Conversion of bis(2-hydroxyethylene terephthalate) into 1,4-cyclohexanedimethanol by selective hydrogenation using RuPtSn/Al2O3

Abstract

1,4-Cyclohexanedimethanol (CHDM) is a highly valued and widely used monomer in the polymer industry. Bis(2-hydroxyethylene terephthalate) (BHET), the product of glycolysis of waste PET, is an excellent raw material for the preparation of CHDM. Herein, a series of monometallic, bimetallic and trimetallic supported catalysts were prepared for the one-pot conversion of BHET into CHDM by the impregnation method and good performance was found over trimetallic RuPtSn/Al₂O₃ catalysts containing various active sites to catalyze the hydrogenation of the phenyl and carbonyl groups. The influences of various reaction parameters including temperature, pressure and time on the hydrogenation reaction were studied, and 100% conversion and 87.1% yield of CHDM were obtained with the trimetallic supported catalyst with Ru/Sn 1.5. Moreover, through the comparison between various methods for the preparation of CHDM, the conversion of BHET into CHDM by the one-pot method is considered one of the most competitive methods.