Reaction paths of the water-assisted neutral hydrolysis of ethyl acetate.
Density functional theory calculations were conducted on the title reactions with explicit inclusion of a variety of water molecules. Concerted reaction paths were examined first in the reaction model, ester(H2O)n --> MeCOOH(H2O)(n-1)EtOH, with n = 1-4. Their Gibbs activation energies are much larger than the experimental value, and the concerted paths are unfavorable. Various stepwise paths were investigated, and the ester(H2O)4 reactant gives a likely stepwise path. The n = 4 based reaction models, n = 4 + 5 and n = 4 + 12, were found to have similar proton-relay shapes with good hydrogen-bond directionality. The distinction of either the concerted or the stepwise path is described by the position of only one proton in the "junction" water molecule.
Yamabe
Shinichi
S
Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan.
Tsuchida
Noriko
N
Hayashida
Yousuke
Y
D000085:Acetates / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D004583:Electrons; D006859:Hydrogen / Q000737:chemistry; D006868:Hydrolysis; D008958:Models, Molecular; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry; D014867:Water / Q000737:chemistry*
D000085:Acetates; D014867:Water; D002244:Carbon; C007650:ethyl acetate; D006859:Hydrogen; D010100:Oxygen