• Journal of the Korean Ceramic Society
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• v.13 no.2
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• pp.3-7
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• 1976

Influences of chlorides(CaCl2, MgCl2, NaCl) on the colouring effect of Fe component in white portland cement was investigated. Chlorides enhance the whiteness of the white portland cement owing to volatilization of Fe2O3 and translation of ferrite composition toward C2F. This translation is caused by consumption of alumina at the formation of C12A7, the formation of which is promoted in the presence of chloride. With decrease of p in ferrite composition C6F1-pAp, transfer of Fe3+ from 4 to 6 coordinated cite is occurred, and as a result, whiteness is raised. Hydration process of the cement containing a small amount of chloride differs little from the one without chloride.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.5
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• pp.309-312
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• 2003

The transformation capacity (T$\_$c/) of Methylosinus trichosporium OB3b in the degradation of ethylene chlorides was determined by measuring the decrease of soluble methane monooxygenase (sMMO) activity of resting cells in batch experiments. All measurements of sMMO activity were taken in the presence of 20 mM formate to avoid the deficiency of reducing power, and within 2 hrs to avoid the effect of natural inactivation from instability of the resting cells. The constant T$\_$c/ values of 0.58 ${\pm}$ 0.132 and 0.80 ${\pm}$ 0.17 ${\mu}$mol/mg cell were obtained for trichloroethylene (TCE) and 1,2-dichloroethylene (cis and trans-1,2-DCE), respectively, regardless of their concentrations. The transformation capacity measured by this method can be used to predict the amount of cells that should be stimulated in in-situ bioremediation.

• Journal of the Korea Concrete Institute
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• v.11 no.3
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• pp.193-203
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• 1999

The corrosion of steel reinforcements in concrete is of great concern in recent years. This study is focused on the corrosion behavior of steel bars induced by internal chlorides in concrete at early ages. The main objective of this study is to determine the chloride thresholds causing depassivation and active corrosion of steel reinforcement in concrete. To examine the threshold concentration of chloride ion, the half-cell potential, chemical composition of expressed pore solutions of concrete and the rate of corosion area of the specimens were measured. Major variables include the added amount of chlorides in concrete, types of binders, and water-to-binder ration. From the present comprehensive experimental results, the factors influencing chloride-induced corrosion are investigated, and the chloride thresholds causing active corrosion of steel bars are proposed. The present study will enable to specify the realistic chloride limit in concrete which can be used in the future technical specification.

• Bulletin of the Korean Chemical Society
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• v.3 no.3
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• pp.110-115
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• 1982

Thermochemistry and photochemistry of picolyl chlorides were studied. The thermal reaction of 2-picolyl chloride in benzene afforded intermolecular condensation product. In the case of 3-picolyl chloride, this type of the reaction did not occur, but polymers were obtained. A cyclic hexamer, suggested by a molecular model, was not formed because of the steric strain and low reactivity. The thermal reaction of 4-picolyl chloride gave a cyclic hexamer as well as a polymer. The cyclic hexamer, identified by NMR spectrum, showed ${\lambda}_{max}$ at 460 nm. The cyclic hexamer was cloven to the linear structure. Photolysis of 2-picolyl chloride at 253.7 nm gave a para-isomer followed by polymerization. When a methyl hydrogen of 2-methylpyridine is substituted by $CH_3O$, iso-PrO, and EtO group, the photoisomerization to the corresponding anilines or para-substituted pyridines did not occur within the range of the time used for 2-picolyl chloride. Thermolysis of picolyl chlorides in an acidic methanol solution did not afford any product.

• Bulletin of the Korean Chemical Society
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• v.7 no.6
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• pp.472-477
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• 1986

The reaction of (E)- or (Z)-1-alkenylmercuric chlorides with acrylic acid derivatives in the presence of 10 mol% of lithium trichloropalladate ($LiPdCl_3$) and an equimolar amount of cupric chloride, as a reoxidant for the palladium, in acetonitrile at room temperature gave the corresponding (E,E)- or (E,Z)-2,4-dienoic acid derivatives stereospecifically in moderate to good yields. The reaction of (E)- or (Z)-3-chloromercuripropenoic acid with olefins under the reaction condintion described above similarly gave good yields of (E,E)- or (Z,E)-2,4-dienoic acids stereospecifically. A side reaction, the homocoupling of alkenylmercuric chlorides, could be minimized by employing the condition described above. However, in the reaction of 3-chloromercuripropenoic acid with olefins under the present condition, the homocoupled side reaction product was not produced.

• Bulletin of the Korean Chemical Society
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• v.13 no.6
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• pp.599-605
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• 1992

Rate constants of methanolyses of para-Z-substituted benzenesulfonyl chlorides have been determined in various isodielectric solvent mixtures. A third-order kinetic behavior has been observed in the methanolysis of p-nitrobenzenesulfonyl chloride in methanol-nitromethane mixture from the correlation figure of logarithms of rate constants were plotted against Y-values based on solvolyses of 1-adamantyl tosylate. $S_N1$-$S_N2$ mixing mechanisms are favored by neutral or weak electron-donating and weak electron-withdrawing substituents of p-Z-substituted benzenesulfonyl chlorides in methanol-nitrobenzene mixture. While the methanolyses of para-Z-substituted benzenesulfonyl chlorides in methanol-ethylene glycol solvent mixture are appropriate for $S_N2$ mechanism from the mechanistic criterion by means of m-values.

• Bulletin of the Korean Chemical Society
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• v.5 no.5
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• pp.187-190
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• 1984

Reaction of acid chlorides with primary alcohols, secondary alcohols, and aryl alcohols in the presence of a catalytic amount of zinc chloride gave the corresponding esters in high yields, whereas the reaction with tertiary alcohols failed to give the esters due to the fast solvolytic reactions of tertiary alcohols with hydrogen chloride generated from the reaction. The use of molecular sieves as a scavenger for hydrogen chloride was found to be moderately effective in the reaction of mesitoyl chloride with tertiary alcohols. Reaction of acid chlorides with thiols in the presence of zinc chloride in acetonitrile proceeded cleanly, yielding the corresponding thiol esters in high yields.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.127-130
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• 1999

Physical properties and microstructure of slag blended cement were investigated to evaluate the influence of sulphates and chlorides. The compressive strength developed as high chloride content dust and gypsum added and accordingly the microstructure modification was showed. The deviation of pore size distribution and hydrates was also observed. From these results we discussed optimum condition of gypsum and high chloride content dust leading to physical properties in this study.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.207-210
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• 1998

Recently it has become general to use the inhibitor with a view to protecting corrosion of rebars in concrete. So, it needs to study effect of protection and reasonable dosage of inhibitor to reduce corrosion of rebar in concrete containing chlorides. In this study, we estimate the corrosion rate of rebar in mortar by Tafel extrapolation method, one of electrochemical techniques, and the reasonable dosage of inhibitor for different chlorides environments.

• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.47-50
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• 1989

The methanolysis reactions of phenylacetyl chlorides have been investigated in methanol-acetonitrile mixtures at temperatures ranging - $15.0-0.0^{\circ}C.$ Substituent and solvent effects on the rate supported an associative $S_N2$ mechanism for the solvolysis. Activation parameters indicated that the reaction is entropy controlled, while the a/s ratios of the Taft's solvactochromic correlation proved to be remarkably constant with a typical value of 0.50 that is consistent for the reactions proceeding by a typical $S_N2$ path.