title: Mechanisms of lactone hydrolysis in neutral and alkaline conditions.
abstract: The neutral and base-catalyzed hydrolysis of nine carboxylic acid esters was studied using a hybrid supermolecule-PCM approach including six explicit water molecules. The molecules studied included two linear esters, four β-lactones, two γ-lactones, and one δ-lactone: ethyl acetate and methyl formate, β-propiolactone, β-butyrolactone, β-isovalerolactone, diketene (4-methyleneoxetan-2-one), γ-butyrolactone, 2(5H)-furanone, and δ-valerolactone. DFT and ab initio methods were used to analyze the features of the various possible hydrolysis mechanisms. For all compounds, reasonable to very good qualitative and quantitative agreement with experimental work was found, and evidence is provided to support long-standing hypotheses regarding the role of solvent molecule as a base catalyst. In addition, novel evidence is presented for the existence of an elimination-addition mechanism in the basic hydrolysis of diketene. A parallel work addresses the acid-catalyzed hydrolysis of lactones.
authors.affiliation: Department of Physics, School of Engineering and Physical Sciences, Heriot-Watt University, EH14 4AS, Edinburgh, United Kingdom.
authors.forename: Rafael
authors.initials: R
authors.lastname: Gómez-Bombarelli
authors.forename: Emilio
authors.initials: E
authors.lastname: Calle
authors.forename: Julio
authors.initials: J
authors.lastname: Casado
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry; D002384:Catalysis; D004952:Esters / Q000737:chemistry; D006868:Hydrolysis; D007783:Lactones / Q000737:chemistry*; D015394:Molecular Structure; D014867:Water / Q000737:chemistry
chemical_list: D000468:Alkalies; D002264:Carboxylic Acids; D004952:Esters; D007783:Lactones; D014867:Water