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Dipole Moments and Hindering Effects of Some N‐Alcohols in N‐Hexane Solution
Author(s) -
Lin WeiChuwan,
Tuan FuTai
Publication year - 1958
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.195800003
Subject(s) - chemistry , dipole , mole fraction , dilution , hexane , dielectric , butanol , moment (physics) , hexanol , analytical chemistry (journal) , thermodynamics , alcohol , chromatography , organic chemistry , ethanol , physics , optoelectronics , classical mechanics
The dielectric constants, specific volumes and refractive indices of n ‐butanol, n ‐hexanol and n ‐decanol in n ‐hexane solution have been measured at 25°C over a range of mole fraction from 0.01 to 0.08. The Kirkwood equation of dielectric polarisation of polar liquids has been applied to solutions of these alcohols. The dipole moments at infinite dilution μ ∞ the moments in the gaseous state μ* and the moments in solution μ have been thus determined. A hindering parameter g was also calculated for solutions of the three alcohols named above in n ‐hexane. This parameter is a direct measure of the extent and nature of molecular association. That the deviation of g from unity becomes less pronounced on going from n ‐butanol through n ‐hexanol to n ‐decanol represents a decrease in the degree of hindered rotation with increasing chain length of alcohols. This was found in essential agreement with the tendency of variation of the slope in the P 2 ‐x 3 curves. All the three alcohols exhibit negative deviation of g from unity in n ‐hexane solution, and the amount of deviation becomes greater with increasing mole fraction. These may be attributed to the association to polymeric alcohols in such a way as to screen their orientation from one another, leading to configurations with decreasingly smaller resultant moment with increasing concentration.