - 2172
(2021/09/20)
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- Reactivity of vanadyl pyrophosphate catalyst in ethanol ammoxidation and β-picoline oxidation: Advantages and limitations of bi-functionality
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This study investigates the catalytic activity of vanadyl pyrophosphate (VPP) for both gas-phase ethanol ammoxidation to acetonitrile and β-picoline oxidation to nicotinic acid. Both reactions may be alternative processes to the industrial technologies used to produce these two chemicals. The reaction networks were investigated, also by feeding possible intermediates; in-situ DRIFT spectroscopy was used to monitor the interaction of ethanol and ammonia with the catalyst. VPP bi-functionality features played an important role in the two reactions; specifically, acidity was detrimental either because it catalyzed undesired reactions, such as ethanol dehydration to ethylene during ethanol ammoxidation, or because it caused a strong interaction with reactants – especially those containing N atoms, ammonia and β-picoline – thus giving rise to some surface saturation phenomena which inhibited the consecutive reactions leading to the final desired compounds, acetonitrile and nicotinic acid. The co-feeding of steam helped product desorption, thus enhancing selectivity in β-picoline oxidation.
- Tabanelli, Tommaso,Mari, Massimiliano,Folco, Federico,Tanganelli, Federico,Puzzo, Francesco,Setti, Laura,Cavani, Fabrizio
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- Redox-Induced Structural Reorganization Dictates Kinetics of Cobalt(III) Hydride Formation via Proton-Coupled Electron Transfer
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Two-electron, one-proton reactions of a family of [CoCp(dxpe)(NCCH3)]2+ complexes (Cp = cyclopentadienyl, dxpe = 1,2-bis(di(aryl/alkyl)phosphino)ethane) form the corresponding hydride species [HCoCp(dxpe)]+ (dxpe = dppe (1,2-bis(diphenylphosphino)ethane), depe (1,2-bis(diethylphosphino)ethane), and dcpe (1,2-bis(dicyclohexylphosphino)ethane)) through a stepwise proton-coupled electron transfer process. For three [CoCp(dxpe)(NCCH3)]2+ complexes, peak shift analysis was employed to quantify apparent proton transfer rate constants from cyclic voltammograms recorded with acids ranging 22 pKa units. The apparent proton transfer rate constants correlate with the strength of the proton source for weak acids, but these apparent proton transfer rate constants curiously plateau (kpl) as the reaction becomes increasingly exergonic. The absolute apparent proton transfer rate constants across both these regions correlate with the steric bulk of the chelating diphosphine ligand, with bulkier ligands leading to slower kinetics (kplateau,depe = 3.5 × 107 M-1 s-1, kplateau,dppe = 1.7 × 107 M-1 s-1, kplateau,dcpe = 7.1 × 104 M-1 s-1). Mechanistic studies were conducted to identify the cause of the aberrant kPTapp-ΔpKa trends. When deuterated acids are employed, deuterium incorporation in the Cp ring is observed, indicating protonation of the CoCp(dxpe) species to form the corresponding hydride proceeds via initial ligand protonation. Digital simulations of cyclic voltammograms show ligand loss accompanying initial reduction gates subsequent PCET activity at higher driving forces. Together, these experiments reveal the details of the reaction mechanism: reduction of the Co(III) species is followed by dissociation of the bound acetonitrile ligand, subsequent reduction of the unligated Co(II) species to form a Co(I) species is followed by protonation, which occurs at the Cp ring, followed by tautomerization to generate the stable Co(III)-hydride product [HCoCp(dxpe)]+. Analysis as a function of chelating disphosphine ligand, solvent, and acid strength reveals that the ligand dissociation equilibrium is directly influenced by the steric bulk of the phosphine ligands and gates protonation, giving rise to the plateau of the apparent proton transfer rate constant with strong acids. The complexity of the reaction mechanism underpinning hydride formation, encompassing dynamic behavior of the entire ligand set, highlights the critical need to understand elementary reaction steps in proton-coupled electron transfer reactions.
- Kurtz, Daniel A.,Dhar, Debanjan,Elgrishi, Noémie,Kandemir, Banu,McWilliams, Sean F.,Howland, William C.,Chen, Chun-Hsing,Dempsey, Jillian L.
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supporting information
p. 3393 - 3406
(2021/03/08)
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- Lewis Acidic Boranes, Lewis Bases, and Equilibrium Constants: A Reliable Scaffold for a Quantitative Lewis Acidity/Basicity Scale
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A quantitative Lewis acidity/basicity scale toward boron-centered Lewis acids has been developed based on a set of 90 experimental equilibrium constants for the reactions of triarylboranes with various O-, N-, S-, and P-centered Lewis bases in dichloromethane at 20 °C. Analysis with the linear free energy relationship log KB=LAB+LBB allows equilibrium constants, KB, to be calculated for any type of borane/Lewis base combination through the sum of two descriptors, one for Lewis acidity (LAB) and one for Lewis basicity (LBB). The resulting Lewis acidity/basicity scale is independent of fixed reference acids/bases and valid for various types of trivalent boron-centered Lewis acids. It is demonstrated that the newly developed Lewis acidity/basicity scale is easily extendable through linear relationships with quantum-chemically calculated or common physical–organic descriptors and known thermodynamic data (ΔH (Formula presented.)). Furthermore, this experimental platform can be utilized for the rational development of borane-catalyzed reactions.
- Mayer, Robert J.,Hampel, Nathalie,Ofial, Armin R.
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supporting information
p. 4070 - 4080
(2021/01/29)
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- Characteristics of Si-Y mixed oxide supported nickel catalysts for the reductive amination of ethanol to ethylamines
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Si-Y mixed oxide synthesis was achieved via Si dissolution from a Pyrex reactor during the synthesis of yttrium hydroxide by the precipitation method at pH 10 and an aging temperature of 100 ℃. The Ni/SY mixed oxide catalysts with 5–25 wt% Ni contents were synthesized using an incipient wetness impregnation method. The characterization of the calcined Ni/SY oxide catalysts was performed using N2-sorption, X-ray diffraction, H2-temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and ethanol-TPD. The reaction parameters such as reaction temperature and the partial pressures of ethanol, NH3, and H2 were varied in the reductive amination reaction, and the catalytic activities for the production of monoethylamine, diethylamine, triethylamine, and acetonitrile as main products were compared. The 10 wt% Ni/SY oxide catalyst containing 11 wt% Si showed the maximum activity, and the presence and absence of H2 and NH3 had a great effect on the conversion and selectivities. The stability after 110 h on stream was observed to be 2.5% less than the initial activity. The cause of this deactivation is the formation of nickel carbonitride, as confirmed by XPS and temperature programmed oxidation (TPO) measurements. On the basis of a detailed proposed reaction mechanism, reaction rates were determined, and the kinetic parameters were estimated by fitting the experimental data obtained under a variety of conditions. Our kinetic model showed that the temperature and the partial pressures of ethanol and hydrogen significantly influenced the conversion, whereas the partial pressure of ammonia had little influence because the imine partial pressure rapidly reached saturation.
- Jeong, Ye-Seul,Woo, Yesol,Park, Myung-June,Shin, Chae-Ho
-
p. 287 - 297
(2019/10/14)
-
- Isolable Copper(I) ?2-Cyclopropene Complexes
-
Treatment of bis(pyrazolyl)borate ligand supported [(CF3)2Bp]Cu(NCMe) with 1,2,3-trisubstituted cyclopropenes produced thermally stable copper(I) ?2-cyclopropene complexes amenable to detailed solution and solid-state analysis. The [(CF3)2Bp]Cu(NCMe) also catalyzed [2 + 1]-cycloaddition chemistry of terminal and internal alkynes with ethyl diazoacetate affording cyclopropenes, including those used as ligands in this work. The tris(pyrazolyl)borate [(CF3)2Tp]Cu(NCMe) is a competent catalyst for this process as well. The treatment of [(CF3)2Tp]Cu with ethyl 2,3-diethylcycloprop-2-enecarboxylate substrate gave an O-bonded rather than a ?2-cyclopropene copper complex.
- Noonikara-Poyil, Anurag,Ridlen, Shawn G.,Dias, H.V.Rasika
-
supporting information
p. 17860 - 17865
(2020/11/30)
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- PROCESS FOR PRODUCING METHACRYLIC ACID OR METHACRYLIC ACID ESTERS
-
The present invention relates to a process for producing methacrylic acid or methacrylic acid esters. The present invention is directed to a new process for the production of methacrylic acid or alkyl methacrylate starting from Acrolein, which is available from glycerol or propane.
- -
-
Page/Page column 15-16
(2020/03/02)
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- PRODUCTION OF ACETONITRILE AND/OR HYDROGEN CYANIDE FROM AMMONIA AND METHANOL
-
The invention relates to a process for producing a product gas comprising acetonitrile and/or hydrogen cyanide from a feed stream comprising ammonia and methanol over a solid catalyst comprising a support, a first metal and a second metal on the support, wherein the first metal and the second metal are in the form of a chemical compound, wherein the first metal is Fe, Ru or Co and the second metal is Sn, Zn, or Ge. The pressure is ambient pressure or higher and the temperature lies in a range from about 400° C. to about 700° C. Thus, the process for producing acetonitrile and/or hydrogen cyanide from ammonia and methanol may be catalyzed by a single catalyst and may be carried out in a single reactor. The invention also relates to a catalyst, a method for activating a catalyst and use of a catalyst for catalysing production of acetonitrile and/or hydrogen cyanide from ammonia and methanol.
- -
-
Paragraph 0046-0049
(2020/04/10)
-
- Oxophosphonium-Alkyne Cycloaddition Reactions: Reversible Formation of 1,2-Oxaphosphetes and Six-membered Phosphorus Heterocycles
-
While the metathesis reaction between alkynes and carbonyl compounds is an important tool in organic synthesis, the reactivity of alkynes with isoelectronic main-group R2E≠O compounds is unexplored. Herein, we show that oxophosphonium ions, which are the
- L?we, Pawel,Feldt, Milica,Wünsche, Marius A.,Wilm, Lukas F.B.,Dielmann, Fabian
-
supporting information
p. 9818 - 9826
(2020/07/10)
-
- Regioselective Intramolecular Allene Amidation Enabled by an EDA Complex**
-
The addition of radicals to unsaturated precursors is a powerful tool for the synthesis of both carbo- and heterocyclic organic building blocks. The recent advent of mild ways to generate N-centered radicals has reignited interest in exploiting highly regio-, chemo-, and stereoselective transformations that employ these reactive intermediates. While the additions of aminyl, iminyl, and amidyl radicals to alkenes and alkynes have been well-studied, analogous additions to allenes are scarce. Allenes offer several attractive features, including potential for selective amidation at three distinct sites via judicious choice of precursor or radical source, the opportunity for axial-to-point chirality transfer, and productive trapping of vinyl or allyl radical intermediates to diversify functionality in the products. In this article, we report a regioselective addition of amidyl radicals to allenes to furnish an array of valuable N-heterocycle scaffolds.
- Liu, Lu,Ward, Robert M.,Schomaker, Jennifer M.
-
supporting information
p. 13783 - 13787
(2020/10/06)
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- Method of preparation of ethylamine or acetonitrile by reductive amination of ethanol
-
The present invention relates to a catalyst for manufacturing ethylamine and a method for manufacturing the same. More specifically, the present invention relates to: a nickel-supported catalyst for manufacturing ethylamine or acetonitrile which has impregnated nickel on a supporter as a catalyst capable of efficiently manufacturing ethylamine or acetonitrile at a normal pressure or lower by reacting ethanol with ammonia, a method for manufacturing the same, and a method for manufacturing ethylamine using the same.COPYRIGHT KIPO 2019
- -
-
Paragraph 0095-0099; 0107; 0135; 0178; 0187; 0205
(2019/06/22)
-
- A method of synthesizing fatty nitrile by the aliphatic aldehyde
-
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.
- -
-
Paragraph 0027-0038
(2019/05/28)
-
- CATALYST COMPOSITIONS AND PROCESS FOR DIRECT PRODUCTION OF HYDROGEN CYANIDE IN AN ACRYLONITRILE REACTOR FEED STREAM
-
The present invention relates to catalyst compositions containing a mixed oxide catalyst of formula (I) or formula (II) as described herein, their preparation, and their use in a process for ammoxidation of various organic compounds to their corresponding nitriles and to the selective catalytic oxidation of excess NH3 present in effluent gas streams to N2 and/or NOx.
- -
-
Paragraph 0266
(2019/01/25)
-
- ZEOLITE CATALYST
-
The present disclosure relates to the preparation of pyridine derivatives, such as α-picoline or α-parvoline, and catalysts useful for the selective preparation of such pyridine derivatives. Particularly, the present disclosure relates to the selective preparation of certain pyridine derivative using dealuminated zeolite catalysts.
- -
-
Paragraph 0101; 0103; 0120; 0122; 0130; 0136-0137
(2019/05/22)
-
- Transition-metal-free addition reaction for the synthesis of 3-(aminobenzylidene/aminoalkylidene)indolin-2-ones and its synthetic applications
-
A novel and efficient transition-metal-free approach for the exclusive synthesis of Z-3-(aminobenzylidene/aminoalkylidene)indolin-2-ones in high yield from 2-oxindole and aryl/alkyl nitrile in the presence of LiOtBu and 2,2′-bipyridine system is described. In addition, we disclosed a new approach towards the metal-free fluorination using selectfluor and the C=C bond cleavage using CuI and environmentally benign O2.
- Bisht, Girish Singh,Gnanaprakasam, Boopathy
-
supporting information
p. 13516 - 13527
(2019/10/19)
-
- Synthetic method of organically synthesized intermediate acetonitrile
-
The invention relates to a synthetic method of organically synthesized intermediate acetonitrile. The synthetic method primarily comprises the following steps: adding 0.5mol of acetamide, 0.7-0.9mol of sulfur dioxide and 0.9mol of oxygen into a reaction container; uniformly mixing the compounds; raising the reaction temperature to 60-65 DEG C to react for 30-40 min; collecting a distillate; washing the distillate with a sodium sulfite solution, washing the distillate with a carbon tetrachloride solution, and washing the distillate with a cyclohexane solution; dehydrating the distillate with adehydrant; filtering the mixture to remove the dehydrant; carrying out reduced pressure distillation on the filtrate; and collecting a fraction at 60-65 DEG C to obtain a finished product acetonitrile.
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-
Paragraph 0006; 0010-0015
(2018/07/30)
-
- Corresponding amine nitrile and method of manufacturing thereof
-
The invention relates to a manufacturing method of nitrile. Compared with the prior art, the manufacturing method has the characteristics of significantly reduced using amount of an ammonia source, low environmental pressure, low energy consumption, low production cost, high purity and yield of a nitrile product and the like, and nitrile with a more complex structure can be obtained. The invention also relates to a method for manufacturing corresponding amine from nitrile.
- -
-
Paragraph 0153; 0154; 0155; 0156; 0157
(2018/05/07)
-
- Synthesis of α-aminonitriles using aliphatic nitriles, α-amino acids, and hexacyanoferrate as universally applicable non-toxic cyanide sources
-
In cyanation reactions, the cyanide source is often directly added to the reaction mixture, which restricts the choice of conditions. The spatial separation of cyanide release and consumption offers higher flexibility instead. Such a setting was used for the cyanation of iminium ions with a variety of different easy-to-handle HCN sources such as hexacyanoferrate, acetonitrile or α-amino acids. The latter substrates were first converted to their corresponding nitriles through oxidative decarboxylation. While glycine directly furnishes HCN in the oxidation step, the aliphatic nitriles derived from α-substituted amino acids can be further converted into the corresponding cyanohydrins in an oxidative C-H functionalization. Mn(OAc)2 was found to catalyze the efficient release of HCN from these cyanohydrins or from acetone cyanohydrin under acidic conditions and, in combination with the two previous transformations, permits the use of protein biomass as a non-toxic source of HCN.
- Nauth, Alexander M.,Konrad, Tim,Papadopulu, Zaneta,Vierengel, Nina,Lipp, Benjamin,Opatz, Till
-
supporting information
p. 4217 - 4223
(2018/09/29)
-
- A Light-Releasable Potentially Prebiotic Nucleotide Activating Agent
-
Investigations into the chemical origin of life have recently benefitted from a holistic approach in which possible atmospheric, organic, and inorganic systems chemistries are taken into consideration. In this way, we now report that a selective phosphate activating agent, namely methyl isocyanide, could plausibly have been produced from simple prebiotic feedstocks. We show that methyl isocyanide drives the conversion of nucleoside monophosphates to phosphorimidazolides under potentially prebiotic conditions and in excellent yields for the first time. Importantly, this chemistry allows for repeated reactivation cycles, a property long sought in nonenzymatic oligomerization studies. Further, as the isocyanide is released upon irradiation, the possibility of spatially and temporally controlled activation chemistry is thus raised.
- Mariani, Angelica,Russell, David A.,Javelle, Thomas,Sutherland, John D.
-
supporting information
p. 8657 - 8661
(2018/07/15)
-
- Ethanol gas-phase ammoxidation to acetonitrile: The reactivity of supported vanadium oxide catalysts
-
New insights on the gas-phase ammoxidation of ethanol to acetonitrile over supported vanadia catalysts were obtained by means of reactivity experiments (in ethanol ammoxidation and oxidation) as well as in situ Raman and DRIFT spectroscopy. It was found that the rate-determining step during the redox process depends on the support type. In the case of V2O5/ZrO2, the V oxidation state under reaction conditions is closer to V5+, whereas with V2O5/TiO2, the reduction of V5+ is faster than the re-oxidation of the corresponding reduced V species by O2; thus, the V oxidation state under steady state conditions is lower than for V2O5/ZrO2. In the latter catalyst, the more oxidized V species is responsible for ammonia activation and reaction with the intermediate acetaldehyde, leading in the end to a better acetonitrile yield than with V2O5/TiO2. It was also found that V2O5/ZrO2 is more selective to acetaldehyde than V2O5/TiO2. With the former catalyst, ethanol is able to reduce V2O5 only to a limited extent. Conversely, V2O5/TiO2 is readily reduced by ethanol but this reduced V species is responsible for an unselective oxidation of the alcohol, giving more CO and CO2.
- Folco,Velasquez Ochoa,Cavani,Ott,Janssen
-
p. 200 - 212
(2017/03/27)
-
- SYSTEMS AND METHODS FOR PRODUCING NITRILES
-
An aspect of the present disclosure is a method that includes a first reacting a molecule from at least one of a carboxylic acid, an ester of a carboxylic acid, and/or an anhydride with ammonia to form a nitrile, where the first reacting is catalyzed using an acid catalyst. In some embodiments of the present disclosure, the molecule may include at least one of acetic acid, lactic acid, and/or 3-hydroxyproprionic acid (3-HPA). In some embodiments of the present disclosure, the molecule may include at least one of methyl acetate, ethyl lactate, and/or ethyl 3-hydroxypropanoate (ethyl 3-HP). In some embodiments of the present disclosure, the anhydride may be acetic anhydride.
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Page/Page column 8
(2017/09/08)
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- A hydrophilic inorganic framework based on a sandwich polyoxometalate: Unusual chemoselectivity for aldehydes/ketones with in situ generated hydroxylamine
-
A hydrophilic inorganic porous catalyst was prepared via the hydrothermal method. The combination of [WZn3(H2O)2(ZnW9O34)2]12- and Co(ii) provides a synergistical catalytic way to promote oximation of aldehyde/ketone with in situ generated hydroxylamine that initially produces an oxime, which further either dehydrates into a nitrile or undergoes a Beckmann rearrangement to form an amide.
- Xing, Songzhu,Han, Qiuxia,Shi, Zhuolin,Wang, Shugai,Yang, Peipei,Wu, Qiang,Li, Mingxue
-
supporting information
p. 11537 - 11541
(2017/09/18)
-
- Palladium-Catalyzed Isomerization/(Cyclo)carbonylation of Pentenamides: a Mechanistic Study of the Chemo- and Regioselectivity
-
A new isomerizing ring-closing amidocarbonylation reaction is reported using Pd catalysis with bulky diphosphane ligands. From terminal as well as internal pentenamide isomers (PAs), cyclic imides were obtained in good yield (92 %) with cationic Pd catalysts supported by bis-PCg ligands (PCg=6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamant-6-yl). An excess of strong acid is required to obtain high selectivity for imide products. From a low-temperature NMR study it was deduced that N coordination of the amide moiety is responsible for a high selectivity to cyclic imide products. In weakly acidic conditions, O coordination of the amide functionality leads to the formation of cyanoacids (i.e., 5-cyanovaleric acid, 2-methyl-4-cyanobutyric acid and 2-ethyl-3-cyanopropionic acid). It is proposed that the formation of these cyanoacids occurs through a novel intramolecular tandem dehydrating hydroxycarbonylation reaction of PAs. This reaction also occurs in intermolecular versions of amidocarbonylation with mixtures of alkene and amide substrates. Experiments with N-alkylated amides have been instrumental in developing mechanistic models. The strong acid co-catalyst ensures double-bond isomerization to occur faster than product formation, resulting in the same product mixture, irrespective of the use of terminal or internal pentenamides. The remaining challenge is to arrive at the desired adipimide by overcoming the undesirable regioselectivity caused by chelation of the amide.
- Limburg, Bart,Gloaguen, Yann,de Bruijn, Hans M.,Drent, Eite,Bouwman, Elisabeth
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p. 2961 - 2971
(2017/08/15)
-
- Coordinatively Labile 18-Electron Arene Ruthenium Iminophosphonamide Complexes
-
The thermodynamics of chloride dissociation from the 18e arene ruthenium iminophosphonamides [(η6-arene)RuCl{(R′N)2PR2}] (1 a–d) [previously known with arene=C6Me6, R=Ph, R′=p-Tol (a); R=Et, R′=p-Tol (b); R=Ph, R′=Me (c); and new with arene=p-cymene, R=Ph, R′=p-Tol (d)] was assessed in both polar and apolar solvents by variable-temperature UV/Vis, NMR, and 2D EXSY 1H NMR methods, which highlighted the influence of the NPN ligand on the equilibrium parameters. The dissociation enthalpy ΔHd decreases with increasing electron-donating ability of the N- and P-substituents (1 a, 1 d>1 b>1 c) and solvent polarity, and this results in exothermic spontaneous dissociation of 1 c in polar solvents. The coordination of neutral ligands (MeCN, pyridine, CO) to the corresponding 16e complexes [(η6-arene)Ru{(R′N)2PR2}]+PF6? (2 a–d) is reversible; the stability of the 2?L adducts depends on the π-accepting ability of L. Carbonylation of 2 a and 2 d resulted in rare examples of cationic arene ruthenium carbonyl complexes (3 a, 3 d), while the monocarbonyl adduct derived from 2 c reacts further with a second equivalent of CO with conversion to carbonyl-carbamoyl complex 3 c, in which one CO molecule is inserted into the Ru?N bond. The new complexes 1 d, 2 d, 3 a, 3 c, and 3 d were isolated and structurally characterized.
- Sinopalnikova, Iana S.,Peganova, Tat'yana A.,Novikov, Valentin V.,Fedyanin, Ivan V.,Filippov, Oleg A.,Belkova, Natalia V.,Shubina, Elena S.,Poli, Rinaldo,Kalsin, Alexander M.
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p. 15424 - 15435
(2017/10/11)
-
- Subsititue Material As Well As Production Process And Application
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The invention relates to a production process of a functionalized material containing acid groups and an application thereof. The material is used as a nonhomogenous catalyst, and can be used for removing organic and inorganic compounds in product streams, process streams and waste liquid, or can be used as a cation and anion exchanger, a metal chromatography material, a solid phase purifying or extracting material, a fixed biological moleculaar material, a solid phase sythesizing material and a chromatography material. The invention also relates to a novel sulfonic acid or hypophosphorous organic funtionalized silica gel and metal salts thereof.
- -
-
Paragraph 0104; 0105
(2017/08/28)
-
- Propane Versus Ethane Ammoxidation on Mixed Oxide Catalytic Systems: Influence of the Alkane Structure
-
Abstract: Catalysts from three different catalytic systems, Ni–Nb–O, Mo–V–Nb–Te–O and Sb–V–O, have been prepared, characterized, and tested during both ethane and propane ammoxidation reactions, in order to obtain acetonitrile and acrylonitrile, respectively. The catalytic results show that Mo–V–Nb–Te–O and Sb–V–O catalyze propane ammoxidation but are inactive for ethane ammoxidation whereas Ni–Nb–O catalysts catalyze both, ethane and propane ammoxidation. The activity results, and the characterization of fresh and used catalysts along with some data from previous studies, indicate that the ammoxidation reaction mechanism that occurs in these catalytic systems is different. In the case of Mo–V–Nb–Te–O and Sb–V–O, two active sites appear to be involved. In the case of Ni–Nb–O catalysts, only one site seems to be involved, which underlines that the mechanism is different and take place via a different intermediate. These catalysts activate the methyl groups in ethane, on the contrary, neither ethane nor ethylene appear to adsorb on the Mo–V–Nb–Te–O and Sb–V–O active sites. Graphical Abstract: [Figure not available: see fulltext.]
- Guerrero-Pérez, M. Olga,Rojas-García, Elizabeth,López-Medina, Ricardo,Ba?ares, Miguel A.
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p. 1838 - 1847
(2016/10/18)
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- New composite catalysts for the synthesis of acetonitrile from ethanol and ammonia, prepared using calcium aluminates (Talyum)
-
Experiments on direct synthesis of acetonitrile from ethanol, ammonia, and hydrogen at 513–573 K in the presence of new Cu-, Cu–Zn–(Zr)-, and Cu–Mg-containing composite catalysts prepared using calcium aluminates (Talyum, technical-grade calcium aluminate) were performed The following results were reached: ethanol conversion 96.0–99.0%, selectivity with respect to acetonitrile 99.0%, and acetonitrile output exceeding the reported level by a factor of 1.2–1.4. The new technology can be implemented in industry.
- Belov,Markov,Sova,Golosman,Nechugovskii
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p. 414 - 420
(2016/07/06)
-
- Agostic versus Terminal Ethyl Rhodium Complexes: A Combined Experimental and Theoretical Study
-
Ethylene insertion into Rh-H bonds in complexes bearing an anionic fac-triphosphane ligand gives hydrido complexes, β-agostic species, or noninteracting ethyl derivatives depending on the reaction conditions. Several chemical equilibria between these species have been analyzed by NMR and DFT calculations, which revealed that they are mainly controlled by the entropy. Moreover, β-agostic species were found to be lower in enthalpy than the corresponding hydride-ethylene complexes, probably due to the steric pressure exerted by the bulky fac-triphosphane ligand.
- Geer, Ana M.,López, José A.,Ciriano, Miguel A.,Tejel, Cristina
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supporting information
p. 799 - 808
(2016/03/25)
-
- Transition-Metal-Free Deacylative Cleavage of Unstrained C(sp3)-C(sp2) Bonds: Cyanide-Free Access to Aryl and Aliphatic Nitriles from Ketones and Aldehydes
-
A transition-metal-free deacylative C(sp3)-C(sp2) bond cleavage for the synthetically practical oxidative amination of ketones and aldehydes to nitriles is first described, using cheap and commercially abundant NaNO2 as the oxidant and the nitrogen source. Various nitriles bearing aryl, heteroaryl, alkyl, and alkenyl groups could be smoothly obtained from ketones and aldehydes in high yields, avoiding highly toxic cyanides or transition metals.
- Ge, Jing-Jie,Yao, Chuan-Zhi,Wang, Mei-Mei,Zheng, Hong-Xing,Kang, Yan-Biao,Li, Yadong
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supporting information
p. 228 - 231
(2016/02/03)
-
- Reactions of Azine Anions with Nitrogen and Oxygen Atoms: Implications for Titan's Upper Atmosphere and Interstellar Chemistry
-
Azines are important in many extraterrestrial environments, from the atmosphere of Titan to the interstellar medium. They have been implicated as possible carriers of the diffuse interstellar bands in astronomy, indicating their persistence in interstellar space. Most importantly, they constitute the basic building blocks of DNA and RNA, so their chemical reactivity in these environments has significant astrobiological implications. In addition, N and O atoms are widely observed in the ISM and in the ionospheres of planets and moons. However, the chemical reactions of molecular anions with abundant interstellar and atmospheric atomic species are largely unexplored. In this paper, gas-phase reactions of deprotonated anions of benzene, pyridine, pyridazine, pyrimidine, pyrazine, and s-triazine with N and O atoms are studied both experimentally and computationally. In all cases, the major reaction channel is associative electron detachment; these reactions are particularly important since they control the balance between negative ions and free electron densities. The reactions of the azine anions with N atoms exhibit larger rate constants than reactions of corresponding chain anions. The reactions of azine anions with O atoms are even more rapid, with complex product patterns for different reactants. The mechanisms are studied theoretically by employing density functional theory; spin conversion is found to be important in determining some product distributions. The rich gas-phase chemistry observed in this work provides a better understanding of ion-atom reactions and their contributions to ionospheric chemistry as well as the chemical processing that occurs in the boundary layers between diffuse and dense interstellar clouds.
- Wang, Zhe-Chen,Cole, Callie A.,Demarais, Nicholas J.,Snow, Theodore P.,Bierbaum, Veronica M.
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p. 10700 - 10709
(2015/09/28)
-
- Bio-based nitriles from the heterogeneously catalyzed oxidative decarboxylation of amino acids
-
The oxidative decarboxylation of amino acids to nitriles was achieved in aqueous solution by in situ halide oxidation using catalytic amounts of tungstate exchanged on a [Ni,Al] layered double hydroxide (LDH), NH4Br, and H2O2 as the terminal oxidant. Both halide oxidation and oxidative decarboxylation were facilitated by proximity effects between the reactants and the LDH catalyst. A wide range of amino acids was converted with high yields, often > 90%. The nitrile selectivity was excellent, and the system is compatible with amide, alcohol, and in particular carboxylic acid, amine, and guanidine functional groups after appropriate neutralization. This heterogeneous catalytic system was applied successfully to convert a pro-tein-rich byproduct from the starch industry into useful biobased N-containing chemicals.
- Claes, Laurens,Matthessen, Roman,Rombouts, Ine,Stassen, Ivo,De Baerdemaeker, Trees,Depla, Diederik,Delcour, Jan A.,Lagrain, Bert,De Vos, Dirk E.
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p. 345 - 352
(2015/01/30)
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- Ruthenium-catalyzed aerobic oxidative decarboxylation of amino acids: A green, zero-waste route to biobased nitriles
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Oxidative decarboxylation of amino acids into nitriles was performed using molecular oxygen as terminal oxidant and a heterogeneous ruthenium hydroxide-based catalyst. A range of amino acids was oxidized in very good yield, using water as the solvent. This journal is
- Claes, Laurens,Verduyckt, Jasper,Stassen, Ivo,Lagrain, Bert,De Vos, Dirk E.
-
supporting information
p. 6528 - 6531
(2015/04/14)
-
- Propane ammoxidation on Bi promoted MoVTeNbOx oxide catalysts: Effect of reaction mixture composition
-
MoVTeNbO catalysts were characterized with XRD, XPS, and FTIR techniques and tested in the ammoxidation of propane. Bismuth-modified MoVTeNbO catalysts showed a higher acrylonitrile yield than the base four-component system. The effect of the reaction mixture composition (C3H8, NH3 and O2) on selectivity towards different products was studied at propane conversion above 80%. The favorable effect of bismuth promoter on the selectivity towards acrylonitrile was explained by suppression of acrylonitrile transformation connected with decreasing acidity of the catalyst.
- Andrushkevich, Tamara V.,Popova, Galina Y.,Chesalov, Yuriy A.,Ischenko, Evgeniya V.,Khramov, Mikhail I.,Kaichev, Vasily V.
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p. 109 - 117
(2015/09/28)
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- Mechanistic insights into the oxidative dehydrogenation of amines to nitriles in continuous flow
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The oxidative dehydrogenation of various aliphatic amines to their corresponding nitrile compounds using RuO2/Al2O3 catalysts in air was successfully applied to a continuous flow reaction. Conversions of amines (up to >99%) and yields of nitriles (up to 77%) varied depending on reaction conditions and the amine utilised. The presence of water was found to be important for the activity and stability of the RuO2/Al2O3 catalyst. The Hammett relationship and in situ infrared spectroscopy were applied to divulge details about the catalytic mechanism of the oxidative dehydrogenation of amines over RuO2/Al2O3 catalysts.
- Corker, Emily C.,Ruiz-Martínez, Javier,Riisager, Anders,Fehrmann, Rasmus
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p. 5008 - 5015
(2015/11/03)
-
- Hierarchical zeolites and their catalytic performance in selective oxidative processes
-
Hierarchical ZSM-5 zeolites prepared using a simple alkali treatment and subsequent HCl washing are found to exhibit unprecedented catalytic activities in selective oxidation of benzyl alcohol under microwave irradiation. The metal-free zeolites promote the microwave-assisted oxidation of benzyl alcohol with hydrogen peroxide in yields ranging from 45-35 % after 5 min of reaction under mild reaction conditions as well as the epoxidation of cyclohexene to valuable products (40-60 % conversion). The hierarchically porous systems also exhibited an interesting catalytic activity in the dehydration of N,N-dimethylformamide (25-30 % conversion), representing the first example of transition-metal free catalysts in this reaction.
- Ojeda, Manuel,Grau-Atienza, Aida,Campos, Rafael,Romero, Antonio A.,Serrano, Elena,Maria Marinas, Jose,García Martínez, Javier,Luque, Rafael
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p. 1328 - 1333
(2015/05/05)
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- One-step synthesis of nitriles by the dehydrogenation-amination of fatty primary alcohols over Cu/m-ZrO2
-
An effective method for one-step synthesis of nitriles employing C 2-C8 fatty primary alcohols and ammonia over 5%Cu/m-ZrO2 has been found. The conversion of alcohols and selectivity of nitriles obtained are > 96 and > 87 wt.%, respectively, and are obviously influenced by the C2-substitution rather than the chain length of fatty primary alcohols. Cu/m-ZrO2 was characterized by XRD, H 2-TPR, CO2-TPD and NH3-TPD. It is revealed that a substantial amount of Cu species over m-ZrO2 is in highly dispersed CuO. A plausible mechanism is proposed and supported by different experiments, and aldehyde generation is an important step in the reaction mechanism.
- Hu, Yunfeng,Jin, Shuhan,Zhang, Zhichao,Zhang, Likun,Deng, Jun,Zhang, Hongsheng
-
-
- METHOD FOR PREPARATION OF ACETONITRILE FROM ETHANOL AND AMMONIA BY AMINATION-DEHYDROGENATION
-
The invention discloses a method for preparation of acetonitrile from ethanol and ammonia by amination-dehydrogenation using cobalt oxide supported on SiO2 as catalyst.
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Page/Page column 14-18
(2014/10/03)
-
- One-step synthesis of nitriles by the dehydrogenation-amination of fatty primary alcohols over Cu/m-ZrO2
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An effective method for one-step synthesis of nitriles employing C2-C8 fatty primary alcohols and ammonia over 5%Cu/m-ZrO2 has been found. The conversion of alcohols and selectivity of nitriles obtained are > 96 and > 87 wt.%, respectively, and are obviously influenced by the C2-substitution rather than the chain length of fatty primary alcohols. Cu/m-ZrO2 was characterized by XRD, H2-TPR, CO2-TPD and NH3-TPD. It is revealed that a substantial amount of Cu species over m-ZrO2 is in highly dispersed CuO. A plausible mechanism is proposed and supported by different experiments, and aldehyde generation is an important step in the reaction mechanism.
- Hu, Yunfeng,Jin, Shuhan,Zhang, Zhichao,Zhang, Likun,Deng, Jun,Zhang, Hongsheng
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- Nitrile imines and nitrile ylides: Rearrangements of benzonitrile N-methylimine and benzonitrile dimethylmethylide to azabutadienes, carbodiimides, and ketenimines. chemical activation in thermolysis of azirenes, tetrazoles, oxazolones, isoxazolones, and oxadiazolones
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Flash vacuum thermolysis (FVT) of 1-methyl-5-phenyltetrazole (5b), 2-methyl-5-phenyltetrazole (1b), and 3-methyl-5-phenyl-1,3,4-oxadiazol-2(3H)-one (3b) affords the nitrile imine (2b), which rearranges in part to N-methyl-N′-phenylcarbodiimide (7b). Another part of 2b undergoes a 1,4-H shift to the diazabutadiene (13). 13 undergoes two chemically activated decompositions, to benzonitrile and CH2=NH and to styrene and N 2. FVT of 2,2-dimethyl-4-phenyl-oxazol-5(2H)-one (16) at 400 C yields 3-methyl-1-phenyl-2-azabutadiene (18) in high yield. In contrast, FVT of 3,3-dimethyl-2-phenyl-1-azirene (21) at 600 C or 4,4-dimethyl-3-phenyl- isoxazolone (20) at 600 C affords only a low yield of azabutadiene (18) due to chemically activated decomposition of 18 to styrene and acetonitrile. There are two reaction paths from azirene (21): one (path a) leading to nitrile ylide (17) and the major products styrene and acetonitrile and the other (path b) leading to the vinylnitrene (22) and ketenimine (23). The nitrile ylide PhC -=N+=C(CH3)2 (17) is implicated as the immediate precursor of azabutadiene (18). FVT of either 3-phenylisoxazol- 5(4H)one (25) or 2-phenylazirene (26) at 600 C affords N-phenylketenimine (28). The nitrile ylide PhC-=N+=CH2 (30) is postulated as a reversibly formed intermediate. N-Phenylketenimine (28) undergoes chemically activated free radical rearrangement to benzyl cyanide. The mechanistic interpretations are supported by calculations of the energies of key intermediates and transition states.
- Begue, Didier,Dargelos, Alain,Berstermann, Hans M.,Netsch, Klaus P.,Bednarek, Pawel,Wentrup, Curt
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p. 1247 - 1253
(2014/03/21)
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- Decarboxylation of a Wide Range of Amino Acids with Electrogenerated Hypobromite
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Bromide-assisted electrochemical decarboxylation efficiently produces valuable nitriles in high yields from a wide range of naturally occurring amino acids in a single step. Bromide salts are used as both redox mediators and supporting electrolytes in a simple one-compartment setup. As demonstrated for lysine, the selectivity of the decarboxylation can be tuned towards nitriles, amines or amides. An electrochemical system is developed that allows the selective decarboxylation of a wide range of amino acids. Valuable nitriles are obtained in high yields in a single step by using bromide salts as both redox mediators and supporting electrolytes. The product selectivity of lysine can be tuned towards nitriles, amines, or amides.
- Matthessen, Roman,Claes, Laurens,Fransaer, Jan,Binnemans, Koen,De Vos, Dirk E.
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p. 6649 - 6652
(2016/02/19)
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- Direct transformation of primary nitro compounds into nitriles with sodium-dithionite
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A new and practical direct transformation of primary nitro compounds into nitriles with sodium dithionite is described. The reaction is simple, convenient and eliminates the use of expensive and moisture-sensitive reagents. Georg Thieme Verlag Stuttgart New York.
- Temelli, Baris,Unaleroglu, Canan
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p. 1407 - 1412
(2014/06/09)
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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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- 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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- An alternative pathway for production of acetonitrile: Ruthenium catalysed aerobic dehydrogenation of ethylamine
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The oxidative synthesis of acetonitrile from ethylamine was studied using a supported ruthenium catalyst. The reaction was conducted in both batch and flow processes and high conversions (over 85%) were achieved in both cases. Selectivity of both reactions was improved by optimisation of reaction conditions, achieving over 90% selectivity in the batch process and 80% selectivity in the continuous flow process. The use of a selective solid catalyst that utilises a feedstock that can be derived from biomass, dioxygen as the oxidant and water as the solvent represents a new, green route for the independent and efficient production of acetonitrile.
- Corker, Emily C.,Mentzel, Uffe V.,Mielby, Jerrik,Riisager, Anders,Fehrmann, Rasmus
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p. 928 - 933
(2013/07/26)
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- Novel ruthenium-terpyridyl complex for direct oxidation of amines to nitriles
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High catalytic activity and selectivity has been demonstrated for the oxidation of both aliphatic and aromatic amines to nitriles under benign conditions with dioxygen or air using the Ru2Cl4(az-tpy) 2 complex. The conversion was found to be strongly influenced by the alkyl chain length of the reactant with shorter chain amines found to have lower conversions than those with longer chains. Importantly, by using the ruthenium terpyridine complex functionalized with azulenyl moiety at the 4 position of central pyridine core provided a much higher reactivity catalyst compared with a series of ruthenium terpyridine-based ligand complexes reported. Mechanistic studies using deuterated benzylamine demonstrated the importance of RuOH in this reaction.
- Cristian, Liliana,Nica, Simona,Pavel, Octavian D.,Mihailciuc, Constantin,Almasan, Valer,Coman, Simona M.,Hardacre, Christopher,Parvulescu, Vasile I.
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p. 2646 - 2653
(2013/09/24)
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