Continuous Synthesis of 1,3,2-Dioxathiolane 2,2-Dioxide (DTD) by Hydrogen Peroxide with Titanium Silicalite-1 Catalyst Using a Fixed-Bed Reactor

Abstract

1,3,2-Dioxathiolane 2,2-dioxide (DTD) plays a significant role as an electrolyte additive in lithium-ion batteries. It can enhance battery performance, stability, and safety. Additionally, it is a commonly used hydroxylation reagent in organic chemistry. This paper presents a highly efficient, safe preparation, and environmentally friendly continuous DTD synthesis process that does not require catalyst separation. A fixed-bed reactor was constructed with spherical TS-1 as the catalyst and H₂O₂ as the oxidizer. Under optimized reaction conditions, efficient oxidation of ethylene sulfite (ES) was achieved using dimethyl carbonate as a solvent. The process involved controlling the reaction temperatures at gradients of 10 and 5 °C, respectively, maintaining a molar ratio of H₂O₂ to substrate of 1.05:1, a liquid hourly space velocity of 0.6 h^–1, and using a 30 wt % concentration of H₂O₂ at a substrate concentration of 1 mol/L. The conversion rate was up to 99.5%, and the selectivity of DTD was 99.1%. To prevent hydrolysis of DTD, a continuous separation operation was initiated immediately after the completion of the reaction, and the yield of DTD reached 96%. The successful application of this process not only improves the production efficiency of DTD and reduces the production cost but also establishes the foundation for the industrialized continuous production of DTD.