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1.
Med Pr ; 73(4): 337-347, 2022 Sep 05.
Artigo em Polonês | MEDLINE | ID: mdl-35912840

RESUMO

BACKGROUND: The presence of inorganic acids in the air poses a threat to the health of workers. Volatile inorganic acids, e.g., hydrochloric acid, hydrobromic acid and nitric acid, may cause respiratory, eye and skin irritation. The presented method uses ion chromatography to determine the concentrations of hydrochloric, hydrobromic and nitric acids in air samples. MATERIAL AND METHODS: The method is based on the collection of airborne volatile acids on impregnated quartz fiber filter, extraction of acids with deionized water, and analysis by ion chromatography with conductivity suppression. The separation was performed on the Dionex IonPac™ AS22 (4 × 250 mm) column for trace anion analysis. The carbonate/bicarbonate eluent was maintained at an isocratic flow rate of 1.2 ml/min. The calibration standard solutions have been covering the range of 0.2-5 mg/l of chloride, bromide and nitrate. RESULTS: The specified chromatographic conditions enable selective measurement of chloride, bromide and nitrate anions. The obtained mass concentration of each anion, having factored in the sample dilution, the conversion factor (to convert anion concentration to acid) and the volume of the air sample, allows the calculation of acid concentrations in the analyzed air. CONCLUSIONS: This method makes it possible to determine the concentration of hydrochloric acid, hydrobromic acid and nitric acid in the workplace air within the concentration range corresponding to 0.1-2 times the exposure limit value in Poland. The method meets the criteria for the performance of procedures for the measurement of chemical agents, listed in PN-EN 482. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering. Med Pr. 2022;73(4):337-47.


Assuntos
Poluentes Ocupacionais do Ar , Poluentes Ocupacionais do Ar/análise , Ânions/análise , Brometos/análise , Cloretos/análise , Cromatografia , Monitoramento Ambiental/métodos , Humanos , Ácido Bromídrico , Ácido Clorídrico/análise , Nitratos/análise , Ácido Nítrico/análise , Local de Trabalho
2.
Acta Crystallogr C Struct Chem ; 78(Pt 8): 437-448, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35924362

RESUMO

Creatinine, a biologically important compound, is used to analyze kidney function and kidney diseases in the human body. The salt form of creatinine is used in the formation of drug materials like anti-HIV, antifungal, antiprotozoal, antiviral and antitumour compounds. Here we report the solid-state structures of three new crystalline salts, namely, creatininium (2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium) bromide, C4H8N3O+·Br-, (I), creatininium 3-aminobenzoate, C4H8N3O+·C7H6NO2-, (II), and creatininium 3,5-dinitrobenzoate, C4H8N3O+·C7H3N2O6-, (III). These salts have been synthesized and characterized by single-crystal X-ray diffraction and Hirshfeld surface analysis. The structural chemistry of salts (I)-(III) and their crystal packing are discussed in detail. The primary interaction between the creatinine cation and the acid anion in the three salts is N-H...Br/O hydrogen bonds. In salt (I), the creatinine cation and bromide anion are connected through a pair of N-H...Br hydrogen bonds forming R42(8) and R42(12) ring motifs. In salts (II) and (III), the creatinine cation interacts with the corresponding anion via a pair of N-H...O hydrogen bonds. The crystal structure is further stabilized by C-H...O and O-H...O hydrogen bonds with the ring motifs R22(8), R21(7) and R21(6). Furthermore, the crystal structures are stabilized by π-π, C-H...π, C-O...π and N-O...π stacking interactions. The contributions made by each hydrogen bond in maintaining the crystal structure stability has been quantified by Hirshfeld surface analysis.


Assuntos
Ácido Bromídrico , Sais , Brometos , Creatinina , Cristalografia por Raios X , Humanos , Ligação de Hidrogênio , Estrutura Molecular , Nitrobenzoatos , Sais/química , meta-Aminobenzoatos
3.
ACS Appl Mater Interfaces ; 12(32): 36799-36809, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32678567

RESUMO

Desoxyribonucleic acid (DNA) origami architectures are a promising tool for ultimate lithography because of their ability to generate nanostructures with a minimum feature size down to 2 nm. In this paper, we developed a method for silicon (Si) nanopatterning to face up current limitations for high-resolution patterning with standard microelectronic processes. For the first time, a 2 nm-thick 2D DNA origami mask, with specific design composed of three different square holes (with a size of 10 and 20 nm), is used for positive pattern transfer into a Si substrate using a 15 nm-thick silicon dioxide (SiO2) layer as an intermediate hard mask. First, the origami mask is transferred onto the SiO2 underlayer, by an HF vapor-etching process. Then, the Si underlayer is etched using an HBr/O2 plasma. Each hole is transferred in the SiO2 layer and the 20 nm-sized holes are transferred into the final stack (Si). The resulting patterns exhibited a lateral resolution in the range of 20 nm and a depth of 40 nm. Patterns are fully characterized by atomic force microscopy, scanning electron microscopy, focused ion beam-transmission electron microscopy, and ellipsometry measurements.


Assuntos
DNA/química , Nanoestruturas/química , Dióxido de Silício/química , Silício/química , Adsorção , Ácido Bromídrico/química , Ácido Fluorídrico/química , Nanotecnologia , Oxigênio/química , Gases em Plasma , Impressão , Propriedades de Superfície
4.
J Am Chem Soc ; 140(38): 12111-12119, 2018 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-30180553

RESUMO

Proton-coupled electron transfer (PCET) is an important chemical and biological phenomenon. It is attractive as an on-off switching mechanism for redox-active synthetic systems but has not been extensively exploited for this purpose. Here we report a core-modified planar weakly antiaromatic/nonaromatic octaphyrin, namely, a [32]octaphyrin(1.0.1.0.1.0.1.0) (1) derived from rigid naphthobipyrrole and dithienothiophene (DTT) precursors, that undergoes proton-coupled two-electron reduction to produce its aromatic congener in the presence of HCl and other hydrogen halides. Evidence for the production of a [4 n + 1] π-electron intermediate radical state is seen in the presence of trifluoroacetic acid. Electrochemical analyses provide support for the notion that protonation causes a dramatic anodic shift in the reduction potentials of octaphyrin 1, thereby facilitating electron transfer from halide anions (viz. I-, Br-, and, Cl-). Electron-rich molecules, such as tetrathiafulvene (TTF), phenothiazine (PTZ), and catechol, were also found to induce PCET in the case of 1. Both the oxidized and two-electron reduced forms of 1 were characterized by X-ray diffraction analyses in the solid state and in solution via spectroscopic means.


Assuntos
Compostos Heterocíclicos de 4 ou mais Anéis/química , Compostos Macrocíclicos/química , Prótons , Ácidos/química , Compostos Heterocíclicos de 4 ou mais Anéis/síntese química , Ácido Bromídrico/química , Ácido Clorídrico/química , Compostos de Iodo/química , Compostos Macrocíclicos/síntese química , Estrutura Molecular , Oxirredução
5.
Eur J Pharm Biopharm ; 117: 224-231, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28385615

RESUMO

The natural variability of gastric pH or gastric acid reducing medications can result in lower and more variable clinical pharmacokinetics for basic compounds in patient populations. Progressing alternative salt forms with improved solubility and dissolution properties can minimise this concern. This manuscript outlines a nonclinical approach comprising multiple biopharmaceutical, in vitro and physiologically based pharmacokinetic model (PBPK) modelling studies to enable selection of an alternative salt form for danirixin (DNX, GSK1325756), a pharmaceutical agent being developed for chronic obstructive pulmonary disease (COPD). The hydrobromide salt of DNX was identified as having superior biopharmaceutical properties compared to the free base (FB) form in clinical development and the impact of switching to the hydrobromide salt (HBr) was predicted by integrating the nonclinical data in a PBPK model (using GastroPlus™) to enable simulation of clinical drug exposure with FB and HBr salts in the absence and presence of a gastric acid reducing comedication (omeprazole, a proton pump inhibitor (PPI)). Subsequent investigation of DNX pharmacokinetics in a Phase 1 clinical study comparing FB with HBr salt forms confirmed that DNX HBr had reduced the variability of drug exposure and that exposure was not affected by PPI co-administration with DNX HBr. This case study therefore adds to the surprisingly few examples of a more soluble salt of a weak base translating to an improvement in human pharmacokinetics and illustrates a clear clinical benefit of salt selection during drug development.


Assuntos
Ácido Bromídrico/sangue , Ácido Bromídrico/química , Piperidinas/sangue , Piperidinas/química , Sulfonas/sangue , Sulfonas/química , Administração Oral , Idoso , Idoso de 80 Anos ou mais , Estudos Cross-Over , Feminino , Mucosa Gástrica/efeitos dos fármacos , Mucosa Gástrica/metabolismo , Humanos , Ácido Bromídrico/administração & dosagem , Masculino , Piperidinas/administração & dosagem , Sulfonas/administração & dosagem
6.
Acta Crystallogr B Struct Sci Cryst Eng Mater ; 72(Pt 5): 723-732, 2016 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-27698313

RESUMO

In the present work, novel salts of the multimodal antidepressant drug vortioxetine (VT) were crystallized with pharmaceutically acceptable acids, aiming to improve the solubility of VT. The acids for VT were selected based on ΔpKa being greater than 2 or 3. Salts of hydrobromic acid (HBr), hydrochloric acid (HCl), p-hydroxybenzoic acid (PHBA), saccharin (SAC) and L-aspartic acid (ASP) were reported. All salts were characterized by single-crystal X-ray diffraction, FT-IR, powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC). The acidic proton is transferred to the secondary N atom on the piperazine ring of VT, forming the charge-assisted hydrogen bond N+-H...X- (X = Cl, Br, O). Solubility and intrinsic dissolution rate (IDR) experiments were carried out in distilled water (pH = 7.0) to compare the solubilities of the salts with that of VT. The VT-ASP-H2O (1:1:2) salt showed 414 times higher solubility and 1722 times faster IDR compared with VT. VT-ASP-H2O (1:1:2) is a high solubility salt that is stable in a slurry experiment at 298 K in 95% ethanol. The experimental data for the VT-ASP-H2O (1:1:2) salt identify it as a promising drug candidate.


Assuntos
Antidepressivos/química , Piperazinas/química , Sulfetos/química , Ácido Aspártico/química , Varredura Diferencial de Calorimetria , Cristalografia por Raios X , Ácido Bromídrico/química , Ácido Clorídrico/química , Ligação de Hidrogênio , Estrutura Molecular , Parabenos/química , Pós/química , Sacarina/química , Sais/química , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Vortioxetina , Difração de Raios X
7.
J Chem Phys ; 145(8): 085104, 2016 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-27586953

RESUMO

Nitrogen chemical shift is a useful parameter for determining the backbone three-dimensional structure of proteins. Empirical models for fast calculation of N chemical shift are improving their reliability, but there are subtle effects that cannot be easily interpreted. Among these, the effects of slight changes in hydrogen bonds, both intramolecular and with water molecules in the solvent, are particularly difficult to predict. On the other hand, these hydrogen bonds are sensitive to changes in protein environment. In this work, the change of N chemical shift with pressure for backbone segments in the protein ubiquitin is correlated with the change in the population of hydrogen bonds involving the backbone amide group. The different extent of interaction of protein backbone with the water molecules in the solvent is put in evidence.


Assuntos
Isótopos de Nitrogênio , Ressonância Magnética Nuclear Biomolecular , Pressão , Ubiquitina/química , Ácido Bromídrico , Ressonância Magnética Nuclear Biomolecular/métodos , Conformação Proteica , Solventes/química , Água/química
8.
J Phys Chem A ; 119(45): 11076-83, 2015 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-26473634

RESUMO

The kinetics of the reaction of OH radicals with p-cymene has been studied in the temperature range of 243-898 K using a flow reactor combined with a quadrupole mass spectrometer: OH + p-cymene → products. The reaction rate constant was determined as a result of absolute measurements, from OH decay kinetics in excess of p-cymene and employing the relative rate method with OH reactions with n-pentane, n-heptane,1,3-dioxane, HBr, and Br2 as the reference ones. For the rate coefficient of the H atom abstraction channel, the expression k1b = (3.70 ± 0.42) × 10(-11) exp[-(772 ± 72)/T] was obtained over the temperature range of 381-898 K. The total rate constant (addition + abstraction) determined at T = 243-320 K was k1 = (1.82 ± 0.48) × 10(-12) exp[(607 ± 70)/T] or, in a biexponential form, k1 = k1a + k1b = 3.7 × 10(-11) exp(-772/T) + 6.3 × 10(-13) exp(856/T), independent of the pressure between 1 and 5 Torr of helium. In addition, our results indicate that the reaction pathway involving alkyl radical elimination upon initial addition of OH to p-cymene is most probably unimportant.


Assuntos
Gases/química , Radical Hidroxila/química , Monoterpenos/química , Temperatura , Ácidos não Carboxílicos/química , Ácidos Bóricos/química , Cimenos , Hélio/química , Heptanos/química , Ácido Bromídrico/química , Hidrogênio/química , Cinética , Espectrometria de Massas , Pentanos/química , Pressão
9.
J Environ Sci (China) ; 33: 156-62, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-26141888

RESUMO

In this study, the mercury adsorption characteristics of HBr-modified fly ash in an entrained-flow reactor were investigated through thermal decomposition methods. The results show that the mercury adsorption performance of the HBr-modified fly ash was enhanced significantly. The mercury species adsorbed by unmodified fly ash were HgCl2, HgS and HgO. The mercury adsorbed by HBr-modified fly ash, in the entrained-flow reactor, existed in two forms, HgBr2 and HgO, and the HBr was the dominant factor promoting oxidation of elemental mercury in the entrained-flow reactor. In the current study, the concentration of HgBr2 and HgO in ash from the fine ash vessel was 4.6 times greater than for ash from the coarse ash vessel. The fine ash had better mercury adsorption performance than coarse ash, which is most likely due to the higher specific surface area and longer residence time.


Assuntos
Poluentes Atmosféricos/química , Cinza de Carvão/química , Ácido Bromídrico/química , Compostos de Mercúrio/química , Adsorção
10.
Org Lett ; 17(12): 2886-9, 2015 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-26010555

RESUMO

An efficient and practical system for inexpensive bromination and iodination of arenes as well as heteroarenes by using readily available dimethyl sulfoxide (DMSO) and HX (X = Br, I) reagents is reported. This mild oxidative system demonstrates a versatile protocol for the synthesis of aryl halides. HX (X = Br, I) are employed as halogenating reagents when combined with DMSO which participates in the present chemistry as a mild and inexpensive oxidant. This oxidative system is amenable to late-stage bromination of natural products. The kilogram-scale experiment (>95% yield) shows great potential for industrial application.


Assuntos
Ácidos/química , Derivados de Benzeno/química , Produtos Biológicos/síntese química , Dimetil Sulfóxido/química , Ácido Bromídrico/química , Compostos de Iodo/química , Produtos Biológicos/química , Halogenação , Estrutura Molecular , Oxirredução
11.
Adv Drug Deliv Rev ; 93: 14-24, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-25982818

RESUMO

Immunogenicity of aggregated or otherwise degraded protein delivered from depots or other biopharmaceutical products is an increasing concern, and the ability to deliver stable, active protein is of central importance. We review characterization approaches for solid protein dosage forms with respect to metrics that are intended to be predictive of protein stability against aggregation and other degradation processes. Each of these approaches is ultimately motivated by hypothetical connections between protein stability and the material property being measured. We critically evaluate correlations between these properties and stability outcomes, and use these evaluations to revise the currently standing hypotheses. Based on this we provide simple physical principles that are necessary (and possibly sufficient) for generating solid delivery vehicles with stable protein loads. Essentially, proteins should be strongly coupled (typically through H-bonds) to the bulk regions of a phase-homogeneous matrix with suppressed ß relaxation. We also provide a framework for reliable characterization of solid protein forms with respect to stability.


Assuntos
Sistemas de Liberação de Medicamentos , Estabilidade de Medicamentos , Proteínas/química , Química Farmacêutica/métodos , Preparações de Ação Retardada , Humanos , Ácido Bromídrico , Proteínas/administração & dosagem , Proteínas/imunologia
12.
Phys Chem Chem Phys ; 17(17): 11898-907, 2015 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-25872169

RESUMO

In continuation of earlier work on La(III), Ni(II) and Mn(II) halides, we present low frequency (30-400 cm(-1)) spectra of solvated HCl and HBr as a function of solute concentration. This frequency range provides direct access to water network modes and changes induced by solvated solutes. We were able to dissect the spectra into components associated to solvated ions and ion pairs using a chemical equilibrium model in combination with principal component analysis. While the Cl(-) rattling mode at 190 cm(-1) is found to be unchanged, the Br(-) resonance around 90 cm(-1) is decreased in intensity below the detection threshold when replacing the divalent or trivalent metal ions by a proton. The solvated proton shows two resonances: a solvation water mode around 140 cm(-1) and a high frequency resonance at 325 cm(-1) that we assign to the rattling motion of an Eigen structure H3O(+) in its solvation cage. This assignment is corroborated by isotopic substitution measurements which show a redshift of the high frequency peak when HCl/H2O is replaced by DCl/D2O. The linewidth of the H3O(+) rattling mode corresponds to a relaxation time of the oscillatory process of τ ≈ 60 fs, considerably faster than the relaxation time of τ ≈ 160 fs for Cl(-). In addition, we find a broad background that we attribute to fast non-oscillatory motions of a proton in a Zundel-like complex. Our results are in agreement with an Eigen-Zundel-Eigen (EZE) model of proton transport. Upon ion pairing the broad background is strongly reduced indicating a reduction of fast proton transfer processes. The Cl(-) resonance blueshifts by 20 cm(-1) which indicates a transition from free ions to a solvent shared ion pair. Surprisingly, the center frequency of the Eigen complex does not change upon ion pairing. This can be rationalized in terms of an unchanged local solvation structure.


Assuntos
Ácido Bromídrico/química , Ácido Clorídrico/química , Simulação de Dinâmica Molecular , Prótons , Estrutura Molecular , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
13.
J Mol Model ; 20(9): 2367, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25119318

RESUMO

Time-dependent quantum wave packet calculations have been performed for the H + DBr and D + HBr reaction using the recent diabatic potential energy surfaces. Reaction probabilities, integral cross sections, and rate constants are obtained. The results show that the isotopic effects have an influence on the nonadiabatic effect which is generally inversely proportional to the atom mass. The calculated rate constants are in good overall agreement with experimental values, indicating that the ab initio surfaces are accurate to describe the isotopic effects.


Assuntos
Ácido Bromídrico/química , Hidrogênio/química , Modelos Químicos , Simulação de Dinâmica Molecular , Teoria Quântica , Transferência de Energia , Cinética
14.
J Hazard Mater ; 278: 25-33, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24945793

RESUMO

In the present work we investigated the fates of zinc, lead, and iron present in electric arc furnace dust during thermal treatment of the dust with tetrabromobisphenol A (TBBPA) and tetrabromobisphenol A diglycidyl ether (TBBPADGE). Mixtures of these materials were compressed into pellets and heated in a laboratory-scale furnace at 550 °C for 80 min, under oxidizing and inert conditions. The solid, condensed, and gaseous-phase products were characterized using an array of analytical methods: scanning electron microscopy, X-ray diffraction, electron probe microscopy, inductively coupled plasma, ion chromatography, and gas chromatography. The results indicated that heating the mixtures under specific conditions enabled high separation of zinc and lead from iron-rich residues, by a bromination-evaporation process. In the case of TBBPADGE, a maximum of 85% of zinc and 81% of lead were effectively separated under the above conditions. The process is based on the reaction between the highly reactive HBr gas evolved during thermal degradation of the flame-retarded materials with zinc (ZnO and ZnFe2O4) and lead in the dust, followed by complete evaporation of the formed metallic bromides from the solid residue.


Assuntos
Retardadores de Chama , Ferro/química , Chumbo/química , Bifenil Polibromatos/química , Zinco/química , Poeira , Poluentes Ambientais/química , Ácido Bromídrico/química , Incineração , Resíduos Industriais , Plásticos , Reciclagem/métodos
15.
Spectrochim Acta A Mol Biomol Spectrosc ; 129: 193-200, 2014 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-24747844

RESUMO

We investigate theoretically the rotational excitation and field free molecular orientation of polar HBr molecule, interacting with train of ultrashort laser pulses. By adjusting the number of pulses, pulse period and the intensity of the pulse, one can suppress a population while simultaneously enhancing the desired population in particular rotational state. We have used train of laser pulses of different shaped pulse envelopes. The dynamics and orientation of molecules in the presence of pulse train of different shapes is studied and explained.


Assuntos
Ácido Bromídrico/química , Lasers , Luz , Teoria Quântica , Fatores de Tempo
16.
Orbit ; 33(5): 375-7, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24694219

RESUMO

INTRODUCTION: Orbital compartment syndrome may rarely occur in the setting of burns where therapy includes aggressive fluid resuscitation. CASE: We report a case of bilateral orbital compartment syndrome in a 13-year-old male, with superficial facial burns secondary to hydrobromic acid, who did not receive aggressive fluid resuscitation. The patient was treated successfully with bilateral lateral canthotomy and cantholysis. COMMENT: Facial burns may lead to orbital compartment syndrome without aggressive fluid resuscitation, likely due to excessive leakage of fluid and protein into the orbit combined with an inflammatory reaction.


Assuntos
Queimaduras Químicas/etiologia , Síndromes Compartimentais/etiologia , Queimaduras Oculares/induzido quimicamente , Traumatismos Faciais/induzido quimicamente , Hidratação , Ácido Bromídrico/efeitos adversos , Doenças Orbitárias/etiologia , Adolescente , Síndromes Compartimentais/cirurgia , Pálpebras/cirurgia , Humanos , Pressão Intraocular , Masculino , Procedimentos Cirúrgicos Oftalmológicos , Doenças Orbitárias/cirurgia , Tomografia Computadorizada por Raios X
18.
Nano Lett ; 13(9): 4356-61, 2013 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-23927558

RESUMO

We report on the first demonstration of stable photoelectrochemical water splitting and hydrogen generation on a double-band photoanode in acidic solution (hydrogen bromide), which is achieved by InGaN/GaN core/shell nanowire arrays grown on Si substrate using catalyst-free molecular beam epitaxy. The nanowires are doped n-type using Si to reduce the surface depletion region and increase current conduction. Relatively high incident-photon-to-current-conversion efficiency (up to ~27%) is measured under ultraviolet and visible light irradiation. Under simulated sunlight illumination, steady evolution of molecular hydrogen is further demonstrated.


Assuntos
Nanofios/química , Nitrogênio/química , Energia Solar , Eletroquímica , Gálio/química , Ácido Bromídrico/química , Óptica e Fotônica , Silício/química
19.
J Hazard Mater ; 261: 163-71, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23921179

RESUMO

In this paper, the bromination reaction between lead oxide and hydrogen bromide originating from the thermal decomposition of tetrabromobisphenol A (TBBPA), under inert and oxidizing atmospheres, was investigated, using a laboratory-scale furnace. The results obtained under inert conditions indicated that bromination of PbO proceeded simultaneously with debromination of TBBPA, with an average effectiveness of 69% (max. 80%). Volatilization of the formed PbBr2 began at 315°C, intensified at 750°C, and reached 98% at 850°C. The formed organic char served as a source of carbon for reduction of the unreacted lead oxide to metallic lead in the range 315-750°C. Additional experiments conducted at selected temperatures under slightly oxidizing (5 vol% O2) and quasi-atmospheric (20 vol% O2) conditions showed no significant effects on bromination-evaporation of lead in the studied mixture. However, in isothermal treatment under quasi-atmospheric oxygen levels, complete vaporization of the formed lead bromide was obtained at a temperature of only 650°C.


Assuntos
Ácido Bromídrico/química , Chumbo/química , Óxidos/química , Bifenil Polibromatos/química , Retardadores de Chama , Temperatura Alta , Resíduos Industriais , Volatilização , Gerenciamento de Resíduos/métodos
20.
Artigo em Inglês | MEDLINE | ID: mdl-23220526

RESUMO

We investigate the effects of delayed infrared laser (IRL) pulse shape on the non-adiabatic rotational excitation and alignment of a polar molecule. We suggest a control scheme for choosing populations of molecular rotational states by wave packet interference. The rotational wave packets of polar molecule (here HBr) excited non-adiabatically by orienting pulse is controlled actually using the second delayed IRL pulse. By adjusting the time delay between the two laser pulses and the shape of delayed IRL pulse, constructive or destructive interference among these wave packets enables the population to be enhanced or repressed for the specific rotational state. We have used fourth order Runge-Kutta method to study the non-adiabatic rotational excitation (NAREX) dynamics.


Assuntos
Ácido Bromídrico/química , Algoritmos , Raios Infravermelhos , Lasers , Teoria Quântica
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