Sulfated Zirconium Catalyst for Synthesis of Dialkylated Diphenylether Disulfonate Gemini Surfactants.

Dialkylated diphenylether disulfonate with different alkyl chain lengths (C-DADS, n = 8, 10 and 12) has been synthesized by Friedel-Crafts alkylation of olefins (C, C and C) and diphenyl oxide, followed by sulfonation and neutralization with fuming sulfuric acid. Sulfated zirconia solid acids were prepared and used to catalyze the alkylation reaction. The structure of sulfated zirconia solid acids was identified by infrared spectroscopy. The title compounds were confirmed by infrared spectroscopy and electrospray ionization-mass spectrometry. Equilibrium surface tension measurements show that the critical micelle concentration (CMC) decreases with an increase in chain length, and the surface tension at CMC ( γ) of C-DADS is the lowest. The minimum area per molecule ( A) values of C-DADS increase, while the surface excess concentration ( Γ) values decrease with the increase of the alkyl chain length. C-DADS has the highest pC and CMC/C among C-DADS. [ABSTRACT FROM AUTHOR]