• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.444-452
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• 2006

This paper reports experimental excess molar volumes $V^E_m$ using a digital vibrating-tube densimeter and excess molar enthalpies $H^E_m$ by means of an isothermal microcalorimeter with a flow mixing cell for the binary mixtures{1,2-dichloropropane + 2-(2-methoxyethoxy)ethanol} and {1,2-dichloropropane + 2-(2-ethoxyethoxy)ethanol} at 298.15 K under atmospheric pressure. All the $V^E_m$ and $H^E_m$ of the two binary mixtures showed S-shaped forms, being negative for poor and positive for rich 1,2-dichloropropane mole fractions. These show that the excess properties were shown to be negative deviation from ideality due to the strong self-association effect among 2-(2-alkoxyethoxy)ethanol molecules at an early stage of mixing, a relatively high energy then is needed to break hydrogen bonds of 2-(2-alkoxyethoxy)ethanol with an increase ofhalogenated hydrocarbon molecular at high mole fraction of 1,2-dichloropropane. The values of excess molar properties($V^E_m$ and $H^E_m$) were fitted by the Redlich-Kister equation using Nelder-Mead's simplex pattern search method. The Wilson, NRTL, and UNIQUAC models were used to correlate the $H^E_m$ values.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.2
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• pp.193-198
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• 2001

2성분계 혼합물(1,2-dichloropropane + 2-methoxyethanol)에 대해 과잉몰 부피(excess molar volumes) $V^E$ 및 과잉 몰엔탈피(excess molar enthalpies) $H^E$를 298.15K에서 측정하였다. 혼합물의 밀도측정은 digital vibrating tube densimeter를 이용하였고, 과잉 몰엔탈피는 isothermal flow microcalorimeter를 이용하였다. 측정한 과잉 몰부피는 전 조성 영역에서 양의 편차를 나타내었으며, 과잉 몰엔탈피는 S 자형용 보였다. 또한 얻어진 data는 Nelder- Mead의 simplex method를 이용하여 Redlich-Kister 다항식에 접합 (fitting)하였다.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.660-667
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• 2017

Equilibrium data of the mixture is essential in the design and operation of separation equipment such as distillation or extraction in chemical processes. These equilibrium data can be obtained through experiments or by calculations using the known binary parameters and the thermodynamic models. Generally, to obtain these parameters, phase equilibrium experimental data such as gas-liquid and liquid-liquid are used. In this study, the excess enthalpy of the mixture was measured using the flow type microcalorimeter which is a simpler method than phase equilibria experiments, and the parameters of various theories were obtained by using this data. In order to investigate the relationship between carbon chain length, enthalpy and binary parameters in the alkane system, excess enthalpies for the n-hexane + alkane (n-pentane, n-heptane, n-octane and n-dodecane) were measured at 298.15 K and the banary interaction parameters of Wilson, NRTL, and UNIQUAC were obtained from the experimental data. In addition, we wanted to obtain basic information on the interaction and association phenomena of the system including electrolyte applicable to various fields by using the excess enthalpy experimental data and the existing theory. First, we investigated the excess enthalpy for the NaOH / Water / Ethanol system as a basic experiment and examined the applicability using the electrolyte-NRTL (eNRTL) theory.

• The Journal of Natural Sciences
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• v.4
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• pp.95-102
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• 1991

The influences of various concentrations of thallium carbonate on the hydration of tricalcium silicate which is widely used to the inorganic materials have been studied using an isothermal microcalorime-ter. The experimental results indicate that the hydration of tricalcium silicate is accelerated in the presence of thallium carbonate, namely the concentration of thallium carbonate is increased, the rate of hydration is also increased. The x-ray diffraction analysis shows that the concentration of tricalcium silicate decreases rapidly in the presence of thallium carbonate. Differential thermal analysis of tricalcium silicate hydrated in the persence of thallium carbonate indicates the presence of calcium carbonate. The nonevaporable water content and the degree of hydration of tricalcium silicate show that the accelerating action of thallium carbonate is more pronounced only during the early period of hydration. Analytical results of the liquid phase in contact with the tricalcium silicate paste indicate that the concentrations of calcium and hydroxyl ions are changed considerably in the presence of thallium carbonate.