Sustainable Petrochemical Alternatives From Plastic Upcycling

Petrochemicals are used across every industry and in countless products. Plastic, the most ubiquitous of these products, has poor end-of-life recovery and recycling prospects. Energy- and carbon-rich plastics instead slowly degrade in landfills and oceans to produce microplastics, or is burned in incinerators for electricity, producing large amounts of greenhouse gases. Meanwhile, many other petrochemicals, like waxes, lubricants, and surfactants, have limited sustainable alternatives, hindering the low-emissions and circular carbon economy transition required for domestic manufacturing sectors. Catalytic hydrogenolysis, a novel chemical upcycling technology, can resolve both issues by converting plastic waste into chemical feedstocks for recirculation into the carbon economy. By diverting plastic waste away from incinerators and back into chemicals that have few sustainable options, one can 1) reduce emissions associated with the plastics lifecycle, 2) reduce cradle-to-gate emissions for various chemical feedstocks, 3) recirculate energy-rich plastics back into the carbon economy, and 4) establish a sustainable alternative to petrochemicals where there are none – through plastic-derived products. This catalytic process uses moderate operating temperatures (< 300 °C) and pressures of hydrogen (< 300 psi) to cleave polyolefins (e.g. high-density and low-density polyethylene, polypropylene, etc.) into smaller alkanes with no presence of aromatics or polycyclic compounds. Excess C-C bond scissions to produce gases is largely avoided by separating out the waxy and liquid products, resulting in a product yield of > 90% for plastic-derived petrochemical alternatives. Prototype lubricant base oils produced through catalytic hydrogenolysis of plastic waste are comparable to standard petrochemical lubricants in chemical structure and performance. Furthermore, a lifecycle analysis of a theoretical 250 metric ton/day plant resulted in a 75% reduction in cradle-to-gate emissions when compared to Group III mineral oils, demonstrating the potential of a drop-in replacement product for existing markets with the intent to lower Scope 3 emissions when producing consumer goods such as candles, cosmetics, detergents, and motor oils.