| Surfactant is a kind of molecules with both hydrophobic and hydrophilic groups, which can change interface state obviously by arranging molecules on the interface of solution. Surfactants are applied widely in many aspects, for example industry of fine chemicals, metal treatment, industrial cleaning, oil exploitation, pesticides, daily-use chemical industry and so on. It’s necessary to develop new surfactant.We studied the synthesis of a new C22tailed sarcosinate anionic surfactant,2-(N-erucacyl-N-methyl amido) acetate (EMAA). Erucic acid and sarcosine are raw materials of EMAA, and we obtained EMAA by the competing reaction of eruacyl chloride between sarcosine and water. The synthesis process of EMAA is simple, mild, economic, and which has a satisfactory conversion rate. The resultant was characterized by1H NMR,13C NMR, Elemental Analysis and FT-IR. Results indicate that EMAA has two isomers, trans/cis ratio is5/1, and the trans conformation is advantageous to forming micelles.The cmc of EMAA is5.6×10-2mmol L-1, which is two magnitudes lower than SDS. Viscosity of EMAA solution increases with improving the EMAA concentration, decreases with rising temperature. Viscosity of50.0mmol L-1EMAA solution increases firstly and decreases at last with improving KC1concentration, and the concentration at which maximizing the viscosity is7%. EMAA forms into wormlike micelles so the solution has a very high viscoelasticity. The solution can support its own weight when upside down, owns the strength of hydrogel. EMAA has a micelles-vesicle translation with changing the pH. When the pH is6.5EMAA aggregates into vesicle and the solution is blueing. The pH responsiveness was also been proved. Viscosity of EMAA solution increases with the pH rising.We compared solution properties of EMAA with2-(N-oleoyl-N-methyl amido) acetate (OMAA) and potassium oleate, and results indicate that the length of hydrophobic chain is important to the rheological property but has little influence on thermal endurance of surfactant solution. We also compared effects of various salts on30.0mmol L-1EMAA solution. The concentrations at which maximizing the solution viscosity of KC1, NaCl, Na2CO3are3%,2%,2%, and the corresponding viscosities are600.0Pa·s,27.5Pa·s,70.0Pa·s respectively. Adding CaCl2into EMAA solution cannot increase the viscosity. The viscosity of solution contains TEMED increases firstly, then decreases, and forms vesicle at last. According to the results, KC1has the best countra-ion effect. |
