Effect of a bimetal Mn/Zn catalyst supported on activated carbon for selective oxidation of ethyl lactate to ethyl pyruvate

Abstract

This study investigated the conversion of ethyl lactate to ethyl pyruvate using a bar reactor. A novel heterogeneous catalyst, AC/Mn/Zn (manganese and zinc supported on mesoporous activated carbon), was synthesized using a cost-effective and efficient approach that prioritizes affordability and accessibility. This approach utilizes readily available starting materials and a streamlined process, making the AC/Mn/Zn catalyst commercially attractive for large-scale production. Furthermore, the synthesis minimizes the use of harmful chemicals and generates minimal waste, contributing to an environmentally friendly process that aligns with growing demands for sustainable production methods. Additionally, the straightforward procedures employed allow for simple and replicable catalyst production, ensuring consistent quality control. Following synthesis, various characterization techniques (XRD, TPD, BET, FT-IR, HR-SEM, HR-TEM) confirmed the successful formation of the AC/Mn/Zn catalyst with desired properties. The AC/Mn/Zn catalyst possessed a unique combination of Brønsted and Lewis acid sites, making it ideal for the target reaction. Reaction parameters were optimized, with a temperature of 90 °C, WHSV of 1.0 h⁻¹, atmospheric pressure, and air as the oxidant being employed. The AC/Mn/Zn catalyst exhibited exceptional performance, achieving a remarkable 91 % conversion and 90 % selectivity for ethyl pyruvate, surpassing other investigated catalysts. This success is attributed to the well-designed structure incorporating zinc into the AC-supported manganese. Interestingly, the formation of additional acidic compounds beyond the desired reaction time was observed, suggesting potential side reactions. Further investigation into these side reactions is necessary for complete optimization. The AC/Mn/Zn catalyst offers a compelling combination of high performance, a cost-effective and environmentally friendly synthesis method, and straightforward production procedures. These factors highlight its potential as a promising candidate for industrial ethyl pyruvate production.