GROUP SELECTIVITY OF ETHOXYLATION OF HYDROXY ACIDS

A study of the ethoxylation of two hydroxy acids was undertaken to determine if there was any group selectivity of ethoxylation. The hydroxy acids chosen for study were 12-hydroxystearic and lactic acid. Standard ethoxylation reactions were carried out using one mole of ethylene oxide to one mole of each hydroxy acid. Unlike typical fatty acids or alcohols, 12-hydroxystearic acid and lactic acid both ethoxylate without catalyst. This could be explained by the presence of both a hydroxyl and carboxyl in the reaction solution or the presence of both groups in the same molecule. We suggest that this may be due to some type of complex forming between the oxide and the carboxyl and hydroxyl groups, since blends of stearic acid and stearyl alcohol fail to ethoxylate without catalyst. Despite the fact that carboxyl groups of the hydroxy acids studied ethoxylate almost exclusively under base catalyst, and predominately with no catalyst, the reaction rate does not show an induction period, which would be expected for carboxyl group ethoxylation. The ethoxylation rates approximate those of primary alcohols under base catalyst. Group Selectivity of Ethoxylation of Hydrox