• Resources Recycling
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• v.23 no.6
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• pp.22-29
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• 2014

Recycling process of iron should be developed for efficient recovery of neodymium (Nd), rare metal, from acid-leaching solution of Nd magnet. In this study, $FeCl_3$ solution as iron source was used for preparation of iron nano particles with the condition of various factors, such as, reductant, and surfactant. $Na_4P_2O_7$ and Polyvinylpyrrolidone (PVP) as surfactants, $NaBH_4$ as reductant, and palladium chloride ($PdCl_2$) as a nucleation seed were used. Iron powder was analyzed by using XRD, SEM for measuring shape and size. Iron nano particles were prepared at the ratio of 1:5 (Fe (III) : $NaBH_4$). Size and shape of iron particles were round-form and 50 ~ 100 nm size. Zeta-potential of iron at the 100 mg/L of $Na_4P_2O_7$ was negative value, which was good for dispersion of metal particle. When $Na_4P_2O_7$ (100 mg/L), PVP($FeCl_3:PVP$ = 1 : 4, w/w) and Pd($FeCl_3:PdCl_2$ = 1 : 0.001, w/w) were used, iron nano particles which were round-shape, well-dispersed and near 100 nm-sized range. In this condition, $FeCl_3$ solution changed with spent Nd leachate solution, and then it is possible to be made round-formed iron nano particles at pH 9 and at the reaction bath over 20 L which is not include any surfactant.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.769-776
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• 2008

The stereoselective synthesis of chiral terminal epoxide is of immense interest due to their utility as versatile starting materials as well as chiral intermediates. In this study, new chiral Co(salen) complexes bearing cobalt(II) chloride, iron(III) chloride and zinc(II) nitrate have been synthesized and characterized. The mass and EXAFS spectra provided the direct evidence of formation of complex. Their catalytic activity and selectivity have been demonstrated for the asymmetric ring opening of terminal epoxides such as styrene oxide and phenylglycidylether by hydrolytic kinetic resolution technology and for the synthesis of glycidyl buthylate. The easily prepared complexes exhibited very high enantioselectivity for the asymmetric ring opening of epoxides with $H_2O$ nucleophile, providing enantiomerically enriched terminal epoxides (>99% ee). The newly synthesized chiral salen showed remakablely enhanced reactivity with substantially low loadings. The system described in this work is very efficient for the sinthesis of chiral epoxide and 1,2-diol intermediates.

• Journal of the Korean Chemical Society
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• v.68 no.2
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• pp.82-86
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• 2024

This paper presents the solid-state synthesis of insoluble Prussian blue (Fe₄[Fe(CN)₆]₃·xH₂O, PB) in a ball mill, utilizing the fundamental components of PB. Solid-state synthesis offers several advantages, such as being solvent-free, quantitative, and easily scalable for industrial production. Traditionally, the solid-state synthesis of PB has been limited to the reaction between iron(II/III) ions and hexacyanoferrate(II/III) complex ions, essentially an extension of the solution-based coprecipitation method to solid-state reaction. Taking a bottom-up approach, a reaction is designed where the reactants consist of the basic building blocks of PB: Fe²⁺ ions and CN^- ions. The reaction, with a molar ratio of Fe²⁺ and CN^- corresponding to 1:2.8, yields PB, while a ratio of 1:6.6 results in a mixture of potassium hexacyanoferrate(II) (K₄Fe(CN)₆), potassium chloride (KCl), and potassium cyanide (KCN). This synthetic approach holds promise for environmentally friendly methods to synthesize multimetallic PB with maximum entropy in nearly quantitative yield.

• Bulletin of the Korean Chemical Society
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• v.14 no.4
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• pp.444-449
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• 1993

Anaerobic oxidation of D-penicillamine by Fe(III) in acidic solution has been studied kinetically by the use of stopped-flow system. The reaction is biphasic with a rapid complexation of 1: 1 complex, $Fepen^+$ (pen= D-penicillamine dianion) which is then internally reduced to Fe(II) and disulfide. Rates of both the complexation and the redox process are pH dependent and also are affected by the presence of chloride ion. Different from the reaction of Cu(II) with D-penicillamine, partially oxidized mixed-valence complex is not formed even transiently in this reaction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6187-6195
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• 2012

Recycling process of iron should be developed for efficient recovery of neodymium(Nd), rare metal, from acid-leaching solution of neodymium magnet. In this study, $FeCl_3$ solution as iron source was used for synthesis of iron nanoparticle with the condition of various factors, etc, reductant, surfactant. $Na_4O_7P_2$ and polyvinylpyrrolidone(PVP) as surfactants, $NaBH_4$ as reductant, and palladium chloride($PdCl_2$) as a nucleation seed were used. Iron powder was analyzed with instruments of XRD, SEM and PSA for measuring shape and size. Iron nanoparticles were made at the ratio of 1 : 5(Fe (III) : $NaBH_4$) after 30 min of reduction time. Size and shape of iron particles synthesized were round-form and 50 nm ~ 100 nm size. Zeta-potential of iron at the 100 mg/L of $Na_4O_7P_2$ was negative value, which is good for dispersion of metal particle. When $Na_4O_7P_2$(100 mg/L), PVP($FeCl_3$ : PVP = 1 : 4, w/w) and Pd($FeCl_3$ : $PdCl_2$ = 1 : 0.001, w/w) were used, iron nanoparticles which are round-shape, well-dispersed, near 100 nm-sized can be made.

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.428-433
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• 1973

The quantitative separations of a mixture containing equal amount of each anion such as Si(IV), As(V), P(V), S(VI), W(VI) and Cr(VI) are carried out by the elution through 20${\times}3.14cm^2$ column of anion exchange resin, Dowex 1${\times}$8. The eluents are a mixture of 0.07 M hydrochloric acid and 0.03 M sodium chloride (pH = 1.30) for Si(IV), As(V) and P(V) species, a mixture of 0.6 M sodium chloride and 0.3 M sodium hydroxide for S(VI), W(VI) and Cr(VI) species, and 0.1 N sodium sulfite (pH = 3.48) for P(V) and As(V) species. The subsidiary anions in a standard mixture such as Si(IV), As(V), S(VI), P(V) and W(VI) are separated together from large amount of Fe(III) by the elution through 30cm${\times}3.14cm^2$ column of the resin, Dowex${\times}$50w${\times}$12, using a mixture of 0.1 M sodium nitrate and 2 percent dimethylsulfoxide aqueous solution as an eluent. Si(IV), As(V), S(VI), P(V) and W(VI) eluted together are separated quantitatively under the same conditions as in the separations of the anion mixture. By the conditions obtained in the separations of the standard mixture, Fe(III) and all of the subsidiary anions in steel are quantitatively separated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.511-517
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• 2002

The complex 1 $([Cp*Fe(CO)_2]_2-(\mu-CH=CH-CH=CH))$ which have butadiene as a bridge were synthesized from $Cp*(CO)_2FeK$ and cis-3,4-dichlorocyclobutene. The derivatives of complex 1 where one or two carbonyl groups are replaced by phosphine ligands have been prepared by photochemical substitution. The new derivatives $([Cp*Fe(L)_2]_2-(\mu-CH=CH-CH=CH))$ where L = $(Ph_2PCH_2CH_2PPh_2)$ and $([Cp*Fe(CO)(L)]_2-(\mu-CH=CH-CH=CH))$ where L : $PPh_3$ have been characterized from $^^1H-$, $^^13C-$,$^^31P-NMR$ and elemental analysis. Obtained complexes have been studied in electrochemical experiment and UV/VIS-near-IR. The mixed-valence radical cation forms of complex 2, 3 species were found to be delocalized as the Class III. Based on the separation of the waves ($\triangle E$ : 0.470 ~ 0.605 V), the efficiency of electronic communication between two metal centers of cation species leading to stabilization relative to neutral species. The phosphine-substitute complexes (2, 3) displays two reversible oxidation waves and oxidation state of metal centers-dependent color change, electrochromism, was observed from yellow to orange and deep blue in methylene chloride.

• Advances in nano research
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• v.2 no.4
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• pp.187-198
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• 2014

Magnetite nanoparticles (MNPs) of different sizes were synthesized by solvothermal process maintaining their stoichiometric composition and unique structural phase. Utilizing hydrated ferric (III) chloride as unique iron precursor, it was possible to synthesize sub-micrometric magnetite clusters of sizes in between 208 and 381 nm in controlled manner by controlling the concentration of sodium acetate in the reaction mixture. The sub-micrometer size nanoclusters consist of nanometric primary particles of 19 - 26.3 nm average size. The concentration of sodium acetate in reaction solution seen to control the final size of primary MNPs, and hence the size of sub-micrometric magnetite nanoclusters. All the samples revealed their superparamagnetic behavior with saturation magnetization ($M_s$) values in between 74.3 and 77.4 emu/g. $M_s$. The coercivity of the nanoclusters depends both on the size of the primary particles and impurity present in them. The mechanisms of formation and size control of the MNPs have been discussed.

• Resources Recycling
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• v.2 no.4
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• pp.27-32
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• 1993

A process has been studied to recover gallium from steelmaking dust which had several hundreds ppm of gallium. Aqueous solution containing 38 mg/l gallium was obtained by leaching of dust with 2.25 mol/l sulfuric acid. The leach liquor contained iron and zinc about 1,000 times greater than gallium. Gallium was then concentrated by ion exchanger of chelating resin with functional group of amino carboxylic acid after reduction of ferric ion to ferrous ion and pH adjustment. Gallium was concentrated to be 13 g/l in the resulting eluate by double ion exchanges. The liquor was further treated to remove impurities by solvent extraction technique empolying TOMAC as extractant. The galluim with 99% purity was finally obtainable.

• Journal of the Korean Applied Science and Technology
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• v.28 no.3
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• pp.335-344
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• 2011

The pearlesent pigment has received attention in a diversity of fields like cosmetics, inks, paints and so on. Ferric Ferrocyanide, one of the nano sized pearlescent pigment, is a kind of surface modification pigment that covers a metal oxidized substance or a coloring agent with uniform thickness. Characteristics of pearlescent pigment are various interference color, intense gloss effect and a three-dimensional effect. We synthesised the pearlesent pigment that ferric ferrocyanide can be deposited on the titania/mica surface by hydrothermal synthesis method. The process parameters are concentration of precursor, controlling pH and reaction temperature. The optimun conditions is that amount of iron(III) chloride hexahydrate is 3.1 wt% and amount of potassim ferrocynide trihydrate is 3.6 wt% in the started pH 4.5 at $70^{\circ}C$. The coating rate and coating efficiency of ferric ferrocyanide was about 1.47 % and 96.7 %, respectively. The synthesised pearlesent pigment was characterized by SEM, XRD, FT-IR and EDS.