Production of Bio-based Lactone Monomers for Intrinsically Recyclable Plastics

The development of intrinsically recyclable plastics is crucial to halt the accumulation of waste plastics in the environment. While great strides have been made in the design of novel polymers that exhibit desirable qualities and degrade back to their respective monomer at mild conditions, the development of scalable synthesis of the monomers for these plastics lags behind. This work aims to develop methods for the synthesis of monomers using heterogeneous catalysts to allow for scaling-up. First, we used a high-throughput computational method to screen binding energies of key reaction species of more than 200 zeolite frameworks to identify potential catalysts that would selectively catalyze our probe reaction of methyl lactate lactonization to lactide. From these computations, we identified titanium-containing zeolite with the MEL topology as a promising catalyst for this reaction in the gas phase. Continuous-flow kinetic studies revealed that Ti-MEL showed 40% increased selectivity to the lactide product at over twice the conversion as Ti-BEA and Ti-MFI. Second, we show a potential pathway for the production of α-cyclohexyl-δ-valerolactone (CVL) starting from formaldehyde and δ-valerolactone (DVL). We developed a continuous gas-phase reactor using alkaline earth oxides supported on silica as catalysts for an aldol condensation reaction. CaO and BaO showed 90% and 83% selectivity, respectively, to α-methylene-δ-valerolactone at 60% DVL conversion. Following this, MVL was functionalized with 1,3-butadiene in a Diels-Alder addition to form the unsaturated form of our desired CVL monomer (CeVL). This reaction was catalyzed over Lewis acid with selectivities reaching 90% of Sn-BEA catalysts at mild temperatures of 55 °C. Finally, the CeVL was able to be hydrogenated to CVL over commercially available palladium on carbon catalysts with flowing hydrogen.

Name thesis:degree_name

Master

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Chemical Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2024

Author dc:creator

• Baston, Lucas A.

Advisor dc:contributor.advisor

• Román-Leshkov, Yuriy

Statement dc:rights

• In Copyright - Educational Use Permitted
• Copyright retained by author(s)

Licence dc:rights.uri

• https://rightsstatements.org/page/InC-EDU/1.0/

Handle dc:identifier.uri

https://hdl.handle.net/1721.1/155329

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/155329