Liquid refractive index

PFC number Formula CAS Registry Number Molecular weight Boiling point, °C Melting point, °C Liquid density, g/mL at °C Liquid refractive index, at°C Critical temp, °C Critical pressure, MPa "... 

Hydrocarbon CAS Registry Number Eree2ing point, °C Normal bp,°C Liquid density, kg/m at 20°C Liquid refractive index, A B C range, K... 

Fig. 8.28 (a) Resonance spectra for three different fluidic refractive indices and (b) resonant wavelength shift as a function of liquid refractive index change in the microtube at the incident angle of 37.5°. Reprinted from Ref. 68 with permission. 2008 Optical Society of America... 

An optical interferometric technique is used to measure the separation D, simultaneously providing also the liquid refractive index n and the curvature R. The mica sheets are made partially reflecting by evaporating a 40 -f 50 nm silver layer on the inner sides of the mica sheets. The cell is then illuminated by a collimated white light beam, in a direction perpendicular to both axis of the cylinders. The two partially reflective silver layers form a sort of three-layer curved interferometer selective transmission occurs only for the spectral components resonating with the mica/liquid/mica cavity . The transmitted wavelengths A are analyzed by an interferometer with a resolution better than 0.1 nm, to get information about the optical properties of the layers, especially the thickness D and the index n of the liquid. 

Refractive index n, liquid Refractive index n, solid 1.221 (92 K) 4.0 ... 

Other control factors besides temperature have been used, such as density of the liquid, refractive index of the liquid, infrared or other spectrographic types of analysis, and freezing point. The factor should be one which gives an indication of product composition and which can be easily and rapidly determined by a relatively inexpensive, stable... 

For example, the definition of a system as 10.0 g FI2O at 10.0°C at an applied pressure p= 1.00 atm is sufficient to specify that the water is liquid and that its other properties (energy, density, refractive index, even non-thennodynamic properties like the coefficients of viscosity and themial condnctivify) are uniquely fixed. 

The b.p., density and refractive Index are valuable constants for the final characterisation of liquid esters. 

Most aliphatic nitro compounds are liquids the physical properties (boiling point, density and refractive index) therefore provide valuable information for purposes of identification. 

Determination of the physical constants and the establishment of the purity of the compound. For a solid, the melting point is of great importance if recrystalhsation does not alter it, the compound may be regarded as pure. For a hquid, the boiling point is first determined if most of it distils over a narrow range (say, 1-2°), it is reasonably pure. (Constant boUing point mixtures, compare Section 1,4, are, however known.) The refractive index and the density, from which the molecular refractivity may be calculated, are also valuable constants for liquids. 

The density and the refractive index of a liquid will frequently be of value in assisting its characterisation. 

Refractive index. The refractive index of a liquid is conveniently determined with an Abbe refractometer. This refractometer possesses the following advantages ... 

The refractive index of a liquid is recorded as where t is the temperature at which the measurement is made, and D refers to the wave length of the D line of sodium. As already pointed out, it is usual to determine both the refractive index and the density of the liquid at 20° in any case they should be determined at the same temperatme. These two constants are useful in assisting the characterisation of a pure hquid they are particularly valuable for ahphatic hydrocarbons and similar compounds where the methods of characterisation by the formation of solid derivatives are not entirely satisfactory. 

Solution Polymers. Acryflc solution polymers are usually characterized by their composition, solids content, viscosity, molecular weight, glass-transition temperature, and solvent. The compositions of acryflc polymers are most readily determined by physicochemical methods such as spectroscopy, pyrolytic gas—liquid chromatography, and refractive index measurements (97,158). The solids content of acryflc polymers is determined by dilution followed by solvent evaporation to constant weight. Viscosities are most conveniently determined with a Brookfield viscometer, molecular weight by intrinsic viscosity (158), and glass-transition temperature by calorimetry. 

Formula GAS Registry Number Molecular weight Boiling poiut, °G Melting poiut, °G Liquid density, g/mL at °G Refractive index, n- at °G... 

Azetidine (1) is a colourless, mobile liquid, b.p. 62.5 C/747 mmHg (56JA4917), which is completely miscible with water. Its density 4 = 0.8412 and refractive index d = 1.4278 (37HCA109). Table 1 gives b.p. and m.p. data for other representative azetidines. 

With liquids, the refractive index at a specified temperature and wavelength is a sensitive test of purity. Note however that this is sensitive to dissolved gases such as O2, N2 or CO2. Under favourable conditions, freezing curve studies are sensitive to impurity levels of as little as 0.(X)1 moles per cent. Analogous fusion curves or heat capacity measurements can be up to ten times as sensitive as this. With these exceptions, most of the above methods are rather insensitive, especially if the impurities and the substances in which they occur are chemically similar. In some cases, even an impurity comprising many parts per million of a sample may escape detection. 

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