Simple chemistry can be used to recycle polystyrene into more valuable products

Plastic waste represents one of the most urgent environmental challenges facing humankind. Upcycling has been proposed to solve the low profitability and high market sensitivity of known recycling methods. Existing upcycling methods operate under energy-intense conditions and use precious-metal catalysts, but produce low-value oligomers, monomers, and common aromatics. Researchers at Virginia Tech have created a tandem degradation-upcycling strategy to exploit high-value chemicals from polystyrene waste with high selectivity. We first degrade polystyrene waste to aromatics using ultraviolet light and then use a value creation process to change the intermediate to a more useful product, diphenylmethane. Low-cost AlCl3 catalyses both the reactions of degradation and upcycling at ambient temperatures under atmospheric pressure. The degraded intermediates can advantageously serve as solvents for processing the solid plastic wastes, forming a self-sustainable circuitry.