Synthesis of Antimicrobial and Emulsifier Compunds through Hydroxyl Group Esterification of Oxidized Ricinoleic Acid

: In this study, ester synthesis from commercial oxidized ricinoleic acid using various carboxylic acid was conducted. The double bond in ricinoleic acid was oxidized using KMnO 4 in alkaline condition to form two hydroxyl groups. Oxidized ricinoleic acid was then esterified chemically using palmitic acid, decanoic acid, and butyric acid by ZnCl 2 as catalyst with the molar ratio of oxidized ricinoleic acid to carboxylic acid was 3:1. Esters produced were characterized using FTIR examined as emulsifier and the antimicrobial activity. The results showed that each ester product gave absorption band C=O ester at the range of 1600 cm -1 -1720 cm -1 . The highest conversion percentage of esterification was obtained by oxidized ricinoleic acid-palmitic acid esters with the value of 75%. Simple emulsifier test was performed for each ester and the result showed that esters were able to maintain an emulsion form approximately 24 hours with water-in-oil emulsion (w/o) type. The antimicrobial activity test of esters gave positive results in the presence of inhibition zone to the growth of Propionibacterium acnes and Staphylococcus epidermidis . The highest antimicrobial activity against P. acnes and S. epidermidis was produced by oxidized ricinoleic acid-decanoic acid esters.