Synthesis and Properties of a Novel Bio-Based Branched Heptadecylbenzene Sulfonate Derived from Oleic Acid

Bio-based surfactants have attracted increasing attention because they are made from renewable resources and have excellent surface/interfacial properties. In this study we prepared a novel bio-based branched alkylbenzene sulfonate surfactant by a four-step route using renewable oleic acids as starting materials. We evaluated the surface behavior, wettability, and biodegradability of our surfactant. The surfactant, 4-(1-heptadecyl) benzene sodium sulfonate (9 phi C17S), was synthesized using a facile four-step route involving alkylation, decarboxylation, sulfonation and neutralization, respectively. The chemical structure of 4-(1-heptadecyl) benzene sodium sulfonate was confirmed by infrared (IR) spectroscopy, electrospray ionization high resolution mass spectrometry (ESI HRMS) and H-1 nuclear magnetic resonance CH NMR) spectroscopy. The surfactant demonstrated an excellent surface tension of 32.54 mN.m(-1) at the critical micelle concentration (CMC) of 317.5 mg.L-1 and outstanding interfacial tension of similar to 10(-2) mN.m(-1) at 8.36 x 10(4) mg.L-1 with 8.48 x 104 mg.L-1 Na2CO3. The surfactant also showed good biodegradability with an ultimate biodegradation score of 2.99. The surfactant had good wettability with an air/water/solid contact angle (theta(average)) of 63.08 degrees for a 0.500 g.L-1 9 phi C17S solution. This novel bio-based branched surfactant contributes to the structural diversity of biobased surfactants from renewable feedstock.