Nucleophilic catalysis of the hydrolysis of phenyl acetates by the succinimide anion in aqueous solution

Journal Article · Fri Sep 10 00:00:00 EDT 1982 · J. Org. Chem.; (United States)

DOI:https://doi.org/10.1021/jo00140a020· OSTI ID:6799784

Huffman, R W

Kinetic studies were conducted on the disappearance of some phenyl acetates in aqueous solutoins buffered by succinimide/succinimide anion at 30/sup 0/C. The most reasonable mechanistic scheme, compatible with the data, involved nucleophilic displacement by the succinimide anion on the ester. Phenyl acetate was the only substrate that had no buffer-dependent disappearance. Although succinimide is converted to succinamic acid by hydrolysis in the buffered solutions used, only about 6% or less of succinimide is lost during the time required for substrate disappearance. The nucleophilic role for the succinimide anion was assigned on the basis of a high Hammett rho value (2.25) for the three phenyl acetates studied and the low solvent deuterium isotope rate effect of 1.13 obtained for the p-nitrophenyl acetate substrate. The low value for the nucleophilic rate constant obtained by p-nitrophenyl acetate cannot be ascribed to ground-state charge delocalization as estimated by MINDO-3 calculations utilizing frontier molecular orbital theory. This observed low reactivity is therefore thought to be the result of a tight anionic solvation shell in the aqueous solutions employed. Media studies in different salts on this reaction show little effects. Finally, the absence of third-order rate terms involving succinimide in this reaction is due to the inability of the succinimide anion to have its nucleophilicity increased by proton removal in the transition state.

• Research Organization: Northern Arizona Univ., Flagstaff
• OSTI ID: 6799784
• Journal Information: J. Org. Chem.; (United States), Journal Name: J. Org. Chem.; (United States) Vol. 47:19; ISSN JOCEA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400302* -- Organic Chemistry-- Isotope Effects-- (-1987)
ACETIC ACID ESTERS
AQUEOUS SOLUTIONS
AROMATICS
CARBOXYLIC ACID ESTERS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
DEUTERIUM
DICARBOXYLIC ACIDS
DISPERSIONS
ESTERS
EXPERIMENTAL DATA
HYDROGEN ISOTOPES
HYDROLYSIS
HYDROXY COMPOUNDS
IMIDES
INFORMATION
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
LYSIS
MIXTURES
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHENOL
PHENOLS
SOLUTIONS
SOLVOLYSIS
STABLE ISOTOPES
SUCCINIC ACID