Photolysis of organic pollutants in wastewater with 206 nm UV irradiation

A new-type UV light source(206 nm) was explored for the degradation of organic pollutants in wastewater for the first time.The degradation performances of triphenyltin chloride(TPTCl),dimethyl phthalate(DMP),as well as rhodamine B(RhB) were investigated.The results indicated that removal efficiency of 50 mg/L RhB,60 mg/L DMP and 120 mg/L TPTCl can reach 88.6%, 92.5%and 89.4%for 60 min,50 min and 75 min,respectively.By comparison of removal efficiency,we found 206 nm is superior to 253.7 nm UV in wastewat...     

Disilylation of N-(2-Halophenyl)-2-phenylacrylamides with hexamethyldisilane via trapping the spirocyclic palladacycles

The palladium-catalyzed disilylation of the spirocyclic palladacycles with hexamethylaisilane has been realized. The key spirocyclic palladacycles are generated from N-(2-haloaryl)-2-arylacrylamide via intramolecular Heck reaction and followed remote C-H activation. A range of 3-((trimethylsilyl)methyl)-3-(2-(trimethylsilyl)phenyl)indolin-2-ones are obtained in good to excellent yields from readily available starting material under mild conditions.     

The Photolysis of Iodoaromatic Compounds

Under appropriate conditions, the photolysis of iodoaromatic compounds yields derivatives of biphenyl and phenanthrene, as well as organometallic compounds. Ring closures of o-terphenyls to triphenylenes and of benzanilides to phenanthridones are described. The formation of dehydrobenzene (benzyne) on photolysis of 1,2-diiodobenzene in solution has been established. The photolysis of various substituted iodoaromatic compounds or of substances such as CH₃I, ICN, ICH₃, COOH, or RC?CI, provides a general method for the generation of a large variety of free radicals in solution. The potential uses of photochemically initiated exchanges of iodine in ArI for ¹³¹I, Li, D, Cl, or Br are noted.     

Electrochemical Studies on the Photolysis of Iron-Arene Complex Photoinitiator

Iron-arene complex was first introduced by researchers in Ciba-Geigy as an effective photoinitiator for the photocuring of epoxy resin. The photolysis of these complexes has been studied by some authors. The electrochemical study reported in this note provides further evidence for the photolysis process which is crucial for the understanding of the photoinitiation mechanism.     

农药光解平均波长量子产率的测定

本文报道一种以高压汞灯复合光为光源测定农药平均波长量子产率的方法。该方法的光最计为草酸铁钾，通过光量计测得光源的照射强度。以气相色谱分析农药降解的残余浓度求得反应速率常数，用紫外分光光度计测定农药在确定波长下的摩尔吸光系数，并与该波长光强相乘进行积分，计算出十二种农药的平均波长Φ。本法所得结果更接近于自然光下的结果，更适合应用于实际环境中。     

Photolysis of 1,1,1-difluorochloroethane (Freon 142) at 147 nm

1,1,1-Difluorochloroethane (Freon 142) was photolyzed at 147 nm in the pressure range of 3.6–20.6 torr. The effects of added NO, H₂S, and CF₄ were investigated. The extinction coefficient at 147 nm and 296°K was determined to be 64 ± 8 atm^?1 · cm^?1. The molecule photodecomposes largely by α,β elimination of HCl to give 1,1-difluoroethylene (Φ = 0.74 ± 0.06). There is no observable elimination of HF, but there is strong evidence for the elimination of the elements of FCl though the relative importance of this process is minor, as are contributions from carbon? carbon and carbon? halogen bond fission. The 1,1-difluoroethylene formed is undoubtedly vibratonally excited and is the source of a pressure-dependent small yield of fluoroacetylene. Over the pressure range studied there is no evidence that the major primary process itself is affected by changes in total pressure as is the case in the 147-nm photolysis of ethyl chloride.     

Kinetic Studies of Nitrate Radicals: Flash Photolysis at 193 nm

Nitrate radicals, NO₃, were produced for the first time by 193 nm laser flash photolysis of N₂O₅ and HNO₃. Detection was achieved due to NO₃'s strong absorption at 622.7 nm confirmed by measurements of the absorption spectrum in the range of 617–625 nm using both NO₃ precursors. Time‐resolved kinetic studies allowed the determination of room temperature rate coefficients for the reactions of NO₃ with 2‐methylbut‐2‐ene and NO₂ of (1.28 ± 0.11) × 10^?11 and (8.4 ± 1.2) × 10^?13 cm³ molecule^?1 s^?1, respectively. The rate coefficients compare well to previous measurements with alternative techniques, suggesting that the reported method is valid and may be applied in follow‐up studies. The rate coefficient for 2‐methylbut‐2‐ene is compared to previous measurements and predictions for the alkene as well as the related alkenol. The new data are consistent with a previously suggested deactivation of the reactive site of the double bond if adjacent to an OH group. A calculated atmospheric lifetime for 2‐methylbut‐2‐ene with respect to NO₃‐initiated oxidation of less than 3 min suggests predominant removal by NO₃ in the atmosphere.     

Photolysis and Cycloaddition Reactivity of Diferrocenyl Substituted Cyclopentadienone

The photolysis results of new diferrocenyl substituted cyclopentadienone(3) show that sunlight and air play an important role in the decomposition of compound 3, and two new compounds, 2-cyclopentenone(4) and α-pyrone(5), were obtained via photolysis of compound 3. The photolysis process was investigated by ¹H NMR, and a plausible mechanism for the formation of compound 5 was deduced. The cycloaddition reactions of substituted cyclopentadienones(3, 7, 9) with maleimide gave substituted imides 8, 10, 11, 12 and an unprecedented diferrocenyl substituted 1H-pyrrol-3(2H)-one derivative 13, respectively. The structures of compounds 4, 5, 8, 10, 11, 12 and 13 were confirmed by X-ray single crystal diffraction analysis technique.     

2-苯基苯并噁唑的光解反应

聚对苯撑苯并二噁唑(PBO)纤维对光较为敏感,在紫外光照射下会发生降解.本文研究了该纤维的单体2-苯基苯并噁唑(PO)的初级光化学反应机理.当PO分子吸收一个光子而跃迁到第一激发态后,克服25.59kJ·mol-1能垒而越过过渡态,此时噁唑环打开,且两个苯环形成大约90°的二面角而得到产物,该产物可进一步与空气中的水发生次级反应.计算结果表明在第一激发态上噁唑开环反应很容易,但在基态势能面并没有发现噁唑的开环路径.分子中的原子(AIM)的计算结果与上述分析过程相吻合.     

Photolysis of Dibenzo[a,d]cycloheptene Dimer

Photolysis reaction of dibenzo[a,d]cycloheptene dimer 3 provides three dibenzo[a,d]cycloheptyl dimers 4 , 5 and 6 under different irradiation conditions via the intramolecular degradative cyclodimerization. A tetracyclic benzo[4,5]cyclohepta[1,2,3‐de]naphthalene core is also synthesized.     

光声量热法测定辅酶B12的光解量子产率

时间可分辨的光声最热法（Time－resolvedphotoacousticcalorimetry；简称PAC）是研究脉冲激光诱发的快速光化学和光生物化学反应过程动力学和热力学信息的一种有效方法[1－5]。本文采用压电陶瓷圆管同时作为样品油和换能器组成的PAC探测系统[6]，以波长λ＝355nm的脉冲激光（脉冲宽度8ns，脉冲重复频率10Hz）为光源激发辅酶B12甲醇溶液；研究其解量子产率，获得了满意的结果．1实验被测溶液注入两端用石英玻璃封口的压电陶瓷圆管内腔，激光束透过石英窗照射溶液（如图］所示）为标定被测样品的非辐射放热量，利用能在极短的时间内（＜l…     

亚硝酸甲酯光解反应的从头算和Cl研究

用从头算和MP2方法求得亚硝酸甲酯的基态、第一和第二激发态解离为CH₃O和NO自由基的解离能分別为238.14、68.99和-183.97kJ/mol,而CH₃O和NO易于生成甲醛和硝酰。由CI方法求出的亚硝酸甲酯直接生成甲醛和硝酰的基态和激发态反应曲线表明,该反应难以按这种机理进行。因此,以上计算支持了实验提出的亚硝酸甲酯光反应生成甲醛和硝酰的两种机理中的光解离机制。     

Metal-Free Far-Red Light-Driven Photolysis via Triplet Fusion to Enhance Checkpoint Blockade Immunotherapy

Metal-free long-wavelength light-driven prodrug photoactivation is highly desirable for applications such as neuromodulation, drug delivery, and cancer therapy. Herein, via triplet fusion, we report on the far-red light-driven photo-release of an anti-cancer drug by coupling the boron-dipyrromethene (BODIPY)-based photosensitizer with a photocleavable perylene-based anti-cancer drug. Notably, this metal-free triplet fusion photolysis (TFP) strategy can be further advanced by incorporating an additional functional dopant, i.e. an immunotherapy medicine inhibiting the indoleamine 2,3-dioxygenase (IDO), with the far-red responsive triplet fusion pair in an air-stable nanoparticle. With this IDO inhibitor-assisted TFP system we observed efficient inhibition of primary and distant tumors in a mouse model at record-low excitation power, compared to other photo-assisted immunotherapy approaches. This metal-free TFP strategy will spur advancement in photonics and biophotonics fields.     

Photolysis of Some N‐Arylbenzamidoximes in Acetonitrile

The photolysis of five N‐arylbenzamidoxime derivatives I‐V in dry acetonitrile gives rise to anilides 8 and benzimidazoles 1 as the major products in addition to benzonitrile 4 , arylamines 5 , benzoic acid 6 , and 2‐phenyl benzoxazoles 7 . In the presence of naphthalene, I gave α‐ and β‐naphthols 2 and 3 beside the previous products. The isolated products have been interpreted in the terms of a free radical mechanism involving the homolysis of N‐O and/or C‐N bonds. This photodegradation process can be considered as an alternative method for the synthesis of anilide, benzimidazole and benzoxazole derivatives in addition to other organic compounds.     

O—酰基—α—酮肟光分解反应的Monte Carlo处理

本文首次对光化学反应体系用Monte Carlo方法进行模拟处理。通过5个O-酰基-α-酮肟光分解反应的Monte Carlo模拟,可避免解析解中由于对吸收光强须采用一级近似求解动力学微分方程组,而造成拟合反应在后期产生与实验结果的偏差。     

Photolysis of thin films of cypermethrin using in situ FTIR monitoring: Products, rates and quantum yields

Cypermethrin is a synthetic pyrethroid insecticide commonly used both indoors and outdoors. Following its application, cypermethrin residues are exposed to atmospheric oxidants, such as ozone and OH radicals, as well as to solar radiation. The current work focuses on the photochemical degradation of cypermethrin under 254 nm, 310 nm, and solar radiation; including kinetic analysis, quantum yields, and identification of volatile and non-volatile products. The investigation was done using a combined FTIR set-up for parallel analysis of condensed and gas phases. Complementary GC–MS analysis was conducted on the pesticide’s residues. Quantum yields of 0.41 and 0.25 were obtained under 254 and 310 nm, respectively. These values are in agreement with outdoor studies and are higher than the known yields for aqueous solution. The values obtained under all tested conditions suggest that photodegradation of adsorbed cypermethrin is a major outdoor degradation pathway. Oxygen presence was found to increase degradation rate and quantum yield.The identified photoproducts include 3-phenoxybenzaldehyde, 3-phenoxybenzoic acid, acetonitrile (m-phenoxyphenyl), and cypermethrin isomers on the surface and formic acid, CO₂ and CO in the gas phase. The condensed phase products are more polar than the parent molecule, suggesting that they may be susceptible to a greater leaching rate in soils.     

Photolysis of pure solid O3 and O2 films at 193 nm

We studied quantitatively the photochemistry of solid O(3) and O(2) films at 193 nm and 22 K with infrared spectroscopy and microgravimetry. Photolysis of pure ozone destroyed O(3), but a small amount of ozone remained in the film at high fluence. Photolysis of pure O(2) produced O(3) in an amount that increased with photon fluence to a stationary level. For both O(2) and O(3) films, the O(3):O(2) ratio at large fluences is ～0.07, about two orders of magnitude larger than those obtained in gas phase photolysis. This enhancement is attributed to the increased photodissociation of O(2) due to photoabsorption by O(2) dimers, a process significant at solid-state densities. We obtain initial quantum yield for ozone synthesis from solid oxygen, Φ(O(3)) = 0.24 ± 0.06, and quantum yields for destruction of O(3) and O(2) in their parent solids, Φ(-O(3)) = 1.0 ± 0.2 and Φ(-O(2)) = 0.36 ± 0.1. Combined with known photoabsorption cross sections, we estimate probabilities for geminate recombination of 0.5 ± 0.1 for O(3) fragments and 0.88 ± 0.03 for oxygen atoms from O(2) dissociation. Using a single parameter kinetic model, we deduce the ratio of reaction cross sections for an O atom with O(2) vs. O(3) to be 0.1-0.2. The general good agreement of the model with the data suggests the validity of the central assumption of efficient energy and spin relaxation of photofragments in the solid prior to their reactions with other species.     

Photolysis of H_2S with interior microwave discharge electrodeless lamps

<正>The luminescent properties of microwave discharge electrodeless mercury lamp(MDEL-Hg) which was ignited within the resonant cavity and photolysis of hydrogen sulfide with low concentration were studied in this paper.Experiment results indicated that the Interior MDEL-Hg could be made the best of energy utihzation and the efficiency of photolysis of H_2S was very significant under the experimental conditions with the initial H_2S concentration of 7.9 mg m~(-1).With residence time of 1.5 s,the removal efficiency of hydrogen sulfide was 91%,the absolute removal amount(ARA) was 3.24μg s~(-1) and the energy consumption was 58.23 mg(kWh)~(-1).     

Photolysis of dicarbonyl(cyclopentadiene)rhodium complexes with a pendent alkyne unit

The syntheses of dicarbonyl[1-(5,5-dimethylhex-3-inyl)-3-phenylcyclopentadienyl]rhodium (7) and its congeners 8 and 9 are reported. Photolysis of 8 and 9 leads to a replacement of one CO ligand by the tethered alkyne unit, yielding 16, and to the dirhodium complexes 17 and 18. The structural assignment of 17 and 18 is based on X-ray studies. The photolysis of 9 leads to 19 and 20.