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We present an innovative process for directly transforming poly(ethylene terephthalate) (PET), a polymer extensively used in food and beverage packaging, into trans‐isomer‐enriched 1,4‐cyclohexanedimethanol (CHDM), a key ingredient in advanced specialty polymers. Our approach leverages a dual‐catalyst system featuring palladium on reduced graphene oxide (Pd/r‐GO) and oxalate‐gel‐derived copper‐zinc oxide (og‐CuZn), utilizing hydrogenation/hydrogenolysis relay catalysis. This method efficiently transforms PET into polyethylene‐1,4‐cyclohexanedicarboxylate (PECHD), which is then converted into CHDM with an impressive overall yield of 95 % in a two‐stage process. Our process effectively handles various post‐consumer PET plastics, converting them into CHDM with yields between 78 % and 89 % across different substrates. Additionally, we demonstrate the applicability and scalability of this approach through a temperature‐programmed three‐stage relay process on a 10‐gram scale, which results in purified CHDM with an isolated yield of 87 % and a notably higher trans/cis ratio of up to 4.09/1, far exceeding that of commercially available CHDM. This research not only provides a viable route for repurposing PET waste but also enhances the control of selectivity patterns in multistage relay catalysis. [ABSTRACT FROM AUTHOR]

We present an innovative process for directly transforming poly(ethylene terephthalate) (PET), a polymer extensively used in food and beverage packaging, into trans-isomer-enriched 1,4-cyclohexanedimethanol (CHDM), a key ingredient in advanced specialty polymers. Our approach leverages a dual-catalyst system featuring palladium on reduced graphene oxide (Pd/r-GO) and oxalate-gel-derived copper-zinc oxide (og-CuZn), utilizing hydrogenation/hydrogenolysis relay catalysis. This method efficiently transforms PET into polyethylene-1,4-cyclohexanedicarboxylate (PECHD), which is then converted into CHDM with an impressive overall yield of 95 % in a two-stage process. Our process effectively handles various post-consumer PET plastics, converting them into CHDM with yields between 78 % and 89 % across different substrates. Additionally, we demonstrate the applicability and scalability of this approach through a temperature-programmed three-stage relay process on a 10-gram scale, which results in purified CHDM with an isolated yield of 87 % and a notably higher trans/cis ratio of up to 4.09/1, far exceeding that of commercially available CHDM. This research not only provides a viable route for repurposing PET waste but also enhances the control of selectivity patterns in multistage relay catalysis., (© 2024 Wiley-VCH GmbH.)

Novel thermally-induced BSA/ι-carrageenan particles are used as a protective carrier for (-)-epigallocatechin-3-gallate (EGCG). The addition of EGCG to BSA/ι-carrageenan particles can highly quench the intrinsic fluorescence of BSA, which is explained in terms of the binding of EGCG to the hydrophobic pockets of BSA mainly through the hydrophobic force. According to the double logarithm equation, the binding constant is determined as 1.1×10(8)M(-1) for the binding of EGCG with BSA/ι-carrageenan particles. The high binding affinity is ascribed to both the molecular structure of EGCG and the partial unfolding state of BSA in BSA/ι-carrageenan particles. The circular dichroism spectra and calculated α-helix of BSA suggest that the bound EGCG leads to a more random secondary structure of BSA. Furthermore, BSA/ι-carrageenan particles are found to be superior to native BSA and pure BSA particles for improving the stability and radical scavenging activity of EGCG., (Copyright © 2014 Elsevier Ltd. All rights reserved.)