Properties of Oxyethylenated Fatty Acid Methyl Esters and Ethyl Esters; Hydrolysis, Critical Micelle Concentrations and Foaming

Abstract

Abstract Oxyethylenated fatty acid methyl esters are considered to be a promising alternative to oxyethylenated fatty alcohols widely used in laundry detergent productions. Oxyethylenated fatty acid methyl esters display propensity to hydrolysis in alkaline washing solutions, which might affect the washing process. The hydrolysis of oxyethylenated fatty acid methyl esters was found to be innocuous towards the washing process since only 10% of the overall amount was hydrolyzed at 60°C, pH = 12 in 1 hour. The cmc depends on a degree of oxyethylenation. The cmc of methyl ester and ethyl ester bearing 10 oxyethylene groups is 0.8 mmol · L−1. The cmc of esters bearing 20 oxyethylene groups is 1.2 mmol · L−1. The foaming properties of oxyethylenated methyl esters bearing between 10 and 20 oxyethylene groups is constant. In case of oxyethylenated ethyl esters the foaming was increasing with the number of oxyethylene groups.