Cleavage Alkylation Coupling with Versatile Amide-Based Eutectic Catalytic Systems

This study introduces amide-based eutectic solvents (ESs) as a versatile and high-efficiency catalytic system for converting polyolefin waste into liquid alkanes in coupled cracking–alkylation. Owing to the rich variety of molecular active species (i.e., [AlCl3(Acetamide)n] and AlCl3) and ionic active species (i.e., [Al2Cl7]− and [AlCl2(Acetamide)n]+) present in the catalytic system, carbocation intermediates can be stably generated, thereby facilitating hydride transfer and cleaving polyethylene C–C bonds during the cracking cycle. For the first time, we establish a direct and quantitative correlation between Al species diversity and carbocation concentration, validated by Et3SiH chemical trapping combined with multinuclear NMR and operando IR spectroscopy. We demonstrate tunable selectivity to either light gasoline (C4–C10) or aviation kerosene (C7–C18) with isopentane or isopentene as alkylation reactants. Time-resolved product analysis together with isotopic labeling clearly confirms that aviation kerosene-range hydrocarbons (C7–C18) are primarily derived from polyethylene fragments and chain-extended by iC5= alkylation. Ab initio molecular dynamics simulations reveal that cooperative dissociation of diverse Al species sustains a stable tert-butyl and chloromethyl carbocations population, rationalizing the superior catalytic efficiency of Acetamide-1.5AlCl3. These advances provide both mechanistic clarity and a broadly applicable strategy for selective production of gasoline- and kerosene-range hydrocarbons from plastic waste, offering new opportunities for premium-grade fuel generation.