Synthesis and properties of sodium undecylenoyl glycinate derived surfactants

Sodium undecylenoyl glycinate (SUG), an amino acid-based anionic surfactant with an unsaturated C11 hydrophobic chain, was synthesized via the Schotten–Baumann reaction. At 25 °C, its critical micelle concentration (CMC) was determined to be 9.21 × 10 −3 mol L −1 , and the surface tension at CMC (γCMC) was measured as 32.88 mN m −1 . Compared with sodium cocoyl glycinate (SCG), SUG exhibited stronger emulsification stability and selective detergency: it showed superior cleaning performance against protein and carbon black stains, while comparable performance was observed on sebum stains. In addition, SUG was found to be non-irritating in the zein test and exhibited inhibitory activity against Malassezia furfur in the antibacterial zone test. These results indicate that SUG is a mild surfactant with anti-Malassezia functionality, showing potential for personal care applications.