Convenient preparation of fatty ester cyclic carbonates

The cyclic carbonate moiety finds many industrial applications because of its unique chemistry and properties. Phosgene, a highly toxic and corrosive reagent, has been utilized in the past to prepare low yields of fatty ester compounds (1) that contain a five-membered cyclic carbonate group. Herein, we show (CH3)(4)N+-HCO3, tetramethylammonium hydrogen carbonate (TMAHC), to react efficiently with methyl or 2-ethylhexyl 9(10)chloro-10(9)-hydroxyoctadecanoate at 50-55 degreesC to give methyl or 2-ethylhexyl 8-(2-oxo-5-octyl-1,3-dioxolan-4-yl)octanoate, 1a and 1b, respectively. These fatty acid ester carbonates were isolated in good yields ranging from 84% to 91% after purification by vacuum distillation. The purified fatty ester carbonate compounds were characterized by H-1 and C-13 nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and gas chromatography-mass spectrometry using electron impact ionization and positive chemical ionization techniques. This work demonstrates that the five-membered cyclic carbonate ring can be effectively introduced onto the alkyl chains of fatty acid esters using fatty ester chlorohydrins and (CH3)4N+-HCO3 chemistry. The well-known lubricating and polymeric properties of the carbonate moiety make these interesting cyclic oleochemical carbonates potential candidates for industrial lubricant, plasticizer, or polymer applications.