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Acrylonitrile+Water, Acetonitrile+Water, Acrylonitrile+Acetonitrile 혼합계의 상평형과 과잉부피

Phase Equilibria and the Excess Molar Volume for the Systems Acrylonitrile+Water, Acetonitrile+Water, and Acrylonitrile+Acetonitrile

박소진 오종혁 최호준 백승관 Fischer K Gmehling J

Park SJ Oh JH Choi HJ Paek SK Fischer K Gmehling J

HWAHAK KONGHAK, October 1997, 35(5), 678-683(6), NONE

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Abstract

Acrylonitrile+water, acetonitrile+water, acrylonitrile+acetonitrile 각 이성분계 혼합물에 대한 323.15 K 등은 기액평형을 headspace gas chromatography(H.S.G.C)법으로 측정하였다. Water를 포함한 혼합계에서는 공비점을 나타내었으며, 특히 acrylonitrile+water 혼합계는 acrylonitrile 조성 0.05-0.90 정도에서 불용영역이 있어 불균일 공비점을 보였다. g^E 모델식에 의한 상관과 modified UNIFAC식을 이용한 추산결과 실측치와의 기상조성의 평균편차가 1% 미만의 작은 편차로 일치함을 확인하였다. 298.15 K에서 측정된 과잉부피는 모두 이상성으로부터 음의 편차를 보였으며, Redlich-Kister 다항식에 1% 미만의 편차로 합치되어 좋은 상관관계를 보였고, 매개변수를 이용하여 무한 희석상태의 부분 과잉 몰부피도 계산하였다. Acetonitrile+water 혼합계에 대해 spinning band 증류기를 이용하여 측정한 정확한 공비점은 323.15 K, 279.9 torr에서 x₁=0.757이었으며, 이는 H.S.G.C에 의한 결과인 x₁=0.755와 거의 일치한다. 이 계의 공비조성은 압력이 감소할수록 acetonitrile이 농후한 지역으로 이동하였다.

Isothermal vapor-liquid equilibria(VLE) for the binary systems of acrylonitrile+water, acetonitrile+water, and acrylonitrile+acetonitrile were measured by headspace gas chromatography(H.S.G.C) at 323.15 K. Both aqueous systems have the azeotropic behaviors. Acrylonitrile+water system has an immiscible region approximately between 0.05 to 0.9 of acrylonitrile mole fractions. VLE data were correlated by common g^E models and compared with predicted values by modified UNIFAC group contribution method. Their mean deviations in vapor phase composition were less than 1%. Excess molar volumes(v^E) of the same binary mixtures at 298.15 K showed negative deviation from the ideality. These data were agreed well within 1% mean deviation with Redlich-Kister equation. Partial molar excess volumes at infinite dilution were calculated from the five Redlich-Kister parameters. Precise azeotropic data were measured directly by spinning band distillator for the acetonitrile+water system. The composition of azeotrope by distillation was x₁=0.757 at 323.15 K and 279.9 torr, which was very close to the result, x₁=0.755, by H.S.G.C. The compositions of azeotropes moved to acetonitrile rich region with decreasing the system pressure.

Keywords

Acetonitrile Acrylonitrile VLE Excess Volume Azeotropes

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