Synthesis And Properties Of Cationic Gemini Surfactants

A series of quaternary ammonium Gemini surfactants and double hydrophibic groups cationic surfactants were synthesized using various long-chain alkyl tertiary amines, epoxy chloropropane, N, N-Dimethylethanolamine and N-Methyldiethanolamine. The physical and chemical properties of them and the mixed systems of Gemini surfactant1,3-bis(dodecyl-N,N-dimethylammonium)-2-propanol(12-3(OH)-12) and laurinol ether carboxylate sodium(AE9C) were investigated.Double chain alkane quaternary ammonium Gemini surfactants were synthesized using epoxy chloropropane and various alkyl tertiary amines by three steps. The optimum conditions of the first step were following : n(HCl):n(amine)=0.95:1. The optimum conditions of the second step were following : n(EPC):n(amine)=1:1,reaction temperature80 ℃, reaction time 4~6h. The optimum conditions of the third step were following :n(amine):n(EPC)=0.9:1, reaction temperature 80 ℃, reaction time 6h. A Series of quaternary ammonium Gemini surfactants, 8-3(OH)-8, 8-3(OH)-12, 8-3(OH)-16,12-3(OH)-12, and 16-3(OH)-16, were synthesized at this optimum conditions and their structures were identified by Hydrogen nuclear magnetic resonance(1HNMR) and Fourier transform infrared spectrum(FT-IR). The physical and chemical properties testing results show this series double chain alkane quaternary ammonium Gemini surfactants have good surface activity and outstanding foam and emulsifying properties. The foam performance and emulsifying property of these Gemini surfactants could be promoted under acid condition.Double hydrophibic groups cationic surfactants, 10-3(OH)-DM, 10-3(OH)-MD,12-3(OH)-DM,12-3(OH)-MD,14-3(OH)-DM,14-3(OH)-MD were synthesized using epoxy chloropropane, various alkyl tertiary amines, N, N-Dimethylethanolamine or N-Methyldiethanolamine at the same reaction condition with the double chain alkane quaternary ammonium Gemini surfactants and their structures were identified by Hydrogen nuclear magnetic resonance(1HNMR) and Fourier transform infrared spectrum(FT-IR).Surface tension results show that the double hydrophibic groups cationic surfactants has asuperior surface activity compared with traditional surfactants. According to the thermodynamic parameters evaluated from electrical conductivity measurements show that the micellization of the double hydrophibic groups cationic surfactants are spontaneous process and micellar process are entropy-driven. The surfactants show the best foam properties when the carbon chain is 12 and a well emulsification also been observed. It also been investigated that an acid environment can promote the emulsifying capability obviously.The surface activity, compatibility, foaming property, wetting power and emulsifying property were investigated for mixed systems of Gemini surfactant1,3-bis(dodecyl-N,N-dimethylammonium)-2-propanol(12-3(OH)-12) and laurinol ether carboxylate sodium(AE9C). These two surfactants show very good compatibility, and the strong synergic effect was shown by the mixed system. When the molar ratio between12-3(OH)-12 and AE9 C was 1:2, i.e. the cationic and anionic head group charge were mixed in equal molar ratio, the mixed system showed the strongest synergic effect, having the lowest critical micelle concentration(CMC) and the surface tension at cmc(γcmc). The foaming properties, wetting power and emulsifying property were also better than that of each component, and all these optimal results were shown while n(12-3(OH)-12) : n(AE9C)was 1:2.