Molecular variations homologous series

The viscosity of a liquid is related directly to the type and size of the molecules which make up the liquid. The variation of liquid viscosity with molecular structure is not known with exactness however, the viscosities of liquids which are members of a homologous series are known to vary in a regular manner, as do most other physical properties. For example, pure paraffin hydrocarbons exhibit a regular increase in viscosity as the size and complexity of the hydrocarbon molecules increase. 

Although aniline does possess a dipole moment the cohesion energy is predominantly of the London type. The critical solubility point—technically actually the i i demixing point—with hydrocarbon mixtures (aniline point) is an important characteristic quantity. The aniline point rises with the molecular weight in a homologous series. For aromatic hydrocarbons the critical solubility point is the lowest, for paraffins the highest, olefins and cyclic hydrocarbons are in between, in agreement with the variation of the specific cohesion (Table 33). 

Molecular Variations in Homologous Series Vinylogues and Benzologues... 

Clusters and Small Homologous Series. - Raptis et a/.150 report studies on the polysulfanes, H2S , using MNDO and ab initio methods. The static and dynamic polarizabilities and hyperpolarizabilities are calculated and the authors find that the forms of change exhibited by a and are similar, so that the variation of the former may be used to predict that of the latter. Large changes in the hyperpolarizability with molecular structure are observed. 

MOLECULAR VARIATIONS IN HOMOLOGOUS SERIES VINYLOGUES AND BENZOLOGUES... 

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