Microchemical investigation of early iron metallurgy slags

A group of slags, dating back to Iron Age II (Aramean period, 800-720 B.C.), that appeared to be iron-smelting by-products, have been found at Tell Afis (North-Western Syria). The microchemistry of these materials has been studied by means of small-area X-ray photoelectron spectroscopy (XPS), X-ray induced Auger electron spectroscopy (XAES), scanning electron microscopy (SEM), electron-probe microanalysis (EPMA) and optical microscopy (OM). The results indicate that the slags can be associated with an iron-smelting process and show the presence of large amounts of Fe(II) and Fe(III) oxides and hydroxides mixed with different glassy and crystalline silicon compounds. The latter consist essentially of quartz and various silicates, such as wollastonite, melilite, Mg[SiO₄] or Mg[SiO₆] compounds and other complex aluminosilicates. This chemical information is used to elucidate some aspects of the early ironmaking process.     

Mössbauer spectroscopic studies of tungsten ores

Tungsten ores from Degana, Rajashthan State, India are studied using Mössbauer spectroscopy. The low grade ore exhibits two types of mineral assemblages as per chemical states of iron. The relation between ferrous/ferric ratio and tungsten concentration also supports the existence of two types of mineral assemblages. The Mössbauer spectroscopy of concentrate ore samples has shown the absence of iron. The energy dispersive X-ray fluorescence spectroscopy on the contrary has evidenced the presence of iron in concentrate ore samples but at lower concentration on comparison with low grade ores. These differences in behaviour in the above spectroscopic studies may be additionally due to higher attenuation of -radiations and higher atomic weight material in the ore concentrates.     

GC-MS characterization and quantification of sterols and cholesterol oxidation products

Summary A GC-MS method has been studied for characterization and quantification of phytosterols, cholesterol and cholesterol oxidation products. Baseline separations have been achieved between cholesterol, cholesterol 5-6-epoxide, 5-cholestene-3-ol-7one (7-keto-cholesterol), cholestene-3-5-6-triol, 5-cholestene-3-25-diol (25-hydroxycholesterol), 5-cholestene-3-20-diol (20-hydroxycholesterol), 5-cholestene-3-7-diol (7-hydroxycholesterol) and 5-cholestene-3-19-diol (19-hydroxycholesterol) as well as between -cholestane, cholesterol, stigmasterol, campesterol and -sitosterol. Excellent linearity of response has been obtained permitting reliable quantification. The characterization of each derivatized sterol has been performed by mass-spectrometry. The results confirm the utility of combined gas chromatography-mass spectrometry in the analysis and characterization of sterols and cholesterol oxidation products.     

AES investigations of the iron surface composition after laser irradiation under atmospheric conditions

The laser induced modification of iron surfaces with atmospheric species was investigated by means of Auger electron spectroscopy (AES) and scanning electron microscopy (SEM). Different laser systems were used for irradiating iron samples in a wide range of the laser processing parameters up to small foci and ultra short pulses.A nitriding of iron connected with an oxidation of the near surface region was observed in the wavelength range between 193 nm and 10.6 m using large foci (0.1 cm²) and short pulses (10...1400ns). In case of small foci (7·10^–6cm²) with ns-pulses (50 ns) an enrichment of the iron melt with nitrogen and an advanced oxidation of the surrounding area of the laser spot were detected. When using shorter pulses (200 fs, 40 ps) no indications for a nitriding were found.     

High performance liquid chromatographic separation and UV determination of cobalt, copper iron and platinum in pharmaceutical preparations using bis(isovalerylacetone)ethylenediimine as complexing reagent

The reagent bis(isovalerylacetone)ethylenediimine(H₂IVA₂en) has been examined for HPLC separation and UV determination of cobalt, copper, iron and platinum using off-line precolumn derivatization and extraction in chloroform. The complexes of cobalt(II), cobalt(III), iron(II), iron(III) and the reagent have been subsequently separated on a Microsorb C-18 column. The complexes were eluted isocratically using ternary mixtures of methanol/water/acetonitrile. Detection was achieved by UV monitoring. Detection limits for Co(II), Co(III), Fe(II) and Fe(III) were 2.5–5.0 ng/injection, based on 0.5–1.0 g/ml with 5 l/injection. The concentration of cobalt(II) and cobalt(III) in aqueous solution have been determined. The presence of oxovanadium(IV), platinum(II), and nickel(II) did not affect the determinations. The HPLC method developed has been applied to the determination of cobalt, copper, iron and platinum in pharmaceutical preparations at the 30 g/g to 15 mg/g level and the obtained results were compared to those of atomic absorption spectrometry.     

Nouveaux échangeurs d'ions hydrophiles pour la chromatographie des protéines: Pipéridine-N-éthyl-cellulose et Di-isopropyl-aminoéthyl-cellulose

Résumé On a étudié la réaction de divers chlorures d'amines aliphatiques [-chloroéthyldiisopropylamine, N-(-chloroéthyl)-pipéridine, N--chloro-éthylpyrrolidine, -chloroéthyl-diméthylamine] avec l'alcali-cellulose. Grâce à l'étude détaillée des courbes de neutralisation des celluloses basiques obtenues et de la triméthylaminoéthyl cellulose (TMAE-cellulose), on a pu mettre en évidence les différences de réactivité des chlorures d'amine pour la formation de liaisons éther avec la cellulose et pour la quaternisation des groupes amine. Dans le cas de la -chloroéthyldi-isopropylamine et de la N-(-chloroéthyl)-pipéridine, on obtient des celluloses à groupes amine tertiaire: respectivement, la di-isopropylamino-éthylcellulose (DIPAE-cellulose) et la Pipéridine-N-éthyl-cellulose (Pipé-NE-cellulose). Dans le cas de la N-(-chloroéthyl)-pyrrolidine, la cellulose basique obtenue a une courbe de neutralisation qui correspond à un échangeur d'ions ayant des groupes amine tertiaire et des groupes ammonium quaternaire. Il en est de même dans le cas du produit de réaction de l'alcali-cellulose avec la -chloroéthyldiméthylamine (cellulose modifiée de capacité supérieure à 0,3 m.équiv./g.).Les propriétés chromatographiques de ces nouveaux échangeurs d'anions hydrophiles ont été étudiées; certains d' entre eux donnent des résultants très intérensants, spécialement, dans le domaine de la chromatographie des protéines. Pour la chromatographie des protéines la Pipéridine-N-éthyl-cellulose qui a une structure fibreuse compacte a un pouvoir séparateur aussi élevé que celui obtenu avec la DEAE-cellulose à structure fibres gélifiées réticulées.

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New hydrophilic ion-exchangers for chromatography of proteins: Piperidine N-ethylcellulose and di-isopropylaminoethyl cellulose

Summary Reaction of different aliphatic amine chlorides [-chloroethyldiisopropylamine, N-(-chloroethyl)-piperidine, N (-chloroethylpyrrolidine, -chloroethyldimethylamine) with alkalicellulose has been investigated. Detailed investigation of titration curves of the basic cellulose thus obtained and of trimethylaminoethylcellulose (TMAE-cellulose) has shown that the reactivity of various amine chlorides varies in the case of formation of ether bonds with cellulose as well as in the case of quaternization of amino-groups. With -chlorethyldiisopropylamine and N-(-chloroethyl-)piperidine, celluloses with tertiary amino-groups were obtained, namely, di-isopropylamino ethyl cellulose (DIPAE-cellulose) and piperidine-N-ethyl-cellulose (Pipe-NE-cellulose). Basic cellulose obtained with N-(-chloroethyl)-pyrrolidine gives a titration curve corresponding to an ion exchanger carrying tertiary amino and quaternary ammonium groups. The same is true for the reaction product of -chloroethyl-dimethylamine with alkali-cellulose (modified cellulose with an exchange capacity greater than 0.3 m.equiv g^–1). Chromatographic behaviour of these new hydrophilic anion exchangers has been investigated. Some of them give very interesting results, mainly in the chromatography of proteins; thus, piperidine-N-ethylcellulose with a dense fibrous texture, has a separating power as great as that of DEAE cellulose with fibres of crosslinked gel type.

     

Theoretical Insights into the Formation, Structure, and Energetics of Some Cyclodextrin Complexes

To investigate the physicochemical aspects relevant for the formation of various cyclodextrin inclusion complexes and to search for corresponding general structure–complex-stability relationships, stability data of 1 : 1 complexes for 179, 310, and 51 guest molecules with unsubstituted -, -, and -cyclodextrin were collected. Statistical analysis using structure-based parameters such as molecular size, hydrophobicity, rotatable bonds, electronic properties, and the presence or absence of more than 150 various functional or structural moieties were performed. The complexation thermodynamics could be well described within the framework of our recently introduced molecular size-based model for nonassociative liquids. With increasing guest size, 1 : 1 complex stability, as measured by ln K or G⁰, increases linearly up to a size limit characteristic for each CD, and the corresponding slopes and intercepts are in agreement with those predicted by the model. For larger structures, values level off and are scattered around an average value depending on shape, goodness of fit, and possibly lipophilicity and some specific effects (e.g. such as those caused by presence of phenol functionality). The complexation between -cyclodextrin and certain large steroidal guest molecules, especially a brain-targeted estradiol chemical delivery systems (E₂-CDS) that is under clinical development, was investigated in details based on fully relaxed semiempirical AM1 quantum chemical calculations. A deformation index (DI) of the CD ring computed using these fully optimized host-guest geometries could be used to characterize the conformational change of the guest.     

Simultaneous determination of aluminium and iron in glasses,phosphate rocks and cement using first- and second-derivative spectrophotometry

First- and second-derivative spectrophoto-metric methods for the simultaneous determination of aluminium and iron in their mixtures are described. The methods are based on the colored complexes formed by aluminium and iron with hematoxylin in the presence of cetyltrimethylammonium bromide as a surfactant. The zero-crossing method has been utilized to measure the first- and second-derivative value of the derivative spectrum. Aluminium (0.05–1 gml^-1) could be determined in the presence of iron (0.09–1.6 gml^-1) and vice versa. The detection limits of aluminium and iron are 0.01 and 0.09 gml^-1, respectively in the first-derivative mode and 0.014 and 0.1 gml^-1 in the second-derivative mode. The proposed method has been applied to the simultaneous determination of aluminium and iron in glasses, phosphate rocks, cement and magnesite alloy.     

A new spectrophotometric method for the micro determination of sulfuric acid esters in sulfatide fractions

Summary A new micro method has been developed for measuring sulfatide fractions. Sulfuric acid ester absorption is measured at 8.02 m () by infrared spectrophotometry, compared with that of a standard sulfatide, and corrected for phosphorus. General problems in measuring sulfatides are noted; procedural details, control studies, advantages, and limitations of the present method are discussed.

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Zusammenfassung Eine neue Mikromethode für die Bestimmung von Sulfatidfraktionen wird beschrieben. Die Absorption der Schwefelsäureester wird im Infrarot bei 8,02 m gemessen, mit jener eines Sulfatidstandards verglichen und für Phosphor korrigiert. Allgemeine, mit der Bestimmung von Sulfatiden verbundene Probleme werden erwähnt; technische Einzelheiten, Kontroll-untersuchungen, Vorteile und Grenzen der beschriebenen Methode werden besprochen.

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Résumé Mise au point d'une nouvelle microméthode pour la détermination de fractions de sulfatides. L'absorption de l'ester sulfurique est mesurée à 8,02 m () par spectrophotométrie infra-rouge et comparée avec celle d'un sulfate standard puis corrigée du fait de la présence du phosphore. Les auteurs rappellent les problèmes généraux rencontrés dans la détermination des sulfatides. Les détails opératoires, les études de contrôle, les avantages et les limitations de la présente méthode sont d'autre part discutés.

     

Hydrogen exchange in intramolecular cycloalkylation of phenylalkanols

Hydrogen exchange in intramolecular cycloalkylation of 2-methyl-4-phenyl-2-butanol (I) and 2-methyl-5-phenyl-2-pentanol (II) in the presence of 85% D₂SO₄ has been studied. The product 1,1-dimethylindane(III) is shown to contain deuterium in both aromatic ring and polymethylene fragment, whereas 1,1-dimethyltetralin (IV) contains deuterium only in the aromatic ring. A probable mechanism of the reaction is discussed.

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2--4--2- (I) 2--5--2- (II) 85% D₂SO₄. , 1,1- (III) , 1,1- (IV) . .

     

Stability constants of iron(III) borate complexes

The ultraviolet absorbance data from experiments conducted at constant pH and total iron concentration but variable B(OH)₃ concentration were used to determined the stability constants of FeB(OH) ₄ ²⁺ and Fe[B(OH)_{4 2} ⁺ at 25°C and an ionic strength of 0.68. The estimates obtained were *₁ = 1.0 ± 0.2 × 10^–2 and *₂ = 2 ± 1 × 10^–5, respectively (uncertainties are two times the standard error of the estimates). A calculation of the extent of iron(III) borate formation in ocean water at pH 8.2 shows that iron(III) borates are not a significantly large component of iron(III) speciation in seawater.     

Relaxation during internal rotation ethane and hydrogen peroxyde

An ab initio SCF-LCAO-MO study of the relaxation process during internal rotation has been performed for ethane and hydrogen peroxyde. A large gaussian basis set has been used, with polarization functions. The total energy has been optimized with respect to the bond lengths and bond angles. The computed barrier for the ethane molecule is 3.07 kcal/mole with the optimized geometry (experimental 2.93 kcal/mole). For hydrogen peroxyde, this yields a cis-barrier of 10.9 kcal/mole (experimental 7.0 kcal/mole) and a trans barrier of 0.6 kcal/mole (experimental 1.1 kcal/mole), with a dihedral angle equal to 123 (experimental 111–120). The eclipsed or cis conformations are found to have more open structures than the staggered or equilibrium conformations.

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Zusammenfassung Der Relaxationsproze\ wÄhrend der inneren Rotation wurde für Äthan und Wasserstoffperoxid mit Hilfe einer ab initio SCF-LCAO-MO-Rechnung untersucht. Dabei wurde eine gro\e Basis von Gau\funktionen mit Polarisationsfunktionen benutzt. Die Gesamtenergie wurde unter Variation der BindungslÄnge und Bindungswinkel optimiert. Die berechnete Rotationsbarriere mit der optimalen Geometrie betrÄgt 3,07 kcal/Mol für Äthan (experimentell 2,93 kcal/Mol). Für Wasserstoffperoxid ergibt sich eine cis-Barriere von 10,9 kcal/Mol (experimentell 7,0 kcal/Mol) und eine trans-Barriere von 0,6 kcal/Mol (experimentell 1,1 kcal/Mol) sowie ein Verdrillungswinkel von 123 (experimentell 111–120). Die verdeckten oder cis-Konformationen besitzen mehr offene Strukturen als die gestaffelten oder die Gleichgewichtskonformationen.

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Résumé Une étude des phénomènes de relaxation liés à la rotation interne a été effectuée pour l'ethane et l'eau oxygénée par la méthode ab initio SCF-LCAO-MO. Avec une base étendue de fonctions gaussiennes comprenant des fonctions de polarisation, on minimise l'énergie par rapport aux longueurs et aux angles des liaisons. La barrière calculée pour l'ethane est de 3,07 kcal/mole (valeur expérimentale 2,93 kcal/mole). Pour l'eau oxygénée, on trouve pour les barrières cis 10,9 kcal/mole, trans 0,6 kcal/mole et pour l'angle dièdre 123 (values expérimentales 7,0 et 1,1 kcal/mole et 111–120). Les conformations éclipsée ou cis possèdent des structures plus «ouvertes» que les conformations en étoile ou trans.

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Quantum Mechanical Calculations on Barriers to Internal Rotation. Part VI. Preceding paper, Ref. [35].     

Analytical study by SEM/EDX and metallographic techniques of materials used in the iron production process during the iberian period

This work is the archaeometric study of different types of materials used in iron production in the Iberian Period (6th-2nd century b.c.). The materials were recovered in several archaeological digs (which makes it possible to date the archaeological remains) on different sites in the Levante area of the Iberian Peninsula. The samples selected for this study belong to different materials used in the ancient iron production process such as ores, slags, finished objects, etc. The use of scanning electron microscopy (SEM) is proposed to observe surface images of the samples to determine their morphological, microstructural and topographic characteristics to obtain valuable information on the materials studied. The study also proposes chemical analysis of the elements in the sample by X-ray microanalysis (SEM/EDX) which provides both qualitative and quantitative information. The archaeometric study suggests that the iron obtained was very good quality, but the process was not economically efficient when viewed from today's perspective. Furthermore, the slag produced in the furnace can be related with the slag or impurities contained in the iron. It has also been possible to relate the ores and slag, some furnace conditions, the use of fluxes and also to differentiate types of slag.     

Kinetic Spectrophotometric Determination of Total Iron in Natural Water by Flow Injection Analysis Using On-Line Preconcentration

A new flow injection catalytic spectrophotometric method for on-line preconcentration and determination of total iron in natural water is described. The method is based on a combination of iron-catalyzed oxidation of diaminoditolyl by potassium bromate and the use of on-line preconcentration of iron onto 8-hydroxy-quinoline immobilized on silica gel. The corresponding calibration graph is linear over the range of 2.0–110ngmL^–1 for Fe(III) using a time-based technique for 5min preconcentration. The relative standard deviation of 11 measurements of 60ngmL^–1 Fe(III) was 0.67%. The method was applied to the determination of iron in natural water. The results obtained by the proposed method were compared with those obtained by ICP-AES. The t-test showed no significant differences between the two methods at a confidence level of 95%.     

The Inclusion Complex of Ferrocene with a Dithiolene Functionalized β-Cyclodextrin

A new cyclodextrin derivative with the anion side-arm, mono[6-deoxy-6-(2-sodium thio-1,2-dicyane ethylenylthio)]-cyclodextrin (6-mnt-CD), and its inclusion complex with ferrocene (6-mnt-CD/Fc), have been prepared and characterized by elemental analysis, IR spectroscopy, UV spectroscopy, mass spectrometry, ¹³C-NMR spectroscopy, thermogravimetry, and cyclic voltammetry (CV). Thermogravimetry analysis of the compound shows that the thermal stabilities of both the host and the guest in the inclusion complex have been greatly improved due to an additional interaction between the side-arm of the host and the guest. The interplay between the guest and the host with side-arm in the complex resulted in smaller positive potential shifts in CV compared to that in the inclusion complex CD/Fc.     

Sol-Gel Derived Titania/γ-Glycidoxypropyltrimethoxysilane and Methyltrimethoxysilane Hybrid Materials for Optical Waveguides

We report here on titania/organically modified silane hybrid materials produced by the sol-gel technique for optical waveguide applications. Acid catalyzed solutions of -glycidoxypropyltrimethoxysilane and methyltrimethoxysilane mixed with tetrapropylorthotitanate have been used as precursors for the hybrid materials. Waveguide films with a thickness about 1.3-m have been prepared on a silicon substrate by a single-coating process and low-temperature heat treatment. Atomic force microscopy (AFM), thermal gravimetric analysis (TGA), UV-visible spectroscopy (UV-VIS), and Fourier transform infrared (FTIR) spectroscopy have been used to investigate the optical and structural properties of these waveguide films. The results have shown that dense, pore-free, and highly transparent films can be obtained by low temperature heat treatment. The planar waveguide propagation loss of the hybrid films has also been measured.     

Determination of Iron in Tap and Waste Water Using Liquid–Liquid Extraction in a Flow-Injection System

A flow-injection procedure for the determination of iron(III) in water is described. The procedure is based on the formation of an ion pair between the tetraphenylarsonium (Ph₄As⁺) (TPA) or tetrabutylammonium (But₄N⁺) (TBA) cations and the tetrathiocyanatoferrate(III) complex (TTF). This ion pair is extracted with chloroform, and the absorbance of the organic phase is measured at 503nm (for Ph₄As⁺) or 475nm (for But₄N⁺). Iron concentrations higher than 0.9×10^–6molL^–1 (50µgL^–1) can be detected in the first case, with a relative standard deviation of 1.9% (n=12), a linear application rangeof between 1.34 and 54.0×10^–6molL^–1 (75–3015µgL^–1), and a sampling frequency of 30h^–1. For the ion pair with But₄N⁺, the detection limit is 0.52×10^–6molL^–1 (29µgL^–1), with a relative standard deviation of 1.6% and a linear application range between 0.73 and 54.0×10^–6molL^–1. Under the proposed working conditions, only Pd(IV), Cu(II) and Bi(III) interfere. With the application of the merging zones technique, considerable amounts of organic reagent can be saved. The TBA method was applied to the analysis of iron(III) in tap and industrial waste waters.     

Archaeometrical study of paleometallurgical materials from the archaeological site “Cerro de las Balsas — Chinchorro” (La Albufereta, Alacant, Spain)

An Iberian archaeological site located in the east of Spain is one of the most important cupellation centers found in the 4th century b.c. Different metallurgical materials were found in the archaeological site as minerals, cast slags, forged slags, metallic lead, cupella fragments and bronzes. Also was found reverbs remains used for cupper-based materials and cupellation procedure, and hearth forge remains for obtained iron material. The recuperated samples were studied by comparing samples of the same type of material by macroanalysis and microanalysis. The microanalysis and quantitation of the different archaeological materials was carried out by SEM/EDX. The information provides about the knowledge of a metallurgic process such as that of silver production by lead cupellation. The microanalysis results reflect the variety of elements that constitute the slags and other materials, and that come from the forge of the worked metallic materials. Also, the process cupellation was confirmed by the identification of lead and silver. The presence of forge slag corroborates the use of the great amount of recovered heart forges in the excavation like metallurgical structures for the iron work.     

Archaeometrical study of paleometallurgical materials from the archaeological site “Cerro de las Balsas — Chinchorro” (La Albufereta,Alacant, Spain)

An Iberian archaeological site located in the east of Spain is one of the most important cupellation centers found in the 4th century b.c. Different metallurgical materials were found in the archaeological site as minerals, cast slags, forged slags, metallic lead, cupella fragments and bronzes. Also was found reverbs remains used for cupper-based materials and cupellation procedure, and hearth forge remains for obtained iron material. The recuperated samples were studied by comparing samples of the same type of material by macroanalysis and microanalysis. The microanalysis and quantitation of the different archaeological materials was carried out by SEM/EDX. The information provides about the knowledge of a metallurgic process such as that of silver production by lead cupellation. The microanalysis results reflect the variety of elements that constitute the slags and other materials, and that come from the forge of the worked metallic materials. Also, the process cupellation was confirmed by the identification of lead and silver. The presence of forge slag corroborates the use of the great amount of recovered heart forges in the excavation like metallurgical structures for the iron work.     

From Molecular Fragments to Crystals: A UV Raman Spectroscopic Study on the Mechanism of Fe‐ZSM‐5 Synthesis

The nucleation process of iron‐exchanged zeolite Fe‐ZSM‐5, from the assembly of distorted tetrahedrally coordinated iron species and silicate rings in the precursor to the final Fe‐ZSM‐5 crystals, as well as variations in the coordination environment of iron, were studied by UV resonance Raman spectroscopy and complementary techniques.