Upcycling PET wastes into high value-added 1,4-cyclohexanedimethanol (CHDM) via tandem reactions

Upcycling polyethylene terephthalate (PET) wastes into high value-added oxygenated chemicals is desirable, yet it remains challenging. Herein, we develop a novel strategy to convert PET into 1,4-cyclohexanedimethanol (CHDM) via two steps, the conversion of PET to dimethyl 1,4-cyclohexanedicarboxylate (DMCD) over Ni-based catalysts, followed by the hydrogenolysis of DMCD to CHDM over a CuMgAl catalyst. The key step is the production of DMCD from PET in one-pot reaction and an unprecedent yield of 86.5% DMCD yield is achieved over Pd-modified Ni/CeO 2 catalyst, which to the best of our knowledge is the highest yield reported to date. Comprehensive characterizations demonstrate that the addition of Pd enhances hydrogen dissociation, but weakens the adsorption activation ability for C–O bond in esters, thus DMCD selectivity is improved. Over CuMgAl catalyst, DMCD is directly converted into CHDM with 83.8% yield. Furthermore, the techno-economic analysis proves the economic feasibility of converting PET into CHDM via our proposed strategy. The study provides a promising and effective approach to upcycle PET wastes into high value-added products.