Recycling Valuable Alkylbenzenes from Polystyrene through Methanol-Assisted Depolymerization

Angew Chem Int Ed Engl. 2024 Apr 8:e202404952. doi: 10.1002/anie.202404952. Online ahead of print.ABSTRACTThe vast bulk of polystyrene (PS), a major type of plastic polymers, ends up in landfills, which takes up to thousands of years to decompose in nature. Chemical recycling promises to enable lower-energy pathways and minimal environmental impacts compared with traditional incineration and mechanical recycling. Herein, we demonstrated that methanol as a hydrogen supplier assisted the depolymerization of PS (denoted as PS-MAD) into alkylbenzenes over a heterogeneous catalyst composed of Ru nanoparticles on SiO2. PS-MAD achieved a high yield of liquid products which accounted for 93.2 wt% of virgin PS at 280 oC for 6 h with the production rate of 118.1 mmolcarbon gcatal.-1 h-1. The major components were valuable alkylbenzenes (monocyclic aromatics and diphenyl alkanes), the sum of which occupied 84.3 wt% of liquid products. According to mechanistic studies, methanol decomposition dominates the hydrogen supply during PS-MAD, thereby restraining PS aromatization which generates by-products of fused polycyclic arenes and polyphenylenes.PMID:38588012 | DOI:10.1002/anie.202404952
Source: Angewandte Chemie - Category: Chemistry Authors: Source Type: research