109-89-7Relevant articles and documents
Bimetallic Ru/Ni supported catalysts for the gas phase hydrogenation of acetonitrile
Braos-García,García-Sancho,Infantes-Molina,Rodríguez-Castellón,Jiménez-López
, p. 132 - 144 (2010)
A family of bimetallic Ni-Ru catalysts supported on a mesoporous SBA-15 silica was prepared by conventional impregnation method, with constant metal molar loadings, but varying Ni/(Ni + Ru) atomic ratios. The corresponding Ni and Ru monometallic catalysts were also prepared for comparison. These catalysts were characterized by XRD, N2 adsorption-desorption at -196 °C, TEM, XPS, H2-TPR, chemisorption of H2 at r.t., H2-TPD and NH3-TPD techniques. Finally, they were also tested in the hydrogenation of acetonitrile reaction, in the gas phase and at atmospheric pressure. Acetonitrile conversion values depended on the Ni/(Ni + Ru) composition of the bimetallic catalysts. Ru-rich bimetallic catalysts exhibited acetonitrile conversion values higher than that of pure Ni one; thus, although selectivity patterns remained almost unchanged, primary amine yields were increased. These higher conversion values resulted as a consequence of enhanced specific activity of Ni0 atoms, attributable to a strong interaction between both metals, Ni and Ru, likely because NiRu alloy nanoparticles were formed.
Transformations of dialkyl(4-hydroxy-2-butynyl)-(3-phenylallyl)ammonium bromides in an KOH aqueous solution or in the presence of powdered KOH
Chukhadjian,Gabrielyan,Chukhadjian,Shahkhatuni,Panosyan
, p. 418 - 424 (2011)
Under the action of a twofold excess of KOH and heating in aqueous solution, and also under the conditions of the Stevens rearrangement (with KOH powder and a small amount of methanol) dialkyl-(4-hydroxy-2-butynyl)(3- phenylallyl)ammonium bromides form dialkyl[4-(1-phenylallyl)-2,5-dihydro-2- furyl]amines. Rearrangement-cleavage reaction also occurs under the same conditions.
Zeolite catalysts for the selective synthesis of mono- and diethylamines
Veefkind, Victor A.,Lercher, Johannes A.
, p. 258 - 269 (1998)
The kinetics and mechanism of ethylamine synthesis from ammonia and ethanol over several large pore acid catalysts are described. Mordenite produced higher monoethylamine yields than the zeolites beta, Y, mazzite, and amorphous silica-alumina. The reaction proceeds via the initial formation of ethylammonium ions, and alkylamines desorb with the assistance of ammonia and equilibrate with other ethylammonium ions before leaving the catalyst pores. The high yields of ethylamines with mordenite are related to the high acid strength of the catalyst stabilizing (alkyl)ammonium ions and so blocking the dehydration of ethanol. By choosing high ammonia partial pressures, reaction temperatures below 573 K (minimizing ethene elimination from ethylammonium ions), and subtle modifications of the parent mordenite material (EDTA leaching, silylation of the external surface) ethene selectivity was further decreased. These measures allowed us to prepare a catalyst on the basis of mordenite with a Si/Al ratio of 5 that showed 99% selectivity to ethyl amines at 60% conversion and that was stable for long times on stream.
Influence of pH on hydrolytic decomposition of diethylpropion hydrochloride: Stability studies on drug substance and tablets using high-performance liquid chromatography
Walters
, p. 1206 - 1209 (1980)
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A cluster growth route to quantum-confined CdS nanowires
Yan, Ping,Xie, Yi,Qian, Yitai,Liu, Xianming
, p. 1293 - 1294 (1999)
Quantum-confined CdS nanowires with diameters around 4 nm and lengths ranging from 150 to 250 nm were grown for the first time from cadmium bis(diethyldithiocarbamate) [Cd(DDTC)2]2 by removal of the four thione groups with ethylenediamine (en) at 117°C for 2 min.
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Higuchi,T. et al.
, p. 626 - 631 (1969)
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Reactions of group 4 amide guanidinates with dioxygen or water. Studies of the formation of oxo products
Sharma, Bhavna,Callaway, Tabitha M.,Lamb, Adam C.,Steren, Carlos A.,Chen, Shu-Jian,Xue, Zi-Ling
, p. 11409 - 11421 (2013)
Reactions of the zirconium amide guanidinates (R2N) 2M[iPrNC(NR2)NiPr]2 (R = Me, M = Zr, 1; M = Hf, 2; R = Et, M = Zr, 3) with O2 or H 2O give products that are consistent with the oxo dimers {M(μ-O)[iPrNC(NR2)NiPr]2} 2 (R = Me, M = Zr, 4; M = Hf, 5; R = Et, M = Zr, 6) and polymers {M(μ-O)[iPrNC(NR2)NiPr]2} n (R = Me, M = Zr, 7; M = Hf, 8; R = Et, M = Zr, 9). Mass spectrometric (MS) analyses of the reactions of water in air with 1 and 2 show formation of the Zr monomer Zr(=O)[iPrNC(NMe2)N iPr]2 (10), oxo dimers 4 and 5, and dihydroxyl complexes M(OH)2[iPrNC(NMe2)NiPr]2 (M = Zr, 11; Hf, 12). Similar MS analyses of the reaction of diethylamide guanidinate 3 with water in air show the formation of Zr(=O)[ iPrNC(NEt2)NiPr]2 (13), Zr(OH) 2[iPrNC(NEt2)NiPr]2 (14), 6, and {(Et2N)Zr[iPrNC(NEt2)N iPr]2}+ (15). Kinetic studies of the reaction between 1 and a continuous flow of 1.0 atm of O2 at 80-105 C indicate that it follows pseudo-first-order kinetics with ΔH? = 8.7(1.1) kcal/mol, ΔS? = -54(3) eu, ΔG ?358 K = 28(2) kcal/mol, and a half-life of 213(1) min at 85 C.
Photocatalytic degradation of dye sulforhodamine B: A comparative study of photocatalysis with photosensitization
Liu, Guangming,Zhao, Jincai
, p. 411 - 417 (2000)
The direct photocatalytic degradation of dye pollutant sulforhodamine B (SRB) in aqueous TiO2 dispersions has been examined and compared to the photosensitization process. The mineralization extent of SRB degradation, the formation of intermediates and final products were monitored to assess the degradation pathways caused by direct photocatalysis. In the initial stage of the direct photocatalysis, SRB is mainly oxidized by a positive hole upon band-gap excitation of TiO2 by UV light (330 nm 420 nm). Diethylamine, N,N-diethylacetamide, N-ethylformamide, N,N-diethylformamide, formic acid and acetic acid were identified as intermediate species; SO42-, NH4+, CO2 and H2O are final mineralized products produced in the direct photocatalytic process.
Effect of surface composition on the catalytic performance of molybdenum phosphide catalysts in the hydrogenation of acetonitrile
Yang, Pengfei,Jiang, Zongxuan,Ying, Pinliang,Li, Can
, p. 66 - 73 (2008)
A series of molybdenum phosphide catalysts with initial Mo/P ratios varying in a narrow range of 0.90-1.10 was prepared by temperature-programmed reaction; characterized by X-ray diffraction, BET, elemental analysis, X-ray photoelectron spectroscopy, and CO chemisorption measurements; and tested for the hydrogenation of acetonitrile at different pressures (0.1-1.0 MPa) and temperatures (473-513 K). The catalysts exhibited attractive catalytic activity, especially at a H2 pressure above 0.2 MPa. The surface composition of the MoP catalysts could be fine-tuned by the initial Mo/P ratio, which consequently led to different surface properties (e.g., CO uptakes) and catalytic behaviors. Catalysts with high initial Mo amount gave high selectivity to the primary amine, ethylamine, whereas those with high initial P amount created more condensed amines, diethylamine and triethylamine.
Kraus, C. A.,Brown, E. H.
, p. 2690 - 2696 (1929)
Ditiocarb: Decomposition in aqueous solution and effect of the volatile product on its pharmacological use
Martens,Langevin-Bermond,Fleury
, p. 379 - 383 (1993)
The kinetic profile for the decomposition of ditiocarb sodium salt in aqueous solution was achieved with UV-visible absorption spectrometry. The kinetic profile indicates that the decomposition reaction is hydrogen ion- catalyzed over the entire 4-10 pH range and enables the determination of the value of the acid-base equilibrium constant (K(a) = 4.0 · 10-4 at 5 °C). Decomposition of ditiocarb produces volatile carbon disulfide, exclusive of hydrogen sulfide, as shown with electrochemical methods. This feature is of interest from a toxicological point of view.
Mechanistic studies on the reaction between R2N-NONOates and aquacobalamin: evidence for direct transfer of a nitroxyl group from R 2N-NONOates to cobalt(III) centers
Hassanin, Hanaa A.,Hannibal, Luciana,Jacobsen, Donald W.,El-Shahat, Mohamed F.,Hamza, Mohamed S. A.,Brasch, Nicola E.
, p. 8909 - 8913 (2009)
Tales of the unexpected: Transfer of a nitroxyl group from R2N-NONOates to aquacobalamin to form nitroxylcobaiamin does not proceed via H+-catalyzed R2NNONOate decomposition, but instead occurs via a probable NONOate-cobalamin intermediate (see scheme; r.
Direct Amination of Ethylene by Zeolite Catalysis
Deeba, Michel,Ford, Michael E.,Johnson, Thomas A.
, p. 562 - 563 (1987)
Formation of ethylamine by addition of ammonia to ethylene is catalysed by acidic zeolites such as H-Y, H-mordenite, and H-erionite.
Selective hydrogenation of acetonitrile to ethylamine using palladium-based alloy catalysts
Arai,Iwasa,Yoshikawa
, p. 5414 - 5420 (2002)
The gas phase hydrogenation of acetonitrile was studied with various Pd-based catalysts using several supports, i.e., ZrO2, CeO2, MgO, SiO2, Al2O3, ZnO, Ga2O3, and In2O3. Pd/ZnO and Pd/Ga2O3 catalysts showed smaller conversions, but selective to the formation of MEA and DEA. For all the catalysts studied, MEA selectivity at 170°C was higher than that at 120°C. In the case of Pd/ZrO2, the total conversion at 120°C was slightly higher than that at 170°C. For the simple supported Pd catalysts after hydrogenation reactions, only metallic Pd could be observed with the catalysts except for the three samples, i.e., Pd/ZnO, Pd/Ga2O3, and Pd/In2O3. For the Pd/ZnO catalyst that is most selective to the formation of MEA, the total conversion and the selectivity of DEA and triethylamine decreased while the selectivity of MEA increased with increasing reduction temperature. The modified Pd catalysts showed larger total activities compared with the corresponding simple supported Pd catalysts reduced at 500°C. Zn addition on the total conversion and product selectivity showed that the conversion was significantly decreased when the quantity of Zn added was Zn/Pd ≥ 0.3:1 The higher selectively to MEA formation was achieved at Zn/Pd > 1. thus, the formation of such a Pd alloy was responsible for the enhancement of the MEA selectivity and the decrease of the total activity.
Characteristics of Si-Y mixed oxide supported nickel catalysts for the reductive amination of ethanol to ethylamines
Jeong, Ye-Seul,Woo, Yesol,Park, Myung-June,Shin, Chae-Ho
, p. 287 - 297 (2020)
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.
Tungsten nitrido complexes as precursors for low temperature chemical vapor deposition of WNxCy films as diffusion barriers for Cu metallization
McClain, K. Randall,O'Donohue, Christopher,Koley, Arijit,Bonsu, Richard O.,Abboud, Khalil A.,Revelli, Joseph C.,Anderson, Timothy J.,McElwee-White, Lisa
, p. 1650 - 1662 (2014)
Tungsten nitrido complexes of the form WN(NR2)3 [R = combinations of Me, Et, iPr, nPr] have been synthesized as precursors for the chemical vapor deposition of WNxCy, a material of interest for diffusion barriers in Cu-metallized integrated circuits. These precursors bear a fully nitrogen coordinated ligand environment and a nitrido moiety (Wi - N) designed to minimize the temperature required for film deposition. Mass spectrometry and solid state thermolysis of the precursors generated common fragments by loss of free dialkylamines from monomeric and dimeric tungsten species. DFT calculations on WN(NMe 2)3 indicated the lowest gas phase energy pathway for loss of HNMe2 to be β-H transfer following formation of a nitrido bridged dimer. Amorphous films of WNxCy were grown from WN(NMe2)3 as a single source precursor at temperatures ranging from 125 to 650 C using aerosol-assisted chemical vapor deposition (AACVD) with pyridine as the solvent. Films with stoichiometry approaching W2NC were grown between 150 and 450 C, and films grown at 150 C were highly smooth, with a RMS roughness of 0.5 nm. In diffusion barrier tests, 30 nm of film withstood Cu penetration when annealed at 500 C for 30 min.
Efficient coupling reactions of allylamines with soft nucleophiles using nickel-based catalysts
Bricout, Herve,Carpentier, Jean-Francois,Mortreux, Andre
, p. 1393 - 1394 (1997)
Substitution reactions of N,N-diethylallylamine 1 with soft nucleophiles such as active methylene compounds 2a-c and piperidine 5 proceed much more rapidly in the presence of Ni(dppb)2 [dppb = 1,4-bis(diphenylphosphino)butane] as catalyst than with comparable palladium systems.
Reiber,Erway
, p. 1881 (1950)
Photocatalysis of Oligo(p-phenylenes). Photoreductive Production of Hydrogen and Ethanol in Aqueous Triethylamine
Matsuoka, Shinjiro,Fujii, Hiroyuki,Yamada, Taisuke,Pac, Chyongjin,Ishida, Akito,et al.
, p. 5802 - 5808 (1991)
Oligo(p-phenylenes) (OPP-n), p-terphenyl (OPP-3) to p-sexiphenyl (OPP-6), catalyze water-reductive H2 formation and reduction of concomitantly formed acetaldehyde to ethanol upon irradiation of heterogeneous suspensions in aqueous organic solution in the presence of triethylamine (TEA) and RuCl3.Colloidal Ru0 is photoformed in situ to work as an electron relay.The activity of OPP-n increases with the number of phenylene units except for the cases of OPP-3 and of the alkylated derivatives, where the net photocatalytic activities are higher, mainly due to the effective homogeneous catalysis, since their solubilities in the solvents employed are significantly larger.The homogeneous catalysis of OPP-3 leads not only to H2 evolution but also to effective formation of ethanol in the absence of colloidal Ru0, being accompanied by photo-Birch reduction of OPP-3.Dynamics studies of OPP-3 reveal that photocatalysis should be initiated by formation of the excited singlet state of OPP-3 (1OPP-3*, which is reductively quenched by TEA at a rate controlled by diffusion to produce the OPP-3 radical anion (OPP-3.-) and the TEA radical cation (TEA.+).From laser flash photolysis and pulse radiolysis experiments, it is concluded that electron transfer from OPP-3.- leads to effective reduction of water to H2 catalyzed by Ru0 colloid.Furthermore, it is confirmed that OPP-3.- gives electrons directly to acetaldehyde without any electron relays like colloidal metals, resulting in the formation of ethanol.During photocatalysis, OPP-3 itself undergoes photo-Birch reduction to some extent.
Is water a suitable solvent for the catalytic amination of alcohols?
Niemeier, Johannes,Engel, Rebecca V.,Rose, Marcus
, p. 2839 - 2845 (2017)
The catalytic conversion of biomass and biogenic platform chemicals typically requires the use of solvents. Water is present already in the raw materials and in most cases a suitable solvent for the typically highly polar substrates. Hence, the development of novel catalytic routes for further processing would profit from the optimization of the reaction conditions in the aqueous phase mainly for energetic reasons by avoiding the initial water separation. Herein, we report the amination of biogenic alcohols in aqueous solutions using solid Ru-based catalysts and ammonia as a reactant. The influence of different support materials and bimetallic catalysts is investigated for the amination of isomannide as a biogenic diol. Most importantly, the transferability of the reaction conditions to various other primary and secondary alcohols is successfully proved. Hence, water appears to be a suitable solvent for the sustainable production of biogenic amines and offers great potential for further process development.
Gas-phase elimination kinetics of ethyl, isopropyl and tert-butyl N,N-diethylcarbamates. Application of Taft-Topsom correlation for substituents other than carbon at the acid side of organic ethyl esters
Herize, Armando,Dominguez, Rosa M.,Rotinov, Alexandra,Nunez, Oswaldo,Chuchani, Gabriel
, p. 201 - 206 (1999)
The elimination kinetics of ethyl, isopropyl and tert-butyl N,N-diethylcarbamates were investigated in a static reaction vessel over the temperature range 220-400°C and pressure range 17-160 Torr. These reactions are homogeneous, unimolecular and follow a first-order rate law. The temperature dependance of the rate coefficients is given by the following equations: for ethyl N,N-diethylcarbamate, log k1 (s-1) = (11.47 ± 0.25) - (178.4 ± 3.1) kJ mol-1 (2.303 RT)-1, for isopropyl N,N-diethylcarbamate, log k1 (s-1) = (12.83 ± 0.70) - (179.8 ± 7.9) kJ mol-1 (2.303 RT)-1; and for tert-butyl N,N-diethylcarbamate, log k1 (s-1) = (12.87 ± 0.62) - (158.6 ± 6.2) kJ mol-1 (2.303 RT)-1. The branching of the alkyl groups at the alcohol side of the ester exerts a significant effect on the rates in the order tert-butyl > isopropyl > ethyl. In addition, the presence of different substituents other than carbon at the acid side of organic ethyl esters gives the best correlation when using the Taft-Topsom equation: log k/kH = -(0.68 ± 0.12)σs + (2.57 ± 0.12)σF - (1.18 ± 0.27)σR (r = 0.984 ± 0.119 at 400°C). According to this relationship, the field (inductive) effect of the substituent has the greatest influence on rate enhancement, while the polarizability (steric) and resonance factors, although small in effect, favour the elimination process. Copyright
Coordination properties of μ-carbidodimeric iron(IV) 2,3,7,8,12,13,17,18-octapropyltetraazaporphyrinate and 5,10,15,20-tetraphenylporphyrinate in reactions with nitrogen-containing bases
Zaitseva,Zdanovich,Kudrik,Koifman
, p. 1257 - 1266 (2017)
The equilibria of μ-carbidodimeric iron(IV) 2,3,7,8,12,13,17,18-octapropyltetraazaporphyrinate and 5,10,15,20-tetraphenylporphyrinate in reactions with nitrogen-containing bases in an inert solvent were studied spectrophotometrically. The equilibrium constants of the studied processes and the compositions of molecular complexes were determined. The effect of the electronic and conformation factors of a macrocycle and the nature of the base on the equilibrium constant was pointed out. A comparative analysis of the substrate specificity of the studied compounds was performed.
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Ivanov et al.
, (1974)
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Discovery and characterization of an acridine radical photoreductant
MacKenzie, Ian A.,Wang, Leifeng,Onuska, Nicholas P. R.,Williams, Olivia F.,Begam, Khadiza,Moran, Andrew M.,Dunietz, Barry D.,Nicewicz, David A.
, p. 76 - 80 (2020/04/17)
Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.
Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound i Type Oxidants
Bugnola, Marco,Shen, Kaiji,Haviv, Eynat,Neumann, Ronny
, p. 4227 - 4237 (2020/05/05)
The reductive activation of molecular oxygen catalyzed by iron-based enzymes toward its use as an oxygen donor is paradigmatic for oxygen transfer reactions in nature. Mechanistic studies on these enzymes and related biomimetic coordination compounds designed to form reactive intermediates, almost invariably using various "shunt" pathways, have shown that high-valent Fe(V)=O and the formally isoelectronic Fe(IV) =O porphyrin cation radical intermediates are often thought to be the active species in alkane and arene hydroxylation and alkene epoxidation reactions. Although this four decade long research effort has yielded a massive amount of spectroscopic data, reactivity studies, and a detailed, but still incomplete, mechanistic understanding, the actual reductive activation of molecular oxygen coupled with efficient catalytic transformations has rarely been experimentally studied. Recently, we found that a completely inorganic iron-tungsten oxide capsule with a keplerate structure, noted as {Fe30W72}, is an effective electrocatalyst for the cathodic activation of molecular oxygen in water leading to the oxidation of light alkanes and alkenes. The present report deals with extensive reactivity studies of these {Fe30W72} electrocatalytic reactions showing (1) arene hydroxylation including kinetic isotope effects and migration of the ipso substituent to the adjacent carbon atom ("NIH shift"); (2) a high kinetic isotope effect for alkyl C - H bond activation; (3) dealkylation of alkylamines and alkylsulfides; (4) desaturation reactions; (5) retention of stereochemistry in cis-alkene epoxidation; and (6) unusual regioselectivity in the oxidation of cyclic and acyclic ketones, alcohols, and carboxylic acids where reactivity is not correlated to the bond disassociation energy; the regioselectivity obtained is attributable to polar effects and/or entropic contributions. Collectively these results also support the conclusion that the active intermediate species formed in the catalytic cycle is consistent with a compound I type oxidant. The activity of {Fe30W72} in cathodic aerobic oxidation reactions shows it to be an inorganic functional analogue of iron-based monooxygenases.
