Synthesis of 2-Methylene-1,3-dioxolane over Silica Gel

• Ethan McClaine, Chemical Engineering, University of Delaware

• Raul Lobo, CLAIRE D. LECLAIRE PROFESSOR OF CHEMICAL ENGINEERING, University of Delaware
• Nicholas Houck, Chemical and Biomolecular Engineering, University of Delaware

Cyclic ketene acetals (CKAs) can be inserted into polyolefin polymer chains, facilitating uniform bond scission when undergoing hydrolysis, and letting commercial plastics be more (bio)degradable and easier to recycle. The production scheme of CKAs, however, generates more waste than product. The reaction takes several days and produces sodium chloride, methanol, and ammonia as by-products (all waste).1

We propose a new catalytic process for using 1,3-dioxolan-2-yl methanol and silica gel (SiO₂) to produce CKAs. Acetic acid dehydration to ketene was tested first to ensure previous literature reports are reliable. After proving that the formation of ketenes was possible in the acetic acid reaction, a similar reaction approach will be investigated for 1,3-dioxolan-2-yl methanol dehydration.

Our method bubbles helium gas through the 1,3-dioxolan-2-yl methanol (DM) solution and flows the reactant into a valve controlling gas flow into the reactor. The combined DM and helium go through the reactor and the silica gel catalyst, producing water and 2-methylene-1,3-dioxolane (the desired CKA). The products were analyzed via a mass spectrometer to show the relative amounts of each product. Initial results should show the formation of 2-methylene-1,3-dioxolane as well as water.

[1] Argade, A. B.; Joglekar, B. R. A short and simple synthesis of ketene acetals Synth. Commun. 1993, 23 (14) 1979– 1984 DOI: 10.1080/00397919308009857