Polyolefin Degradation by Application of Tandem Catalytic Cross-Alkane Metathesis : Process Evaluation for Industrial Application
Year: 2023
Type: dissertation
Abstract: While waste generation is continuously high and increasing even, the overall awareness of plastic waste accumulation in landfills and oceans is rising and plastic recycling has become a “hot topic” in politics, industry and academia alike. Mechanical plastic recycling continues to be the established method, but chemical recycling is quickly garnering more attention as plastic producers invest in chemical recycling technologies and researchers investigate appropriate strategies.\nPolyolefins are recognized as particularly difficult-to-chemically-recycle plastics due to the inherent inertness of C−C and C−H single bonds and lack of exploitable functionalities for chemical transformation. However, it is these polymers (HDPE, LDPE & PP) that represent about 50% of the annually converted plastics in Europe. To make matters worse, they are primarily utilized in production of packaging, which tends to be of short lifetime if not intended for single-use applications altogether. The catalytic conversion of such polymeric materials into significantly smaller molecules, ideally new building blocks for reuse in future applications has become a particularly challenging field.\nIn a joint project of the Institute of Catalysis (INCA) at JKU Linz and Borealis Polyolefine GmbH, the previously published cross-alkane metathesis (CAM) process was to be investigated with respect to its applicability in polyolefin degradation. It involves a catalytic tandem reaction, during which the polyolefin and an n-alkane solvent are dehydrogenated, cross-metathesized and re-hydrogenated using a partially heterogeneous catalyst system that comprises a heterogenized Ir-based catalyst for de- and re-hydrogenation and a Re-based catalyst for olefin cross-metathesis. In this dissertation the results of the investigation of the tandem catalyst system and its application in cross-alkane metathesis of polyethylene and other polyolefins are presented.
Author: Faust, Kirill
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7005033518