IP Library › Granted Patent US 12,577,365
Granted Patent B2
US 12,577,365 · App. 17/972,166 · Granted Mar 17, 2026

Polyester hydrogenolytic deconstruction via tandem catalysis

Inventors: Yosi Kratish (Evanston, IL); Tobin J. Marks (Evanston, IL)
Assignee: Northwestern University
C08J11/16C08J2367/02
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Quick Facts
Patent No.
US 12,577,365
App. No.
17/972,166
Granted
Mar 17, 2026
Kind
B2
Abstract

Provided are methods for depolymerizing polyesters, e.g., PET, PBT, and PEN. In embodiments, a method for depolymerizing a polyester comprises combining a polyester comprising a plurality of ester linking groups (R′C(O)OR), a metal triflate catalyst, and a hydrogenation catalyst, under conditions to cleave a C—O bond in an alkoxy group (OR) of an ester linking group of the plurality of ester linking groups.

Claims (3)

1 . A method for depolymerizing a polyester, the method comprising combining a polyester comprising a plurality of ester linking groups (R′C(O)OR), a metal triflate catalyst, and a hydrogenation catalyst, under conditions to cleave a C—O bond in an alkoxy group (OR) of an ester linking group of the plurality of ester linking groups to depolymerize the polyester to a dicarboxylic acid and an alkane, wherein the carbon of the cleaved C—O bond is a primary carbon, R is a saturated aliphatic group, and R′ is an aromatic group or a heterocyclic group wherein the metal triflate catalyst is Hf(OTf) 4 ; the hydrogenation catalyst is Pd/C; depolymerization of polyester is carried out at a temperature of 265° C., for a time period of 24 hours, under a pressure of 1 atm H 2 , and an (ester):(Hf):(Pd) molar ratio of 400:6:1; and said method achieves an initial yield of at least 81% of the dicarboxylic acid, and further wherein the polyester is PET, PBT, or a combination thereof.

2 . The method of claim 1 , wherein the polyester, the metal triflate catalyst, and the hydrogenation catalyst form a reaction mixture that is free of a solvent and free of an additive other than H 2 .

3 . The method of claim 1 , wherein the polyester is provided as a blend with a non-polyester polymer and the non-polyester polymer remains intact after the method, and further wherein the non-polyester polymer is polypropylene.

Assignments (2)
CONFIRMATORY LICENSE Recorded Jun 1, 2023
From: NORTHWESTERN UNIVERSITY
To: UNITED STATES DEPARTMENT OF ENERGY
Reel/Frame 063830/0122 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded May 23, 2023
From: KRATISH, YOSI; MARKS, TOBIN J.
To: NORTHWESTERN UNIVERSITY
Reel/Frame 063733/0925 →
Continuity (2)
Provisional Application 63271311 · Oct 25, 2021
Related Publication 20230159722A1 · May 25, 2023
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