Synthesis And Properties Of Fatty Amide Quaternary Ammonium Salts

Study of this subject is series of fatty acid amide propyl-N, N-dimethyl amine salts and quaternary ammonium cationic surfactant. The molecular structure of the quaternary ammonium salt (Quat-n) is RCNH(CH2)3CNH3CH3O + CH2 COHHC H2OH Cl-, Systemic examinations of the Quat-n were carried out from synthesis, analysis, characterization, chemical properties, application performance, micellar aggregation and micelle thermodynamics in this dissertation.With different kinds of fatty acids, N,N-dimethyl-1,3-propanediamine, 3-chloro-1,2- propanediol as raw material, we synthesize corresponding fatty amidopropyldimethylamines and quaternary ammonium salts. Its structure was characterization by IR, MS analysis, by single factor and orthogonal experiment, the better synthesis routes is showed as below: In the reation of amidation, fatty acids, N,N-dimethyl-1,3-propanediamine (molar ratio 1:1.8), reacted for 9h, at 140℃, with conversion rate of fatty acid was 94.2%; In the reaction of quaternary ammonium, amidopropyldimethylamine, 3-chloro-1,2–propanediol (molar ratio 1:1.1), reacted for 5h, at 85℃, with conversion rate of tertiary amines was 93.2%. After separation and purification of the active matter content of the final product was 92.1%. The surface tension (γcmc) value of Quat-12, Quat-14, Quat-16 were 25.39 mN/m, 26.77 mN/m, 29.33 mN/m ,meanwhile the critical micelle concentration (cmc) were 5.012×10-4mol/L, 1.798×10-4mol/L, 0.992×10-4mol/L, which were measured with drop volume method at 303±0.5K. And measured the application of this series of amine salts and quaternary ammonium cationic surfactant, the results showed that the product of quaternary ammonium has a good properties of foam, emulsify, wettability and solubilization.Surface chemical properties and thermodynamic properties of Quat-12 was measured with drop volume method at different temperature(298～308K) and different concentration of NaCl(0.1～0.2mol/L). And its counter-ion binding degree and the micellar aggregation was measured, the critical micelle aggregation number ([Nm]) was 51.Compared with Dodecyltrimethylammonium bromide(DTAB), the bactericidal activities against Staphylococcus aureus, Escherichia coli, Bacillus subtilis of the Quat-12 surfactants were measured, the result showed that the Quat-12 surfactants has antibacterial activity anginst Staphylococcus aureus, meanwhile, has a strong bactericidal activity against Bacillus subtilis.