524-42-5Relevant articles and documents
Environmental photochemistry on semiconductor surfaces: Photosensitized degradation of a textile azo dye, Acid Orange 7, on TiO2 particles using visible light
Vinodgopal,Wynkoop, Darrel E.,Kamat, Prashant V.
, p. 1660 - 1666 (1996)
Photosensitized degradation of a textile azo dye, Acid Orange 7, has been carried out on TiO2 particles using visible light. Mechanistic details of the dye degradation have been elucidated using diffuse reflectance absorption and FTIR techniques. Degradation does not occur on Al2O3 surface or in the absence of oxygen. The dependence of the dye degradation rate on the surface coverage shows the participation of excited dye and TiO2 semiconductor in the surface photochemical process. Diffuse reflectance laser flash photolysis confirms the charge injection from the excited dye molecule into the conduction band of the semiconductor as the primary mechanism for producing oxidized dye radical. The surface-adsorbed oxygen plays an important role in scavenging photogenerated electrons, thus preventing the recombination between the oxidized dye radical and the photoinjected electrons. Diffuse reflectance FTIR was used to make a tentative identification of reaction intermediates and end products of dye degradation. The intermediates, 1,2-naphthoquinone and phthalic acid, have been identified during the course of degradation. Though less explored in photocatalysis, the photosensitization approach could be an excellent choice for the degradation of colored pollutants using visible light.
Chemoselective one-pot access to benzo[e]indole-4,5-diones and naphtho[2,1-b]thiophene-4,5-diones via copper-catalyzed oxidative [3 + 2] annulation of α-oxoketene N,S-acetals/β-ketothioamides with α-/β-naphthols
Yadav, Dhananjay,Shukla, Gaurav,Ansari, Monish A.,Srivastava, Abhijeet,Singh, Maya Shankar
, p. 5920 - 5931 (2018)
An operationally simple and efficient one-pot method for the synthesis of 1-aroyl (or alkanoyl)-2-thioalkyl-3-aryl (or alkyl)-3H-benzo[e]indole-4,5-diones and naphtho[2,1-b]thiophene-4,5-diones has been devised by copper-catalyzed cross-coupling of α-oxoketene N,S-acetals/β-ketothioamides with α-/β-naphthols in open air for the first time. The key to the success of this transformation is the room temperature oxidation of α-/β-naphthol to 1,2-naphthoquinone as a reactive species, which undergoes formal [3 + 2] annulation with α-oxoketene N,S-acetals/β-ketothioamides via cascade sequence of Michael addition/tautomerization/oxidation/cyclization/aromatization reactions, enabling addition of a pyrrole/thiophene ring onto naphthoquinone moiety. Further, benzo[e]indole-4,5-diones were transformed to pentacyclic fused phenazine derivatives under solvent-free conditions. Based on our experimental outcomes, a tentative mechanistic rationale for this chemoselective protocol is proposed, which is well validated and supported by the control experiments.
RuCl3 Catalyzed and Uncatalyzed Oxidative Decolorization of Acid Orange 7 Dye with Chloramine-B in Acid Medium: Spectrophotometric, Kinetic and Mechanistic Study
Manjunatha, Adalagere Somashekar,Puttaswamy
, p. 1312 - 1321 (2015)
Acid orange 7, chemically known as sodium 4-[(2E)-2-(2-oxonaphthalen-1-ylidene)hydrazinyl]benzenesulfonate, is extensively used for dyeing textiles, paper and leather. The discharge of wastewater containing this dye, causes environmental and health related problems. Therefore, in the present research, we have developed optimum conditions for the facile oxidative decolorization of this dye with sodium N-chlorobenzenesulfonamide or chloramine-B (CAB). The kinetics and mechanism of oxidative decolorization of acid orange 7 dye with CAB in acidic medium have also been studied spectrophotometrically at 303 K in the presence and absence of RuCl3 catalyst. Under similar experimental conditions, the reaction exhibits a first-order dependence of rate each on [CAB]o and [dye]o, and an inverse-fractional-order dependence on [H+] for both the RuCl3 catalyzed and uncatalyzed reactions. The order with respect to RuCl3 is fractional. Activation parameters have been computed. Dielectric effect is negative in both the cases. Oxidation products of the acid orange 7 dye are identified as 1,2-naphthoquinone and benzenesulfonic acid by GC-MS data. The RuCl3 catalyzed reaction is about four fold faster than the uncatalyzed reaction. The chemical oxygen demand value of the dye was determined. The mechanistic pathways and kinetic modelings have been computed based on experimental results. The developed oxidative decolorization method is expected to be helpful to treat acid orange 7 dye present in wastewater after suitable modifications. (Chemical Equation Presented).
Substituent effects on azo dye oxidation by the FeIII-EDTA-H2O2 system
Nam, Sangkil,Renganathan,Tratnyek, Paul G.
, p. 59 - 65 (2001)
The effect of substituents on the oxidation of azo dyes in the FeIII-EDTA-H2O2 system was examined at pH 7. 4-(4′-sulfophenylazo)phenol and 2-(4′-sulfophenylazo)phenol, with methyl, methoxy, and halo substituents on the phenolic ring, were used as model systems. Oxidation of the naphthol dyes Orange I and Orange II were also examined. All of the dyes tested were decolorized in the FeIII-EDTA-H2O2 system, but the degree of decolorization varied over a factor of 10. Dyes substituted with one or two halogens were oxidized to a greater extent than the corresponding methyl- or methoxy-substituted dyes. One explanation for the effect of halogen substituents is that they make the phenolic moieties more acidic, which favors the phenolate anion, which is more readily attacked by ·OH. This explanation is supported by the observed correlation between charge density of the phenolate anion and the degree of decolorization. Based on an analysis of products formed from Orange II, a probable mechanism for decolorization of phenolic azo dyes by ·OH is proposed. In addition, the optimal levels of H2O2 needed for the process have been examined. It appears that high levels of H2O2 could reduce decolorization by scavenging the ·OH.
Microwave-assisted selenium dioxide mediated selective oxidation of 1-tetralones to 1,2-naphthoquinones
Gelman, Danny M.,Perlmutter, Patrick
, p. 39 - 40 (2009)
We report an improved procedure for the selective transformation of substituted 1-tetralones to 1,2-naphthoquinones by microwave-assisted selenium dioxide oxidation. The reaction time is effectively reduced from hours to seconds without any loss of yield (40-70%) or selectivity.
Analysis of commercial Acid Black 194 and related dyes by micellar electrokinetic chromatography
Sebastiano, Roberto,Contiello, Nunzia,Senatore, Stanislao,Righetti, Pier Giorgio,Citterio, Attilio
, p. 258 - 265 (2012)
The commercial dye C.I. Acid Black 194 was analyzed by reversed-phase HPLC, Capillary Zone Electrophoresis and Micellar ElectroKinetic Chromatography under different operative conditions, with the scope to detect the impurity distribution typical of any production processes and synthetic batch. The three chrome(III) complexes deriving from the industrial synthesis of C.I. Acid Black 194, and one of the main impurities were isolated by silica flash chromatography and identified by mass spectrometry and NMR. More than twelve compounds present in the commercial mixture, but undetectable by the analytical protocols known in literature, were fully separated by the MECK mode capillary electrophoresis with low % Relative Standard Deviation of the main electrophoretic parameters. Two of them were identified by isolation from the commercial mixture. As additional examples two other commercial metal-based dyes, C.I. Acid Brown 432 and C.I. Acid Brown 434, were analyzed by the same protocol with very good results.
One-pot multistep synthesis of bipolar carbazolo-phenazines: Hydrogen bond control of Diels-Alder cycloaddition and application for fluoride sensing
Mishra, Abhaya Kumar,Mukhopadhyay, Arindam,Moorthy, Jarugu Narasimha
, p. 2210 - 2216 (2017)
Access to novel bipolar carbazolo-phenazines is demonstrated by one-pot IBX-initiated multistep cascade, which involves oxidation of 2-naphthols to 1,2-naphthoquinones, Diels-Alder cycloaddition, aerial dehydroaromatization and cyclocondensation. With unprotected dienic indolylacrylates, N[sbnd]H?O hydrogen bonding in the transition state controls the product selectivity almost exclusively in favor of Diels-Alder cycloaddition over the competing Michael addition. The utility of one of the carbazolo-phenzines as applied to selective naked-eye sensing of fluoride is demonstrated.
Kinetic and mechanistic studies on the oxidative decolourisation of orange-II dye with alkaline chloramine-T
Vaz, Nirmala,Manjunatha,Puttaswamy
, p. 363 - 367 (2015)
The mono-azo dye, Orange-II (acid orange 7), is mainly used to dye materials like textiles, paper, leather and cosmetics. It is important to understand the kinetic and mechanistic aspects of the oxidative decolourisation of Orange-II dye. A simple, efficient and cost-effective oxidation method is developed for the reaction. A detailed kinetic study of the oxidative decolourisation of orange-II dye with chloramine-T (CAT) in alkaline medium at 308 K has been carried out spectrophotometrically at 486 nm. The reaction shows a first-order dependence of rate both on [CAT]o and [Orange-II]o and an inverse-fractional- order on [OH-]. The reaction was studied at different temperatures and the thermodynamic parameters have been evaluated. The reaction was subjected to change in (i) ionic strength, (ii) p-toluenesulfonamide and (iii) chloride ions, and the effects of these on the reaction rate were determined. Oxidation products of Orange-II were characterised as 1,2-naphthaquinone and benzenesulfonic acid by GC-MS analysis. The observed kinetic results have been explained by a general mechanism to understand the elementary pathways of this redox system. The relevant kinetic modelling has been worked out.
1,2-Dihydro-1,2-dihydroxynaphthalene dehydrogenase containing recombinant strains: Preparation, isolation and characterisation of 1,2- dihydroxynaphthalenes and 1,2-naphthoquinones
Cavallotti, Camilla,Orsini, Fulvia,Sello, Guido,Di Gennaro, Patrizia,Galli, Enrica,Bestetti, Giuseppina
, p. 4467 - 4480 (1999)
1,2-Dihydroxynaphthalenes are produced by dehydrogenation of the corresponding 1,2-dihydro-1,2-dihydroxynaphthalenes using an Escherichia coli recombinant strain containing the dihydrodiol naphthalene dehydrogenase gene cloned from Pseudomonas fluorescens N3. Conversions are led in carefully controlled conditions to minimise product polymerisation. A multistep procedure using a weakly basic resin permits isolation of good product amounts, solving the toxicity problem. Products are isolated and characterised as t-butyldimethylsilyl derivatives that are stable compounds. The transformation of the 1,2-dihydroxynaphthalenes into the corresponding 1,2-naphthoquinones is also reported.
Room temperature stable multitalent: highly reactive and versatile copper guanidine complexes in oxygenation reactions
Paul, Melanie,Hoffmann, Alexander,Herres-Pawlis, Sonja
, p. 249 - 263 (2021)
Inspired by the efficiency of natural enzymes in organic transformation reactions, the development of synthetic catalysts for oxygenation and oxidation reactions under mild conditions still remains challenging. Tyrosinases serve as archetype when it comes to hydroxylation reactions involving molecular oxygen. We herein present new copper(I) guanidine halide complexes, capable of the activation of molecular oxygen at room temperature. The formation of the reactive bis(μ-oxido) dicopper(III) species and the influence of the anion are investigated by UV/Vis spectroscopy, mass spectrometry, and density functional theory. We highlight the catalytic hydroxylation activity towards diverse polycyclic aromatic alcohols under mild reaction conditions. The selective formation of reactive quinones provides a promising tool to design phenazine derivatives for medical applications. Graphic abstract: [Figure not available: see fulltext.]
