Observations of transient intermediates during flash photolysis of 1,3-diphenyl-2-pyrazoline and its sulphonated derivative in solution

1975 ◽  
Vol 28 (6) ◽  
pp. 1301 ◽  
Author(s):  
KF Langley
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Flash Photolysis ◽  
Eosin Y ◽  
Transient Species ◽  
Absorption Bands ◽  
Transient Intermediates

At least two transient species have been observed during flash photolysis of a sulphonated derivative of 1,3-diphenyl-2-pyrazoline in aqueous solution. One of these, with absorption bands at 455 and 625 nm, has also been generated by sensitization with methylene blue and eosin Y, and appears to be a semi-oxidized species.

Ionizing Irradiation Property of L(+)-Alpha-Phenylglycine in Acid Aqueous Solution

2011 ◽  
Vol 343-344 ◽  
pp. 469-475
Author(s):  
Wen Yan Shi ◽  
Jian Zhong Gu ◽  
Zheng Jiao ◽  
Wen Jing Wu ◽  
Gang Xu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Steady State ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Transient Species ◽  
Ionizing Irradiation ◽  
Steady State Analysis ◽  
Applied Dose ◽  
Acid Aqueous Solution

(+)-alpha-phenylglycine are significant contaminants at pharmaceutical intermediates production. To study processes for the destruction of contaminant L(+)-alpha-phenylglycine in acid aqueous solution we have investigated the transient species using both laser flash photolysis. The OH· reaction with L(+)-alpha-phenylglycine process was investigated and formed polymer. Furthermore, the results of steady-state analysis suggested that L(+)-alpha-phenylglycine removal was found to be more efficient with increasing applied dose. L(+)-alpha-phenylglycine, decreased by 44.50%, using a dose of 14kGy.

The photo-oxidation of an aromatic amine studied by flash photolysis

1965 ◽  
Vol 287 (1410) ◽  
pp. 363-380 ◽  
Keyword(s):  
Thin Film ◽  
Aqueous Solution ◽  
Aromatic Amine ◽  
Rate Constants ◽  
Flash Photolysis ◽  
Radical Cations ◽  
Reaction Scheme ◽  
Transient Species ◽  
Kinetic Spectroscopy ◽  
Photo Oxidation

Photo-oxidation of the amine N -/β-hydroxyethyl N -methyl aniline ( HEMA ) by daylight and oxygen leads to interesting discoloration effects: when the amine is exposed as a thin film a blue product is formed. The formation of this blue product in solution has been studied by the flash photolysis technique. Maximum formation of the blue product occurs when HEMA is flash-photolysed in air-saturated aqueous solution and the pH is about 3.5. Examination of the flash photolysis of HEMA by kinetic spectroscopy shows that two transient species are associated with the formation of this product. These transients are the radical cations + ϕN + R 1 R 2 and dimer* +. The second transient dimer•+ is formed by the reaction ϕN + R 1 R 2 + ϕN R 1 R 2 → dimer•+ and in nitrogen-saturated solution it further reacts by 2 dimer *+ → dimer 2+ + dimer. Values are obtained for th e rate constants of these reactions. A reaction scheme involving the reaction of dimer •+ and dimer 2+ with oxygen is given for the formation of the blue product in aqueous solution and an explanation is put forward to account for the daylight discoloration behaviour of HEMA .

Using of modified-bentonite as low-cost sorbent for removal of methylene blue dye from aqueous solution

2020 ◽  
Vol 27 (2) ◽  
pp. 45-54
Author(s):  
Saraa Muwafaq Ibrahim ◽  
Ziad T. Abd Ali
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Silanol Group ◽  
Infrared Spectrometry ◽  
Blue Dye ◽  
Ammonium Bromide ◽  
Vibration Band ◽  
Order Kinetic ◽  
Methylene Blue Dye ◽  
Modified Bentonite

Batch experiments have been studied to remove methylene blue dye (MB) from aqueous solution using modified bentonite. The modified bentonite was synthesized by replacing exchangeable calcium cations in natural bentonite with cationic surfactant cetyl trimethyl ammonium bromide (CTAB). The characteristics of modified bentonite were studied using different analysis such as Scanning electronic microscopy (SEM), Fourier transform infrared spectrometry (FTIR) and surface area. Where SEM shows the natural bentonite has a porous structure, a rough and uneven appearance with scattered and different block structure sizes, while the modified bentonite surface morphology was smooth and supplemented by a limited number of holes. On other hand, (FTIR) analysis that proved NH group aliphatic and aromatic group of MB and silanol group are responsible for the sorption of contaminate. The organic matter peaks at 2848 and 2930 cm-1 in the spectra of modified bentonite which are sharper than those of the natural bentonite were assigned to the CH2 scissor vibration band and the symmetrical CH3 stretching absorption band, respectively, also the 2930 cm-1 peak is assigned to CH stretching band. The batch study was provided the maximum removal efficiency (99.99 % MB) with a sorption capacity of 129.87 mg/g at specified conditions (100 mg/L, 25℃, pH 11 and 250rpm). The sorption isotherm data fitted well with the Freundlich isotherm model. The kinetic studies were revealed that the sorption follows a pseudo-second-order kinetic model which indicates chemisorption between sorbent and sorbate molecules.

Pattern Formation in the Methylene Blue-Fructose-Oxygen System in Aqueous Solution and in Gel Systems

2000 ◽  
Vol 65 (9) ◽  
pp. 1394-1402 ◽  
Author(s):  
Ľubica Adamčíková ◽  
Mária Hupková ◽  
Peter Ševčík
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Pattern Formation ◽  
Alkaline Ph ◽  
Initial Reactant ◽  
Nonlinear Reaction ◽  
Oxygen System ◽  
Hydrodynamic Processes ◽  
Liquid Layer Thickness ◽  
Catalyzed Oxidation

Spatial patterns in methylene blue-catalyzed oxidation of fructose at alkaline pH were found in aqueous solution and in gel systems. In a thin liquid layer (thickness >2.4 mm) a mixture of spots and stripes was formed by interaction of a nonlinear reaction and the Rayleigh or Maragoni instabilities. The pattern formation was affected by initial reactant concentrations and by the thickness of the reaction mixture layer. Long-lasting structures were formed in gel systems (polyacrylamide, agar, gelatin). These patterns also arise primarily from hydrodynamic processes.

2-Deoxyribose Radicals in the Gas Phase and Aqueous Solution. Transient Intermediates of Hydrogen Atom Abstraction from 2-Deoxyribofuranose

2005 ◽  
Vol 70 (11) ◽  
pp. 1769-1786 ◽  
Author(s):  
Luc A. Vannier ◽  
Chunxiang Yao ◽  
František Tureček
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Gas Phase ◽  
Computational Study ◽  
Hydrogen Atom Abstraction ◽  
Oh Radical ◽  
Free Energies ◽  
Intramolecular Hydrogen ◽  
Solvation Free Energies ◽  
Transient Intermediates

A computational study at correlated levels of theory is reported to address the structures and energetics of transient radicals produced by hydrogen atom abstraction from C-1, C-2, C-3, C-4, C-5, O-1, O-3, and O-5 positions in 2-deoxyribofuranose in the gas phase and in aqueous solution. In general, the carbon-centered radicals are found to be thermodynamically and kinetically more stable than the oxygen-centered ones. The most stable gas-phase radical, 2-deoxyribofuranos-5-yl (5), is produced by H-atom abstraction from C-5 and stabilized by an intramolecular hydrogen bond between the O-5 hydroxy group and O-1. The order of radical stabilities is altered in aqueous solution due to different solvation free energies. These prefer conformers that lack intramolecular hydrogen bonds and expose O-H bonds to the solvent. Carbon-centered deoxyribose radicals can undergo competitive dissociations by loss of H atoms, OH radical, or by ring cleavages that all require threshold dissociation or transition state energies >100 kJ mol-1. This points to largely non-specific dissociations of 2-deoxyribose radicals when produced by exothermic hydrogen atom abstraction from the saccharide molecule. Oxygen-centered 2-deoxyribose radicals show only marginal thermodynamic and kinetic stability and are expected to readily fragment upon formation.

scholarly journals Self-Assembled Nanomaterials Based on Complementary Sn(IV) and Zn(II)-Porphyrins, and Their Photocatalytic Degradation for Rhodamine B Dye

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3598
Author(s):  
Nirmal K. Shee ◽  
Hee-Joon Kim
Keyword(s):  
Aqueous Solution ◽  
Visible Light Irradiation ◽  
Rhodamine B ◽  
Self Assembly ◽  
The Self ◽  
Assembly Process ◽  
Absorption Bands ◽  
Ligand Coordination ◽  
Rhodamine B Dye ◽  
Metal Ligand

A series of porphyrin triads (1–6), based on the reaction of trans-dihydroxo-[5,15-bis(3-pyridyl)-10,20-bis(phenyl)porphyrinato]tin(IV) (SnP) with six different phenoxy Zn(II)-porphyrins (ZnLn), was synthesized. The cooperative metal–ligand coordination of 3-pyridyl nitrogens in the SnP with the phenoxy Zn(II)-porphyrins, followed by the self-assembly process, leads to the formation of nanostructures. The red-shifts and remarkable broadening of the absorption bands in the UV–vis spectra for the triads in CHCl3 indicate that nanoaggregates may be produced in the self-assembly process of these triads. The emission intensities of the triads were also significantly reduced due to the aggregation. Microscopic analyses of the nanostructures of the triads reveal differences due to the different substituents on the axial Zn(II)-porphyrin moieties. All these nanomaterials exhibited efficient photocatalytic performances in the degradation of rhodamine B (RhB) dye under visible light irradiation, and the degradation efficiencies of RhB in aqueous solution were observed to be 72~95% within 4 h. In addition, the efficiency of the catalyst was not impaired, showing excellent recyclability even after being applied for the degradation of RhB in up to five cycles.

scholarly journals Sulfobetaine Cryogels for Preferential Adsorption of Methyl Orange from Mixed Dye Solutions

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 208
Author(s):  
Ramona B. J. Ihlenburg ◽  
Anne-Catherine Lehnen ◽  
Joachim Koetz ◽  
Andreas Taubert
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Methyl Orange ◽  
Dye Removal ◽  
Selective Adsorption ◽  
Water Soluble ◽  
Organic Substances ◽  
Preferential Adsorption ◽  
Dimethyl Ammonium ◽  
Dye Solutions

New cryogels for selective dye removal from aqueous solution were prepared by free radical polymerization from the highly water-soluble crosslinker N,N,N’,N’-tetramethyl-N,N’-bis(2-ethylmethacrylate)-propyl-1,3-diammonium dibromide and the sulfobetaine monomer 2-(N-3-sulfopropyl-N,N-dimethyl ammonium)ethyl methacrylate. The resulting white and opaque cryogels have micrometer sized pores with a smaller substructure. They adsorb methyl orange (MO) but not methylene blue (MB) from aqueous solution. Mixtures of MO and MB can be separated through selective adsorption of the MO to the cryogels while the MB remains in solution. The resulting cryogels are thus candidates for the removal of hazardous organic substances, as exemplified by MO and MB, from water. Clearly, it is possible that the cryogels are also potentially interesting for removal of other compounds such as pharmaceuticals or pesticides, but this must be investigated further.

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