One-pot synthesis of biodegradable surfactant via hydrothermal reactions with saccharides as the sole carbon source

ABSTRACT Bio-derived and bio-degradable surfactants are vital for environmental sustainability. A nonionic surfactant was synthesized from sugars via hydrothermal reactions with Mn powder. The surface tension of reaction products was as low as 45.7 mN/m, and the mass yields of unrefined and refined surfactants reached 44.7 and 17.4%, respectively. Meanwhile, a porous, carbonaceous byproduct was obtained. The Mn powder can be reused in successive reactions without the impact of coke deposition, and a small amount of Mn entrained in the surfactant can be eliminated via pH adjustment and filtration. This surfactant had bio-degradability, and its degradation behavior was inhibited at −20 °C, making its storage and transportation feasible. This surfactant consists of furan rings, hydrocarbyl groups, hydroxyl and carbonyl groups. Mn was evidently consumed in the reaction, and it was covered by Mn(II) compounds after the reactions. According to the results of control experiments and XPS, Mn(0) reacted with carboxylic acids and hot water, and H 2 was generated to produce an intermediate 1-hydroxy-2-hexanone, while Mn(OH) 2 catalyzed the transformation of 1-hydroxy-2-hexanone and 2-acetylfuran into this surfactant via aldol and dehydration reactions. This work demonstrates the feasibility of synthesis of surfactants from carbohydrates alone.