Preparation of 1,4-cyclohexanedimethanol by selective hydrogenation of a waste PET monomer bis(2-hydroxyethylene terephthalate)
A new approach is developed for the preparation of 1,4-cyclohexanedimethanol (CHDM) by hydrogenation of bis(2-hydroxyethylene terephthalate) (BHET) obtained from waste poly(ethylene terephthalate) (PET). The influences of various reaction parameters including temperature, pressure and time, on the hydrogenation reaction were studied, and the 100% conversion of BHET and 78% yield of CHDM were achieved with Pd/C and Cu-based catalysts. X-ray diffraction, low temperature N2 adsorption–desorption and H2 temperature-programmed reduction were used to characterize the Cu-based catalysts, demonstrating that the Cu+/Cu0 species are the active sites. This study not only provides a new route for the production of CHDM, but also an approach for the efficient utilization of waste PET.