Amphiphilic molecules affording efficient aqueous degradation of unsaturated polyester resin.

• An environmental-friendly and cost-effective system, MSA/SLS/H 2 O, was developed for chemical recycling of waste UPR via selective disconnection of the ester bond. • A small amount of amphiphilic molecules, i.e., SLS, significantly promoted the degradation of UPR. • The viable catalytic mechanism of UPR in the MSA/SLS/H 2 O system is elucidated. • The superiority of the MSA/SLS/H 2 O system over other catalytic systems was attributed to the amphiphilic molecules improving the wettability and affinity between the UPR surface and water. • The high value-added products, i.e., the copolymer of styrene and maleic anhydride (SMA) and phthalic acid (PA), were reclaimed. Enormous challenges have been encountered in the degradation and recycling of unsaturated polyester resin (UPR) in water, primarily due to its water resistance. Herein, a novel, efficient and green catalytic system of methanesulfonic acid (MSA)/sodium laurylsulfonate (SLS) was proposed to aqueously degrade UPR under mild conditions (200°C). This method is considerably milder compared to other reported works based on aqueous hydrolysis (230°C-380°C). What's more, amphiphilic SLS as a phase transfer reagent enhanced the concentration of catalyst at the H 2 O-UPR interface, which facilitated the mass transfer between organic motifs with inorganic reagents and thus accelerated the reaction. The NMR and FT-IR characterizations indicated the ester bonds were cleaved via hydrolysis with H 2 O catalyzed by MSA, and high value-added products, i.e., copolymer of styrene and maleic anhydride (SMA) and phthalic acid (PA), were reclaimed by a simple separation process, with the yield of 86.77% and 84.37%, respectively. Furthermore, a viable mechanism for degradation was proposed through the degradation performance of the model compounds. This study provides a practical approach for the chemical degradation and conversion of other resins containing ester bonds. [ABSTRACT FROM AUTHOR]