Synthesis of single and double long-chain 1,3,5-triazine amphoteric surfactants and their surface activity

This paper discusses a series of single and double long-chain 1,3,5-triazine amphoteric surfactants, which were synthesized by cyanuric chloride, aliphatic amines and sodium 2-(methyl amino) ethane sulfonate. Their structures were confirmed by MS, NMR and IR. The critical micelle concentrations (CMC) and surface tensions at CMC (γCMC) of all prepared amphoteric surfactants were determined by K100C processor tensiometer at 25 °C. As the length of the hydrophobic chain of single long-chain 1,3,5-triazine amphoteric surfactants increases, the values of their CMC and γCMC gradually decrease, and the minimum average area per surfactant molecule (Amin) increases. The γCMC values of double long-chain 1,3,5-triazine amphoteric surfactants are observed to be obviously lower than that of the single long-chain ones. For double long-chain 1,3,5-triazine amphoteric surfactants, the more symmetrical hydrophobic chains are, the lower γCMC values are. When two hydrophobic chains are symmetrical, the longer hydrophobic chains, the lower values of γCMC and Amin. However, the γCMC and Amin of the surfactant with double 12 hydrophobic chains ascends.

Graphical abstractA series of single and double long-chain 1,3,5-triazine amphoteric surfactants were synthesized, and their physicochemical properties such as critical micelle concentrations (CMC), surface tensions at CMC (γCMC) and the minimum average area per surfactant molecule (Amin) were studied.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The surfactants A-MCTn and A-DCTn-m are synthesized from cyanuric chloride. ► It is controllable to prepare symmetrical and unsymmetrical alkyl chains of A-DCTn-m. ► The surface properties of A-MCTn and A-DCTn-m surfactants were determined and compared. ► The A-DCTn-m surfactants have a great efficiency in lowering the surface tension.