Formation Of Molecular Chlorine Research Articles

Dynamics of individual biochemical parameters of blood of intact white mice under the action of the drug “Vitosept”

The active substance of the drug “Vitosept” is high-purity sodium hypochlorite (HPSH), obtained by the direct electrochemical reaction on a newly developed diaphragm-free flow cell, bypassing the formation of molecular chlorine. The developers (Altapharm, Dnipro) used an isotonic (0.9 %) sodium chloride solution prepared in water purified by special technology as the starting electrolyte. The study aimed to determine the effect of different concentrations of Vitosept on the dynamics of serum biochemical parameters of intact white mice. During our research, we found that intragastric administration of even the highest concentrations (500 mg/L) of the drug “Vitosept” did not cause the death of animals or visible signs of intoxication. According to the analysis of clinical manifestations, behavioral reactions, assessment of discomfort, reflex reactions, and the course of metabolic processes, the animals of the experimental groups did not differ from the analogs of the control group. Assessing the protein-synthesizing function of the liver, it was found that the total protein content in the serum of white mice depended on the concentrations of the studied hypochlorite-containing drug and the duration of its receipt. In the animals of the first, second, and third experimental groups during the whole period of the experiment (20 days), the level of total protein in the serum was close to that of the animals of the control group. In animals of groups R4 and R5, on the 10th day of the experiment with the highest applied concentrations of Vitosept (400 and 500 mg/L), the content of total protein in the serum of white mice probably decreased by 8.3 and 7.7 %. It is established that such reduction occurs against the background of changes in the fractional composition of proteins. In white mice of group R5 on the 10th day of the experiment revealed a decrease in blood glucose by 5.9 % (P < 0.05), urea – by 7.4 % (P < 0.05), creatinine – by 9.1 % (P < 0.05). The activity of alkaline phosphatase was 32.1 % (P < 0.05) and GGTP – 70 % (P < 0.05) higher than in the blood of animals of the control group. On the 20th day of the experiment, the level of the studied indicators decreased slightly compared to the similar ones on the 10th day. It was within the limit values, although in most cases, it still differed from the indicators of the animals of the control group. It is obvious that when too high concentrations of even a slightly toxic drug are received, the animal's body reacts with a compensatory-adaptive reaction to the arrival of a foreign substance. Thus, we state that the hypochlorite-containing drug “Vitosept” with the long-term intragastric intake of white mice did not cause hepato- and nephrotoxic effects and revealed some deviations in biochemical parameters in animals of the fourth and fifth groups, on the background of 400–500 mg/L, is most likely the result of adaptive-compensatory response to the intake of the test substance.

Morphological and biochemical parameters of blood of rats for the long-term effect of the drug “Vitosept”

The basis of the drug “Vitosept” is a solution of high-purity sodium hypochlorite (SH), which is obtained in a specially developed dyadiafragm flow electrolyzer, in the process of direct electrochemical reaction, bypassing the formation of molecular chlorine. As an initial electrolyte, an isotonic solution of sodium chloride (0.9% NaCl) was prepared on water purified by a special technology. Such solutions do not contain impurities of organic substances and transition metal ions. The resulting solution of SH is the optimal carrier of active oxygen. The purpose of the study was to find out the effects of various dosage of the drug “Vitosept” for its intravenous introduction, in a long-term experiment. As a result of the conducted experiments, it was found that during the entire observation period of the investigated drug “Vitosept” signs of inadequate reaction, intoxication or death of animals were not observed. At the same time, there were no reservations regarding behavioral reactions, reflex excitability, clinical manifestations of respiratory distress, urinary excision and defecation. Only animals of the 4th group, after administration of the highest dosage of the drug (500 mg/l), were slightly suppressed, were slightly responsive to acoustic and light stimuli, had somewhat disturbed reflex excitability. However, an hour after the cessation of giving the drug, the evidence of all the animals in this group disappeared. It was found out that for long-term intradermal introduction to the laboratory animals of the drug “Vitosept” at dosages of 50 and 100 mg/l, the abnormalities in the studied morphological and biochemical parameters of blood, compared to the same in the control group were not found. Concerning the rats of the IV group that received the highest study dosage of the drug (500 mg/l) through the probe, certain possible changes in the hematological, biochemical parameters of blood (leukocyte count increase in blood, activity of AsAT, LF, decrease in serum urea blood concentration, creatinine) were observed, in our opinion, compensatory and disappeared within a few days after discontinuation of the drug. Consequently, taking into account our previous studies on the establishment of the parameters of acute toxicity of the drug “Vitosept” and the results obtained regarding its effects on hemopoiesis and the functional state of the liver and kidneys, it can be argued that the drug “Vitocet” belongs to the IV class of compounds – low toxicity.

Photochemical oxidation of chloride ion by ozone in acid aqueous solution.

The experimental investigation of chloride ion oxidation under the action of ozone and ultraviolet radiation with wavelength 254 nm in the bulk of acid aqueous solution at pH 0-2 has been performed. Processes of chloride oxidation in these conditions are the same as the chemical reactions in the system O3 - OH - Cl(-)(aq). Despite its importance in the environment and for ozone-based water treatment, this reaction system has not been previously investigated in the bulk solution. The end products are chlorate ion ClO3(-) and molecular chlorine Cl2. The ions of trivalent iron have been shown to be catalysts of Cl(-) oxidation. The dependencies of the products formation rates on the concentrations of O3 and H(+) have been studied. The chemical mechanism of Cl(-) oxidation and Cl2 emission and ClO3(-) formation has been proposed. According to the mechanism, the dominant primary process of chloride oxidation represents the complex interaction with hydroxyl radical OH with the formation of Cl2(-) anion-radical intermediate. OH radical is generated on ozone photolysis in aqueous solution. The key subsequent processes are the reactions Cl2(-) + O3 → ClO + O2 + Cl(-) and ClO + H2O2 → HOCl + HO2. Until the present time, they have not been taken into consideration on mechanistic description and modelling of Cl(-) oxidation. The final products are formed via the reactions 2ClO → Cl2O2, Cl2O2 + H2O → 2H(+) + Cl(-) + ClO3(-) and HOCl + H(+) + Cl(-) ⇄ H2O + Cl2. Some portion of chloride is oxidized directly by O3 molecule with the formation of molecular chlorine in the end.

Ground state surface formation of Cl2 in the dissociation of CCl4 and CHCl3 and comparisons with Br species

The formation of molecular chlorine from the ground state dissociation of CCl4 and CHCl3 was investigated at the M06, MP2 and CCSD(T) levels of theory, all using the cc-pVTZ basis set. All levels of theory showed the presence of two transition states and an ion-pair isomer intermediate. The presence of the isomer in the dissociation pathway is in agreement with previous studies on the ground state dissociation of similar halocarbons.

Formation of Molecular Chlorine by the Decomposition of 1, 2-Dichloroethane over Ru Supported on Titania-Silica

Decomposition of 1, 2-dichloroethane was examined over Ru, Rh, Pd, Pt, Cu, and Cr catalysts supported on TiO2-SiO2 in air. A large amount of Cl2 was formed over Ru/TiO2-SiO2 catalyst at 400°C, whereas Rh, Pd, and Pt catalysts did not produce Cl2 even at 450°C. Although Cu and Cr catalysts also produced Cl2 effectively, the maximum activity observed at 650°C was still lower than that of Ru at 400°C.

Formation of molecular chlorine in dark condition: Heterogeneous reaction of ozone with sea salt in the presence of ferric ion

Uptake coefficients of O3 on NaCl and synthetic sea salt (SSS) were found to be enhanced from < 10−5 to ∼ 3.5 × 10−2 in the presence of water‐soluble Fe3+ in the Fe/Na weight ratio larger than 0.1%. Cl2 release was observed without radiation in the reaction of O3 and a FeCl3/NaCl mixture with surface adsorbed water at the yields of 0.48 and 0.28 for Fe/Na ratio of 1.0 and 0.5 weight %, respectively. Only Br2 release was observed for a FeCl3/SSS sample. These results imply that when bromide is deficient in sea salt, Cl2 would be released from the sea salt with the coexistence of Fe3+. The estimate was made to show that the Cl2 releasing rate can be high enough to explain sporadically observed Cl2 at nighttime in a coastal area.

Presence of Chlorine Radicals and Formation of Molecular Chlorine in the Post-Flame Region of Chlorocarbon Combustion

This study is concerned with the formation and persistence of atomic and molecular chlorine in the late stages of chlorocarbon combustion under fuel-lean conditions as well as in postcombustion cooling stages, since chlorine-containing hazardous organic pollutants including dioxin precursors can be formed through reactions involving these active forms of chlorine. In bench-scale experiments with a chlorine-containing fuel mixture (C2H4/CH3Cl or CH4/CH3Cl, with Cl/C in the range of 0 to 2.2%) the fuel is oxidized in a relatively short time (10−20 ms). The major chlorine-containing product is HCl; however, the cooled combustion gases contain significant concentrations of Cl2 (up to 18% of the total chlorine load), with the exact amount depending on the fuel equivalence ratio, the residence time in the combustor, the H/C ratio of the fuel, and the rate of cooling of the gas products. Calculations indicate that the Cl2 measured in the cold exhaust gas is formed by recombination during the quenching of Cl radi...

A study of chlorine behavior in a simulated fluidized bed combustion system

Fluidized bed combustion techniques have been widely used throughout the world in an effort to reduce sulfur oxide emissions, especially from burning high-sulfur coal. However, in the utilization of FBC systems for co-firing high chlorine coals with municipal solid waste (MSW) there are some concerns about the possible emission of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). PCDD/Fs may be produced from the reaction of volatile organic compounds (VOCs) and molecular chlorine under relatively low combustion temperature conditions. In oxygen-rich conditions during combustion molecular chlorine can be formed through the Deacon Reaction when the temperature is around 600°C. It is also likely that chloride might affect the detailed chemistry of desulfurization in FBC processes. In order to better understand the behavior of chlorine in an FBC system during combustion processes, a comprehensive study was carried out in a simulated FBC system with an on-line feeder at Western Kentucky University. Conditions used simulated the flue gas and operating conditions of an FBC system. Optimum operating conditions to suppress HCl, Cl2 and SOx emissions from FBC systems were determined. A better understanding of the chlorine behavior during combustion will help in controlling possible PCDD and PCDF formation and reducing corrosion in FBC systems. The test results indicated that the formation of molecular chlorine is favored at temperatures above 600°C, in oxygen-rich atmospheres, and in relatively high HCl concentrations. The reaction temperature plays a key role in the capture of HCl. The optimum combustion conditions for controlling PCDD/Fs formation in FBC systems is to maintain combustion temperature around 850°C in the bed area, 600°C in the freeboard area, low oxygen concentrations in the flue gas and enough residence time for fine particles in the freeboard.

The Effect of Sulfur Dioxide on the Formation of Molecular Chlorine during Co-Combustion of Fuels

This project was designed to evaluate the combustion performance of and emissions from a fluidized bed combustor during the combustion of mixtures of high sulfur and/or high chlorine coals and municipal solid waste (MSW). The effect of sulfur dioxide on the formation of molecular chlorine during co-combustion of fuels was examined in this study. Sulfur dioxide was shown to be an effective inhibitor for the formation of molecular chlorine through the Deacon Reaction and, subsequently, the formation of chlorinated organics. Theoretically, co-firing high sulfur coals with MSW will decrease the possibility of polychlorodibenzodioxin/furan (PCDD/F) formation during the combustion process. A mixture of coal and PVC pellets was burned in a 0.1 MWth bench-scale fluidized bed system at WKU and no detectable amounts of chlorinated organics were found in the flue gas and bed ash. The results from this study indicated the practical effects of using coal as a combustion support fuel when burning MSW.

99/03317 Near-real-time measurement of trace volatile organic compounds from combustion processes using an on-line gas chromatograph

Fluidized bed combustion techniques have been widely used throughout the world in an effort to reduce sulfur oxide emissions, especially from burning high-sulfur coal. However, in the utilization of FBC systems for co-firing high chlorine coals with municipal solid waste (MSW) there are some concerns about the possible emission of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). PCDD/Fs may be produced from the reaction of volatile organic compounds (VOCs) and molecular chlorine under relatively low combustion temperature conditions. In oxygen-rich conditions during combustion molecular chlorine can be formed through the Deacon Reaction when the temperature is around 600°C. It is also likely that chloride might affect the detailed chemistry of desulfurization in FBC processes. In order to better understand the behavior of chlorine in an FBC system during combustion processes, a comprehensive study was carried out in a simulated FBC system with an on-line feeder at Western Kentucky University. Conditions used simulated the flue gas and operating conditions of an FBC system. Optimum operating conditions to suppress HCl, Cl2 and SOx emissions from FBC systems were determined. A better understanding of the chlorine behavior during combustion will help in controlling possible PCDD and PCDF formation and reducing corrosion in FBC systems. The test results indicated that the formation of molecular chlorine is favored at temperatures above 600°C, in oxygen-rich atmospheres, and in relatively high HCl concentrations. The reaction temperature plays a key role in the capture of HCl. The optimum combustion conditions for controlling PCDD/Fs formation in FBC systems is to maintain combustion temperature around 850°C in the bed area, 600°C in the freeboard area, low oxygen concentrations in the flue gas and enough residence time for fine particles in the freeboard.

Formation of molecular chlorine from the photolysis of ozone and aqueous sea-salt particles

Halogen atoms from the reactions of sea-salt particles may play a significant role in the marine boundary layer. Reactions of sodium chloride, the major component of sea-salt particles, with nitrogen oxides generate chlorine atom precursors. However, recent studies suggest there is an additional source of chlorine in the marine troposphere. This study shows that molecular chlorine is generated from the photolysis of ozone in the presence of sea-salt particles above their deliquescence point; this process may also occur in the ocean surface layer. Given the global distribution of ozone, this process may provide a global source of chlorine.

Hypervalent Iodine Chemistry: Mechanistic Investigation of the Novel Haloacetoxylation, Halogenation, and Acetoxylation Reactions of 1,4-Dimethoxynaphthalenes

Treatment of 1,4-dimethoxynaphthalenes with iodosobenzene diacetate and trimethylsilyl chloride or bromide furnished the haloacetoxylated, acetoxylated, and halogenated 1,4-dimethoxynaphthalenes in excellent yield. The reaction pathway for each transformation was shown to be a function of reagent stoichiometry. A mechanistic hypothesis is presented that rationalizes the reaction pathways and explains the subtle differences in the halogenation reactions. The acetoxylation, for example, is thought to involve the formation of an iodonium ion that promotes the nucleophilic addition of acetate ion and subsequent 1,2-acetyl migration. Bromination occurs as a direct result of the oxidation of trimethylsilyl bromide to bromine, followed by electrophilic aromatic substitution. Chlorination is thought to proceed via a radical process and not the formation of molecular chlorine from the dissociation of iodosobenzene dichloride. The haloacetoxylation reaction also appears to be fairly specific for 1,4-dimethoxynaphthalenes, since the analogous reaction with a 1,4-dimethoxybenzene derivative was unsuccessful.

97/02935 Properties of Danish biofuels and the requirements for power productions

Fluidized bed combustion techniques have been widely used throughout the world in an effort to reduce sulfur oxide emissions, especially from burning high-sulfur coal. However, in the utilization of FBC systems for co-firing high chlorine coals with municipal solid waste (MSW) there are some concerns about the possible emission of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). PCDD/Fs may be produced from the reaction of volatile organic compounds (VOCs) and molecular chlorine under relatively low combustion temperature conditions. In oxygen-rich conditions during combustion molecular chlorine can be formed through the Deacon Reaction when the temperature is around 600°C. It is also likely that chloride might affect the detailed chemistry of desulfurization in FBC processes. In order to better understand the behavior of chlorine in an FBC system during combustion processes, a comprehensive study was carried out in a simulated FBC system with an on-line feeder at Western Kentucky University. Conditions used simulated the flue gas and operating conditions of an FBC system. Optimum operating conditions to suppress HCl, Cl2 and SOx emissions from FBC systems were determined. A better understanding of the chlorine behavior during combustion will help in controlling possible PCDD and PCDF formation and reducing corrosion in FBC systems. The test results indicated that the formation of molecular chlorine is favored at temperatures above 600°C, in oxygen-rich atmospheres, and in relatively high HCl concentrations. The reaction temperature plays a key role in the capture of HCl. The optimum combustion conditions for controlling PCDD/Fs formation in FBC systems is to maintain combustion temperature around 850°C in the bed area, 600°C in the freeboard area, low oxygen concentrations in the flue gas and enough residence time for fine particles in the freeboard.

96/06783 TG/MS study of organic compounds evolved during the co-firing of coal and refuse derived fuels

The Environmental Protection Agency reported that the total municipal solid waste (MSW) produced in the U.S. increased from 179 million tons in 1988 to 195 million tons in 1990. It is predicted that the country will produce about 216 million tons of garbage in the year 2000. Waste-to-energy conversion of MSW appears to be most attractive because of the energy recovered, economic value of the recycled materials, and the cost saving derived from reduced landfill usage. However, extra care needs to be taken in burning MSW or Refuse Derived Fuel (RDF) to optimize the operating conditions of a combustor so that the combustion takes place in an environmentally acceptable manner. For instance, polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) have been found in the precipitator fly ash and flue gas of a number of incinerator facilities in the United States and Europe. Though the amount of PCDDs and PCDFs is only in the parts-per-billion to parts-per-trillion range, these chlorinated organics exhibit very high toxicity (LD{sub 50} < 10 {mu}g/Kg) and 2,3,7,8-tetrachlorodibenzodioxin has been found to be acnegenic, carcinogenic, and teratogenic. This has slowed or even stopped the construction and operation of waste-to-energy plants. In previous work, the study of singlemore » materials has given us a good understanding of the characteristics and thermal behavior of these materials, their relative thermal stability and temperature relationships, their decomposition products and the evolution profiles of different gaseous products. The formation of molecular chlorine during combustion processes could be a key step for the formation of chlorinated organic compounds. The production of phenol and furan during the combustion of newspaper and cellulose could provide the important precursors for the formation of polychlorinated dibenzodioxin (PCDD) and polychlorinated dibenzofuran (PCDF).« less

ChemInform Abstract: MECHANISM OF THE CHLORINE EVOLUTION ON A RUTHENIUM OXIDE TITANIUM OXIDE ELECTRODE AND ON A RUTHENIUM ELECTRODE

Abstract The mechanism of the chlorine evolution on titanium electrodes coated with a layer of ruthenium oxide and titanium oxide under different experimental conditions, and on a ruthenium electrode, both in acidic chloride solution, has been investigated. Potentiodynamic current density—potential curves were recorded as a function of the time anodic pre-polarisation, the composition of the solution and the temperature. Moreover, potential decay curves were determined. Theoretical potential decay curves were deduced for both the Tafel reaction (2 Clad→Cl2) and the Heyrovsky reaction (Cl− + Clad → Cl2 + e−) as a rate determining step in the formation of molecular chlorine. They were compared with those found experimentally. The influence of possible diffusion of atomic chlorine out of the electrode was also taken into consideration. It was found that for all the electrodes investigated, molecular chlorine is formed both at anodic polarisation and on open circuit according to the Volmer—Heyrovsky mechanism, where the Heyrovsky reaction is the rate-determining step. The transfer coefficient is 0.5 for the chlorine evolution at an “ideal” ruthenium oxide titanium oxide electrode and at a ruthenium electrode.

Mechanism of the chlorine evolution on a ruthenium oxide/titanium oxide electrode and on a ruthenium electrode

The mechanism of the chlorine evolution on titanium electrodes coated with a layer of ruthenium oxide and titanium oxide under different experimental conditions, and on a ruthenium electrode, both in acidic chloride solution, has been investigated. Potentiodynamic current density—potential curves were recorded as a function of the time anodic pre-polarisation, the composition of the solution and the temperature. Moreover, potential decay curves were determined. Theoretical potential decay curves were deduced for both the Tafel reaction (2 Cl ad→Cl 2) and the Heyrovsky reaction (Cl − + Cl ad → Cl 2 + e −) as a rate determining step in the formation of molecular chlorine. They were compared with those found experimentally. The influence of possible diffusion of atomic chlorine out of the electrode was also taken into consideration. It was found that for all the electrodes investigated, molecular chlorine is formed both at anodic polarisation and on open circuit according to the Volmer—Heyrovsky mechanism, where the Heyrovsky reaction is the rate-determining step. The transfer coefficient is 0.5 for the chlorine evolution at an “ideal” ruthenium oxide titanium oxide electrode and at a ruthenium electrode.

Electrolysis of an acidic NaCl solution with a graphite anode—IV. Chlorine evolution at a graphite electrode after switching off current

During electrolysis of an acid chloride solution, atomic chlorine is taken up by a graphite anode. After switching off the current the evolution of molecular chlorine continues. This phenomenon we call residual gas evolution (r.g.e.) It is established that the molecular chlorine is formed according to the Volmer-Heyrovsky mechanism, ▪ The rate of r.g.e. is determined by an equilibrium between the diffusion of atomic chlorine out of the graphite and the formation of molecular chlorine. During the first seconds it is the latter that mainly determines the rate of r.g.e.; thereafter the diffusion becomes more and more the rate-determining step.