Novel Method for PET Chemical Recycling

NU 2020-056

INVENTORS

• Tobin J. Marks*
• Yanshan Gao*
• Yosi Kratish
• Jiaqi Li

SHORT DESCRIPTION

A novel process for the hydrolysis of polyethylene terephthalate (PET) and recycling of its monomers.

The catalyst C/MoO₂ catalyzes the hydrogenolytic deconstruction of PET to its monomers, terephthalic acid and ethylene. This catalyst can be recycled multiple times without loss of activity.

ABSTRACT

Polymer-based plastics are among the most widely used synthetic materials. However, their impact on finite natural resources as well as plastic waste accumulation presents worldwide environmental consequences. Thus, there is a rising need for their recycling. Current technologies produce lower grade plastics or side products that are difficult to separate. Northwestern researchers have developed a process for the hydrolysis of polyethylene terephthalate (PET) where both the monomer products and catalyst can be separated and reused. This process involves the hydrogenolysis of PET catalyzed by carbon-supported single-site molybdenum-dioxo complex and yields the starting monomers terephthalic acid and ethylene. Additionally, the catalyst can be easily separated and reused at the end of reaction. This processs is effective for both commercial and waste PET and the catalyst exhibits high stability and recyclability. Thus, this novel process offers an efficient and cost-effective method for PET chemical recycling that could have a tremendous impact on sustainably recycling the massive accumulation of plastic waste in the world.

APPLICATIONS

• Chemical plastic recycling

ADVANTAGES

• Cost-effective
• Recovery of catalyst

PUBLICATION

• Kratish, Y, Li, J, Gao, Y, Marks, T (2020) Polyethylene Terephthalate Deconstruction Catalyzed by a Carbon-Supported Single-Site Molybdenum-Dioxo Complex. Angewandte Chemie. 59(45), 19857–19861.
• Naveen Malik, Jiaqi Li, Amol Agarwal, Yosi Kratish, and Tobin J. Marks (2025) Thermodynamically leveraged solventless aerobic deconstruction of polyethylene-terephthalate plastics over a single-site molybdenum-dioxo catalyst, Journal of Green Chemistry. Green Chem., 2025, 27, 2427-2438

IP STATUS

• US Non-Provisional Patent pending
• Published WIPO (PCT) Patent No. WO2021211423A1

IN THE NEWS

'Plastic recycling gets a breath of fresh air - Scientists break down plastic using a simple, inexpensive catalyst and air' - Northwestern Now, March 11, 2025, by Amanda Morris

"Harnessing moisture from air, Northwestern University chemists have developed a simple new method for breaking down plastic waste.

The non-toxic, environmentally friendly, solvent-free process first uses an inexpensive catalyst to break apart the bonds in polyethylene terephthalate (PET), the most common plastic in the polyester family. Then, the researchers merely expose the broken pieces to ambient air. Leveraging the trace amounts of moisture in air, the broken-down PET is converted into monomers — the crucial building blocks for plastics. From there, the researchers envision the monomers could be recycled into new PET products or other, more valuable materials. " - Read more...