A photocatalyzed polyethene dehydrogenation process that utilizes inexpensive and commercially available reagents for polyethylene transformations. Problem: Industry produces 258 million tons of polymer annually. Polyolefins, including polyethylene, account for 60% of this total. Established polymerization routes control the chain architecture (i.e., branching frequency and branch length) in polyethylenes to modify polymer processability and properties, giving rise to the plethora of commercial polyethylene grades. In contrast, synthetic routes are limited with respect to controlling the chain architecture in polyethylene copolymers, such as poly(ethylene-co-acrylic acid). Separately, polyethylenes represent a major contributor to plastic waste generation due to their widespread single-use applications. Currently, industries recycle plastic waste inefficiently, which drives strong interest in developing innovative upcycling methods for post-consumer plastics. However, polyethylene is a highly unreactive polymer, which makes chemical upcycling into higher-value products particularly challenging. Both chain architecture control in polyethylene copolymers and chemical upcycling of polyethylene can be addressed by partial dehydrogenation. To date, researchers have proposed various dehydrogenation strategies that rely on costly metal-based catalysts and require rigorous synthetic steps, which increase costs and processing time, ultimately creating a significant barrier for commercialization. Solution: A photocatalyzed dehydrogenation process for polyethylene utilizes inexpensive, commercially available aromatic ketones as photocatalysts and nickel complexes as co-catalysts, producing dehydrogenated polyethylene with up to 2.8% unsaturation within 3 hours and little to no decrease in number-average molecular weight and chain architecture. Technology: The photocatalyzed dehydrogenation process for polyethylene is carried out by introducing benzophenone (BP) and a nickel (II) bromide – DME complex with a 370 nm light source. BP acts as a photocatalyst, and the nickel complex serves as a cocatalyst. This photocatalyzed procedure avoids the need for extensive catalyst and ligands synthesis, which shortens dehydrogenation reaction time compared to existing methods. Furthermore, this reaction achieves dehydrogenation without significantly altering the molecular weight and chain architecture of the polyethylene backbone. Advantages:
Stage of Development:
Proposed mechanism of the photocatalyzed dehydrogenation of polyethylene. The reaction proceeds via hydrogen atom abstraction (HAT), followed by beta-hydride elimination, ultimately regenerating the photocatalyst and liberating hydrogen. Intellectual Property:
Reference Media:
Desired Partnerships:
Docket #26-11370