Refraction molecular

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 molecular refractivity can be computed from the Lorenz and Lorentz equation ... 

In the calculation of the molecular refractivity of esters, the C—O value for acetals is employed. 

Early work on the exaltation of the molecular refractivity of in-dazole and its 1- and 2-alkyl derivatives by Auwers and Diiesberg was considered to indicate that structure 18 represented the predomi-... 

The amino structure 173 was suggested for 5-aminoisoxazoles rather than the imino structure 174 on the basis of tentative chemical data and evidence from the exaltation of the molecular refractivity however, forms of type 175 were not taken into consideration in these... 

The molecular refraction of oxaziranes is in accordance with the values calculated from the individual refractions. For the isomeric nitrones, exaltation occurs. ... 

Its molecular refraction is 42 37, appearing to indicate a tricyclic compound, whilst the value calculated for a tricyclic body is... 

Auwers has paid considerable attention to the terpinene question, and especially in regard to the tact that the molecular refraction of the terpinenes shows considerable variation according to the method of preparation, and often appears to indicate that the terpinenes are exceptions to Briihl s laws of refraction. He came to the conclusion that the terpinenes are usually mixtures of more than one modification, together with a certain amount of a hydrocarbon of the formula —... 

Boiling-point Specific gravity Refractive index Molecular refraction. ... 

Boiling-point at 9 mm. Specific gravity at 20° Optical rotation. Refractive index. Molecular refraction. ... 

Prepared from. Boiling-point. Molecular Refraction. ... 

Dextro-dihydroverbenol melts at 58° C. and boils at 218° C. it yields an acetic ester, the odour of which recalls that of bornyl acetate. Dextro-dihydroverbenone is produced by the oxidation of the above alcohol by means of chromic acid, or by the reduction of verbenone by means of hydrogen in presence of colloidal palladium. It boils at 222° C. (Djj 0-9685 [a]o + 52-1 9° 1-47535 molecular refraction 44 45) and gives... 

The molecular refraction is a constant frequently quoted for individual chemical compounds, and is of considerable value as evidence of constitution, since it is generally true that the molecular refraction of a compound is composed additively of the refractive powers of the atoms contained in the-mmolecular refraction is the value obtained by multiplying the refractive power by the molecular weight. 

Bruhl found that the increase of CHj in all the homologous series of fatty compounds corresponds to a difierence of 4 57 in the molecular refraction for the red hydrogen line. By deducting n times this value from the molecular refraction cf an aldehyde or ketone of the formula C H2 0, he found 2 328 to be the value for intra-radical oxygen. Similarly the values of other groupings have been determined which may be summarised as follows —... 

To indicate the value of this constant in deciding the constitution of a compound, the case of geraniol, Cj HigO, may be examined. Calculated from the above values the molecular refraction would be the Sum of the atomic refractions, as follows — ... 

But by experimental determination the molecular refraction is found to be 48 71, which is 3-235 in excess of the value calculated from the atomic refractions. Two double bonds between carbon atoms would account for 3-414 in excess, so that it is evident that geraniol contains two such double linkages. No alcohol of the formula Cj HjgO with two double linkages can contain a ring, so that geraniol must belong to the open chain series, a conclusion entirely supported by its chemical characters. 

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