Effect of the sulphonic group position on the properties of monoazo dyes

Wojciechowski, Krzysztof; Szadowski, J.

doi:10.1016/s0143-7208(99)00085-6

Cited by 19 publications

(7 citation statements)

References 27 publications

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“…Table 8 Thermodynamic parameters for the adsorption of OG on A2 The band at 426 cm −1 corresponds to the wagging vibration mode of SO 3 group. The chromophore group (C-N=N-C) appears as an intense band at 1,003 cm −1 , and stretching vibration C-N of azo compound appears in IR spectrum at 1,207 cm −1 [51].…”

Section: Ft-ir Spectramentioning

confidence: 99%

Batch and fixed bed column studies on removal of Orange G acid dye by a weak base functionalized polymer

Dulman

Cucu-Man

Bunia³

et al. 2016

Desalination and Water Treatment

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The performance of a weak base anion-exchange resin in removing Orange G dye from aqueous solutions in batch and column system was investigated. The adsorption capacity was found to depend on: pH, dye concentration, contact time, adsorbent dosage, electrolyte presence and temperature. The adsorption equilibrium is best described by the non-linear Langmuir isotherm model. At the optimum pH of 2, the maximum adsorption capacity was 1,076 and 1,218 mg g −1 , at 20 and 50˚C, respectively. The adsorption kinetics could be described by the pseudo-second-order reaction model. The thermodynamic parameters indicated that adsorption is a spontaneous and endothermic process. FT-IR and SEM analyses provided additional information on adsorption mechanism and on morphological changes of the adsorbent. The breakthrough experimental results were processed by means of Thomas, Yoon-Nelson and Wolborska models. The reusability of the column was examined by conducting several cycles of adsorption and desorption (with 0.05 M NaOH).

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Section: Ft-ir Spectramentioning

confidence: 99%

Batch and fixed bed column studies on removal of Orange G acid dye by a weak base functionalized polymer

Dulman

Cucu-Man

Bunia³

et al. 2016

Desalination and Water Treatment

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“…Changes in the electron density are relatively low at the carbon atoms at which the sulfonic groups are substituted. 57 Furthermore, the participation of the sulfur d orbital in the conjugated system is very low, and the contribution to C-S bond is practically negligible. The very strong band at 1047 cm 1 in the IR spectrum and the medium intensity band at 1053 cm 1 in the Raman spectrum had been identified as the symmetric stretching vibration of the SO 3 group.…”

Section: Sulfonate Group Vibrationsmentioning

confidence: 99%

FT‐Raman, IR and UV‐visible spectral investigations and ab initio computations of a nonlinear food dye amaranth

Snehalatha¹,

Ravikumar²,

Sekar

et al. 2008

J Raman Spectroscopy

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Amaranth (E123, Food Red 9, FD & C Red 2) is a sulfonated azo dye used as a color additive in foodstuffs, pharmaceuticals and cosmetics. FT-IR and FT-Raman spectra of amaranth were recorded and analyzed. Density functional theory (DFT) calculations were performed to derive the equilibrium geometry, vibrational wavenumbers, intensities and first hyperpolarizability. The results of the optimized molecular structure gave clear evidence for the intramolecular charge transfer (ICT) and intramolecular hydrogen bonding in the molecule. Azo stretching wavenumbers are lowered owing to conjugation and p-electron delocalization. Time-dependent density functional theory (TD-DFT) calculations of the electronic spectra were performed on the optimized structure and compared with the experimental UV-visible spectrum. Vibrational spectra, natural bonding orbitals (NBO) analysis and optimized geometry indicate C-H· · ·N hydrogen bonding in the molecule. The first hyperpolarizability of the molecule was calculated. The optical nonlinearity of the dye is due to the donation of the electron density from the hydroxyl group of the conjugated system via naphthalene (2) ring into p * -orbital of the azo moiety.

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“…12 In the present work, we expand the previous studies and explore the effect of various ionic additives on the mesomorphic properties and structure of SSY, Figure 1. [13][14][15][16][17][18][19][20] SSY as an LCLC has been studied by Ormerod, 13 Luoma, 14 and recently, by Horowitz et al 15 and Edwards et al 16 The aggregate structure of SSY is somewhat better established than that of DSCG: the stacks of SSY in water have been shown to contain only one molecule in cross-section; 15,16 the molecules are on average perpendicular to the aggregate axis. The underlying mechanism of aggregate self-assembly in LCLCs is similar to the one responsible for worm-like micelles formed by surfactant mol- ecules in solutions and the so-called "living" polymerization.…”

Section: Introductionmentioning

confidence: 99%

Self-Assembly of Lyotropic Chromonic Liquid Crystal Sunset Yellow and Effects of Ionic Additives

et al. 2008

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Lyotropic chromonic liquid crystals (LCLCs) are formed by molecules with ionic groups at the periphery that associate into stacks through noncovalent self-assembly while in water. The very existence of the nematic (N) phase in the typical LCLC, the dye Sunset Yellow (SSY) is a puzzle, as the correlation length associated with the stacking, as measured in the X-ray experiments, is too short to explain the orientational order by the Onsager model. We propose that the aggregates can be more complex than simple rods and contain "stacking faults" such as junctions with a shift of neighboring molecules, 3-fold junctions, etc. We study how ionic additives, such as salts of different valency and pH-altering agents, alter the N phase of SSY purified by recrystallization. The additives induce two general trends: (a) stabilization of the N phase, caused by the mono and divalent salts (such as NaCl), and evidenced by the increase of the N-to-I transition temperature and the correlation length; (b) suppression of the N phase manifested in the decrease of the N-to-I transition temperature and in separation of the N phase into a more densely packed N phase or the columnar (C) phase, coexisting with a less condensed I phase. The scenario (b) can be triggered by simply increasing pH (adding NaOH). The effects produced by tetravalent spermine fall mostly into the category (b), but the detail depends on whether this additive is in its salt form or a free base form. The base form causes changes through changes in pH and possible excluded volume effects whereas the salt form might disrupt the structure of SSY aggregates.

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Effect of the sulphonic group position on the properties of monoazo dyes

Cited by 19 publications

References 27 publications

Batch and fixed bed column studies on removal of Orange G acid dye by a weak base functionalized polymer

Batch and fixed bed column studies on removal of Orange G acid dye by a weak base functionalized polymer

FT‐Raman, IR and UV‐visible spectral investigations and ab initio computations of a nonlinear food dye amaranth

Self-Assembly of Lyotropic Chromonic Liquid Crystal Sunset Yellow and Effects of Ionic Additives

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