Synthesis, physicochemical and antimicrobial properties of cardanol-derived quaternary ammonium compounds (QACs) with heterocyclic polar head

As new biomass derived raw material, cardanol has attracted the attention of numerous academic and industrial groups due to its renewability and unique structural features. In this work, seven cardanol-derived quaternary ammonium compounds (QACs) were synthetized with their physicochemical properties and antimicrobial ability evaluated. The surface tension was measured in aqueous medium by the platinum ring method, 2b has the optimal surface activities, which is considerably better than commercialized QAC product cetyltrimethylammonium bromide. Both broth dilution method and agar dilution method were used to obtain the MIC and MBC values of the targeted QACs. la, lb, 2b inhibit the tested bacterial at a concentration of 32 mu g/mL Scanning electron microscopy (SEM) results intuitively showed that the QACs could interact with the bacterial cell membrane, for disrupting the integrity of the membrane. Meanwhile, it was found that the antimicrobial activity depended not only on the alkyl chain length, but also on the CMC value. To sum, seven cardanolderived QACs were synthetized easily, which showed excellent surface activities and antimicrobial activity, as a promising alternative to the existing fossil fuel derived cationic surfactants and antiseptics. (C) 2019 Elsevier B.V. All rights reserved.