Friday, Dec 2 @ 2:00PM in Beren Conference Center (G192 Slawson)

Organic Electrosynthesis of Carboxylic Acids Facilitated by CO₂-eXpanded Electrolytes (CXEs)

{Abstract}

The increase in global carbon dioxide (CO₂) emissions has driven sustainable chemists and engineers to develop technologies that focus on the sustainable production of fuels and chemicals. To further enhance the sustainability of these technologies, researchers have utilized electrochemistry to reduce CO₂ to form fuels and chemicals. Carbon dioxide is a wonderful carbon source due to its high availability and low cost; however, it is very difficult to use in electrochemistry. The thermodynamic stability and low selectivity of carbon-carbon bond formation make CO₂ electrochemistry very challenging. Instead of direct CO₂ reduction, organic electrosynthesis can utilize CO₂ as a reactant circumventing its stability. We have investigated the carboxylation of acetophenone to atrolactic acid as a function of CO₂ concentration by utilizing CO₂ eXpanded Electrolytes or CXEs. CXEs are capable of we overcome the mass transfer limitations and low selectivity associated with traditional electrochemical systems by supporting multi-molar concentrations of CO₂ in the liquid phase. As the CO₂ concentration increased, the selectivity shifted from producing 1-phenylethanol ([CO₂ ] < 0.1 M) to exclusively producing atrolactic acid ([CO₂ ] > 1.7 M).

The electrochemical reduction of acetophenone was further studied using finite element analysis (FEA) simulation to provide insights into the kinetics of the acetophenone carboxylation. Typically, kinetic information on irreversible systems is not easily attainable through traditional electrochemical techniques. Simulations were developed to regress key kinetic parameters characteristic of the acetophenone reduction and helped identify that the electrochemical chemical electrochemical (ECE) reaction pathway is the most likely reaction pathway. Additionally, we identified the first electron transfer as the rate-determining step. These simulations provide insight into fundamental electrochemical information previously unavailable for acetophenone reduction.