- Synthesis of N-aryl and N-heteroaryl hydroxylamines via partial reduction of nitroarenes with soluble nanoparticle catalysts
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Polystyrene-supported ruthenium nanoparticles enable the selective hydrazine-mediated reduction of nitroarenes to hydroxylamine products in high yield and selectivity. Key to obtaining the hydroxylamine product in good yield was the use of organic solvents capable of solubilizing the polystyrene-supported nanoparticle catalyst. N-aryl and N-heteroaryl hydroxylamines are generated under exceptionally mild conditions and in the presence of a various easily reduced functional groups.
- Tyler, Jefferson H.,Nazari, S. Hadi,Patterson, Robert H.,Udumula, Venkatareddy,Smith, Stacey J.,Michaelis, David J.
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supporting information
p. 82 - 86
(2016/12/23)
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- Selective conversion of nitroarenes using a carbon nanotube-ruthenium nanohybrid
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Ruthenium nanoparticles were assembled on carbon nanotubes and the resulting nanohybrid was used in the hydrazine-mediated catalytic hydrogenation of various nitroarenes, at room temperature. Depending on the solvent, a selective transformation occurred, giving either access to the corresponding aniline or hydroxylamine derivative.
- Jawale, Dhanaji V.,Gravel, Edmond,Boudet, Caroline,Shah, Nimesh,Geertsen, Valérie,Li, Haiyan,Namboothiri, Irishi N. N.,Doris, Eric
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supporting information
p. 1739 - 1742
(2015/03/03)
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- Solvent hydrogen bonding and structural influences on the CrVI oxidation of anilines in aqueous acetic acid medium
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The oxidation of meta- and para-substituted anilines by CrVI oxidant, imidazolium fluorochromate (IFC), in aqueous acetic acid mixtures of varying compositions in the presence of p-toluenesulfonic acid (PTS) is first order in IFC and PTS. Michaelis-Menten type kinetics is observed with all of the anilines. The IFC oxidation of 15 meta- and para-substituted anilines at 299-322 K complies with the isokinetic relationship but not to any of the linear free energy relationships. The isokinetic temperature lies within the experimental range. The rate data failed to correlate with macroscopic solvent parameters such as relative permittivity, εr, and ionizing power, Y, correlation of rate data with Kamlet-Taft solvatochromic parameters (hydrogen bond donor acidity, α, hydrogen bond acceptor basicity, β, and dipolarity/polarizability, π*) is linear which suggests that the specific solute-solvent interactions play a dominating role in governing the reactivity.
- Bhuvaneshwari,Elango
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experimental part
p. 242 - 249
(2010/04/26)
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- Effect of solvent on the rate of oxidation of substituted anilines with nicotinium dichromate in aqueous-acetic acid media
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Mechanistic studies on the oxidation of 15 para- and meta-substituted anilines by nicotinium dichromate in water-acetic acid medium of varying mole fractions have been performed. The reaction can be characterized by the experimental rate equation, -d[oxidizing agent]/dt = Kk [substrate] [HCrO 4-]/(1 + K [substrate]) The addition of p-toluenesulfonic acid enhances the reaction. The oxidation substituted anilines at 299-322 K complies with the isokinetic relationship but not to any of the linear free energy relationships, the isokinetic temperature lies within the experimental range. Correlation of rate data with Kamlet-Taft solvatochromic parameters (α, β, π*) suggests that the specific solute-solvent interactions play a major role in governing the reactivity.
- Bhuvaneshwari,Elango
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p. 999 - 1005
(2007/10/03)
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- Effect of substituents on the rate of oxidation of anilines with peroxomonosulfate monoanion (HOOSO3-) in aqueous acetonitrile: A mechanistic study
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Mechanistic studies on the oxidation of 18 meta-, para-, and ortho-substituted anilines (Ans) by HOOSO3- in aqueous acetonitrile medium have been performed. The reaction can be characterized by the experimental rate equation, -d[HSO5-]/dt = k[An][HSO5-] The addition of p-toluenesulfonic acid (TsOH) retards the reaction. The increase in the reactivity of anilines as the medium is made more aqueous is interpreted. The reaction is enhanced by electron-donating groups on the amine in the series consistent with the rate-limiting nucleophilic attack of the amine on the persulfate oxygen. The proposed mechanism involves the conversion of phenylhydroxylamine to nitrosobenzene in a fast step. The ESR study reveals the absence of free radicals in the reaction. Various attempts have been made to analyze the experimental rate constants in terms of LFER plots. Improved correlations are obtained with σ- values and the σ- form of the Yukawa-Tsuno equation.
- Meenakshisundaram, Subbiah,Selvaraju,Made Gowda,Rangappa, Kanchugarakoppal S.
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p. 649 - 657
(2007/10/03)
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- Mechanism and reactivity in perborate oxidation of anilines in acetic acid
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Perborate but not percarbonate in acetic acid generates peracetic acid on standing and the peracetic acid oxidation of anilines is fast. The oxidation with a fresh solution of perborate in acetic acid is smooth and second order but the specific oxidation rate increases with increasing [perborate]0 or [boric acid]. Perborate on dissolution affords hydrogen peroxide and a borate; the latter assists the former in the oxidation. The oxidation rates of anilines under identical conditions do not conform to any of the linear free energy relationships but the reaction rates of molecular anilines do. Perborate oxidation proceeds via two reaction paths but the overall oxidation rates of molecular anilines conform to structure reactivity relationships; the transition states do not differ significantly. Analysis of the oxidation rates of perborate and percarbonate reveals that while perborate oxidation is faster than percarbonate it is at least as selective as the latter.
- Karunakaran, Chockalingam,Kamalam, Ramasamy
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p. 2011 - 2018
(2007/10/03)
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- Reaction of dimethyldioxirane with aniline hydrohalides
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Oxidation of aromatic amine hydrohalides (aniline hydrochloride, hydrobromide, and hydrofluoride; 4-methylaniline hydrochloride and hydrobromide; 3-methylaniline and N,N-diethylaniline hydrochlorides) with dimethyldioxirane was studied. The product composition was analyzed in relation to the reactant ratio.
- Ivanova,Grabovskii,Kabal'nova,Shereshovets
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p. 2101 - 2105
(2007/10/03)
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- Kinetics and Mechanism of Oxidation of para-Substituted Anilines by Peroxomonosulphate
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Kinetics of oxidation of several para-substituted anilines by peroxomonosulphate (PMS) in aqueous acetic acid medium have been investigated. The reaction follows a total second order, first order each in [PMS] and [substrate]. The reaction rate is retarted by both electron-releasing and withdrawing groups. Absence of free radical formation is confirmed. Activation energy and thermodynamic parameters have been computed. A probable mechanism has been proposed.
- Abdul Jameel,Maruthamuthu
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p. 368 - 370
(2007/10/03)
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- Synthesis, Properties, and Thermodynamic Ionization Constants of α-Phenylstyrylacrylohydroxamic Acids
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The synthesis and properties of eight new hydroxamic acids derived from α-phenylstyrylacrylic acids are described. These hydroxamic acids, which are crystalline compounds, were characterized by their ultraviolet, infrared, and NMR spectra. The purity was checked by HPLC and HPTLC. The nonaqueous titrations and alkaline hydrolysis are reported. Thermodynamic ionization constants at (25 and 35 +/- 0.1) deg C are determined. Preliminary studies show that these acids form a chloroform-extractable violet complex with vanadium(V) in 6 M hydrochloric acid solutions.
- Patel, Kalpesh R.,Menon, Sobhana K.,Agrawal, Yadvendra K.
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p. 423 - 425
(2007/10/03)
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