Direct ethoxylation of fatty methyl ester over Al‐Mg composite oxide catalyst

Abstract

AbstractFor the purpose of estimating the reaction mechanism of the direct ethoxylation of a fatty ester in the presence of an Al‐Mg composite oxide catalyst, a labeled fatty methyl ester C11H23CO18OCH3 containing 18O isotope was synthesized and directly ethoxylated. The product was evaluated by gas chromatography‐mass spectrometry (GC‐MS). The GC‐MS spectra showed that the 18O isotope label was present only in the methoxy group at the molecular end of the ethoxylated fatty methyl ester. This supports the reaction mechanism of coordination anionic polymerization where the bond between the acyl and methoxy groups of the fatty methyl ester molecule was broken, caused by the bifunctional effect of the acid‐base active sites; an intermediate chemisorption species was formed; and then ethylene oxide was addition‐polymerized sequentially, in parallel.