• Title/Summary/Keyword: 평형상수

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The Effect of Solvent Density on the Ethyl Acetoaceate Tautomerism (에틸 아세토아세테이트 토토머리즘 평형 상수의 밀도 의존성)

  • Park, YoonKook
    • Applied Chemistry for Engineering
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    • v.17 no.3
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    • pp.291-295
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    • 2006
  • The keto-enol tautomeric equilibrium constant, K, of ethyl acetoacetate in compressed and supercritical carbon dioxide was determined by using FT-IR (Fourier transform infrared) spectroscopy at three different temperatures. In order to investigate the effect of solvent density, the $CO_{2}$ pressure was systematically changed at a constant temperature. As the $CO_{2}$ density is increased, the amount of keto tautomer is increased, causing the K value to decrease. The modified lattice fluid hydrogen bonding theory has been applied to investigate the effect of density on the K.

신경망에 의한 토카막 플라즈마의 위치, 형상 및 평형상수 계산

  • 오병훈;이광원;한장민;최병호
    • Proceedings of the Korean Nuclear Society Conference
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    • 1997.05b
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    • pp.571-576
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    • 1997
  • 비원형 토카막 플라즈마의 위치, 형상 및 평형상수들을 신경망 해석법을 이용하여 계산하고 그 결과를 평가하였다. KT-2 토카막에서 가능한 245개의 평형계산 결과에 의해 학습된 신경망은 32개의 자장탐침과 15개의 자속 루프(flux loop)데서의 자장 값들이 입력으로 주어지면, 그에 따른 플라즈마 위치, 형상 및 평형관련 상수들의 값들을 즉시 구해낼 수 있다. 계산결과의 정확성과 앞으로의 연구 방향 등에 대하여 논의한다.

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Comparison and Estimation of Equilibrium Constants for Deoxyribonucleosides by Plate Theory and Moment Method (단이론과 모멘트방법을 이용한 데옥시리보뉴클레오사이드의 평형상수의 계산 및 비교)

  • Lee, Ju Weon;Row, Kyung Ho
    • Applied Chemistry for Engineering
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    • v.8 no.3
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    • pp.403-409
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    • 1997
  • The equilibrium constants of five deoxyribonucleosides (dDyd, dUrd, dGuo, dThd, dAdo) were estimated by the plate theory and the moment method under isocratic conditions of the Reversed-Phase High Performance Liquid Chromatography (RP-HPLC). The mobile phase in this system was composed of water and organic modifiers(acetonitrile and methanol) The plate theory of linear adsorption isotherm was treated on the basis of continuous flow of eluent through the plates of the column. The moment method was utilized to find the equilibrium constant from the first absolute moment of experimental data. The equilibrium constants of five deoxyribonucleosides in the two methods were very close, and also the equilibrium constants calculated by capacity factor were similar to those by both the plate theory and the moment method. The equilibrium constant was expressed as a semi-log function of the quantity of organic modifier. Excellent agreements between the calculated elusion profile by the plate theory and the experimental data were observed.

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A Study on Complexation of Cu(Ⅱ) Ion with Hydrazide Schiff Base Lignads (Cu(Ⅱ) 이온과 Hydrazide Schiff Base 리간드와의 착물형성에 관한 연구)

  • Cho, Hwee Kyung;Cha, Bun Hee;Hur, Young Ae;Choi, Kyu Seong
    • Journal of the Korean Chemical Society
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    • v.39 no.4
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    • pp.281-287
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    • 1995
  • Copper(Ⅱ) complexes with N,N'-oxalylbis(salicylaldehydehydrazone), N,N'-malonylbis(salicylaldehydehydrazone) and N,N'-succinylbis(salicylaldehydehydrazone) have been prepared in 95% DMF. Their protonation and stability constants were investigated by potentiometric titration. We observed that MBSH ligand showed the largest protonation constant. The values of the protonation constants among three different ligands were increased as following order SBSH < OBSH < MBSH. However, the increasing order of stability constants was somewhat different such as Cu(Ⅱ)-SBSH < Cu(Ⅱ)-MBSH < Cu(Ⅱ)-OBSH. In addition, thermodynamic parameters, ΔH and ΔS of Cu(Ⅱ) complexes have been studied. As a result, we found the SBSH ligand produced the best stable copper (Ⅱ) complex.

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Calculation of the Activity Coefficients of Ions in Weak Electrolyte Solutions (묽은 전해질용액에서 이온의 활동도계수 계산)

  • Lee, Man-Seung;Son, Seong Ho
    • Resources Recycling
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    • v.27 no.5
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    • pp.9-13
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    • 2018
  • The equilibrium constant of a chemical reaction is related to the standard Gibbs free energy change. Since equilibrium constant is defined as the ratio of the activities of the chemical species, it is necessary to consider the non-ideal behavior of the solutes as ionic strength of the solution increases. In this paper, the derivation of Debye-$H{\ddot{u}}ckel$ limiting law and its modification by which the activity coefficient of an ion can be calculated was explained. Moreover, the method to obtain the activity coefficient of an ion from the experimentally determined mean activity coefficients of an electrolyte was explained.

Ionic Equilibria and Comparison of Solvent Extraction of Cobalt(II) and Manganese(II) from HCl Solution by Alamine336 (염산용액(鹽酸溶液)에서 코발트(II)와 망간(II)의 이온 평형(平衡) 및 Alamine336에 의한 용매추출(溶媒抽出) 비교(比較))

  • Lee, Man-Seung;Shin, Shun-Myung
    • Resources Recycling
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    • v.19 no.4
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    • pp.29-34
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    • 2010
  • Distribution diagram of $CoCl_2$ and $MnCl_2$ was obtained by analyzing ionic equilibria of the two metals in HCl solution. In the HCl concentration range of 4 and 10 M, most of cobalt exists as $CoCl_2$, whereas Mn exists $MnCl_{3}^-$ and $MnCl_2$. Extraction isotherm of Co(II) and Mn(II) was calculated by using the equilibrium constant for the solvent extraction of the two metals by Alamine336. Although the equilibrium constant for the solvent extraction of Mn was higher than that of Co, extraction isotherm indicated that cobalt could be extracted more efficiently than manganese at the same initial extraction conditions.

Numerical Study of Chemical Reaction for Liquid Rocket Propellant Using Equilibrium Constant (평형상수를 이용한 액체로켓 추진제의 화학반응 수치연구)

  • Jang, Yo Han;Lee, Kyun Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.4
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    • pp.333-342
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    • 2016
  • Liquid rocket propulsion is a system that produces required thrust for satellites and space launch vehicles by using chemical reactions of a liquid fuel and a liquid oxidizer. Monomethylhydrazine/dinitrogen tetroxide, liquid hydrogen/liquid oxygen and RP-1/liquid oxygen are typical combinations of liquid propellants commonly used for the liquid rocket propulsion system. The objective of the present study is to investigate useful design and performance data of liquid rocket engine by conducting a numerical analysis of thermochemical reactions of liquid rocket propellants. For this, final products and chemical compositions of three liquid propellant combinations are calculated using equilibrium constants of major elementary equilibrium reactions when reactants remain in chemical equilibrium state after combustion process. In addition, flame temperature and specific impulse are estimated.

Solvent Extraction of Nd from Chloride Solution with PC88A (염산용액에서 PC88A에 의한 Nd의 용매추출)

  • Lee Gwang-Seop;Lee Jin-Young;Kim Sung-Don;Kim Joon-Soo;Lee Man-Seung
    • Resources Recycling
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    • v.13 no.4
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    • pp.39-45
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    • 2004
  • Solvent extraction experiments of Nd from chloride solution were studied with PC88A. Solvent extraction reaction of Nd with PC88A and the equilibrium constant were evaluated from the extraction experimental data and extraction conditions. Nd$aq^{3+}$ + 1.5 $H_2$$A_2$,org = $NdA_3$,org + 3H/sun $aq^{+}$ , K=0.25 The predicted distribution coefficients of Nd agreed well with the experimental results. The effect of saponification of PC88A on the extraction of Nd and on the change of equilibrium pH was investigated. Saponified PC88A present as a monomer in the organic reaction and enhanced the distribution coefficient of Nd. The initial extraction conditions had a great effect on the equilibrium pH.

The Effects of Charge Transfer Complex on the Reaction of Aniline and Iodine (Aniline과 Iodine간의 반응에 있어서 전하이동 착물의 영향)

  • Oh-Yun Kwon;U-Hyon Paek;Eung-Ryul Kim
    • Journal of the Korean Chemical Society
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    • v.36 no.2
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    • pp.174-179
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    • 1992
  • Reaction of aniline and iodine in$CHCl_3,\;CH_2Cl_2 : CHCl_3$(1 : 1), and $CH_2Cl_2$ has been studied kinetically by using conductivity method, Pseudo first-order rate constants ($k_{obs}$) and second-order rate constants ($k_{obs}$/[aniline]) are dependent on the aniline concentration. Second-order rate constants obtained were increased with increasing aniline concentration. We analysed these results on the basis of formation of charge transfer complex as reaction intermediate. From the construction of react ion scheme and derivation of rate equation, we calculated equilibrium constants and activation parameters for the formation and transformation of charge transfer complex. The equilibrium constants were decreased by an increase in the dielectric constant of the solvent and the value is 1.7-3.7$M^{-1}$. The rate of transformation are markedly affected by the solvent polarity. ${\Delta}H^{\neq}$ is about 14.2kJ/mol, and ${\Delta}S^{\neq}$ is large negative value of -243J/mol K.

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중금속이온과 포단드와의 착물형성에 관한 연구

  • Choi, Kyu Seong;Kang, Dong Hyun;Kim, Yong Seong;Lee, Shim Sung;Huh, Whang
    • Journal of the Korean Chemical Society
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    • v.45 no.2
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    • pp.131-137
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    • 2001
  • The protonation and stability constants of complexation of Zn(II), Cd(II) and Pb(II), Hg(II) ion with sulfur-containing podand ligands such as tri(phenylthio-2-ethy1)amine (Podand N$_1$S$_3$)tetra(phenylthio-2-ethyl)ethylenediamine (Podand N$_2$S$_4$) , tris(1-benzylaminoethyl)amine (Podand N$_4$) have been determined by potentiometric titration in 95% methanol at variable temperatures, From these studies, we observed that podand N$_4$ ligand showed the largest protonation constant. Protonation constant, stability constant, enthalpy, entropy of Zn(II), Cd(II) and Pb(II), Hg(II),ions increased with the following order podand N$_1$S$_3$$_2$S$_4$$_4$.

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