When levulinic acid (CH3CCH2CH2CO2H) was hydrogenated at high pressure over a nickel catalyst at 220C, a single

Question:

When levulinic acid (CH3CCH2CH2CO2H) was hydrogenated at high pressure over a nickel catalyst at 220°C, a single product, C5H8O2, was isolated in 94% yield. This compound lacks hydroxyl absorption in its infrared spectrum and does not immediately liberate carbon dioxide on being shaken with sodium bicarbonate. What is a reasonable structure for the compound?