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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Chemical Society
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Journal DOI :
Korean Chemical Society
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Volume & Issues
Volume 22, Issue 6 - Dec 1978
Volume 22, Issue 5 - Oct 1978
Volume 22, Issue 4 - Aug 1978
Volume 22, Issue 3 - Jun 1978
Volume 22, Issue 2 - Apr 1978
Volume 22, Issue 1 - Feb 1978
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Nucleophilic Displacement at Sulfur Center (X). Solvolysis of Phenylmethanesulfonyl Chloride
Ikchoon Lee ; Wang Ki Kim ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 111~116
The kinetics of phenylmethanesulfonyl chloride in methanol-water, ethanol-water, acetone-water and acetonitrile-water has been investigated. The rate was faster in protic solvents than in aprotic solvents while susceptibility of rate to the ionizing power, i. e., m of the Winstein plot and solvation number of the transition state were much smaller in protic solvents. This was considered in the light of initial state stabilization by hydrogen-bonding solvation of the protic solvents. It was concluded that the reaction proceeds by an
mechanism in which bond-formation precedes bond-breaking at the transition state in all solvent systems.
Application of the Expansion Method for Spherical Harmonics for Computation of Overlap Integrals in Molecular System
Sangwoon Ahn ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 117~127
Slater type orbitals, located at two different points A and B, are expressed in a common coordinate system by expanding the spherical harmonics and the radial part of these orbitals in terms of the reference point A. Master formulas for two center overlap integrals are derived, using the general expansion formulas of slater type atomic orbitals. Two center overlap integrals for
molecules are evaluated, using master formulas for two center overlap integrals. The results are in agreement with those of two center overlap integrals of Mulliken.
Errors in Potentiometric End-Point of Redox Titrations Determined by Zero Second Derivative Method
Q. Won Choi ; Kyong Ryul Kim ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 128~132
The potentiometric end-point of redox titrations determined by nulling the second derivative of the titration curve by numerical differentiation method is analyzed by using an electronic digital computer. The error involved in the method is shown to be dependent on the location of the equivalence point in the titrant addition increment that encompasses the latter. The error increases as the equivalence point moves away from the mid-point of the increment toward a maximum value that is as great as a half of the increment. Therefore, when the numerical differentiation method is used to null the second derivative, the end-point should be compared with the steepest point of the titration curve or diluted titrant should be used in the vicinity of the end-point.
Metal Complexes Containing Multidentate Ligands (II). Dichloro and Dinitro Coblat (III) Complexes of 1,10-Dipropyl-5R-methyltriethylenetetraamine
Moo-Jin Jun ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 133~137
A straight chain flexible tetraamine ligand, 1,l0-dipropyl-5R-methyltriethylenetetraamine(R-
metrien) has been synthesized, and the dichloro and dinitro cobalt(III) complexes of this ligand have been prepared. The ligand has been expected to show a topological preference for the trans isomer. As expected, only trans geometrical isomers have been obtained and their structures have been elucidated via elemental analyses, nmr, electronic absorption and CD data.
The Origin of Diamonds (II). Theoretical Study
R. Everett Langford ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 138~148
A discussion of the various theories of natural diamond formation is given. Experimental data from mass spectrometric analysis of included gases is related to theoretical data on the carbon-hydrogen-oxygen gas phase under geologic conditions.Possible temperature-pressure conditions for natural diamond formation are proposed.
Kinetics and Mechanism of the Hydrolysis of N-(p-Nitrophenyl)-benzohydrazonyl Azide Derivatives
Nack-Do Sung ; Ki-Sung Kwon ; Tae-Rin Kim ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 150~157
The rate constants for the hydrolysis of the derivatives of N-(p-nitrophenyl)-benzohydrazonyl azide (p-
, p-Cl, p-Br) have been determined by UV spectrophotometry in 50% dioxane-water at
and a rate equation which can be applied over wide pH range was obtained. Below pH 5, the rate of hydrolysis of hydrazonyl azides is accelerated by electron-donating group (
= -0.47), whereas at the pH values greater than 7, the
-value is 0.68. The effect of salt, solvent, substituent and azide ion on the rate of hydrolysis are rationalized in terms of
mechanism; below pH 5, the hydrolysis proceed through
, however, above pH 7, the hydrolysis is started by the attack of hydroxide ion and in the range of pH 5∼7, these two reactions occur competitively.
Thermal Rearrangement of 1,1-Disubstituted 2-Vinylcyclopropanes to 4,4-Disubstituted Cyclopentenes
Iwhan Cho ; Kwang-Duk Ahn ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 158~163
The four 1,1-disubstituted 2-vinylcyclopropanes, 1,1-diphenyl-2-vinylcyclopropane (1a), 1,1-dicyano-2-vinylcyclopropane(1b), ethyl 1-cyano-2-vinylcyclopropanecarboxylate(1c), and diethyl 2-vinylcyclopropane-1,1-dicarboxylate(1d) rearranged below
to the corresponding 4,4-disubstituted cyclopentenes, 4,4-diphenylcyclopentene(2a), 3-cyclopentene-1,1-dicarboxylate(2d). Diphenpyl derivative 1a rearranged almost quantitatively to 4,4-diphenylcyclopentene(2a) at the temperature of
. Although dicyano derivative 1b in solution underwent the thermal rearrangement at rather low temperature of
, the other vinylcyclopropanes, 1c and 1d, in solution rearranged thermally above
. In the thermal reaction of 1b, 1c, and 1d considerable amounts of polymers 3 were also produced. Also detected product was the ring-opened diene, ethyl 2-cyano-2,4-hexadienoate(4), in case of the pyrolysis of 1c. The observed facile rearrangement of disubstituted vinylcyclopropanes was explained by the radical stabilization effect of substituents on the diradical intermediates 5.
Effect of External and Intramolecular Nucleophiles on Nature of Products of Carboxypeptidase A-Catalyzed Hydrolysis of Esters. Attempted Trapping of Acyl-Enzyme Intermediate
Junghun Suh ; Emil Thomas Kaiser ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 164~172
Carboxypeptidase A-catalyzed hydrolysis of ester substrates was carried out at room temperature in the presence of a number of external reagents. If the acyl-enzyme intermediate, an anhydride, is attacked by the external reagents, products formed by trapping at the acyl portion or at the enzyme portion of the anhydride group can be obtained. Examination of the uv/vis spectral properties of the reaction products and of changes in enzyme activity indicated that such trapping reactions did not occur. Also performed was evaluation of enzymatic rate parameters for the the hydrolysis of O-(o-hydroxyphenylacetyl)-L-
-phenyllactate. Detection of 2-coumaranone possibly formed by attack of the o-hydroxy group as an intramolecular trapping group at the acyl-enzyme intermediate was tried, but no evidences for the intramolecular trapping reaction were obtained. Failure to trap the intermediate was discussed in terms of steric hindrance imposed on the approach of the trapping reagents to the anhydride group of the acyl-enzyme intermediate and of the fast enzymatic breakdown of the intermediate.
Formaton of Macrozwitterions in the Cationic Polymerization of Propylene Sulfide Initiated with o-Sulfobenzoic Anhydride
Man Jung Han ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 173~183
Bulk polymerization of propylene sulfide with o-sulfobenzoic anhydride as initiator was carried out and the polymerization proceeded by a zwitterionic mechanism. Chemical and spectroscopic investigation of the purified polymer revealed that the polymer contained two end groups-thiolester of benzoic acid o-sulfonate anions and acyclic tert-sulfonium ions which were formed by termination of episulfonium ions with sulfide groups in the polymer chains. The concentration of sulfonate anions was nearly the same as the concentration of acyclic tert-sulfonium ions, as expected for macrozwitterions. The cocatalysis mechanism by a trace of water was excluded and the other possible mechanisms were discussed on the basis of end group analysis.
Studies on the Synthesis of Aluminum Chloride Polymeric Catalysts and Its Catalytic Effect for the Esterification
Kyu Ja Whang ; Yong Keun Lee ;
Journal of the Korean Chemical Society, volume 22, issue 3, 1978, Pages 184~193
Various aluminum chloride polymeric catalysts have been prepared by the reaction of anhydrous aluminum chloride with styrene-divinylbenzene copolymer bead in the carbon disulfide solvent. The shapes of aluminum chloride polymeric catalysts have been investigated by the use of optical microscope, scanning electron microscope and analysis of atomic absorption and electron microprobe X-ray. The catalytic effect of aluminurn chloride polymeric catalysts in the process of esterification of various organic acids with several aliphatic and aromatic alcohols have been studied.