Synthesis and Properties Evaluation of Sodium Fatty Alcohol Polyoxyethylene Ether Sulfonate

Abstract

Sodium salts of fatty alcohol polyoxyethylene ether sulfonates with different length of hydrophobic chain (C_nE₃SO₃, n +; 14, 16, 18) were synthesized from sodium isethionate, then the structure was verified by IR. The temperature resistance, calcium-tolerant stability and salt tolerance were evaluated by pyrogenetic decomposition, phase separation and middle phase emulsion respectively. In addition the mixture of C_nE₃SO₃ and heavy alkylbenzene sulfonate (HABS) was studied. The results showed that: (1) C_nE₃SO₃ was very stable at 150°C especially in neutral, weak acid and weak alkaline conditions; (2) C_nE₃SO₃ performed a good salt tolerance and have a rank of C₁₈E₃SO₃ > C₁₆ E₃SO₃ > C₁₄E₃SO₃; (3) the calcium-tolerant stability of C_nE₃SO₃ reached 8700 mg/L, 9500 mg/L and 10000 mg/L respectively; (4) C_nE₃SO₃ was very good for improving the salt tolerance of mixture of C_nE₃SO₃ and HABS. C₁₈E₃SO₃ was the best in mixtures of Daqing crude oil/water containing C₁₈E₃SO₃ and HABS in a ratio of ω(C₁₈E₃SO₃):ω(HABS) = 3:7 and showed the strongest synergistic effect. The interfacial tension in the system Daqing crude oil/water reached a minimum in the order of 10^–3 mN/m and was always below 10^–2 mN/m for c_NaCl from 0 to 15000 mg/L.