Density and refractive index

Therein, n, V, N, a, and Rl respectively represent the refractive index, molecular volume, Avogadro s number, polarizability, and molecular refraction. The Gladstone-Dale equation is derived from Equation (18.1) when n is close to 1, as shown below [15]. 

A NdF3-Al203-Si02 HoF3-BaF2-AlF3-Ge02 

A NdF3-AIF3-Ge02 TbF3-BaF2-AlF3-Si02 

A NdF3-BaF2-Ge02 ( data from INTERGRAD[14]) 

The effect of water content on density and refractive index of glasses is much smaller than for Tg and viscosity. The density of vitreous silica decreases by 0.003 g cm while the refractive index decreases by 0.0001 for an increase of 600 wtppm of water, for glasses with identical fictive temperatures. 

Limited data for alkali silicate glasses indicate that water has the opposite effect on density and refractive index from that found for vitreous silica, with an increase of 0.001 gcm in density and an 

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Because of the chemical inertness of the paraffin hydrocarbons and of the closely related cycZoparaffins, no satisfactory crystalline derivatives can be prepared. Reliance is therefore placed upon the physical properties (boding point, density, and refractive index) of the redistilled samples. These are collected together in Table III,6. 

Chakactkrisation of Unsaturatkd Aliphatic Hydrocarbons Unlike the saturated hydrocarbons, unsaturated aliphatic hydrocarbons are soluble in concentrated sulphuric acid and exhibit characteristic reactions with dUute potassium permanganate solution and with bromine. Nevertheless, no satisfactory derivatives have yet been developed for these hydrocarbons, and their characterisation must therefore be based upon a determination of their physical properties (boiling point, density and refractive index). The physical properties of a number of selected unsaturated hydrocarbons are collected in Table 111,11. 

Di- and poly-halogenated aliphatic hydrocarbons. No general procedure can be given for the preparation of derivatives of these compounds. Reliance must be placed upon their physical properties (b.p., density and refractive index) and upon any chemical reactions which they undergo. 

The low reactivity of aliphatic ethers renders the problem of the preparation of suitable crystalline derivatives a somewhat difficult one. Increased importance is therefore attached to the physical properties (boding point, density and refractive index) as a means for providing preliminary information. There are, however, two reactions based upon the cleavage of the ethers which are useful for characterisation. 

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. 

The physical constants of furfuryl alcohol are Hsted in Table 1. When exposed to heat, acid or air the density and refractive index of furfuryl alcohol changes owing to chemical reaction (51), and the rate of change in these properties is a function of temperature and time of exposure. 

Density and refractive index are nearly linear functions of formaldehyde and methanol concentration. Based on available data (16—19), the density may be expressed ia g/cm by the following approximation ... 

Methylene iodide [75-11-6], CH2I2, also known as diio dome thane, mol wt 267.87, 94.76% I, mp 6.0°C, and bp 181°C, is a very heavy colorless Hquid. It has a density of 3.325 g/mL at 20°C and a refractive index of 1.7538 at 4°C. It darkens in contact with air, moisture, and light. Its solubiHty in water is 1.42 g/100 g H2O at 20°C it is soluble in alcohol, chloroform, ben2ene, and ether. Methylene iodide is prepared by reaction of sodium arsenite and iodoform with sodium hydroxide reaction of iodine, sodium ethoxide, and hydroiodic acid on iodoform the oxidation of iodoacetic acid with potassium persulfate and by reaction of potassium iodide and methylene chloride (124,125). Diiodoform is used for determining the density and refractive index of minerals. It is also used as a starting material in the manufacture of x-ray contrast media and other synthetic pharmaceuticals (qv). 

Physical Properties. Properties of some alkyl peroxyesters are Hsted in Table 13 and the properties of some alkyl areneperoxysulfonates are given in Table 14. Mass spectra (226), total energies, and dipole moments (227) oxygen—oxygen bond-dissociation energies (44,228) and boiling points, melting points, densities, and refractive indexes (44,168,213) have been reported for a variety of tert-huty peroxycarboxylates. 

Melting points, boiling points, densities, and refractive indexes for carboxyUc acids vary widely depending on molecular weight, stmcture, and the presence of unsaturation or other functional groups (Tables 1,2,3, and 5). In addition, some useful constants for alkanoic acids are Hsted in Table 1. Some constants for selected unsaturated and substituted acids are given in Table 7. 

Br. CHa. CHa. CHa. CH(NHa). CH(CHa). CHa. CHjBr HBr. which on treatment with dilute alkali gives di-heliotridane (II). As the latter contains two asymmetric carbon atoms, two diastereoisomeric racemates might be produced in this reaction but only one was formed. It had density and refractive index in general agreement with those recorded for Z-heliotridane, as were also the melting points of characteristic derivatives. Density Df °0-902, refractive index wf, 1-4638 (<. with Adams and Rogers,3i Df ° 0-935, iijf° 1-4641), picrate, m.p. 234-6° (literature 232-6°), picrolonate, m.p. 162-3°, aurichloride, m.p. 200-1° (Konovalova and Orekhov give for these two constants 152-3° and 199-200° respectively). 

Typical physical characteristics of SENAs are given in Table 3.7. Gareev and coworkers synthesized a large number of phosphoryl-containing SENAs and characterized these compounds by densities and refractive indexes (255, 256). 

Soltzberg, Goepp and Freudenberg10 proved the constitution of arlitan by a synthetic method. They obtained a liquid tetramethyl derivative of arlitan, characterized it by its boiling point, density and refractive index, and compared it with 2,3,5,6-tetramethyl-l,4-anhydro-D-sorbitol (V) synthesized by the following method. Tetramethyl-D-glucofuranose... 

The cell is fitted with windows, and the concentration of polymer along its length is determined by optical methods which are based on measurements of refractive index of absorption solvents to be used for ultracentrifugation experiments must be chosen for difference from the polymer in both density and refractive index. An effort be made to avoid mixed solvents. Low solvent viscosity is also desirable. 

Diamond. In this structure (see Chapter 7) all the atoms are equivalent each atom being surrounded by a perfect tetrahedron of four other carbons, forming with each one of them a localized two-electron bond. Diamond has a high density and refraction index and thermal conductivity and the highest melting point ( 4000°C) of any element. 

Rogers, J.F., Farazmand, H., and Creasy, D.E. Solubility, density, and refractive index of aqueous solutions of pentaerythritol,... 

Fig. 7.1 Automated system to measure density and refractive index of fragrances and flavours.

Spin the samples with 200 000 x g at 4 °C for 15 -17 h. After the run, displace the gradient using a more dense solution, e.g., 40% sucrose in Soln. A, colored by a droplet Amido Black 10 B solution. The principle of a displacement apparatus is shown in Fig. 5.4. The RNA content of the fractions is measured either by reading the UV absorption at 260 nm or, if labeled material was used, by counting the radioactivity. To monitor the sucrose gradient, estimate the refractive index of the obtained fractions (concentration, density and refractive index of sucrose solutions are given in Table 8.17). 

In solutions and in mixtures of liquids, additional light scattering arises from irregular changes in density and refractive index due to fluctuations in composition. If the solution is dilute, the density fluctuations are essentially identical to those existing in the pure solvent [9]... 

Measurements are made of the simple physical properties of the freezing point (this property will usually already have been measured in the determination of purity), boiling point, density, and refractive index. The foregoing properties are necessary. The following properties may also be determined if equipment is available viscosity, solubility in a proper solvent, and critical solution temperature in a proper solvent. 

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