Micellization properties of cardanol as a renewable co-surfactant

Sulphonates' mixtures and emulsions obtained from technical cashew nut shell liquid and cardanol for control of Aedes aegypti (Diptera: Culicidae)

Aedes aegypti is the main mosquito vector of dengue, zika, chikungunya, and yellow fever diseases. The low effectiveness of vector control options is mainly related to the increased insect's resistance and to the toxicity of products used for non-target organisms. The development of new environmentally friendly and safer products is imperative. Technical cashew nut shell liquid (tCNSL), mostly composed by cardanol (C), is an abundant by-product of the cashew (Anacardium occidentale L.) production chain, available at low cost, and with proven larvicidal activity. However, chemical modifications in both tCNSL and cardanol were required to increase their water solubilities. Our objectives were to synthesise and characterise sustainable, low-cost and easy-to-use multiple function products based on tCNSL, cardanol, and the sulphonates obtained from both; and to evaluate all these products efficacy as surfactants, larvicidal, and antimicrobial agents. None of the sulphonates presented antimicrobial and larvicidal activities. tCNSL and cardanol were successfully emulsified with sodium technical cashew nut shell liquid sulphonate (NatCNSLS, complex mixture of surfactants). The emulsions obtained presented larvicidal activity due to the presence of tCNSL and cardanol in their composition. Our results showed that the tCNSL+NatCNSLS mixture emulsion was an effective larvicide and surfactant multiple function product, with high availability and easy-to-use, which can facilitate its large-scale use in different environments. Graphical abstract.

Improved Synthesis and Properties of N-(3-octadecylamino-2-hydroxyl) Propyl Trimethyl Ammonium Chloride

The cationic surfactant, N-(3-octadecylamino-2-hydroxyl) propyl trimethyl ammonium chloride was synthesized by an improved synthesis method and the structure was confirmed by Mass Spectrometry and 1H NMR Spectrometry. The physiochemical properties of the product were investigated systematically by surface tension and conductivity measurements. Various physiochemical parameters were calculated to evaluate the surface activities of the surfactant. The results show that both the critical micelle concentration and the degree of counterion dissociation increased with increasing temperature, but the surface tension at CMC decreased, which is opposite to that obtained on the previous condition with increasing NaCl concentration. The thermodynamic parameters obtained from conductivity measurement show that the micelle formation of the surfactant is entropy-driven in the investigated temperature range. While used as an asphalt emulsifier, N-(3-octadecylamino-2-hydroxyl) propyl trimethyl ammonium chloride exhibited an excellent emulsifying ability and it was a medium-set asphalt emulsifier.