Studies on SDLC (Sodium Dilauraminocystine) and SDMC (Sodium Dimyristaminocystine) Gemini Surfactants

Abstract

The present work reports the synthesis and evaluation of surface active properties of amino acid-based gemini surfactants, namely, sodium dilauraminocystine (SDLC) and sodium dimyristaminocystine (SDMC) derived from L-cystine and fatty acids. The effect of reaction variables like molar ratio of raw materials and temperature has been studied for the synthesis of these gemini surfactants. In preparation of these gemini surfactants, fatty acids (lauric/myristic) were reacted with thionyl chloride to obtain respective acid chlorides (lauroyl/myristoyl). These acid chlorides were further reacted with L-cystine at different reaction conditions to get amino acid based-gemini surfactants. The study revealed that 1:2.5 molar ratio of reactants, namely, L-cystine and lauroyl/myristoyl chloride and 10–15° reaction temperature resulted in maximum yield of amino acid-based gemini surfactants (SDLC and SDMC). Surface active properties of synthesized gemini surfactants (SDLC and SDMC) were also compared with their corresponding monomeric units, namely, sodium lauroyl cysteine (SLC) and sodium myristoyl cysteine (SMC), respectively. The results demonstrated that gemini surfactants (SDLC and SDMC) had better surface active properties than their corresponding monomeric units. The structures of synthesized amino acid-based gemini surfactants were also confirmed by FTIR, ¹H NMR, ¹³C NMR, and ESI-MS spectral data.

Keywords:

• Amino acid
• L-cystine
• fatty acids
• gemini surfactants
• surface active properties

Notes

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