Viscosities and excess viscosities of aqueous solutions of some diethanolamines

Viscosities, η, of aqueous diethanolamine (DEA), methyldiethanolamine (MDEA), ethyldiethanolamine (EDEA) and n-butyldiethanolamine (BDEA) solutions were determined at an interval of 5 K between 303.15 and 323.15 K at different compositions in the range 0 ≤ x2 ≤ 1, where x2 is the mole fraction of alkanolamines. Excess viscosities, ηE, have been found to be positive for all systems in the whole range of composition at all temperatures. The heights of maxima in ηE vary as W + DEA > > W + MDEA > W + EDEA > W + BDEA. The effect of temperature on both η and ηE is significantly large - the more the temperature the less the viscosity as well as the excess viscosity. For all the systems, η and ηE data have been fitted well with six degree polynomial and Redlich-Kister equations, respectively.