• Polymer(Korea)
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• v.30 no.3
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• pp.224-229
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• 2006

Quaternary ammonium salt terminated silane was prepared from aminopropyldimethylethoxysilane with methyliodide and ionized 7,7,8,8-tetracyanoquinodimethane $(Li^+TCNQ^-)$ was prepared from TCNQ with methyliodide and lithium iodide. Quaternary ammonium salt silane-TCNQ adduct (ST) was prepared by reacting quaternary ammonium salt terminated silane with $Li^+TCNQ^-$ solution. Poly (dimethylsiloxane)-ST adduct (PST) was prepared by condensation of $\alpha,\omega-hydroxyl$ group terminated poly (dimethylsiloxane) (PDMS) with ST. Maleated polyethylene modified with PDMS (PST-g-MPE) was prepared by melt polymerization of maleated PE and PST in internal mixer and PST-g-MPE/carbon black (CB) and MPE/CB composites were prepared by compounding PST with MPE and PST-g-MPE, respectively. The thermal and mechanical properties of the composites were measured and dispersion characteristics of CB in matrix rosins show that the dispersion of CB in PST-g-MPE/CB was better than that of MPE/CB composite.

• Corrosion Science and Technology
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• v.6 no.6
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• pp.304-307
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• 2007

As to the reflection electrode of LCD (liquid crystal displays), silver-copper-gold alloy (hereafter, it is called as ACA (Ag98%, Cu1%, Au1%)) is an effective material of which weathering resistance can be improved more compared with pure silver. However, there is a problem that gold remains on the substrate as residues when ACA is etched in cerium ammonium nitrate solution or phosphoric acid. Gold can not be etched in these etchants as readily as the other two alloying elements. Gold residue has actually been removed physically by brushing etc. This procedure causes damage to the display elements. Another etchant of iodine/potassium iodide generally known as one of the gold etchants can not give precise etch pattern because of remarkable difference in etching rates among silver, copper and gold. The purpose of this research is to obtain a practical etchant for ACA alloy. The results are as follows. The cyanogen complex salt of gold generates when cyanide is used as the etchant, in which gold dissolves considerably. Oxygen reduction is important as the cathodic reaction in the dissolution of gold. A new etchant of sodium cyanide / potassium ferricyanide whose cathodic reduction is stronger than oxygen, can give precise etch patterns in ACA alloy swiftly at room temperature.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.377-380
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• 2015

In this paper, we have investigated the optimization of $I_2$ recovery process from $NH_4I$ solution, which is generated as by-product during the amination reaction of p-diiodobenzene (PDIB) for p-phenylenediamine (PPD) synthesis. The recovered $I_2$ is then recycled as a raw material for PDIB synthesis. We have employed a cation exchange resin to recover $I_2$ from $NH_4I$ sample solution, and determined the breakthrough point and exchange capacity from the breakthrough curve. Furthermore, we have suggested optimum conditions of our $I_2$ recovery process by measuring the purity and yield of recovered $I_2$ with respect to the concentrations of $NH_4I$ and oxidant ($H_2O_2$) solutions, the oxidation time, and the temperature of drying process. Finally, the yield and purity as high as 94.96% and 96.65%, respectively were obtained by reusing the residual solution still containing unrecovered iodide ions.

• Analytical Science and Technology
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• v.26 no.1
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• pp.11-18
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• 2013

Perchlorate ($ClO{_4}^-$) is the material that is used as propellants of rockets and material of explosive as a form of ammonium perchlorate salts. Ammonium perchlorate solution of high concentration is recovered from expired rocket through demilitarization process by the water-jet method. If people take perchlorate in food and water, it interferes with adsorption of iodide which is the substance needed to synthesize thyroid hormone in the thyroid gland. It has an bad influence upon disturbing pregnancy and synthesis of growth hormone. So the effective method is necessary to remove perchlorate anion in water. By considering economic aspect, we studied effective desorption (regeneration) of perchlorate anion from adsorbent with studies on removal and adsorption of perchlorate anion. Desorption experiment was conducted as batch type. Depending on various conditions (concentration, pH, cation anion form) elution, we evaluated amount, efficiency of desorption(amount of adsorption/desorption ${\times}$ 100). Also, research confirmed the efficiency of mixed resins between anion exchange resin and activated carbon and expected synergic effect from advantages of both adsorbents.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.3923-3927
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• 2011

A noble method for pre-concentration and speciation of ultra trace As (III) and As (V) in urine and whole blood samples based on dispersive liquid-liquid microextraction (DLLME) has been developed. In this method, As (III) was complexed with ammonium pyrrolidine dithiocarbamate at pH = 4 and Then, As (III) was extracted into the ionic liquid (IL). Finally, As (III) was back-extracted from the IL with hydrochloric acid (HCl) and its concentration was determined by flow injection coupled with hydride generation atomic absorption spectrometry (FI-HGAAS). Total amount of arsenic was determined by reducing As (V) to As (III) with potassium iodide (KI) and ascorbic acid in HCl solution and then, As (V) was calculated by the subtracting the total arsenic and As (III) content. Under the optimum conditions, for 5-15 mL of blood and urine samples, the detection limit ($3{\sigma}$) and linear range were achieved 5 ng $L^{-1}$ and 0.02-10 ${\mu}g\;L^{-1}$, respectively. The method was applied successfully to the speciation and determination of As (III) and As (V) in biological samples of multiple sclerosis patients with suitable precision results (RSD < 5%). Validation of the methodology was performed by the standard reference material (CRM).

• Journal of the Korean Applied Science and Technology
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• v.6 no.2
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• pp.29-37
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• 1989

Using the quarternary ammonium salts as phase transfer catalyst, the nucleophilic substitution reaction of 1-chlorooctane with sodium-cyanide was investigate kinetically with respect to the formation of octanenitrile. The product was analyzed with gas chromatograph, and quantity of octanenitrile was measured. The reaction condition was considered by the effect of the reaction temperature, of the species and the amount of catalyst, of the speed of strirring, and of the concentration of reactants. The reaction was carried out in the first order on the concentration of 1-chlorooctane and sodium cyanide, respectively. The over-all order was 2nd. The activation energies for the nucleophilic substitution reaction of 1-chlorooctane and 1-bromooctane under tetrabutylammonium hydrogen-sulfate were calculated as 2.05 and 10.08kcal/mol, respectively. The effect of various caltalysts was decreased in the order of tetrabutylammonium bromide, terabutylammonium, tetrabutylammonium hydrogensulfate, and tetrabutylammonium iodide. The reaction rate was dependent on the concentration of sodium-cyanide dissolved in the aqueous phase, and the good result was shown when the mol ratio between 1-chlorooctane and sodium cyanide was one per three.

• Archives of Pharmacal Research
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• v.17 no.4
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• pp.281-283
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• 1994

5-sec-butylthiomethyl-5-alkyl (methyl or phenyl) hydantoins (3-x) were prepared by the reaction of sec-buylthiomethyl alkyl (methyl or phenyl) ketone (1-2), potassium cyanide and ammonium carbonate. 3-(2-Bromoethyl) hydantoins (5-6) were the reaction products of 5-sec-buythiomethyl-5-alkyl (methyl or phenyl) hydantoin and 1, 2-dibromothane in the presence of potassium hydroxide. Alkylation of 5 and 6 with an excess of alkyl (methyl or ethyl iodide in THF with sodium hydride as base gave three 1-alkyl (methyl or ethyl)-3-(2-bromoethyl) hydantoins (7-9). Treatment of the 2-bromothyl group with potassium thioacelate and triethylamine gave three 1-alkyl (methyl or ethyl)-3-92-acetylthioethyl) hydantoins (10-12). Hydrolysis of the 2-acetylthiuoethyl group with sodium hydroxide in methanol afforded the three 1-alkyl (methyl or ethyl)-3-(2-mercaptorthyl) hydantoins.

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.547-551
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• 2003

In the present work, the interaction of three water soluble porphyrins, tetra(p-trimethyle) ammonium phenyl porphyrin iodide (TAPP) as a cationic porphyrin, tetra sodium meso-tetrakis (p-sulphonato phenyle) porphyrin (TSPP) as an anionic porphyrin and manganese tetrakis (p-sulphonato phenyl) porphinato acetate (MnTSPP) as a metal porphyrin, with histone H₂B have been studied by isothermal titration microcalorimetry at 8 mM phosphate buffer, pH 6.8 and 27 °C. The values of binding constant, entropy, enthalpy and Gibbs free energy changes for binding of the first MnTSPP, and first and second TSPP and TAPP molecules were estimated from microcalorimetric data analysis. The results represent that the process is both entropy and enthalpy driven and histone induces self-aggregation of the porphyrins. The results indicate that both columbic and hydrophobic interactions act as self-aggregation driving forces for the formation of aggregates around histone.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.8
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• pp.542-548
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• 2014

Effects of bromide ($Br^-$) and iodide ($I^-$) concentrations, chlorine ($Cl_2$) doses, pH, temperature, ammonia nitrogen concentrations, reaction times and water characteristics on formation of iodinated trihalomethanes (I-THMs) during oxidation of iodide containing water with chlorine were investigated in this study. Results showed that the yields of I-THMs increased with the high bromide and iodide level during chlorination. The elevated pH significantly increased the yields of I-THMs during chlorination. The formation of I-THMs was higher at $20^{\circ}C$ than $4^{\circ}C$, $10^{\circ}C$ and $30^{\circ}C$. In chloramination study, addition of ammonium chloride ($NH_4Cl$) markedly increased the formation of I-THMs. Among the water samples collected from seven water sources including wastewater treatment plant (WWTP) effluent water (EfOM water), prepared humic containing water (HA water) and algal organic matter (AOM) containing water (AOM water), EfOM water generated the highest yields of I-THMs ($12.31{\mu}g/mg$ DOC), followed by HA water ($4.96{\mu}g/mg$ DOC), while AOM water produced the lowest yields of I-THMs ($0.99{\mu}g/mg$ DOC). $SUVA_{254}$ values of EfOM water, HA water and AOM water were $1.38L/mg{\cdot}m$, $4.96L/mg{\cdot}m$ and $0.97L/mg{\cdot}m$, respectively. The I-THMs yields had a low correlation with $SUVA_{254}$ values ($r^2$ = 0.002).

• Journal of the Korean Chemical Society
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• v.23 no.4
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• pp.237-242
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• 1979

The equivalent conductances of sodium, potassium, ammonium, tetramethylammonium, triethylammonium, diethylammonium and ethylammonium iodide, and picrate salts of sodium and potassium in ethylene carbonate have been measured at 40.0 $^{\circ}C. The limiting equivalent conductances of the salts have been computed by Fuoss-Onsager-Skinner equation. The limiting ionic equivalent conductances of $Na^+,\;K^+,\;and\;NH^+$ are in order of $Na^+ which is the reverse order of solvation for the ions in any solution, And the order of limiting ionic equivalent conductances for alkylammonium ions is $(C_2H_5)_4N^+<(C_2H_5)_3NH^+<(CH_3)_4N^+<(C_2H_5)_2NH_2^+<(C_2H_5)NH_3^+$ which coincides with the order of mass transfer. From the dissociation constants of the saltss determinde by Fuoss-Kraus method, it is found that ethyene carbonate is a good ionizing solvent for the salts. In addition, Stokes radii and effective fadii of ions have been calculated by Stokes law and Nightingale method, repectively. From the results, it appears tha alkylammonium ions and picrate ion seem to be not solvated, and tha iodide ion is fairly solvated in ethylene carbonate.