Catalytic Hydrogenolysis at Low Temperature and Pressure of Polyethylene and Polypropylene to Diesels or Lower Alkanes by a Zirconium Hydride Supported on Silica-Alumina: A Step Toward Polyolefin Degradation by the Microscopic Reverse of Ziegler-Natta Polymerization

Abstract

Cleavage and polymerization with the same catalyst: The catalyst system named in the title, which cleaves polyethylene and polypropylene under a hydrogen atmosphere, is also capable of polymerizing ethylene or propylene. This shows the close relationship between olefin insertion and β-alkyl elimination [Eq. (a), (P)=polymer chain(P)].

Efficient and selective degradation of polyethylenes into liquid fuels and waxes under mild conditions

“…In addition, branched, cyclic, and aromatic hydrocarbons are formed along with linear alkanes ( 5 , 8 , 11 ). As for the few milder PE recycling methods, some involve highly reactive radical species ( 12 ), whereas others form light hydrocarbon gases (methane and ethane) as the predominant products at high conversions ( 13 , 14 ).…”

Converting Waste Plastics into Liquid Fuel by Pyrolysis: Developments in China

“…Each has its own suitable process, as shown in Figure 28 [63,64], gasification [65,66], pyrolysis in supercritical water [67,68], coliquefaction with coal [69][70][71], and so on.…”

“…Hydrogenation [63,64] or hydrocracking involves the pyrolysis of plastics under a hydrogen atmosphere at a pressure of approximately 10 MPa, in three steps: depolymerization; hydrogenation of the liquid phase; and hydrogenation of the products. Owing to the presence of hydrogen, saturated hydrocarbons are produced in the reaction process.…”

Acid‐Catalyzed Cracking of Polyolefins: Primary Reaction Mechanisms

“…Dufaud and Basset demonstrated this by employing a zirconium hydride Ziegler-Natta catalyst to crack PE in a hydrogen atmosphere [25]. Ding et al studied the hydroconversion of PE with sulfided Ni and NiMo silica-alumina and compared these catalysts with HZSM-5 [76].…”