Chemical Recycling of Polyethylene by Tandem Catalytic Conversion to Propylene.

Although polyethylene (PE) and polypropylene (PP) are by far the world's largest volume plastics, only a tiny fraction of these energy-rich polyolefins are currently recycled. Depolymerization of PE to its constituent monomer, ethylene, is highly endothermic and conventionally accessible only through unselective, high-temperature pyrolysis. Here, we provide experimental demonstrations of our recently proposed tandem catalysis strategy, which uses ethylene to convert PE to propylene, the commodity monomer used to make PP.

Fluorocarbene, fluoroolefin, and fluorocarbyne complexes of Rh.

The manuscript reports the synthesis, characterization, and analysis of electronic structure in a series of complexes of small perfluorocarbon ligands with the (PNP)Rh fragment (where PNP is a diarylamido/bis(phosphine) pincer ligand). Reactions of (PNP)Rh(TBE) as the source of (PNP)Rh with CHF and CHF produced perfluoroalkylidene complexes (PNP)Rh[double bond, length as m-dash]CF and (PNP)Rh[double bond, length as m-dash]C(F)(CF). (PNP)Rh[double bond, length as m-dash]CF could also be obtained the reaction of (PNP)Rh(TBE) with MeSiCF/CsF, with an admixture of (PNP)Rh(CF), where TBE = -butylethylene.

Reactivity of a Pd(I)-Pd(I) dimer with O2: monohapto Pd superoxide and dipalladium peroxide in equilibrium.

The Pd(I)-Pd(I) dimer [((F)PNP)Pd-](2) reacts with O(2) upon exposure to light to produce either the superoxide ((F)PNP)PdO(2) or the peroxide [((F)PNP)PdO-](2), which exist in equilibrium with free O(2). Both complexes contain square-planar Pd(II) centers. The unpaired electron density in ((F)PNP)PdO(2) is localized on the superoxide ligand.