Production of Carboxylic Acids from Waste Plastics: A Sustainable Pathway Via Pyrolysis and Hydroformylation

The current life cycle of plastic packaging highlights the potential to implement processes to increase recycling rates and reduce mismanaged plastic. Commercial production of carboxylic acids is primarily sourced from fossil feedstocks through a series of energy demanding processes. Carboxylic acids can be alternatively produced from waste plastics, offering a sustainable alternative for the production of mono- and di-carboxylic acids. Thermal decomposition of waste plastics yields an olefin-rich oil which produces a wide range of aldehydes after hydroformylation. To demonstrate a sustainable route for carboxylic acid production, two Pinnick oxidation procedures with different scavengers were employed to determine which process had a higher selectivity for the acid products. Gas chromatography-mass spectrometry was used to characterize the oxidation of the aldehyde model compound. The Pinnick oxidation which employed a hydrogen peroxide scavenger had a higher selectivity for the octanoic acid product. Gas chromatography was used to determine the retention times for C6-C12 acids to determine the concentrations of products after oxidation of the hydroformylated oil. Employing the Pinnick oxidation with a hydrogen peroxide scavenger may yield a product with C6-C21 carboxylic acids. Oxidation of the hydroformylated oil which produces carboxylic acids may prove a sustainable route for acid production from waste polyolefins.