In the process of producing nonionic, in the course of the hydroxyethylation –as by products- poly (oligo) ethylene glycol will be always formed as well. It has been found earlier that its amount depends first of all on the type of the catalyst and the temperature. In their study, the authors have found that in case of aralkyl alcohol type starting molecules this molecule itself, the activity of its hydroxyl group plays also part in the forming of the oligo(poly)ethylene glycol by – product.