UV Direct Photolysis of Amisulbrom in Buffer solutions: Kinetics, Quantum yield, Products Identification, DFT, Mechanism and Predict Toxicity

2021 ◽  
pp. 106594
Author(s):  
Kyongjin Pang ◽  
Honglei Zhao ◽  
Jiye Hu
Keyword(s):  
Quantum Yield ◽  
Direct Photolysis ◽  
Buffer Solutions

Hg(63P1)-sensitized decomposition of HNCO vapor and HNCO–H2 mixtures; the reaction of hydrogen atoms with HNCO

1968 ◽  
Vol 46 (4) ◽  
pp. 527-530 ◽  
Author(s):  
N. J. Friswell ◽  
R. A. Back
Keyword(s):  
Quantum Yield ◽  
Cross Section ◽  
Initial Step ◽  
Primary Process ◽  
Hydrogen Atoms ◽  
Direct Photolysis ◽  
A Value ◽  
The Cross

The Hg(63P1)-sensitized decomposition of HNCO vapor has been briefly studied at 26 °C with HNCO pressures from about 3 to 30 Torr. The products detected were the same as in the direct photolysis, CO, N2, and H2. The quantum yield of CO was appreciably less than unity, compared with a value of 1.5 in the direct photolysis under similar conditions. From this and other observations it is tentatively concluded that a single primary process occurs:[Formula: see text]From a study of the mercury-photosensitized reactions in mixtures of HNCO with H2, it was concluded that hydrogen atoms react with HNCO to form CO but not N2. The initial step is probably addition to form NH2CO. From the competition between reaction [1] and the corresponding quenching by H2, the cross section for reaction [1] was estimated to be 2.3 times that of hydrogen.

scholarly journals Comparison of the degradation of molecular and ionic ibuprofen in a UV/H2O2 system

2018 ◽  
Vol 77 (9) ◽  
pp. 2174-2183 ◽  
Author(s):  
Rongkui Su ◽  
Liyuan Chai ◽  
Chongjian Tang ◽  
Bo Li ◽  
Zhihui Yang
Keyword(s):  
Quantum Yield ◽  
Rate Constant ◽  
Degradation Rate ◽  
Molecular Form ◽  
Degradation Kinetics ◽  
Dominant Role ◽  
Radical Scavenging ◽  
Operating Conditions ◽  
Direct Photolysis ◽  
H2o2 System

Abstract The advanced oxidation technologies based on •OH can effectively degrade the pharmaceutical and personal care products under operating conditions of normal temperature and pressure. In this study, direct photolysis of ibuprofen (IBU) is slow due to the relatively low molar extinction coefficient and quantum yield. Compared to direct photolysis, the degradation kinetics of IBU was significantly enhanced in the UV/H2O2 system, mainly by •OH radical mediated oxidation. In the UV/H2O2 system, the degradation rate of ionic IBU was slightly faster than that of the molecular form. Kinetic analysis showed that the second-order reaction rate constant of ionic IBU (5.51 × 109 M−1 s−1) was higher than that of the molecular form (3.43 × 109 M−1 s−1). The pseudo first-order rate constant for IBU degradation (kobs) increased with increasing H2O2 dosage. kobs can be significantly decreased in the presence of natural organic matter (NOM), which is due to (i) NOM radical scavenging effects (dominant role) and (ii) UV absorption. The degradation of IBU was inhibited by HCO3–, which was attributed to its scavenging effect. Interestingly, when NO3– was present in aqueous solution, a slight increase in the degradation rate was observed, which was due to NO3– absorbing photons to generate •OH at a low quantum yield. No obvious effects were observed when SO42 and Cl− were present.

Direct Photolysis of 2-Propanol Vapor

1972 ◽  
Vol 50 (14) ◽  
pp. 2217-2223 ◽  
Author(s):  
O. S. Herasymowych ◽  
A. R. Knight
Keyword(s):  
Quantum Yield ◽  
Wavelength Range ◽  
Exposure Time ◽  
Yield Enhancement ◽  
Quantum Yields ◽  
Unimolecular Decomposition ◽  
Direct Photolysis ◽  
Volatile Products ◽  
Temperature And Pressure

The photolysis of 2-propanol vapor in the 1800–2000 Å wavelength range has been investigated. The volatile products of the reaction and their quantum yields at 80 °C and 200 Torr substrate pressure are H2 (0.64), CH3COCH3 (0.34), CH4 (0.39), CH3CHO (0.29), CO (0.15), and C2H6 (0.08). A mechanism is proposed that accounts for the observed rate variations with substrate pressure, exposure time, temperature, and pressure of inert addend. Acetone and acetaldehyde undergo significant secondary decomposition and this is the source of CO, CH4, and C2H6. Acetaldehyde is formed in the unimolecular decomposition of C3H7O radicals produced in the primary process.The effects of CO2 and CF4 as inert addends have been examined and it has been established that the quantum yield enhancement through collision induced predissociation that has been reported to occur in methanol is not a characteristic of the 2-propanol photolysis.

Pressure Dependence of Product Yields in the Direct Photolysis of Methanol Vapor at 1849°Å

1973 ◽  
Vol 51 (1) ◽  
pp. 147-148 ◽  
Author(s):  
O. Sonia Herasymowych ◽  
Arthur R. Knight
Keyword(s):  
Quantum Yield ◽  
Exposure Time ◽  
Pressure Dependence ◽  
High Pressures ◽  
Yield Enhancement ◽  
Direct Photolysis ◽  
Methanol Vapor ◽  
Product Yields

Hydrogen and methane yields from the 1849 Å photolysis of methanol vapor in an all-quartz system have been investigated as a function of exposure time and pressure of CH3OH and added CO2.Product yields are decreased by the inert addend, and by the substrate itself at high pressures, in contrast to the collision-induced quantum yield enhancement reported to be occurring in this system.

The photochemistry of 2-furaldehyde vapour. II. Photodecomposition: direct photolysis at 253.7 and 313 nm and Hg(3P1)-sensitized decomposition

1976 ◽  
Vol 54 (19) ◽  
pp. 3095-3101 ◽  
Author(s):  
A. Gandini ◽  
J. M. Parsons ◽  
R. A. Back
Keyword(s):  
Quantum Yield ◽  
Pressure Dependence ◽  
Low Pressure ◽  
Major Product ◽  
The Other ◽  
Direct Photolysis

The photolysis of furaldehyde vapour at 253.7 nm, 65 °C, and pressures from about 0.2 to 7 torr, produces CO, propyne, allene, furan, cyclopropene, CO2, and C2H2. The quantum yield of CO approaches 2 at low pressure and decreases towards zero with increasing pressure of furaldehyde or added CO2. Yields of the other products also decrease but show a more complex pressure dependence. A mechanism involving excited furaldehyde and excited C4H4O and C3H4 intermediates is suggested.The Hg(3P1)-photosensitized decomposition gives products very similar to those of the direct photolysis. Photolysis at 313 and 366 nm also leads to similar products but in much lower yields, with the major product, CO, having a quantum yield of about 0.01. Some photopolymerization was observed in all Systems.

Photolysis of 5,5-dimethyl-4-phenyl-Δ-1,2,4-triazolin-3-one. Fragmentation to nitrogen, carbon monoxide, and isopropylidene phenyl amine

1981 ◽  
Vol 59 (21) ◽  
pp. 3087-3089
Author(s):  
Lubomira M. Cabelkova-Taguchi ◽  
John Warkentin
Keyword(s):  
Carbon Monoxide ◽  
Excited State ◽  
Quantum Yield ◽  
Triplet Excited State ◽  
Direct Photolysis ◽  
Norrish Type ◽  
Initial Cleavage

Photolysis of 5,5-dimethyl-4-phenyl-Δ1-1,2,4-triazolin-3-one (2) produces the same products as thermolysis; namely, nitrogen, carbon monoxide, and isopropylidene phenyl amine (acetone anil). The quantum yield for direct photolysis of 2 in methanol with 313 nm light is 0.066. Sensitization with benzophenone in the same solvent, and quenching with 1,3-cyclohexadiene, revealed that photolysis of 2 involves a triplet excited state. The most likely photo processes are thought to involve initial cleavage of the C3—N4 bond or the C3—N2 bond (Norrish, type 1 cleavage).

Size-dependent emission of a dipole coupled to a metal nanoparticle

MRS Advances ◽  
2020 ◽  
Vol 5 (62) ◽  
pp. 3315-3325
Author(s):  
Viktoriia Savchuk ◽  
Arthur R. Knize ◽  
Pavlo Pinchuk ◽  
Anatoliy O. Pinchuk
Keyword(s):  
Numerical Analysis ◽  
Quantum Yield ◽  
Electric Dipole ◽  
Incident Radiation ◽  
Metal Nanoparticle ◽  
Plasmonic Nanoparticle ◽  
Size Dependent ◽  
Emission Enhancement ◽  
Electric Dipoles

AbstractWe present a systematic numerical analysis of the quantum yield of an electric dipole coupled to a plasmonic nanoparticle. We observe that the yield is highly dependent on the distance between the electric dipole and the nanoparticle, the size and permittivity of the nanoparticle, and the wavelength of the incident radiation. Our results indicate that enhancement of the quantum yield is only possible for electric dipoles coupled to a nanoparticle with a radius of 20 nm or larger. As the size of the nanoparticle is increased, emission enhancement occurs at wavelengths dependent on the coupling distance.

Highly Fluorescent Au25-xAgx Nanoclusters Protected with Poly(ethylene glycol) - and Zwitterion-Modified Thiolate Ligands

2018 ◽  
Author(s):  
Dinesh Mishra ◽  
Sisi Wang ◽  
Zhicheng Jin ◽  
Eric Lochner ◽  
Hedi Mattoussi
Keyword(s):  
Quantum Yield ◽  
Near Infrared ◽  
Small Diameter ◽  
Binding Energies ◽  
Thiolate Ligands ◽  
Nir Emission ◽  
Thiolate Complexes ◽  
Long Lifetime ◽  
Poly Ethylene

<p>We describe the growth and characterization of highly fluorescing, near-infrared-emitting nanoclusters made of bimetallic Au<sub>25-x</sub>Ag<sub>x</sub> cores, prepared using various monothiol-appended hydrophobic and hydrophilic ligands. The reaction uses well-defined triphenylphosphine-protected Au<sub>11</sub> clusters (as precursors), which are reacted with Ag(I)-thiolate complexes. The prepared nanoclusters are small (diameter < 2nm, as characterized by TEM) with emission peak at 760 nm and long lifetime (~12 µs). The quantum yield measured for these materials was 0.3 - 0.4 depending on the ligand. XPS measurements show the presence of both metal atoms in the core, with measured binding energies that agree with reported values for nanocluster materials. The NIR emission combined with high quantum yield, small size and ease of surface functionalization afforded by the coating, make these materials suitable to implement investigations that address fundamental questions and potentially useful for biological sensing and imaging applications.<br></p>

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