Acrylate synthesis from carbon dioxide - ethylene coupling catalyzed by first-row transition metal complexes

Abstract

Carbon dioxide (CO2) is an abundant and renewable carbon source than can be used as feedstock for the synthesis of value-added materials. One such material is acrylic acid, and acrylate derivatives, which can be used in the production of super absorbent polymers, adhesives, and coatings. The oxidative coupling of CO2 and ethylene offers a more atom-economical and sustainable approach acrylic acid formation relative to the petroleum-based synthesis currently in use. This dissertation examines the ability of the first-row transition metals Nickel (Ni) and Iron (Fe) to yield acrylate from CO2 and ethylene. A wealth of research on Ni-mediated CO2-ethylene coupling reactions laid the groundwork for a variety of in-depth investigations into ancillary ligand effects and the role of additives in the multi-component system. Moderate improvements to catalytic activity were observed but ultimately the progress of this system has stalled, and investigations turned to the development of novel Fe complexes. A family of low valent Fe complexes were found to facilitate CO2-ethylene coupling. However, the insertion of two CO2 units was observed, resulting in the formation of the dicarboxylate product methylmalonic acid (MMA). A one electron oxidation was found to slow the rate of second CO2 insertion and mixtures of propionic acid (PA) and MMA were obtained.