Metal‐Catalyzed, Photo‐Assisted Selective Transformation of Tertiary Alkylbenzenes and Polystyrenes into Carbonyl Compounds

Abstract

Every year, thousands of tons of polystyrene are produced and discarded, filling landfills and polluting the marine environment. Although several degradation alternatives have been proposed, the need for an effective procedure for the chemical recycling of polystyrene still remains. Here, a vanadium-catalyzed reaction, assisted by visible light, promoted the direct, selective conversion of tertiary alkylbenzenes into acetophenone and other ketone derivatives. Likewise, standard polystyrene sam-ples as well as polystyrenes from insulation and packaging waste could be chemically recycled into acetophenone in a scalable way regardless of their molecular weight, polydispersity, or form. Preliminary mechanistic investigations revealed the participation of singlet oxygen, superoxide, and hydroxyl radical species in this homogenously catalyzed process. Acetophenone could be used as an additive to accelerate the reaction and to increase the yields in some cases.

Upcycling Waste Plastics with a C–C Backbone by Heterogeneous Catalysis

“…Therefore, the development of efficient catalysts for abstract hydrogen is a critical step. Homogeneous catalysts have been proven to be feasible, and the application of heterogeneous catalysts in the oxidation of PS will be highlighted in the following paragraphs. − …”

Catalytic conversion of mixed polyolefins under mild atmospheric pressure

“… 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 Concurrently, a series of photocatalytic chemical recovery methods for PS have also been developed. 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 Despite these advancements, the upcycling of PS under mild non-light conditions, the upcycling of PE under mild conditions, 51 and especially the upcycling of mixed polyolefins, have not yet been accomplished. Recently, Beckham, Stahl, and their colleagues have demonstrated significant chemical oxidation of mixed PE and PS, using the resulting products for further biological funneling treatment ( Figure 1 B).…”