Iron Chloride Complexes Research Articles

Accelerated removal of naproxen in the iron-based peracetic acid activation system by chloride ions: Enhancement of reactive oxidative species via the formation of iron-chloride complexes

Iron-based PAA activation process is a promising advanced oxidation process for water decontamination which depends on Fe(II) as the main reactive site for PAA activation, resulting in various reactive oxidative species (ROSs) generation. For practical application, the impact of water matrix chloride ion (Cl−) on ROSs production and contaminants removal should be carefully considered. In this study, it’s found that the introduction of Cl− (0.1–10 mM) could significantly enhance the reaction rate of the rapid stage (kobs1) up to 2.15 times at the initial pH of 4.25 in the Fe(II)/PAA system. Further studies demonstrated that the improved removal capacity of NAP resulted from Cl− induced R-O• generation as indicated by the exposure dose of R-O• increasing from 7.74 × 10−11 M•s to 1.44 × 10−10 M•s, rather than chlorine-containing radicals’ generation. DFT calculation results suggested that the formed Fe(II)-Cl− complexes could easily activate PAA to generate more ROSs for NAP removal. Moreover, Fe(II)/PAA treatment can alleviate the biological toxicity of pollutants via both the Escherichia coli test and toxicity assessment. The obtained new knowledge manifested that Cl− can boost ROSs generation and conversion in iron-based PAA systems, providing guidance for the efficient decontamination of chlorine-containing sewage with PAA-based AOPs.

Evolution of the Mantle Fluids Composition in the Precambrian (on the example of the Ukrainian shield ferruginous formation)

The basic world ferruginous formations evolve from 3.5 to 1.9 billion years and have three main peaks of manifestation: 3.2—2.7, 2.6—2.5, and 2.0—1.9 billion years ago. Three ferruginous formations, which correspond to these periods, are highlighted at the Ukrainian shield: ferruginous-siliceous-volcanogenic (FSV), ferruginous-siliceous-shale (FSS), and ferruginous-siliceous-carbonate (FSC). The source of the material for ferruginous formations, associated primary volcanogenic and chemogenic-sedimentary formations are magmatic melts of the thermal asthenosphere. The FSV Archean formation occurs in greenstone structures of granite-greenstone areas. The ferruginous rocks are jespers, consisting of a mixture of quartz-magnetite, volcanogenic silicate and carbonate (siderite and breinerite) layers. They occur mainly among amphibolites and komatiites, and obligatory contain ferruginous amphiboles and pyroxenes. Similar melts and fluids form in the presence of oxidized fluids (О2–, СО2, Н2О, SiO2), at high activity of Cl–, which provides miscibility of melts and fluids. Ferruginous-siliceous-shale formation is generated at the boundary of Archean and Paleoproterozoic. Lower and upper parts of productive strata are folded by the iron carbonates, and in the center quartz-magnetite and quartz-hematite interlayers are separated, alternating with each other. Separation into an independent phase of a water-silicate fluid carrying iron chloride complexes indicates an increase in the alkalinity of fluids and melts of the feeding asthenosphere while maintaining a high oxidizing potential. An increase in alkalinity is indicated by the presence of graphite in the accompanying shale formations. FSC formation is territorially connected with mantle fault zones of deep laying. Associates with igneous rocks (serpentinites) and shale formations (high magnesian and high alumina shales with graphite) formed in an alkaline environment (with the participation of carbonate-fluoride-sodium fluids) at a depth of at least 250 km, with a high oxidizing potential. Ferro carbonate rocks, including olivine and hematite, are formed from a carbonate phase separating from similar depths. A directed change in the ferruginous formations’ composition reflects the deep fluids and melts composition evolution and is associated with the self-organization of the Earth’s shells.

The Selective Monobromination of a Highly Sterically Encumbered Corrole: Structural and Spectroscopic Properties of Fe(Cl)(2-Bromo-5,10,15-tris(triphenyl)phenyl corrole).

The corrole ligand serves as a versatile tri-anionic, macrocyclic platform on which to model biological catalytic systems, as well as to effect mechanistically challenging chemical transformations. Here in we describe the synthesis, structure, and characterization of an isomerically pure corrole ligand, selectively mono-brominated at the β-carbon position adjacent to the corrole C-C bond (2-C) and produced in relatively high yields, as well as its iron chloride complex. Analysis of the iron metalated complex by cyclic voltammetry shows that the bromine being present on the ligand resulted in anodic shifts of +93 and +63 mV for first oxidation and first reduction of the complex respectively. The Mossbauer spectrum of the iron metalated complex shows negligible change relative to the non-brominated analog, indicating the presence of the halide substituent predominantly effects the orbitals of the ligand rather than the metal.

Effect of Chloride on the Photometric Determination of Thiocyanates in Solutions Using Iron(III)

In determining thiocyanates by photometry as complexes with iron in chloride-containing solutions, it is necessary to take into account the complex dependence of the absorbance of solutions on their composition because of the formation of iron chloride complexes, as well as ternary colored iron thiocyanate and chloride complexes. A mathematical model relating the equilibrium concentrations of components in solutions with the total concentrations of all forms of these components is developed, and the molar absorption coefficients of the [Fe(SCN)]2+ and [Fe(SCN)Cl]+ complexes are determined on its basis. An example of a technological process for the purification of a thiocyanate-containing solution by a two-temperature sorption method is considered, the analytical support of which by the known methods leads to incorrect results, but becomes possible using the developed model.

Decolorization of reactive dyes in solar pond reactors: Perspectives and challenges for the textile industry

In the past three decades, Fenton and photo-Fenton processes have been the subject of a large number of research studies aimed at developing a low-cost and robust alternative to treat complex wastewater. Aspects such as installation and operating costs and technical complexity of reactors have limited the commercial applications of Fenton processes. In this study, we evaluated the potential of solar pond reactors to carry out degradation of the dye reactive orange 16 (RO16). Decolorization (D = 99 ± 0.6%), chemical oxygen demand reduction (COD = 55 ± 2%), total organic carbon removal (TOC = 28 ± 0.5%), and biocompatibilization can be accomplished using 15% peroxide (0.6 mg H2O2/mg RO16), which is theoretically required to mineralize the dye. Under dark conditions, decolorization and aromatic removal were scarcely affected (2%), whereas COD and TOC removal were reduced to 37% and 16%, respectively. The application of multivariable analysis and the use of low-cost reactors may lead to a reduction in annual treatment costs of colored effluents to 0.76 (US/m3). Furthermore, the treatment capacity can be increased from 0.6 m3 wastewater/m2 reactor surface to 1.7 m3 wastewater/m2 reactor surface without compromising process efficiency or the biodegradability (BOD5/COD ratio) of the effluent. Dyeing auxiliaries, mainly NaCl, appreciably reduced the decolorization performance in Fenton (13 ± 0.4%) and photo-Fenton (83 ± 0.5%) processes due to the formation of iron-chloride complexes and less powerful oxidants. To reduce the impact of auxiliary agents on process performance and treatment capacity, the Fe2+ concentration should be increased from 5 mg/L to 15 mg/L. The results seem promising; however, additional studies at pilot and semi-industrial scales should be conducted to demonstrate the potential of low-cost reactors to carry out colored wastewater treatment.

Sulfur-poor intense acid hydrothermal alteration: A distinctive hydrothermal environment

A fundamentally distinct, sulfide-poor variant of intense acid (advanced argillic) alteration occurs at the highest structural levels in iron oxide-rich hydrothermal systems. Understanding the mineralogy, and geochemical conditions of formation in these sulfide-poor mineral assemblages have both genetic and environmental implications. New field observations and compilation of global occurrences of low-sulfur advanced argillic alteration demonstrates that in common with the sulfide-rich variants of advanced argillic alteration, sulfide-poor examples exhibit nearly complete removal of alkalis, leaving a residuum of aluminum-silicate+quartz. In contrast, the sulfur-poor variants lack the abundant pyrite±other sulfides, hypogene alunite, Al-leached rocks (residual “vuggy” quartz) as well as the Au-Cu-Ag±As-rich mineralization of some sulfur-rich occurrences. Associated mineralization is dominated by magnetite and/or hematite with accessory elements such as Cu, Au, REE, and P. These observations presented here indicate there must be distinct geologic processes that result in the formation of low-sulfur advanced argillic styles of alteration.Hydrolysis of magmatic SO2 to sulfuric acid is the most commonly recognized mechanism for generating hypogene advanced argillic alteration, but is not requisite for its formation. Low sulfur iron-oxide copper-gold systems are known to contain abundant acid-styles of alteration (e.g. sericitic, chloritic), which locally reaches advanced argillic assemblages. A compilation of mapping in four districts in northern Chile and reconnaissance observations elsewhere show systematic zoning from near surface low-sulfide advanced argillic alteration through chlorite-sericite-albite and locally potassic alteration. The latter is commonly associated with specular hematite-chalcopyrite mineralization. Present at deeper structural levels are higher-temperature styles of sodic-calcic (oligoclase/scapolite – actinolite) alteration associated with magnetite±chalcopyrite mineralization. These patterns are in contrast to the more sulfur-rich examples which generally zone to higher pyrite and locally alunite-bearing alteration.Fluid inclusion evidence from the systems in northern Chile shows that many fluids contain 25 to >50wt% NaCleq with appreciable Ca, Fe, and K contents with trapping temperatures >300°C. These geological and geochemical observations are consistent with the origin of the low-sulfur advanced argillic assemblages from HCl generated by precipitation of iron oxides from iron chloride complexes from a high-salinity fluid by reactions such as 3FeCl2+4H2O=Fe3O4+6HCl+H2. Such HCl-rich (and relatively HSO4=-poor) fluids can then account for the intense acid, Al-silicate-rich styles of alteration observed at high levels in some iron-oxide-coppe-gold (IOCG) systems. The geochemical differences between the presence of sulfide-rich and sulfur-poor examples of advanced argillic alteration are important to distinguishing between system types and the acid-producing capacity of the system, including in the modern weathering environment. They have fundamental implications for effective mineral exploration in low-sulfur systems and provide yet another vector of exposed alteration in the enigmatic IOCG clan of mineral deposits. Furthermore, understanding the geochemistry and mineralogy of this distinct geologic environment has applications to understanding the acid generating capacity and deleterious heavy metals associated with advanced argillic alteration.

Iron transport and deposition mechanisms in the Taochong iron-rich skarn deposit, Middle–Lower Yangtze Valley, Eastern China

The Taochong skarn iron deposit is one of 38 iron prospects in the Fanchang iron ore district of the Middle–Lower Yangtze River Valley, one of the most important economic mineral districts in China. Orebodies are hosted mainly within the middle–upper Carboniferous Huanglong dolomitic limestone. In this deposit, two types of ore (types 1 and 2) are recognized based on the mineral assemblage. The type 1 ore is dominant throughout the deposit and consists mainly of hematite, magnetite, quartz, and calcite. This ore is characterized by euhedral and skeletal textures, and massive, brecciated, comb-like, and vein structures. The type 2 ore is composed of hematite, garnet, pyroxene, actinolite, chlorite, quartz, and calcite, and has a relict metasomatic texture and disseminated structure. Field evidence and petrographic observations indicate that three stages of hydrothermal activity (i.e., the skarn, iron oxide, and carbonate stages) contributed to the formation of the Taochong iron deposit. The iron oxide stage can be further divided into early and late oxide stages, which saw the formation of the type 2 and type 1 ores, respectively.Fluid inclusion and stable isotope data indicate that the skarn formed at depths of ~2km under lithostatic pressure of ~500bars, from high-temperature (~500°C), acidic, saline (up to ~50wt.% NaCl equiv.), and iron-rich fluids that had chemical and isotopic compositions (δ18Owater=4.5‰–11.7‰) similar to those of magmatic fluid replacing a certain amount of the Huanglong dolomitic limestone. The iron ores formed under hydrostatic conditions after fracturing of the early skarn. Fluid inclusions within quartz in equilibrium with hematite in the type 2 ores yields homogenization temperatures of 372–390°C and salinities of 31–39wt.% NaCl equiv., whereas fluid inclusions within quartz in equilibrium with hematite in the type 1 ores has lower homogenization temperatures (280–320°C) and variable salinities (0–40wt.% NaCl equiv.). During the formation of the type 1 ores, fluids contained moderate concentrations of ions, variable δ13C values (−5.3‰ to +5.8‰), and relatively convergent δ18O values (1.7‰–4.5‰). The temporal decrease in the concentration of ions and δ18O values in the fluid inclusions is matched by marked decreases in fluid salinity and temperature, suggesting that the fluids of the oxide stage were mixtures of magmatic brine and meteoric water. The coexistence of saline and vapor-rich fluid inclusions as internal trails or clusters within individual quartz grains of the late oxide stage, with contrasting homogenization characteristics (for the liquid and vapor) at similar temperatures, strongly suggests that fluid boiling occurred during the late oxide stage.Our estimates of the physico-chemical conditions during ore formation, together with fluid inclusion data and the results of previous experimental studies, indicate that iron in the Taochong deposit was transported mainly as FeCl4–, along with minor amounts of other chloride complexes (e.g., FeCl2+ and FeCl2(H2O)4+). The precipitation of hematite followed the breakdown of the iron chloride complexes, probably induced by a decrease in temperature and ligand (chloride) ion activity, and an increase in pH. Based on the results, we infer that deposition of the type 2 ore was caused by the replacement of garnet and pyroxene by a retrograde alteration assemblage, which was likely induced by fluid–rock interaction and the mixing of magmatic brine and meteoric water. The type 1 ore was deposited in open spaces, probably induced by fluid boiling.

Syntheses and crystal structures of vanadium and iron chloride complexes with diglyme.

A mononuclear molecular complex fac-[VCl3(diglyme)] (1) resulted from the reaction of VCl3 and diglyme (diglyme = di(2-methoxyethyl)ether) in dichloromethane. The violet complex 1 is a sensitive substance which slowly oxidized to a new, blue mononuclear molecular complex, fac-[VOCl2(diglyme)] (2) in the presence of air. The synthesis of iron(II), iron(III) complex [FeCl(diglyme)(THF)]2[FeCl4)]2 (3) was achieved by the reaction of yellow-green, partly oxidized FeCl2.4H2O, diglyme and chlorotrimethyl-silane in tetrahydofuran. The compound consists of the dinuclear cations with octahedral environment of iron(II) and the tetrahedral anions of iron(III). A pure iron(II) chloride-diglyme complex [FeCl2(diglyme)]2 (4) was gained by the reaction of freshly prepared iron(II) chloride hydrate, diglyme and chlorotrimethylsilane in dichloromethane. Diglyme is coordinated in the meridional mode to octahedral iron(II) in dinuclear cations of 3 and in dinuclear molecules 4.

Selective Iron‐Catalyzed Oxidation of Benzylic and Allylic Alcohols

AbstractA convenient and selective oxidation of alcohols with hydrogen peroxide to give aldehydes and ketones has been developed. Using in situ generated iron chloride complexes [Fe(L3)2Cln] [n=0–1, L3 =6‐(N‐phenylbenzimidazoyl)‐2‐pyridinecarboxylic acid], aldehydes and ketones were obtained in good yield and excellent selectivity after a short reaction time at room temperature.

Synthesis, characterization and spectral properties of substituted tetraphenylporphyrin iron chloride complexes.

A series of substituted tetraphenylporphyrin iron chloride complexes [RTPPFe(III)Cl, R=o/p-NO2, o/p-Cl, H, o/p-CH3, o/p-OCH3] were synthesized by a novel universal mixed-solvent method and the spectral properties of free base porphyrins and iron porphyrin compounds were compared with each other. The experimental results showed that the one-pot mixed solvent method was superior to the two-step method in the yields, reaction time and workup of reaction mixtures for the synthesis of iron porphyrin compounds. The highest yields (28.7%–40.4%) of RTPPFe(III)Cl were obtained in the mixed solvents propionic acid, glacial acetic acid and m-nitrotoluene under reflux for 2 h. A detailed analysis of ultraviolet-visible (UV-vis), infrared (IR) and far-infrared (FIR) spectra suggested the transformation from free base porphyrins to iron porphyrins. The red shift of the Soret band in ultraviolet-visible spectra due to the presence of p-nitrophenyl substituents and the blue shift of Fe-Cl bond of TPPFeCl in far-infrared spectra were further explained by the electron transfer and molecular planarity in the porphyrin ring.

Zeolyst ups zeolite capacity

A fundamentally distinct, sulfide-poor variant of intense acid (advanced argillic) alteration occurs at the highest structural levels in iron oxide-rich hydrothermal systems. Understanding the mineralogy, and geochemical conditions of formation in these sulfide-poor mineral assemblages have both genetic and environmental implications. New field observations and compilation of global occurrences of low-sulfur advanced argillic alteration demonstrates that in common with the sulfide-rich variants of advanced argillic alteration, sulfide-poor examples exhibit nearly complete removal of alkalis, leaving a residuum of aluminum-silicate + quartz. In contrast, the sulfur-poor variants lack the abundant pyrite ± other sulfides, hypogene alunite, Al-leached rocks (residual “vuggy” quartz) as well as the Au-Cu-Ag ± As-rich mineralization of some sulfur-rich occurrences. Associated mineralization is dominated by magnetite and/or hematite with accessory elements such as Cu, Au, REE, and P. These observations presented here indicate there must be distinct geologic processes that result in the formation of low-sulfur advanced argillic styles of alteration.Hydrolysis of magmatic SO2 to sulfuric acid is the most commonly recognized mechanism for generating hypogene advanced argillic alteration, but is not requisite for its formation. Low sulfur iron-oxide copper-gold systems are known to contain abundant acid-styles of alteration (e.g. sericitic, chloritic), which locally reaches advanced argillic assemblages. A compilation of mapping in four districts in northern Chile and reconnaissance observations elsewhere show systematic zoning from near surface low-sulfide advanced argillic alteration through chlorite-sericite-albite and locally potassic alteration. The latter is commonly associated with specular hematite-chalcopyrite mineralization. Present at deeper structural levels are higher-temperature styles of sodic-calcic (oligoclase/scapolite – actinolite) alteration associated with magnetite ± chalcopyrite mineralization. These patterns are in contrast to the more sulfur-rich examples which generally zone to higher pyrite and locally alunite-bearing alteration.Fluid inclusion evidence from the systems in northern Chile shows that many fluids contain 25 to >50 wt% NaCleq with appreciable Ca, Fe, and K contents with trapping temperatures >300 °C. These geological and geochemical observations are consistent with the origin of the low-sulfur advanced argillic assemblages from HCl generated by precipitation of iron oxides from iron chloride complexes from a high-salinity fluid by reactions such as 3FeCl2 + 4H2O = Fe3O4 + 6HCl + H2. Such HCl-rich (and relatively HSO4=-poor) fluids can then account for the intense acid, Al-silicate-rich styles of alteration observed at high levels in some iron-oxide-coppe-gold (IOCG) systems. The geochemical differences between the presence of sulfide-rich and sulfur-poor examples of advanced argillic alteration are important to distinguishing between system types and the acid-producing capacity of the system, including in the modern weathering environment. They have fundamental implications for effective mineral exploration in low-sulfur systems and provide yet another vector of exposed alteration in the enigmatic IOCG clan of mineral deposits. Furthermore, understanding the geochemistry and mineralogy of this distinct geologic environment has applications to understanding the acid generating capacity and deleterious heavy metals associated with advanced argillic alteration.

Smectic bimetallomesogens: synthesis, characterization and mesomorphic properties and the crystal structure of bis[N-(3-hydroxypropyl)-4-octanoylsalicylaldiminato]copper(II) complex

The synthesis, characterization and mesomorphic properties of copper(II), palladium(II), vanadyl(IV) and iron(III) chloride complexes derived from salicylaldimine structures are reported. The copper and palladium complexes exhibited smectic A phases, however vanadyl and iron chloride complexes showed crystalline phase. The palladium complexes have lower melting and clearing points, and a wider temperature range of mesophase. This lowering in clearing points between M = Pd and M = Cu analogues was attributed to the weaker core-core interaction between palladium centres within layers in the mesophase. The crystal and molecular structures of bis[N-(3-hydroxypropyl)-4-octanoylsalicylaldiminato]copper(II) were determined by means of X-ray analysis. This complex crystallizes in the monoclinic space group p21/c, with a = 5.4908(23) A, b = 19.847(5) A, c = 16.636(4) A, beta = 96.87(3) degree, and Z = 2. The intramolecular separation of Cu-Cu atoms is 3.022(3)A. The structure shows that the molecular shape is nearly flat with two copper atoms lying 0.067(4)A above and below the plane of N1, O1a, O1 and O2 atoms.

X-ray crystallographic and absorption spectroscopic analyses of structures of catecholato (pyridine)iron chloride complexes in relevance to functional model complexes for catechol 1,2-dioxygenases

Catecholatoiron complexes were isolated in the crystalline or non-crystalline form from the reaction solution of catechols with FeCl 3 in the presence of pyridine in THF; they form a functional model system for catechol dioxygenases. Two types of complex were obtained, depending on substituent on catechol and pyridine: [FeCl (catechol)(pyridine)](pyridine) and [FeCl 2(catechol)] −·2[pyridine·H] +. An X-ray quality single crystal was obtained with the 3.5-di-tert-butycatecholato(2,6-lutidine)iron chloride complex: it is monoclinic, space group C2 m , with cell dimensions a = 11.947(3), b = 16.122(3), c = 14.725(2) A ̊ , β = 100.38(2)°, and Z = 2. The [Fe 2(catechol) 2Cl 4] 2− anion forms a dinuclear complex with two crystallographically equivalent iron centers, each metal ion of which is in a five-coordinated distorted square-pyramidal geometry with two chloride anions and two oxygen atoms of two bridging catechol molecules. Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) studies have revealed that the other isolated complexes are also dimeric in the solid state and become monomeric in the THF solution. The presence of FeCl bonding and its conversion to Fe-pyridine in solution are shown by the Br K-edge EXAFS analysis of the analogous bromide complex.

Experimental study of iron-chloride complexing in hydrothermal fluids

Mineral assemblage solubilities were measured in cold-seal pressure vessels as a function of pressure, temperature, and potassium chloride concentration in order to determine the nature and thermodynamic properties of iron-chloride complexes under hydrothermal conditions. The assemblage pyritepyrrhotite-magnetite was used to buffer ƒS 2 and ƒO 2 , and K + H + ratios were buffered at reasonable geologic values using the assemblage potassium feldspar-muscovite (or andalusite)-quartz. The pressure-temperature ranges were 0.5-2.0 kbar and 300–600°C, and initial fluid compositions ranged from 0.01–2.0 molal KCl. With all other factors constant, the concentration of iron in solution increases with increasing temperature, with decreasing pressure, and with increasing total potassium chloride concentration. Changes in iron concentrations as a function of KCl concentration, in conjunction with charge balance, mass action, and mass balance constraints on the system, place constraints on the stoichiometry of the important iron-chloride complexes under each of the experimental conditions. Using least-squared linear regression fits to determine these slopes, the calculations yield values for the average ligand numbers that are in the range 1.2-1.9, with uncertainties ranging from ±0.1-0.6 at the several PT conditions considered. The slopes of the regressed fits to the data suggest that both FeCl + and FeCl 2 0 are important in the experimental fluids, with FeCl 2 0 becoming dominant at the higher temperatures. Theoretical calculations, however, indicate that FeCl + does not contribute significantly to the solubility. Because of the large uncertainties associated with some of the calculated average ligand numbers, we base our data analysis on the theoretical calculations. A statistical analysis is applied to the solubility data in order to determine the values and uncertainties of the dissociation constant for FeCl 2 0 that best fit the data at each of the experimental pressures and temperatures. The calculated stability of FeCl 2 0 increases with increasing temperature and total chloride concentration, and with decreasing pressure. The values of the dissociation constant of FeCl 2 0that are calculated in this study are in moderately good agreement with FeCl 2 0dissociation constants from other studies of iron-chloride complexing in supercritical fluids. Differences are likely due to different assumptions made concerning activity coefficients of aqueous species. Log k d values for full dissociation of FeCl 2 0 at 0.5 kbar—300°C—and at 1 kbar—400, 500, and 600°C, respectively—are −3.75 ± 0.40, −6.25 ± 0.10, −9.19 ± 0.44, and −13.29 ± 0.09.

Polymerization of ϵ-caprolactone with photoreduction of an iron chloride complex catalyst

Photochemical polymerization of ϵ-caprolactone was studied in the presence of complexed iron halogides. It was found that UV irradiation of the initial reaction mixture, and also of the complex catalyst solution leads to increased rate of caprolactone polymerization, and permits the polymerization temperature to be lowered down to the room value. The mechanism of the process was studied; it was found that Fe +3 is reduced to Fe +2 and the lactone ring is activated by the proton liberated during photoreduction. In the absence of organic solvents, polymerization is accompanied by polymer degradation by the generated chlorine radical; this process can be prevented by the addition of small amounts of aromatic solvents.

MÖSSBAUER SPECTROSCOPY STUDIES OF POLYACETYLENE DOPED CHEMICALLY AND ELECTROCHEMICALLY WITH IRON CHLORIDES

Doping of polyacetylene with iron chloride complexes has been studied by MBssbauer spectroscopy. It was proved that the doped polymer undergoes degradation in air manifested by the formation of FeOlxaE^O with the simultaneous chlorination of the double bond.

Mőssbauer spectroscopy studies of polyacetylene doped with iron chloride complexes

The 57 Fe Mőssbauer resonance has been applied to study polyacetylene films doped chemically and electrochemically to different doping levels. Both methods lead to the insertion of a high spin Fe III complex with Mőssbauer parameters characteristic of FeCl − 4. Degradation of [CH(FeCl 4) y] x in air leads to gradual transformation of Fe III into a high spin Fe II.

Electrodissolution Kinetics of Iron in Chloride Solutions: Part II . Alkaline Solutions

The anodic behavior of pure iron in alkaline chloride solution was studied by potential sweep and galvanostatic methods. For active dissolution anodic Tafel slopes of 65 and 66 mV/decade were obtained from the galvanostatic and potential sweep experiments, respectively. These values can be interpreted in terms of the Bockris mechanism with Temkin adsorption. Passivation was also observed. The peak current or critical current which appeared in the potential‐current curve obtained by potential sweeps was proportional to the square root of the sweep rate. The potential associated with the peak current varied linearly in the anodic direction as the log of the sweep rate with a slope of 33 mV/decade. The square root of the passivation time obtained from galvanostatic polarization was inversely proportional to the current. These results were interpreted by assuming that passivation occurred when the iron chloride complex attained its solubility limit.