Synthesis, characterization of novel double long-chain alkyl quaternary ammonium salts and their catalytic performance in the preparation of organic sulfonates

Two double long alkyl chains quaternary ammonium salts, DDOAB and 12-DE-12, were synthesized through the reactions of octadecyl bromide, dichloroethyl ether with N, N-dimethyl long-chain alkyl tertiary amine, respectively. The chemical structures of these compounds were characterized by ¹H NMR and HRMS. The critical micelle concentrations of DDOAB and 12-DE-12 in aqueous solution were measured to be 0.07 g/L (0.13 mmol/L) and 0.25 g/L (0.43 mmol/L), respectively. In aqueous solutions, the micelles of DDOAB and 12 - DE - 12 have diameters of approximately 5 nm and 2 nm, respectively. The catalytic activity of cetyltrimethylammonium bromide (CTAB), DDOAB, and 12-DE-12 in the reaction of alkyl halides with sulfites for the preparation of organosulfonates was evaluated. The reaction between CH₂Br₂ and K₂SO₃ was catalyzed by DDOAB (10 CMC) at 100 °C for 8 h, resulting in a 93 % yield of K₂[CH₂(SO₃)₂]. Under the same conditions, when 12-DE-12 (12 CMC) was used as the catalyst for 8 h, the yield of K₂[CH₂(SO₃)₂] reached 96 %. Compared with CTAB and DDOAB, the gemini surfactant 12-DE-12 exhibits better catalytic performance in the reaction of alkyl halides with sulfite. Additionally, a reaction mechanism for the reaction between CH₂Br₂ and K₂SO₃ has been proposed.