Synthesis of a novel dialkylaryl disulfonate gemini surfactant

摘要

A single-step route was developed for synthesizing a dialkylaryl disulfonate gemini surfactant using α-olefin sulfonic acid. The new process is very simple and effective, requiring neither the conventional alkylation unit nor strong acid catalysts. The resulting dialkylaryl disulfonica acids differ from existing products by having the sulfonyl group attached to the alkyl chain rather than the aromatic ring. To optimize the reaction conditions, a reliable double-wavelength spectrophotometric method was studied to analyze the conversion of an aromatic (benzene or methylnaphthalene) based on the difference in ultraviolet absorption spectra between the aromatic and the corresponding dialkylaryl disulfonate. The experiments suggested that the reaction time and temperature affected the conversion and optimal condition; a reaction time of 5 h (or 4 h) and a reaction temperature of 150°C were obtained and applied to the products ditetradecylmethylnaphthalene disulfonate (DTMNDS) and ditetradecylbenzene disulfonate (DTBDS). In addition, the surface-active properties of DTMNDS and DTBDS were investigated in detail. Their critical micelle concentrations were 2×10−5 and 1.7×10−4 mol·L−1, respectively. The data showed that the two new dialkylaryl disulfonate gemini surfactants had higher surface activities than the conventional dodecylbenzene sulfonate, suggesting they will have broad utility in industrial and household applications in the future.