Effect of process variables, degree of ethoxylation and alcohol structure on relative ethoxylation rate constants

Abstract

Supercritical fluid chromatographic determinations of ethylene oxide distributions in ethoxylated alcohols with subsequent computer calculations of relative propagation to initiation ethoxylation rate constants for each ethoxylated oligomer have been carried out for normal octanol under varying reaction conditions. A number of other alcohols were also ethoxylated under essentially constant conditions. In the normal octanol studies, within an approximately fifteen-fold change in absolute ethoxylation rates due to variations in temperature, pressure, and potassium hydroxide catalyst concentration, the data indicate that such changes do not affect ethylene oxide distributions. Suggestions by earlier workers of changes in relative ethoxylation rate constants with the average degree of ethoxylation were verified. Chain length for normal alcohol feeds does not affect distributions in the C-8 to C-13 range, but branching at the carbon α to the hydroxyl carbon increases the relative propagation to initiation rate constants, and a secondary alcohol exhibits an even higher ratio.