Chlorine Molecules Research Articles

Decontamination of chlorine gas by organic amine modified copper-exchanged zeolite

Removal of chlorine gas (Cl2) from air is of critical requirement in order to address point-source emissions possibly during a terrorist attack or an industrial accident resulting in Cl2 contamination of the atmosphere. In this work, copper (Cu) exchanged zeolite Y (CuY) was functionalised with triethylenediamine (TEDA) and the capacity to remove Cl2 was evaluated. The materials were characterised by nitrogen (N2) adsorption–desorption studies, Fourier Transform Infrared (FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The materials' ability to remove Cl2 was investigated via a dynamic breakthrough test. Copper exchanged zeolite displayed a low adsorption of Cl2 in spite of its large surface area. However, Cl2 removal greatly improved following functionalisation with TEDA. XPS analysis revealed that Cl2 was removed via a catalytic hydrolysis reaction where adsorbed water vapour transformed Cl2 into Cl− which could be further trapped in the zeolite structural framework. Moisture could increase the Cl2 removal capacity, but the competition for adsorption between water and chlorine molecules was also observed. The spent adsorbent after exposure to Cl2 could be easily recycled with an excessive water vapour treatment. The reusability was also investigated and the adsorbent could be used for more than five times. This material can potentially be used in air filters. It may provide an efficient way for decontaminating Cl2 during a terrorist attack or an industrial accident.

Identification of overlapping resonances in dissociative electron attachment to chlorine molecules

A combined highly differential momentum imaging experiment and ab initio potential-energy curve calculation using density-functional theory (DFT) have been performed to understand the broad resonant peak around 5.7 eV due to dissociative electron attachment (DEA) to the chlorine molecule. Both the kinetic energy and angular distribution over the entire $2\ensuremath{\pi}$ angle of the fragment negative ions have been measured. Two heavily overlapping resonances are identified for the observed broad resonant peak that could settle the long-standing debate. The symmetry of the involved two temporary negative ion (TNI) states are determined from the angular distribution data. Experimental observations are strongly supported with the computed potential-energy curve using DFT.

Physicochemical, Biochemical and Statistical Analysis of Beverages Industry Effluent

The beverages industry faces growing scrutiny of responsible use and protection of the natural environment through conservation and sustainable practices. These industries cause high probability of polluting the environment by discharging untreated wastewater in to the soil and water which lead to agricultural loss and human health hazards. The aim of this study was to characterize various physiochemical parameters such as pH, temperature, TS, BOD, COD and DO etc. from effluent samples collected from four different beverage industries located in Delhi-NCR along with the biochemical characterization of isolated bacterial strains from effluent. Analysis of the collected samples states that the pH values were 4.57, 4.91, 5.17 and 5.11; Total Dissolved Solids were 1175 mg/l, 1210mg/l, 1270 mg/l and 1250 mg/l; total hardness was measured as 226, 223, 244 and 220 mg/l and alkalinity were 130, 138, 145 and 141 mg/l, respectively. Chloride test was found negative for effluent samples revealing the absence of chlorine molecule. Dissolved Oxygen were 3.3, 2.8, 3.1 and 3.2 mg/l, Biological Oxygen Demand were 211, 256, 237 and 272 mg/l where as Chemical Oxygen Demand was found 1067, 1098, 1078 and 1092 mg/l, respectively. Results suggested that pH values, DO, total hardness, alkalinity; BOD and COD were exceeded to the permissible standard limits. This study provides a detailed insight that beverage industries do produce waste linked problems and there is a high probability of polluting the environment by these industries as a result of discharge of untreated wastewater into the water body or soil that may lead to death of crops or reduction in crops yield, contamination of drinking water supplies and/or accumulation and dissemination of toxic chemicals that may further endanger ecosystems and threaten public health. It is hoped that waste water management practices being used in beverages and other food industries will benefit to sustain the natural environment.

ЯКР 35CL И ЗАТОРМОЖЕННАЯ ПОДВИЖНОСТЬ В МОЛЕКУЛЯРНОМ КОМПЛЕКСЕ CL2·БЕНЗОЛ

Temperature dependences of the resonance frequency and the spin-lattice relaxation time of the chlorine nuclei are investigated in the equimolecular addition compound of chlorine with benzene in the temperature range between 77 K and the melting point. The experimental data reveal a complex picture of thermally activated molecular motion involving both components of this compound. At temperatures 77–130 K the quadrupole relaxation is determined by the action of three types of molecular motions: 1– background molecular librations, 2– reorientational movement of the benzene rings, modulating the electric field gradient at the chlorine nuclei, created by donor-acceptor interaction of the partner molecules, and 3– reorientational movement of the chlorine molecules at a rate less than the NQR frequency, causing the broadening of the 35 Cl spectral line and its fading out at 130 K. In this temperature region consistent separation of the respective contributions to the chlorine relaxation rate is made and the quantitative parameters of the movements defined. At higher temperatures, the development of hindered rotation of the chlorine molecules leads to the appearance of the resonance signal again at 150 K to ~4 MHz lower in frequency, and the relaxation time of the chlorine nuclei increases with increasing temperature. Both these facts indicate that the reorientation rate of the chlorine molecules becomes much higher than the nuclear quadrupole resonance frequency. By analogy with the known NQR data for 1,2-dichloroethane these results show that the “fast” reorientation of the chlorine molecule occurs about the axis that forms the angle ~14° with the Cl–Cl direction. The spin-lattice relaxation time of the chlorine nuclei, as measured in the field of both “slow” and “fast” reorientations, revealed that the activation energy of motion in these areas varies considerably (~22.5 kJ/mol and ~6.2 kJ/mol, respectively). The set of obtained data allows to conclude that at the temperatures 130–150 K in the sample, apparently, there are structural changes, leading to a sharp change in the mobility of the chlorine molecules. Received 0 7 .0 6 .201 6 ; accepted 23 .0 6 .201 6

Reaction of Chlorine Molecules with Unsaturated Submicron Organic Particles

Abstract The reaction of closed shell Cl2 molecules with sub-micron droplets composed of unsaturated molecules, oleic acid (OA), linoleic acid (LA), linolenic acid (LNA), or squalene (Sqe), are investigated in an atmospheric pressure flow tube reactor in conjunction with a vacuum ultraviolet photoionization aerosol mass spectrometer and a scanning mobility particle sizer. Cl2 is found to react with all particles, and the reactive uptake coefficients depend on the number of unsaturated reaction sites, e.g., γ Cl2 Sqe = (0.66 ± 0.03) × 10−4 versus γ Cl2 OA = (0.23 ± 0.01) × 10−4 . In addition, the chemical evolution of squalene and its chlorinated products reveal that the reaction becomes slower for higher chlorinated products.

Characteristics and parameters of plasma of a gas-discharge UV–VUV lamp on a system of bands of argon chloride and chlorine molecules

The results of experimental study of the characteristics of a two-wave UV–VUV lamp on a mixture of argon and freon vapors (CCl4) with pumping by a nanosecond barrier discharge are presented. The spectral characteristics of the radiator in the wavelength range of 160–300 nm and the current and voltage oscillograms have been studied. The intensity of the radiation of the 175 nm ArCl (B → X) and 258 nm Cl2 (D' → A') bands were optimized during the variation of pressure and partial composition of the working mixture Ar–CCl4, and also the conditions of the ignition of the nanosecond discharge with two dielectric barriers. The main processes of the formation of the argon chloride molecule have been considered in the barrier discharge on the basis of the Ar–CCl4 mixture.

Synthesis and self-aggregation of chlorophyll derivatives possessing a pyrazole ring at the C3 position

Abstract Chlorophyll compounds possessing an N-(un)substituted pyrazole ring at the C3 position were synthesized by the reaction of chlorophyll-a derivative having a trifluoromethyl-β-diketonate group with (substituted) hydrazines in 2,2,2-trifluoroethanol through the pyrazoline ring. The substituents on the C3-heterocyclic 5-membered ring affected the electronic absorption and emission of the monomeric chlorin molecules. Vis, CD and 1H NMR spectra of the zinc chlorin bearing an N-unsubstituted pyrazole showed its dimerization in a nonpolar organic solvent.

The process of dissociation of Cl2 molecule on the Ge(0 0 1)-p(1 × 2) surface

In this paper, we analyze theoretically four possible reaction paths during dissociative adsorption of chlorine molecule at the germanium surface. We have calculated the temporary atomic structures, local density of states and spatial distributions of charge density during the processes of dissociation and adsorption. Depending on the reaction path the properties of the system in the process can differ significantly from the final state.

System study of MPO promoter high-frequency polymorphic variants on transcription factor network

The neutrophil myeloperoxidase (MPO) promotes the oxidative stress by the production of active chlorinated molecules. The aim of this study was to investigate the association between MPO promoter polymorphic variants (rs2243827 and rs2333227) and, its serum level in patients with the stenosis of coronary arteries. Furthermore, a system approach was applied to create the MPO transcription factor network. A total of one hundred fifty six subjects (controls, stenosis<5%, n=71 and patients, stenosis>70%, n=85) undergoing coronary angiography were recruited. The polymorphic haplotypes and serum MPO level were identified using ARMS-PCR and ELISA techniques, respectively. The MPO transcription factor network was primarily created with PSICQUIC and ChIP data and, was improved with the predicted transcription factors. The regression analyses did not show an association between the serum MPO level and the extent of stenosis in coronary arteries. The network showed that the predicted transcription factors at the flanking regions of polymorphic variants are not directly interacted to MPO. In conclusion, the population and prediction studies showed no association between the serum MPO level, the promoter high-frequency polymorphic frequencies and the extent of stenosis in coronary arteries. A gene sub-cluster with MYB as central node was suggested to be involved with MPO on the transcription factor network.

Characterization of molecular channel in photodissociation of SOCl2 at 248 nm: Cl2 probing by cavity ring-down absorption spectroscopy.

A primary elimination channel of the chlorine molecule in the one-photon dissociation of SOCl2 at 248 nm was investigated using cavity ring-down absorption spectroscopy (CRDS). By means of spectral simulation, the ratio of the vibrational population in the v = 0, 1, and 2 levels was evaluated to be 1 : (0.10 ± 0.02) : (0.009 ± 0.005), corresponding to a Boltzmann vibrational temperature of 340 ± 30 K. The Cl2 molecular channel was obtained with a quantum yield of 0.4 ± 0.2 from the X(1)A' ground state of SOCl2via internal conversion. The dissociation mechanism differs from a prior study where a smaller yield of <3% was obtained, initiated from the 2(1)A' excited state. Temperature-dependence measurements of the Cl2 fragment turn out to support our mechanism. With the aid of ab initio potential energy calculations, two dissociation routes to the molecular products were found, including one synchronous dissociation pathway via a three-center transition state (TS) and the other sequential dissociation pathway via a roaming-mediated isomerization TS. The latter mechanism with a lower energy barrier dominates the dissociation reaction.

Multiple single-crystal-to-single-crystal guest exchange in a dynamic 1D coordination polymer.

A novel 1D coordination polymer that dynamically expands or shrinks upon the uptake of vapours of volatile small chlorinated molecules, such as 1,2-dichloroethane (DCE), dichloromethane (DCM) and trichloromethane (TCM), is reported. This system is robust enough to withstand multiple guest exchange via single-crystal-to-single-crystal transformation, as proved by (1)H-NMR and X-ray diffraction. The single crystal of guest-free, host framework, stable at 400 K, can also be obtained.

Emission characteristics of pulse-periodic barrier-discharge plasma in a mixture of krypton with argon and liquid freon vapor

Radiation of a nanosecond barrier discharge in a mixture of krypton, argon, and carbon-tetrachloride vapor is studied in the spectral range of 150–300 nm. The plasma radiation spectra and the dependences of the intensities of the 258 nm Cl2(D′ → A′), 222 nm KrCl(B → X), and 175 nm ArCl(B → X) bands on the partial pressure of liquid freon vapor, argon, and krypton, as well as on the discharge excitation conditions, are studied. The optimal compositions of gas mixtures for creating a broadband UV-VUV emitter based on the band system of argon chloride, krypton chloride, and chlorine molecule are determined.

Aerosolized Droplet Mediated Self-Assembly of Photosynthetic Pigment Analogues and Deposition onto Substrates

Self-assembled photosynthetic molecules have a high extinction coefficient and a broad absorption in the infrared region, and these properties can be used to improve the efficiency of solar cells. We have developed a single-step method for the self-assembly of synthetic chlorin molecules (analogues of native bacteriochlorophylls) in aerosolized droplets, containing a single solvent and two solvents, to synthesize biomimetic light-harvesting structures. In the single-solvent approach, assembly is promoted by a concentration-driven process due to evaporation of the solvent. The peak absorbance of Zn(II) 3-(1-hydroxyethyl)-10-phenyl-13(1)-oxophorbine (1) in methanol shifted from 646 nm to 725 nm (∼ 80 nm shift) after assembly, which is comparable to the shift observed in the naturally occurring assembly of bacteriochlorophyll c. Although assembly is thermodynamically favorable, the kinetics of self-assembly play an important role, and this was demonstrated by varying the initial concentration of the pigment monomer. To overcome kinetic limitations, a two-solvent approach using a volatile solvent (tetrahydrofuran) in which the dye is soluble and a less volatile solvent (ethanol) in which the dye is sparingly soluble was demonstrated to be effective. The effect of molecular structure is demonstrated by spraying the sterically hindered Zn(II) 3-(1-hydroxyethyl)-10-mesityl-13(1)-oxophorbine (2), which is an analogue of 1, under similar conditions. The results illustrate a valuable and facile aerosol-based method for the formation of films of supramolecular assemblies.

Short-wavelength nanosecond-barrier-discharge-pumped emitter operating on lines of argon chloride (175 nm) and chlorine (258 nm) molecules

The emission characteristics of a pulsed-periodic nanosecond-barrier-discharge-pumped source of ultraviolet and vacuum ultraviolet radiation are presented. The source emits into a set of electronic-vibrational bands with maxima at λ = 175 nm ArCl(B→X) and λ = 258 nm Cl2(D′→A′). The emission intensity of ArCl and Cl2 molecules is optimized for the pressure and composition of an argon-freon vapor (CCl4) mixture and also for excitation conditions.

Efficient Photosensitization by a Chlorin–Polyoxometalate Supramolecular Complex

The 4:1 supramolecular complexed ionic salt between pyridinium chlorin and polyanionic [α-SiMo12O40](4-) exhibits significantly enhanced photodynamic activity against A549 cell lines because of increased singlet oxygen photogeneration through high cellular penetration and localization of the chlorin molecules on the ionic salt into the cancer cell. Confocal laser scanning microscopy images clearly represent a higher uptake and photodynamic effect of this supramolecular complex corresponding to the lower IC50 value compared to the free chlorin.

Chlorine molecule adsorbed on graphene and doped graphene: A first-principle study

Adsorption of molecular chlorine (Cl2) on intrinsic and B-, Si-, Cr-, Cu-, Fe-, Mn-, Ni-, Ti- and Au-doped graphene was theoretically studied using first-principle approach based on density functional theory in order to develop their potential applications as Cl2 gas sensors. The structural, electronic and magnetic properties of the graphene-molecule adsorption adducts are strongly dependent on the dopants. Cl2 molecule is adsorbed weakly on intrinsic and B-doped graphene; in general, strong chemisorption is observed on Si-, Cr-, Cu-, Fe-, Mn-, Ni-, Ti- and Au-doped graphene. The most stable adsorption geometries, energies, magnetic moments, charge transfers and density of states of these systems are thoroughly discussed. This work reveals that the sensitivity of graphene-based chemical gas sensors for Cl2 can be drastically improved by introducing appropriate dopant, and Ti as well as Au is the best choice among all the dopants.

Chemical composition of the essential oil of Microsorum insigne

The genus Microsorum is composed of about 40 species mainly distributed in the tropical area of Asia. In China, there are 9 species [1]. Phytochemical studies on plants of the Microsorum genus have yielded various types of compounds such as triterpenoids, sesquiterpenoids, flavonoids, lignan, uracil, uridine, sterols, and volatiles [2–7]. M. insigne Copel. has been grown in southern China and other countries in southeastern Asia and is used in traditional Chinese medicine to treat arthralgia, traumatic injury, cut wound, and hemorrhage [8]. It has also been used as a popular and healthful vegetable in Yunnan of southwestern China. Previously there has been no report on its chemical constituents. We report here the results of our studies on the composition of the essential oil from the dried aerial parts of M. insigne. The fresh aerial parts of M. insigne Copel. were collected from Pingbian, Yunnan of China and identified by Mr. Liang-Chao Qian, a botanist from the National Natural Reserve in Dawei Mountain, Pingbian, Yunnan of China. A voucher specimen is kept in the Herbarium of the Department of Chemistry, Yunnan Normal University, Kunming, China (No. 09051501). The dried aerial part was crumbled and hydrodistilled for 5 hours using a Clevenger apparatus. The yield of yellowish oil was 0.0175% (w/w). The oil was subsequently dried over anhydrous sodium sulfate and stored at 4 C until analysis. The essential oil was subjected to gas chromatographic/mass spectral analysis using an Angilent 6890 GC with an Agilent 5973 mass selective detector. The analytical conditions included an HP-5MS (30 m 0.25 mm 0.25 m) quartz capillary chromatography column; carrier gas: helium with flow rate 1.0 mL/min; volume injected: 1.0 L; split ratio: 15:1; 80 C thermostat temperature programmed at 5 C/min to 260 C, and 230 C detector and vaporizer temperature. Constituents of the oil were identified by comparing the mass spectra of the products with data in the Wiley7N.L mass-spectra library. The identified components and their percentages are given in Table 1, where the components are listed in the order of their elution on the column. Forty-four components were detected in the oil, representing 92.1% of the total oil. As can be seen, the major components of the oil are n-hexadecanoic acid (31.9%) and N-(2-phenethyl)-3-chloropropionamide (15.9%). The aliphatics (46.5%) were the dominant group in the oil. The aromatic compounds (31.8%) were the second, whereas terpenes (monoterpenes, 8.6%; sesquiterpenes, 2.6%; diterpenes, 1.9%) accounted for 13.1%. It is interesting that 23.6% of nitrogencontaining compounds were found in the oil, among which the anticonvulsant chlorinated molecule N-(2-phenethyl)-3chloropropionamide accounted for 15.9% [9].

Elucidating the higher stability of vanadium(V) cations in mixed acid based redox flow battery electrolytes

The vanadium(V) cation structures in mixed acid based electrolyte solution were analyzed by density functional theory (DFT) based computational modeling and 51V and 35Cl nuclear magnetic resonance (NMR) spectroscopy. The vanadium(V) cation exists as di-nuclear [V2O3Cl2·6H2O]2+ compound at higher vanadium concentrations (≥1.75 M). In particular, at high temperatures (>295 K) this di-nuclear compound undergoes ligand exchange process with nearby solvent chlorine molecule and forms chlorine bonded [V2O3Cl·6H2O]2+ compound. This chlorine bonded [V2O3Cl2·6H2O]2+ compound might be resistant to the de-protonation reaction which is the initial step in the precipitation reaction in vanadium based electrolyte solutions. The combined theoretical and experimental approach reveals that formation of chlorine bonded [V2O3Cl2·6H2O]2+ compound might be central to the observed higher thermal stability of mixed acid based vanadium(V) electrolyte solutions.

Internal detection of surface plasmon coupled chemiluminescence during chlorination of potassium thin films

The interaction of chlorine with potassium surfaces is a prototype reaction with a strong non-adiabatic energy transfer leading to exoemission and chemiluminescence. Thin film K/Ag/p-Si(111) Schottky diodes with 8 nm potassium on a 5-200 nm thick Ag layer are used as 2π-photodetectors for the chemiluminescence during chlorination of the K film at 110 K. The observed photocurrent shows a sharp maximum for small exposures and decreases gradually with the increasing chloride layer. The time dependence can be explained by the reaction kinetics, which is governed initially by second-order adsorption processes followed by an electric field-assisted diffusion. The detector current corresponds to a yield of a few percent of elementary charge per reacting chlorine molecule and is orders of magnitude larger than for external detection. The photoyield can be enhanced by increasing the Ag film thickness. For Ag films of 30 and 50 nm, the yield exhibits a maximum indicating surface plasmon coupled chemiluminescence. Surface plasmon polaritons in the Ag layer are excited by the reaction and decay radiatively into Si leading to the observed currents. A model calculation for the reverse process in attenuated total reflection is applied to explain the observed current yield maxima.

Highly Effective Surface Passivation of PbSe Quantum Dots through Reaction with Molecular Chlorine

PbSe nanocrystal quantum dots (NQDs) are a promising active material for a range of optoelectronic devices, including solar cells, high-sensitivity infrared (IR) photodetectors, and IR-emitting diodes and lasers. However, device realization has been constrained by these NQDs' chemical instability toward oxidation, which leads to uncontrollable changes in optical and electronic properties. Here, we present a simple method to enhance the stability of PbSe NQDs against oxidation and to improve their optical properties through reaction with molecular chlorine. The chlorine molecules preferentially etch out surface Se ions and react with Pb ions to form a thin (1-2 monolayers) PbCl(x) passivation layer which effectively prevents oxidation during long-term air exposure while passivating surface trap states to increase photoluminescence efficiency and decrease photocharging. Our method is simple, widely applicable to PbSe and PbS NQDs of a range of sizes, compatible with solution-based processes for fabricating NQD-based devices, and effective both in solution and in solid NQD films; thus, it is a practical protocol for facilitating advances over the full range of optoelectronic applications.