Graduate Thesis Or Dissertation
 

Structure-Property Relationships of Supported Palladium and Rhenium Oxide for the Alkane Rearrangement of Hydrocarbons and Deconstruction of Polyethylene via Tandem Dehydrogenation and Olefin Metathesis

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/2f75rh77w

Descriptions

Attribute NameValues
Creator
Abstract
  • The rapid accumulation of plastic waste in landfill, waterways and oceans is becoming a critical problem, one that current recycling technologies are not capable of solving. Recent proposed approaches in the depolymerization of waste plastics employ an Olefin-Intermediate Process (OIP), where feedstocks like polyolefin plastics are ‘activated,’ producing an olefin intermediate. This olefin can then be reacted with an orthogonal and tandem chemistry, that results in new overall reaction pathways to alkanes or alkenes without the need for exogenous hydrogen. This paper outlines an OIP that leverages a fully heterogeneous, tandem, catalyst system that couples dehydrogenation and olefin metathesis (Tandem D/OM) to depolymerize polyethylene feedstocks at temperatures < 200C. For example, at 200C, with excess n-pentane solvent, Tandem D/OM achieves 65% conversion of a 5 wt% (g/g) n-eicosane (a model compound for polyethylene) in 15 hr. Furthermore, applications to polyethylene (Mw = 54 ± 2 kDa) exhibit significant accumulation of liquid alkane products with a demonstrated 90% reduction in molecular weight. Dehydrogenation is proposed to be limiting in Tandem D/OM, thus various dehydrogenation catalysts and their effects on reaction activity are investigated. Using a gamma-alumina Pd-based dehydrogenation catalyst showed a 114% activity increase compared to results using a platinum-based or tin-platinum-based catalyst. The method of catalyst preparation, prior to reaction, demonstrated in-situ synthesis of a bifunctional catalyst with reduced rates of deactivation. Interestingly, though kinetic investigations confirm that dehydrogenation is the limiting chemistry of Tandem D/OM, the bifunctional catalysts demonstrate a surprising promotion of olefin metathesis activity.
Contributor
License
Resource Type
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Rights Statement
Related Items
  • Research Group Website
Funding Statement (additional comments about funding)
  • This venture would not have been possible without the generous support from the National GEM Consortium and Oregon State University, who helped fund my research.
Publisher
Peer Reviewed
Language

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details MooreSelenaC2024.pdf 2024-03-05 Public Download