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Lanthanide metal ionic liquids (MILs) are tunable catalysts for the glycolysis of poly(ethylene terephthalate). Enhanced cooperativity with high ionic liquid : metal salt ratios lowers the required metal content to increase catalyst sustainability. 

Reaction of poly(vinyl chloride) (PVC) with 5 equiv. of triethyl silane in THF, in the presence of in situ generated (xantphos)RhCl catalyst, results in partial reduction of PVC via hydrodechlorination to yield poly(vinyl chloride- co -ethylene). Increasing catalyst loading or using N , N -dimethylacetamide (DMA) as a solvent both diminished selectivity for hydrodechlorination, promoting competitive dehydrochlorination reactions. Reaction of PVC with 2 equiv. of sodium formate in THF in the presence of (xantphos)RhCl affords excellent selectivity for hydrodechlorination along with complete PVC dechlorination, yielding polyethylene-like polymers. Higher catalyst loadings were necessary to activate PVC towards reduction in this case. In contrast, reaction of PVC with 1 equiv. of NaH in DMA, in the presence of (xantphos)RhCl, exhibited good selectivity for dehydrochlorination, as well as much higher reaction rates. These results combined shed light on the interplay between critical reaction parameters that control PVC's mode of reactivity. 

Combined hydrodechlorination and Friedel–Crafts alkylation of poly(vinyl chloride) can contain secondary Friedel–Crafts alkylation reactions that modify thermal properties of products, depending on the arene substrate and reaction temperature.