Understanding the azeotropic diethyl carbonate–water mixture by structural and energetic characterization of DEC(H2O)n heteroclusters

摘要: Diethyl carbonate (DEC) is an oxygenated fuel additive. During its synthesis through a promising green process, DEC-water azeotrope formed, which decreases DEC production efficiency in the gas phase. Molecular information about this system scarce but could be of benefit understanding (and potentially improving) synthetic process. Therefore, we report detailed computational study conformers DEC, and their microsolvation with up to four water molecules, goal observed 1:3 DEC:H2O molar ratio. The most stable (with mutual energy differences < 1.5 kcal mol−1) contribute energetic structural properties complexes. An exhaustive stochastic exploration each potential surface DEC-(H2O) n , (where n = 1, 2, 3, 4) heteroclusters discovered 8, 7, 4 heterodimers, heterotrimers, heterotetramers, heteropentamers, respectively, at MP2/6-311++G(d,p) level theory. energies structures heterocluster size were refined using CCSD(T)/6-311++G(d,p). Energy decomposition, electron density topology, cooperative effects analyses carried out determine relationship between geometrical features non-covalent interaction types responsible for stabilization. Our findings show that electrostatic exchange are stabilization, also suggest weakening among hydrogen bonds when more than three molecules present. All described results complementary explanation molecular experimental ratio (DEC:H2O) azeotrope.