Effects of ethoxylate structure on surfactant properties of ethoxylated fatty methyl esters

In the presence of a surface-modified Al-Mg composite oxide catalyst, ethoxylated fatty methyl esters with different hydrophobic group structures and different chain-lengths of polyoxyethylene were synthesized from fatty methyl esters by direct ethoxylation. Each ethoxylated fatty methyl ester obtained showed a narrow ethylene oxide (EO) adduct distribution. Foaming, ability to lower surface tension, ability to lower interfacial tension, wettability, and dye solubilization were measured. Ethoxylated methyl laurate with about 60 to 70% EO content was found to be the most suitable as a base surfactant for household detergents.