Synthesis and Surface Properties of Disodium Monoalkyl Diphenyl Oxide Disulfonate

Abstract

AbstractDisodium monoalkyl diphenyl oxide disulfonates (MADS) with different carbon chains (Cn‐MADS, n = 8, 12, 16) were synthesized through the steps of alkylation‐sulfonation‐neutralization using fatty alcohols (C8, C12, C16), diphenyl oxide and fuming sulfuric acid (20 % free SO3) as reagents. The structures of the products were identified by infrared spectroscopy and electrospray ionization‐mass spectrometry. The surface properties, emulsification, wettability alteration and salinity and hardness tolerance of the products were systematically investigated. The results show that the critical micelle concentration (CMC) of C8MADS, C12MADS and C16MADS are 7.24 × 10−3, 1.49 × 10−3 and 2.09 × 10−4 mol/L. The surface tensions at the CMC (γCMC) of each product are 37.5, 38.9 and 46.8 mN/m. The negative logarithm of the surfactant concentration in the bulk phase required to produce a 20 mN/m reduction in the surface tension of the solvent (pC20) increases with the increase in the alkyl chain length. The emulsifying ability of C12‐MADS is better than C8‐MADS and C16‐MADS, and the MADS showed less oil‐wet nature. The salinity and hardness tolerance of MADS is much stronger than that of conventional surfactants.