594-70-7Relevant academic research and scientific papers
Comparison of Heterogeneous and Homogeneous Electron-Transfer Rates for Some Nitroalkanes and Diketones
Evans, Dennis H.,Gilicinski, Andrew G.
, p. 2528 - 2533 (1992)
Redox catalysis has been used to investigate the homogeneous electron-transfer reactions between the substrates (nitroalkane or diketone) and the reduced form of the catalyst, which was terephthalonitrile.The substrates were RNO2 (R=Me, Et, i-Pr, and t-Bu) and RC(O)C(O)R (R=Me, Et, and t-Bu).The experiments were conducted in acetonitrile solvent at 298 K with three different electrolytes, R4NClO4 (R=Et, n-Bu, and n-C7H15).The effect of added water and alcohols (methanol, ethanol, and s-butanol) was investigated.Formal potentials and standard heterogeneous electron-transfer rate constants, ks, were also determined.It was found that increasing the size of the cation of the electrolyte resulted in a decrease in ks but did not affect the rate of the homogeneous electron-transfer reactions.The result is interpreted as a decrease in electron-tunneling rate with increasing thickness of a compact layer of adsorbed cations, a double-layer effect that cannot influence the homogeneous reaction.Addition of the hydroxylic solutes, S, caused diminution of both ks and the rate constant of homogeneous electron transfer from the anion radical of the substrate to the catalyst.This result is discussed in terms of two models, viz., complexation or adduct formation between the anion radical and S or increasing solvation energy of the anion radical.
Copper(II) mediated phenol ring nitration by nitrogen dioxide
Kumar, Vikash,Ghosh, Somnath,Saini, Anoop Kumar,Mobin, Shaikh M.,Mondal, Biplab
, p. 19909 - 19917 (2015/12/01)
Cu(ii) complexes of N2O2 type ligands, L1H2 and L2H2 [L1H2 = 6,6′-(((pyridin-2-ylmethyl)azanediyl)bis(methylene))bis(2,4-di-tert-butylphenol); L2H2 = 2,4-di-tert-butyl-6-(((3-(tert-butyl)-2-hydroxy-5-methylbenzyl)(pyridin-2-yl-methyl)amino)methyl)phenol], have been synthesized. Addition of nitrogen dioxide (NO2) in THF solutions of the complexes resulted in the nitration at the 4-position of a coordinated equatorial phenolate ring of the ligand frameworks. This nitration did not occur at the phenol ring which is axially coordinated to the metal center. Spectroscopic evidence suggests that the reaction proceeds through a phenoxyl radical complex formation.
Silver(I)-Promoted ipso-Nitration of Carboxylic Acids by Nitronium Tetrafluoroborate
Natarajan, Palani,Chaudhary, Renu,Venugopalan, Paloth
, p. 10498 - 10504 (2015/11/18)
A novel and efficient method for the regioselective nitration of a series of aliphatic and aromatic carboxylic acids to their corresponding nitro compounds using nitronium tetrafluoroborate and silver carbonate in dimethylacetamide has been described. This transformation is believed to proceed via the alkyl-silver or aryl-silver intermediate, which subsequently reacts with the nitronium ion to form nitro substances. Mild reaction conditions, tolerant of a broad range of functional groups, and formation of only the ipso-nitrated products are the key features of this methodology when compared to known methods for syntheses of nitroalkyls and nitroarenes.
HYDROCARBON FEED FLEXIBLE HIGH PRESSURE NITRATION PLANT DESIGN
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Page/Page column 21-26, (2011/07/09)
Disclosed is an apparatus for synthesizing nitroalkanes by reaction of a hydrocarbon feedstock with aqueous nitric acid. The apparatus may be designed such that it can synthesize more than one nitroalkane using the same equipment.
NITRATED HYDROCARBONS, DERIVATIVES, AND PROCESSES FOR THEIR MANUFACTURE
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Page/Page column 27-29; 33, (2009/12/02)
Provided is a process for the formation of nitrated compounds by the nitration of hydrocarbon compounds with dilute nitric acid. Also provided are processes for preparing industrially useful downstream derivatives of the nitrated compounds, as well as novel nitrated compounds and derivatives, and methods of using the derivatives in various applications.
Spin trapping of Au-H intermediate in the alcohol oxidation by supportedand unsupported gold catalysts
Conte, Marco,Miyamura, Hiroyuki,Kobayashi, Shu,Chechik, Victor
supporting information; experimental part, p. 7189 - 7196 (2009/09/30)
Electron paramagnetic resonance (EPR) spectroscopy and spin trapping were used to explore the mechanism of alcohol oxidation over gold catalysts. Reaction of secondary alcohols with supported and unsupported gold catalysts (e.g., Au/CeO2, polymer-Incarcerated Au nanoparticles,PPh 3-protected Au nanoparticles) In the presence of spin tr aps led to the formation of a hydrogen spin adduct. Using Isotope labeling, we confirmed that the hydrogen In the spin adduct originates from the cleavage of the C-H bond In the alcohol molecule. The formation of thehydrogen spin adduct most likely results from the abstraction of hydrog en from the Au surface by a spin trap. These results thus strongly suggest Intermediate formation of Au-H species during alcohol oxidation. The role of oxygen In this mechanism Is to restore the catalytic activity rather than oxidize alcohol. This was further confirmed by carrying out gold-catalyzed alcohol oxidation In the absence of oxygen, with nitroxidesas hydrogen abstractors. The support (e.g., metal oxides) can activate oxygen and act as an H abstractor from the gold surface and hence lead t o a faster recovery of the activity. Peroxyl radicals were also observedduring alcohol oxidation, consistent with a free-radical autoxidation m echanism. However, this mechanism Is likely to be a minor side reaction,which does not lead to the formation of an appreciable amount of oxidat ion products.
Oxidation of azides by the HOF·CH3CN: A novel synthesis of nitro compounds
Carmeli, Mira,Rozen, Shlomo
, p. 4585 - 4589 (2007/10/03)
The HOF·CH3CN complex, readily prepared by passing F 2 through aqueous acetonitrile, is an exceptionally efficient oxygen transfer agent. It is unique in its capacity to oxidize various azides into the corresponding nitro derivatives. This method requires short reactions times and room temperature or below, and the desired nitro compounds were usually isolated in very good yields. The respective nitroso derivatives are believed to be the intermediates in this reaction. Functional groups such as aromatic rings, ketones, nitriles, halides, alcohols, and esters are tolerated. Sulfides react with HOF·CH3CN usually at the same rate as azides. Amines and olefins, however, react faster, so they have to be protected first. Nitro derivatives with various oxygen isotopes can be made using the labeled H 18OF·CH3CN. In the case of chiral azides the stereochemistry around the nitrogen-bonded carbons is retained.
Aqueous biphasic oxidation: A water-soluble polyoxometalate catalyst for selective oxidation of various functional groups with hydrogen peroxide
Sloboda-Rozner, Dorit,Witte, Peter,Alsters, Paul L.,Neumann, Ronny
, p. 339 - 345 (2007/10/03)
A "sandwich" type polyoxometalate, Na12[(WZn 3(H2O)2][(ZnW9O34) 2], was used as an oxidation catalyst in aqueous biphasic reaction media to effect oxidation of alcohols, diols, pyridine derivatives, amines and aniline derivatives with hydrogen peroxide. The catalyst was shown by 183W NMR to be stable in aqueous solutions in the presence of H 2O2 and showed only minimal non-productive decomposition of the oxidant. Secondary alcohols were selectively oxidized to ketones, while primary alcohols tended to be oxidized to the corresponding carboxylic acids, although secondary alcohols were selectively oxidized in the presence of primary alcohols. Vicinal diols yielded carbon-carbon bond cleavage products in very high yields. Pyridine derivatives were oxidized to the respective TV-oxides, but strongly electron-withdrawing moieties inhibited the oxidation reaction. Primary amines were oxidized to the oximes, but significantly hydrolyzed in situ. Aniline derivatives were oxidized to the corresponding azoxy or nitro products depending on the substitution pattern in the aromatic ring. Catalyst recovery and recycle was demonstrated.
An efficient nitration of light alkanes and the alkyl side-chain of aromatic compounds with nitrogen dioxide and nitric acid catalyzed by N-hydroxyphthalimide
Nishiwaki, Yoshiki,Sakaguchi, Satoshi,Ishii, Yasutaka
, p. 5663 - 5668 (2007/10/03)
Nitration of light alkanes and the alkyl side-chain of aromatic compounds with NO2 and HNO3 was successfully achieved by the use of N-hydroxyphthalimide (NHPI) as a catalyst under relatively mild conditions. For example, the nitration of propane with NO2 catalyzed by NHPI at 100 °C for 14 h gave 2-nitropropane in good yield without formation of 1-nitropropane and cleaved products such as nitroethane and nitromethane. Various aliphatic nitroalkanes, which are difficult to prepare by conventional methods, could be selectively obtained by means of the present methodology by using NHPI as the key catalyst. In addition, the side-chain nitration of alkylbenzenes such as toluene was selectively carried out to lead to α-nitrotoluene without the ring nitration. The present reaction provides an efficient selective method for the nitration of light alkanes and alkylbenzenes, which has been very difficult to carry out so far.
Increased intensity of tert-butoxyl radical emission in 4-chloro-2- methylphenoxyacetic acid (MCPA) synthesis
Jezierski, Adam,Zakrzewski, Jerzy,Moszczyski, Wiesaw
, p. 1229 - 1232 (2007/10/03)
The important herbicide, 2-methyl-4-chlorophenoxyacetic acid (MCPA) was synthesized by the chlorination of 2-methylphenoxyacetic acid with tert-butyl hypochlorite in the presence of methyl N,N-dimethylglycinate as a catalyst, giving a high yield and regioselectivity. The reaction was investigated using the spin-trapping technique in electron paramagnetic resonance measurement conditions, with nitrosodurene as a spin trap. Increased intensity emission of the tert-butoxyl radical (2.9 times in relation to the starting level) was observed after the catalyst had been introduced into the reaction mixture, indicating a free radical mechanism for the reaction.
