UV-spectral changes for some azo compounds in the presence of different solvents

Sıdır, Yadigar Gülseven; Sıdır, İsa; Berber, Halil; Taşal, Erol

doi:10.1016/j.molliq.2011.07.002

Cited by 48 publications

(12 citation statements)

References 27 publications

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“…The latter band is related the lone pair in the N=N bridge and its contribution to the interaction between the solvents and the lone pair of the Cl substituent in a polar aprotic solvent. 32 After the electrolysis, the band at 284 nm remains constant, whereas the band relative to the azo group shifts to 501 nm and the absorbance decreases slightly. This behavior is identical to that of the UV-Vis spectrum recorded for the dye DR-13 (same chemical structure without chloride substituent) during electrolysis in Bu 4 NBF 4 /DMF, since the same absorbance band is detected at 502 nm before electrolysis and there is no change in the chromophore band after 3 hours of electrolysis ( Figure 3, curve b).…”

Section: Resultsmentioning

confidence: 99%

Electroanalytical Determination of Disperse Red-13 in Wastewaters

Bahram

Pourabdollah

2013

J. Electrochem. Soc.

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The electrochemical reduction of the dye Disperse Red-13 at a glassy carbon electrode in N,N-dimethylformamide was investigated. The dye was better determined using a mixture of DMF/Britton-Robinson buffer (1:1, v/v), which displayed a well-defined peak at −0.40 V vs Ag/AgCl due to reduction of the protonated nitro group. This method was successfully applied for electroanalytical determination of DR-13 via a very simple and inexpensive way. All of the differential pulse voltammetry parameters were optimized using a glassy carbon electrode modified with poly(glutamic acid) films. The electroanalytical method presented a linear response from 2.5 × 10 −7 to 3 × 10 −6 mol L −1 to DR-13 (r = 0.997), with a detection limit of 1.5 × 10 −8 mol L −1 and recoveries from 89.7 to 95.10% in water samples. The dye was successfully determined in the wastewater after pre-extraction in a solid-phase extraction cartridge.Disperse dyes consist of non-ionic low molecular weight organic compounds that are sparingly soluble in water. 1 They are widely used in the dyeing of synthetic hydrophobic fabrics such as polyester, cellulose acetate, and nylon, among others. 2 Most of these disperse dyes contain an azo group as chromophore. They also contain polar groups and dyes of small molecular size, which improve their aqueous solubility in some special conditions. 3 As in the case of other dyes, dispersion dyes fixation does not reach 100%, so part of the dye that is not bound to the fabric during the dyeing process is drained into the wastewater. Because these dyes are designed to be chemically and photochemically stable in the aquatic biota, their determination in the dyeing bath and in the wastewater effluent is relevant for monitoring of their occurrence in the environment and control of their waste.However, methods that are suitable for the analysis of environmentally significant levels are scarce, due to the low solubility of disperse dyes in water. In addition, the toxicologic and ecotoxicologic properties of this kind of dyes have been brought to attention in the literature. The main papers on the determination of disperse dyes are based on UV-Vis spectrophotometry with multivariate calibration, total organic carbon analysis, 4 capillary electrophoresis, and liquid chromatography with UV or mass spectrometry detection, 5 which all require long preconcentration time and/or cleaning steps as well as special procedures concerning column poisoning in chromatographic experiments.There are a number of previous works, which detected disperse dyes based on electrochemical methods. Zanoni et al. 6 used cathodic stripping voltammetry for determination of two anthraquinonebased chlorotriazine dyes (procion blue MX-R and cibacron blue 3GA) at a hanging mercury drop electrode. They revealed that the reduction of the anthraquinone moiety in these dyes obtained no peak in differential pulse voltammetric stripping mode, while the signal was present in linear sweep mode. They concluded that the anthraquinone moiety is reduced so rapidly that reduct...

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Section: Resultsmentioning

confidence: 99%

Electroanalytical Determination of Disperse Red-13 in Wastewaters

Bahram

Pourabdollah

2013

J. Electrochem. Soc.

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“…As expected in non-polar solvents benzene and CCl4, azo dyes show three electronic absorption bands. These bands are due to the conjugation between the azo bridge and aromatic rings, the lone-pair located on the azo bridge and hydroxyl (OH) groups and intramolecular O-H…N hydrogen bond formation, respectively (Issa et al 1972;Gülseven et al 2009;Gülseven et al 2011a;Gülseven et al 2011b). According to Table 2, the induction of electrons in substituents (OH, OCH3, C2H5) of benzene ring produce bathochromic shifts on the band wavelength absorption maximum as compared to that of Az1 in solvents.…”

Section: Resultsmentioning

confidence: 99%

An experimental study on relationship between hammett substituent constant and electronic absorption wavelength of some azo dyes

Sıdır¹,

Sıdır²,

Berber³

et al. 2015

Bitlis Eren University Journal of Science and Technology

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In this study, absorption spectra of sixteen azo dyes have been recorded in various solvents. These azo dyes have substituents such as OH, SO3H, Cl, I, NO2, C2H5 and OCH3 in different positions of phenyl ring. There is a shift in λmax whose amount is dependent upon the type and position of substituent on the ring. The effects of substituent on the absorption spectra of azo dyes are interpreted by correlation of absorption maximum wavelengths (nm) with the hammett substituent parameters. Charge transfer transitions are observed in inverse direction for azo dyes with electron acceptor substituent compared to azo dyes with electron donor.

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“…The first band ( π − π * electronic transition) is due to the aromatic rings of the compound, while the second band corresponds to the lowest observed absorption, ascribed to the partly forbidden ( n − π *) electronic transition. The latter band is related to the lone pair in the N=N bridge and its contribution to the interaction between the solvents and the lone pair of the Cl substituent in a polar aprotic solvent . After the electrolysis, the band at 284 nm remains constant, whereas the band relative to the azo group shifts to 501 nm and the absorbance decreases slightly.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical method for quantitative determination of trace amounts of disperse dye in wastewater

Santos

Trindade

Oliveira

et al. 2013

Coloration Technology

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The electrochemical behaviour of Disperse Red 13 dye at a glassy carbon electrode was investigated in both organic and aqueous organic mixtures. Best results were obtained in N,N‐dimethylformamide/Britton–Robinson buffer (1:1, v/v), which displays a well‐defined peak at ‐0.40 V (vs Ag/AgCl) owing to reduction of the protonated nitro group. This method can be successfully applied to the electroanalytical determination of Disperse Red 13 in a very simple and inexpensive way. All the differential pulse voltammetry parameters were optimised by using a glassy carbon electrode modified with poly(glutamic acid) films. The targeted analytical method presented a linear response from Disperse Red 13 concentrations between 2.5 × 10−7 and 3 × 10−6 mol l−1 (r = 0.997), with a detection limit of 1.5 × 10−8 mol l−1 and recoveries of 89.7–95.10% in water samples. Disperse Red 13 was successfully determined in textile industry wastewater by means of the proposed method after pre‐extraction in a solid‐phase extraction cartridge.

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UV-spectral changes for some azo compounds in the presence of different solvents

Cited by 48 publications

References 27 publications

Electroanalytical Determination of Disperse Red-13 in Wastewaters

Electroanalytical Determination of Disperse Red-13 in Wastewaters

An experimental study on relationship between hammett substituent constant and electronic absorption wavelength of some azo dyes

Electrochemical method for quantitative determination of trace amounts of disperse dye in wastewater

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