• Bulletin of the Korean Chemical Society
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• 제8권3호
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• pp.168-170
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• 1987

The reaction between 1-benzyl-3-carbamoyl-1,4-dihydropyridine (BNAH) 1 and various 1-arylpyridinium salts 2, and the reaction between 1-(4-methylphenyl)-1,4-dihydropyridine 4b and 1-aryl-3-carbamoylpyridinium (1-arylnicotinamide) salts 5 were carried out. The extents of reaction in equilibrium were estimated by nmr integration data. The equilibrium constants for the reactions, K, and the standard Gibbs free energy changes for the reduction of the pyridinium salts to the corresponding 1,4-dihydropyridines ${\Delta}G^{\circ}'$ were evaluated. The Hammett plot of log K for the reaction between 1 and 2, and ${\Delta}G^{\circ}'$ against ${\sigma}_p$ of the substituents in 1-aryl moiety shows linear correlation with the reaction constant ${\rho}$ of 9.4 (for log K vs ${\sigma}_p$) and -54.5 KJ/mole (for ${\Delta}G^{\circ}'$ vs ${\sigma}_p$). It was found that 1-aryl-1,4-dihydropyridines have much higher reducing power than the corresponding 1-aryl-1,4-dihydronicotinamides, and the power is affected greatly by the electron-withdrawing ability of the substituents in aryl group. The reactions were utilized for preparation of 1,4-dihydropyridines bearing highly electron-withdrawing groups such as 4-nitrophenyl and 2,4-dinitrophenyl, which could not be obtained by conventional dithionite reduction of the corresponding pyridinium salts due to the base-labile nature of the salts.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.77-82
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• 1996

The study was performed for the purpose of obtaining the fundamental data to improve the durability of concrete structures due to de-icing salts. To assume the degree of concrete deterioration, soluble chloride content in concrete, the depth of carbonation and compressive strength of core specimens were measured. The porgress of corrosion of concrete bridge was electrochemically monitored. The results show that the concrete structure was deteriorated and reinforced steel in concrete was corroded due to de-icing salts.

• YAKHAK HOEJI
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• 제18권3호
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• pp.197-202
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• 1974

The data pf dosspcoatopm cpmstamts for aliphatic amines and quaternary ammonium-methylorange salts are based on the electrosatic theory of conductance. Dissociation constants for primary amines nad quaternary ammonium-methylorange salts (1$\times$10$^{-5}$~1$\times$10$^{-3}$ M) in nitrobenzene solution or water solution was evaluated from the relation of the concentration and the electric conduction and the electric conductance at $25^{\circ}C$ Plots of ${\delta}C$ against reciprocal conductance were linear ; hence the center-to-center distance of this salt was 1.75 $\AA$ in nitrobenzene solution.

• Fibers and Polymers
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• 제3권4호
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• pp.147-152
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• 2002

Copper (II) salts are used as metallizing agents in the synthesis of new non-genotoxic direct dyes for cotton. Specifically, cotton fabric is dyed with non-genotoxic disazo direct dyes and then treated with copper salts. The complexes are characterized by neutron activation analysis, absorption spectrometry and standard Salmonella mammalian mutagenicity assay, and the after-treated fabrics are evaluated for lightfastness and washfastness. Direct dyes possessing ortho-propoxy and ortho'-hydroxy substituted systems formed the corresponding nonmutagenic 1:2 dye:metal complex and undergo significant improvement in lightfastness following metallization.

• Bulletin of the Korean Chemical Society
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• 제33권3호
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• pp.881-884
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• 2012

We report a quantum chemical study of an extremely efficient nucleophilic aromatic fluorination in molten salts. We describe that the mechanism involves solvent anion interacting with the ion pair nucleophile $M^+F^-$(M = Na, K, Rb, Cs) to accelerate the reaction. We show that our proposed mechanism may well explain the excellent efficiency of molten salts for SNAr reactions, the relative efficacy of the metal cations, and also the observed large difference in rate constants in two molten salts $(n-C_4H_9)_4N^+\;CX_3SO_3^-$, (X=H, F) with slightly different sidechain ($-CH_3$ vs. $-CF_3$).

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2093-2097
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• 2009

Novel fluorescent anion chemosensors based on anthracene-isothiouronium derivatives were synthesized. Isomerism due to the intramolecular mobility in these isothiouronium salts was detected by $^1H$ NMR spectroscopy. The effect of the substituent, temperature and solvent on the isomerism was also examined. The anthracene-isothiouronium sensor showed significant fluorescent enhancement upon the addition of various anions such as fluoride, acetate, and dihydrogen phosphate, even in the presence of water.

• Applied Chemistry for Engineering
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• 제9권1호
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• pp.155-157
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• 1998

Dinitramide salts may be useful as effective solid oxidizers because of higher oxygen content than nitrate salts. 3-Nitramino-propanoate was given by base treatement in the retro-Michael reaction of N-nitro-4-azaheptanedioate, which was prepared by nitration of 4-azaheptanedioate using $HNO_3$-TFAA(trifiluoroacetic anhydride)-$Br_2$. The nitramino compound was treated wile $NO_2BF_4$ to give dinitramino compound which was subsequently reacted with bases to give dinitramide salts.

• Journal of the Korean Applied Science and Technology
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• 제12권2호
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• pp.115-120
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• 1995

Diazotization of 2-Amino-5-nitrophenol was Synthesized by the direct diazotization method. The diazonium salts are usually stabilized in the from of double salts. The double salts of zinc chloride are the Commonest, and the double salt method is Specially applicable to the yield-up of coupling. The azo dye(2-naphthol-1-(2'-diazo-5'-nitrophenol)) is Converted into a chromium Complex by heating($100^{\circ}C$) with chromic formate, and DMF. The removal of inorganic salts from dyestuffs was performed in DMF solvent. This effect was more pronounced. From these results, It was obtained to liquid dyestuffs of metal complex with High fastness and high adsorption.

• Environmental Engineering Research
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• 제15권1호
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• pp.41-48
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• 2010

This paper describes the influence of nutrient salts eluted from the bottom of a closed water area where polluted sediment has been deposited by inflowing river water. The elution pattern was monitored at our experimental facility. Both the sediment pore water and water above the bottom were sampled using a dialyzer sampler (peeper). The pore water of the eutrophicated sediment contained a large amount of nutrient salts, and the effect of elution was confined to a limited area of the bottom surface. The nutrient concentration of the sediment pore water was closely related to both the water temperature and dissolved oxygen (DO) concentration. The eluted nutrients from the sediment provided a source for phytoplankton and algae growth. This experimental data indicated that the water quality of the surface was not directly connected to the eluted nutrient salts, while it was indirectly affected by the total ecosystem, including all the organisms within an area and their environment.

• Membrane and Water Treatment
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• 제8권4호
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• pp.369-380
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• 2017

Performance evaluation of four commercially available tubular membranes (AFC 80, AFC 30, PU 608, ES 404) was accomplished in self-assembled membrane testing unit. Effects of varying transmembrane pressure, feed concentration and anion type were investigated. Aqueous solutions of salts such as calcium chloride, calcium sulfate, tin chloride and tin sulfate were prepared for this study. It was noted that the investigated parameters e.g., pressure and concentration had significant effects on membrane's performance. Nevertheless, anion type effectively played its role in the rejection of salts since salt having SO4-2 anions had a better rejection than the salts containing Cl-1. It is observed that rejection was dominated by Donnon exclusion for strongly charged nanofiltration membranes whereas for weakly charged ultrafiltration membranes, size exclusion was the key mechanism to reject the ions.