Critical Opalescence of a Binary Liquid Mixture, n-Decane—β,β′-Dichloroethyl Ether. I. Light Scattering

Abstract

Opalescence of a binary liquid mixture, n‐decane and β,β′‐dichloroethyl ether, has been investigated at and near the critical solution concentration over a range of temperatures near the critical solution temperature in the one phase region. Both components were purified by preparative gas chromatography with estimated organic impurities at less than 1 ppm. Corrections for attenuation and density scattering were briefly discussed. It was found that trace impurities (essentially water) did not affect the over‐all molecular interaction range of the principal components. Within the range of the values s/λ [s=2 sin (θ/2),λ= wavelength in the medium, s/λ varied from 1.29×10^—4 to 7.46×10^—4 Å^—1] and temperatures studied, the light scattering data were in good agreement with the Debye theory [J. Chem. Phys. 31, 680 (1959)]. The average range of molecular forces (l) was found to be 13.4 Å.