Hydroborative Depolymerization of Polyesters and Polycarbonates to Diols Catalyzed by Heterogeneous Lanthanum...

Chemical recycling is a promising strategy to establish a circular plastic economy, and it is still in an early stage of development. In this work, the reductive depolymerization of polyesters and polycarbonates into their corresponding borylated alcohols promoted by heterogeneous lanthanum materials was described. Grafting the easily accessible lanthanum tris(aminobenzyl) complex La(CH₂C₆H₄NMe₂-o)₃ (1) onto the partially dehydroxylated silica support SBA-15 (SBA-15₅₀₀ or SBA-15₇₀₀) gave the inorganic-organic hybrid materials 1@SBA-15₅₀₀ and 1@SBA-15₇₀₀. These hybrid lanthanum materials, in combination with pinacolborane (HBpin), could serve as highly active heterogeneous catalysts for the selective depolymerization of aliphatic and aromatic polyesters, as well as polycarbonates into their corresponding borylated diols through a hydroboration reaction under mild conditions. The lanthanum materials exhibited a practical application in plastic waste recycling for their easy preparation, high catalytic efficiency, and recyclable property.