Theoretical study of catalytic baeyer-villiger oxidation with applications in polyolefin degradation

• Main Author: Wijaya, Christopher Kevin
• Other Authors: Naohiko Yoshikai
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Science::Chemistry::Physical chemistry::Catalysis; Science::Chemistry::Physical chemistry::Physical organic chemistry
• Online Access: https://hdl.handle.net/10356/144509
• Institution: Nanyang Technological University

Baeyer-Villiger oxidation is a common organic reaction used for many different purposes, known for its robustness and diverse substrate scope. With the rising interest in developing environmentally friendlier versions, the reaction that is catalyzed by Co(III) with N,N′-bis(salicylidene)ethylenediamine (salen) derivatives is found to be particularly appealing. Various greener improvements were effectively combined compared to the original reaction, while maintaining high yields and good enantioselectivity altogether. Potentially, the catalyst could also be developed further to aid polyethylene degradation. In this work, a theoretical study involving DFT calculations was carried out to study this class of catalysts. The uncatalyzed Baeyer-Villiger oxidation between a model ketone, butanone, and hydrogen peroxide was first investigated to find possible mechanistic pathways. The ground state multiplicity of the model catalyst, Co(III)-salen, was then analyzed further. This information was then used to elucidate the catalytic reaction pathway and mechanism. In short, it was found that the major catalyzed mechanism consists of two major steps, Criegee intermediate formation and alkyl migration. The model catalyst was found to lower the activation energy barrier at every step, thus improving the rate of reaction. To gain further insights into the catalyst mode of action, a modified version of the catalyst was investigated. The modifications affected the cis position relative to the substrate and resulted in modest activation energy lowering compared to that of the original catalyst.