Synthesis and surface properties of oxyethylenated 2‐alkyl‐5‐hydroxymethyl‐5‐ethyl‐1,3‐dioxanes

Abstract

AbstractIn acid‐catalyzed reactions of long chain aliphatic aldehydes (I) (R=n−C7H15; n−C9H19; n−C11H23) with 1,1,1‐tris(hydroxymethyl)propane (II), 2‐alkyl‐5‐hydroxymethyl‐5‐ethyl‐1,3‐dioxanes (III) were obtained. The latter were then reacted with ethylene oxide in the presence of sodium methoxide.Three series of oxyethylenated cyclic acetal derivatives (IV) were obtained. They constitute a new group of chemodegradable surfactants which readily hydrolyze and oxidize in natural water reservoirs. Physical data of the new compounds and some surface properties such as cloud points (Cp), critical micelle concentrations (cmc), changes of free energy of micellization, (ΔG°cmc), surface tensions of aqueous solutions near cmc, γmin, and wetting and foaming properties, were determined. The surfactants (IV) have aqueous solution properties similar to those of oxyethylenated longchain aliphatic alcohols. It is shown that the micellization of surfactants (IV), expressed in terms of ΔG°cmc, depends both on the length of the aliphatic chain at the C‐2 carbon atom and on the presence of ethyl group at C‐5 of 1,3‐dioxane ring which enhances the hydrophobic character of derivatives (III). Hence, the surfactants have a higher surface activity than oxyethylenated 2‐alkyl‐4‐hydroxymethyl‐1,3‐dioxolanes or 2‐alkyl‐5,5‐bis‐(hydroxymethyl)‐1,3‐dioxanes. The use of 2‐alkyl‐5‐hydroxymethyl‐5‐ethyl‐1,3‐dioxanes (III) in surfactant synthesis is an example of applying hydrophobic intermediates obtained from aldehydes only. This, and the chemodegradability mentioned make the compounds a very interesting group of new surfactants.