Optical measurement of the Soret coefficient and the diffusion coefficient of liquid mixtures

被引:164
作者
Zhang, KJ
Briggs, ME
Gammon, RW
Sengers, JV
机构
[1] UNIV MARYLAND,INST PHYS SCI & TECHNOL,COLLEGE PK,MD 20742
[2] UNIV MARYLAND,DEPT CHEM ENGN,COLLEGE PK,MD 20742
关键词
D O I
10.1063/1.471355
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
A temperature gradient in a liquid mixture causes a concentration gradient through the Soret effect. We have developed an instrument to measure the Soret effect by observing the bending of a laser beam propagating horizontally through the liquid mixture subjected to a temperature gradient in the vertical direction. Our design of the liquid cell, with a long path length and controlled temperature uniformity, enables us to measure Soret coefficients with an accuracy of 1-3%, higher than that obtained by previous investigators. In addition, by measuring the dynamic response of the beam deflection after imposition of the temperature gradient, we can also determine the mutual diffusion coefficient. We have applied the technique to mixtures of toluene and n-hexane over the temperature range 5-45 degrees C and to mixtures of ethanol and water at 25 degrees C. We have verified that the measured value of the Soret coefficient is independent of the magnitude of the temperature gradient imposed up to 14 K/cm. The Soret coefficients obtained for mixtures of toluene and n-hexane differ from the values obtained by previous investigators with a thermogravitational column method, but they are in good agreement with the results recently obtained by Kohler and Muller with a forced Rayleigh scattering method. For mixtures of ethanol and water, our Soret coefficients agree with the results obtained earlier by Kolodner et al., also with an optical beam-bending technique. (C) 1996 American Institute of Physics.
引用
收藏
页码:6881 / 6892
页数:12
相关论文
共 45 条
[21]   THERMODIFFUSION IN POLYMER-SOLUTIONS AS OBSERVED BY FORCED RAYLEIGH-SCATTERING [J].
KOHLER, W .
JOURNAL OF CHEMICAL PHYSICS, 1993, 98 (01) :660-668
[22]   HOLOGRAPHIC GRATING STUDY OF MASS AND THERMAL-DIFFUSION OF POLYSTYRENE TOLUENE SOLUTIONS [J].
KOHLER, W ;
ROSENAUER, C ;
ROSSMANITH, P .
INTERNATIONAL JOURNAL OF THERMOPHYSICS, 1995, 16 (01) :11-21
[23]  
KOHLER W, 1995, J CHEM PHYS, V103, P4367, DOI 10.1063/1.470677
[24]   OPTICAL MEASUREMENT OF THE SORET COEFFICIENT OF ETHANOL WATER SOLUTIONS [J].
KOLODNER, P ;
WILLIAMS, H ;
MOE, C .
JOURNAL OF CHEMICAL PHYSICS, 1988, 88 (10) :6512-6524
[25]  
Landau L. D., 1987, FLUID MECH-SOV RES
[26]   NONCRITICAL LIQUID-MIXTURES FAR FROM EQUILIBRIUM - THE RAYLEIGH LINE [J].
LAW, BM ;
NIEUWOUDT, JC .
PHYSICAL REVIEW A, 1989, 40 (07) :3880-3885
[27]   MEASUREMENT OF TRANSPORT-PROPERTIES OF LIQUIDS WITH EQUILIBRIUM AND NONEQUILIBRIUM RAYLEIGH-SCATTERING [J].
LI, WB ;
SENGERS, JV ;
GAMMON, RW ;
SEGRE, PN .
INTERNATIONAL JOURNAL OF THERMOPHYSICS, 1995, 16 (01) :23-31
[28]   DETERMINATION OF THE TEMPERATURE AND CONCENTRATION-DEPENDENCE OF THE REFRACTIVE-INDEX OF A LIQUID-MIXTURE [J].
LI, WB ;
SEGRE, PN ;
GAMMON, RW ;
SENGERS, JV ;
LAMVIK, M .
JOURNAL OF CHEMICAL PHYSICS, 1994, 101 (06) :5058-5069
[29]  
LI WB, 1992, J PHYS-CONDENS MAT, V6, pA119
[30]  
LI WB, 1984, PHYSICA A, V204, P399