Fine-Structure Discontinuities in the Intermolecular Activation Energy of Flow of 2 to 30% Aqueous Ethyl Alcohol

A. K. M. Ahsanullah, M. M. Qurashi
1965 Proceedings of the Royal Society A  
The intermolecular activation energy Ev for viscous flow of a l using the differential relation Ev/B = A In 1?/A(1/T) = -T2A In in a small temperature interval, T to T -f AT. Application of this equation with AT = 5 degC to the standard viscosity data on the alcohol-water system available at temperatures from 0 to 70 °C indicates the probable existence of several rather large jumps in the values of at quite specific temperatures for each alcohol concentration. Therefore, our previously
more » ... previously developed experimental technique for the accurate measurement of Ev with AT as small as 1 degC has been applied to several solutions of alcohol in water in the range of 2*5 to 30 % alcohol. The results confirm the presence of a series of sharp jumps in Ev at intervals of 4 to 8 degC, the magnitude of the change AEV at each jump being of the order of 0*1 to 0*3 kcal/mole. Further detailed examination of these features has been attempted in the range of 0 to 11 % alcohol by working with four solutions of intermediate concentration, and it is found that (i) there is a general trend of movement of each jump towards a higher temperature and a higher value of JL as the alcohol concentration is increased, and (ii) superposed on this general trend there are certain discontinuous changes in the region of 26 to 42 °C, particu larly for 2*5 to 7 % alcohol. A preliminary theoretical interpretation of these phenomena is suggested, and further measurements on other properties of these solutions are planned.
doi:10.1098/rspa.1965.0120 fatcat:p2pdlngxofgqhcmxbuxa4vtd5q