(335e) Selective Propylene Epoxidation from Plasma-Liquid Interactions Using Water As the Oxygen Source

Propylene oxide (PO) is a critical feedstock chemical for the large-scale production of polyurethane plastics and other compounds. While centralized and large-scale PO production has its advantages, due to the high toxicity of PO and the high transportation and long-term storage costs, there is also a strong incentive to produce PO on-site and in time on a smaller scale for applications that do not necessarily require a high volume and concentration. These niche applications include using PO as a fumigant and disinfectant for food,¹ a sterilizer for medical equipment,² and in forming modified food such as starch and alginate.³ Herein, we designed a plasma-liquid interaction catalytic process using only water and propylene (C₃H₆) as reactants to form PO. Plasma-liquid interactions can activate a wide range of chemical transformations at ambient conditions and form hydrogen peroxide (H₂O₂) with relatively high efficiencies.^{4, 5} The H₂O₂ generated in the plasma-liquid interactions serves as an oxidizing agent that epoxidizes the dissolved C₃H₆ over a titanium silicate-1 (TS-1) catalyst dispersed in the water solution. We explored different reactor designs to suppress the generation of deep oxidation products (i.e., CO₂) and reach a carbon-based selectivity of more than 98%. Also, the influence of plasma parameters on the activity and selectivity of PO production is investigated. The findings provide us with a method to produce on-demand PO using only C₃H₆ and water, which can be suitable for various specialized applications.

References

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4. Bruggeman, P. J.; Frontiera, R. R.; Kortshagen, U. R.; Kushner, M. J.; Linic, S.; Schatz, G. C.; Andaraarachchi, H.; Exarhos, S.; Jones, L. O.; Mueller, C. M.; Rich, C. C.; Xu, C.; Yue, Y. F.; Zhang, Y., Plasma-Driven Solution Electrolysis. J Appl Phys 2021, 129, 200902.
5. Wang, H. H.; Wandell, R. J.; Tachibana, K.; Vorac, J.; Locke, B. R., The Influence of Liquid Conductivity on Electrical Breakdown and Hydrogen Peroxide Production in a Nanosecond Pulsed Plasma Discharge Generated in a Water-Film Plasma Reactor. J Phys D Appl Phys 2019, 52, 075201.