Synthesis And Properties Of Triethylene Tetramine Sulfonate Anionic Surfactants

Sulfonate surfactant is a vital anionic surfactant,widely used in daily chemicals industry,tertiary oil recovery and environmental protection and other fields.Sulfonate surfactans can be divided into traditional,Gemini,trimeric and tetrameric according to different structures.It develops towards the direction of multi-branched synthesis and direct modification of the parent group in terms of preparation.In this paper,three sulfonate surfactants with four hydrophilic groups and two oil-philic groups were designed and synthesized based on triethylene tetramine.Triethylene tetramine sulfonate anionic surfactants with different carbon chain lengths were synthesized from long chain bromoalkane,triethylene tetramine and sodium3-chloro-2-hydroxypropane sulfonic acid by substitution and sulfonation reaction.The optimum reaction conditions of the three surfactants were determined by orthogonal experiment,and their structures were characterized by FT-IR and ¹HNMR and MS,and they were confirmed as the target products.The properties of triethylene tetramine sulfonate anionic surfactant were studied by means of surface tension,conductivity test and solution method.The results showed that the CMC value and surface tension of series of sulfonate surfactants increased with the increase of hydrophobic alkyl chain.The surface tension and CMC value of C₁₂-N₄-C₁₂ were 21.45m N/m and 0.217 mmol/L respectively.₈（6）decreases with the increase of hydrophobic carbon chain,A_min increase,and p C₂₀ decrease.With the increase of alkyl chain length,the surface activity becomes worse.The three surfactants in pure water have good solubility.Among the three surfactants,C₁₂-N₄-C₁₂ has the best salt resistance,which can resist 48000mg/L salinity in the concentration range of 0.1 wt%-0.5 wt%.With the increase of hydrophobic carbon chain,the salt resistance decreases,C₁₆-N₄-C₁₆<C₁₄-N₄-C₁₄<C₁₂-N₄-C₁₂.The surface properties of the three surfactants show same trends with the increase of salinity,and the surface activity becomes worse with the increase of salinity.The emulsifying properties of anionic triethylene tetramine sulfonate were studied by means of emulsifying properties and emulsification rate.The results showed that the emulsifying properties of the three surfactants:C₁₄-N₄-C₁₄>C₁₆-N₄-C₁₆>C₁₂-N₄-C₁₂.Under the same concentration condition,C₁₄-N₄-C₁₄ has the best emulsifying performance,and the best emulsifying power is 77.5%.With the increase of temperature,the emulsification rate increased by 43.07%for 30 s and 17.2%for 10 min,and the emulsification capacity and stability increased obviously.When the temperature increased from 25℃to 35℃,the increase of emulsification rate of surfactant decreased.Increasing the ratio of dispersant and oil can significantly improve the emulsification rate,but with nonlinear growth,the optimal ratio of dispersant and oil is between 20%and 30%.When the ratio of dispersant and oil is 20%,the emulsification rate is 67%for 30s and 39%for 10min.When the ratio of dispersant and oil reaches 40%,the emulsification rate of surfactant tends to be stable or even decrease.Measuring emulsification rate was used to study the compound system of surfactant C₁₄-N₄-C₁₄ with different anionic surfactants and non-ionic surfactants.The result show that:/The compound system of C₁₄-N₄-C₁₄ and non-ionic surfactant AEO-9 has the best emulsification performance.With studied the interaction of（interaction parameters of the surface absorption layer）,⁸)（interaction parameters of the mixed micelle layer）and△G_ex（excess Gibbs free energy）,the theoretical calculation is consistent with the experimental results.When the mass ratio of the compound system is 1:2,the emulsification rate is 97.99%for 30 s and 89.16%for 10 min,which has a good application prospect in the treatment of offshore oil spill.