Study of the surface properties of Alkyl-DEA from palmitic acid for cleaning and cosmetic applications

Abstract

A surface active agent is a substance added to a liquid that is useful for increasing the spreading properties by weakening the surface tension of the liquid. The need for biosurfactants continues to increase along with industrial developments and increasing human awareness of good health and the environment. In this study, the surfactant alkyl diethanolamide (Alkyl-DEA) was synthesized using one type of amine alcohol, namely diethanolamine, through an amidation reaction between palmitic acid and using hexane-isopropanol solvent and calcium oxide catalyst. Surface properties in the form of acid number, saponification number, and HLB value were studied by observing the effect of the reaction variables on the three surface properties. This study showed that the best conversion of palmitic acid was obtained at 70oC and 80oC for a reaction time of 5 hours and a stirring speed of 150, 200, and 250 rpm. The relationship between reaction rate and time is directly proportional; the longer the reaction time, the reaction rate will increase. However, increasing the reaction time did not give significant results to the surfactant product. The relationship between reaction temperature and conversion gain decreased with increasing reaction temperature. The acid number obtained under the best conditions was 39.27, the saponification number was 30.85, and the HLB value was 4.29.