Excess Refractive Index Research Articles

EXCESS VOLUMES AND VOLUME EXCESS REFRACTIVE INDEXES OF BINARY MIXTURES CONTAINING TETRACHLOROMETHANE

The excess volumes and volume excess refractive indexes have been measured over entire composition range at 293.15 and 298.15K for tetrachloromethane + 1-methyl-2-pyrrolidinone, +cyclopentanone +pyridine, +2-butanone, +1-pentanol, +2-propanol, or +methylcyclohexane. The results show that V(2) for CCl(4) + C(5)H(9)NO, + C(5)H(8)O, +C(5)H(5)N are large negative value. It is attributed to a charge-transfer interaction between tetrachloromethane and the second components. The excess volumes for (CCl(4) + C(5)H(9)NO) are the largest negative, its minimum value is -1.19cm(3)mol(-1) at 298.15K. The V(E) for CCl(4) + (CH(3))(2)CHOH, + C(5)H(11)OH are positive or slight negative, suggesting that there is not the specific interaction between tetrachloromethane and alcohol molecules. We propose a semi-empirical formula for predicting excess volume of binary mixtures on volume excess refractive index. The results are satisfactory.

Röntgenkleinwinkelbrechung an Metalldrähten, Glasfäden und hartelastischem Polyproplen

Very thin equatorial small-angle scattering of Cu Kα radiation is observed from metallic wires, glass fibres and hard elastic polypropylene which can be explained quantitatively as a refraction phenomenon if the excess refractive indices n = 1 - ∊ of the samples are smaller than unity. For Cu Kα radiation and SiO2 glass ∊ has a value of 7.2 × 10-6. The intensity Is of reflection within a total reflection angle δ = 3.8 × 10-3 = 13' is negligibly small compared with the intensity of refraction IB. In addition to refraction, diffraction by gaps and holes in strained polypropylene was observed. The scattering of 60 μm particles of Li-Ba silicate glass powders [Nau & Brückner (1971). Kolloid Z. Z. Polym. 244, 223-233] can be explained by transforming the observed scattering of spheres to cylinders yielding the refraction IB as calculated.

Refractive index and excess volume for binary liquid mixtures. Part 1.—Analyses of new and old data for binary mixtures

The relation between the refractive index and the excess molar volume for binary liquid mixtures has been clarified using the additivity rule. The excess volume is represented by two terms due to the excess refractive index and the refractive index difference. Refractive indices have been measured by a differential refractometer for the isorefractive binary mixtures 1-chlorobutane (BuCl)–butan-2-ol (BuOH), 1-chlorobutane–2-methoxyethanol (MOEt), and isopropyl acetate (IPA)–methylethyl ketone (MEK). For the isorefractive binary systems the excess volume was represented by the excess refractive index term and compared with the observed one without knowing the explicit form of the refractive index equation. Coherent correlations were found between the observed excess volume and refractive index for the systems BuCl–BuOH and BuCl–MOEt. The relation of the excess volume and refractive index for the system IPA–MEK suggested a contradiction to the additivity rule. The analyses of the old data for the system propan-1-ol–1,2-dibromoethane have elucidated a strong dependence of the refractive index difference term on the functional form of the refractive index equation. The binary systems studied are not described by a unique equation for the refractive index.

Excess volumes and refractive indices in the benzene-tert-amyl methyl ether and cyclohexane-tert-amyl methyl ether systems at 298.15 K

Excess molar volumes in the benzene-tert-amyl methyl ether and cyclohexane-tert-amyl methyl ether systems were measured by a vibrating-tube densimeter at 298.15 K and compared with the data for the methanol-tert-amyl methyl ether system determined previously. Besides, the refractive indices in both the systems were measured at the same temperature.

Some physical properties of long chain hydrocarbons

The densities, refractive indices, and viscosities of liquid n-nonadecane and n-nonadecyl benzene were investigated at temperatures not too far above their respective melting points. Except for the viscosities, no significant differences were observed in the behavior of the two hydrocarbons. The n-nonadecane + n-nonadecyl benzene system exhibits small positive excess volumes and small negative excess viscosities. The excess refractive index is zero in the entire concentration range.

CALCULATION OF REFRACTIVE INDEX OF A GLASS AS A DIRECT FUNCTION OF ITS COMPOSITION*

AbstractMethods have been presented for the direct calculation of refractive index of a glass from its composition. For a given region of composition and structure of silicate glasses, defined by the ratio of Si to the total number of oxygen, or NSi, the excess refractive index (n— 1) is found to be linearly additive of composition. Equations and constants are given for various expressions of composition, including the weight percentages. Part of the constants have physical significance since they represent the refractive‐index contribution of the components concerned.