The Nucleophilic Displacement of the Nitrate Group. 1. The Hydrolysis of a Series of Benzyl Nitrates in Water

Abstract

The temperature dependence of the rates of hydrolysis of a series of substituted benzyl nitrates in water provided estimates of the heat capacities of activation. These values varied with the substituent over a wide range (−28 → −101 cal mol−1 deg−1).An approximate parallelism has been found to exist between the ΔCp≠ values and kinetic α-deuterium effects obtained for the nitrates and chlorides.While recognizing the existence of specific factors contributing to individual differences, the relative values of these parameters for the individual members of the two series provide a useful measure of the ionic character of the transition state.

Neutral Solvolysis of Acyl Carbon and the Temperature Dependence of the Kinetic Solvent Isotope Effect

“…values, like those for acetic and propionic anhydrides (I), do not decrease smoothly with increasing temperature (see Fig. 1) as had been found in the hydrolysis of halides (2), sulfonyl chlorides (23), nitrates (24), and alkyl trifluoroacetates (5); the last presumably reacting by a BAC2 mechanism.…”

Reaction Mechanisms Underlying Unfunctionalized Alkyl Nitrate Hydrolysis in Aqueous Aerosols

“…Two main factors affect kinetics of the reactions: ring strain in the TSs and higher nucleophilicity of the N site. For example, in the AN + H 2 O → alcohol + HNO 3 reaction outlined in many studies, ,− the H 2 O molecule can attack both carbon and nitrogen sites, but the barrier height related to the attack on the N site is lower than that of the alkyl carbons because the negative partial charge of the bridging oxygen in C–O–NO 2 is more than that of the dangling oxygen atoms. Therefore, it is easier for the bridging oxygen to form hydrogen bonds with the water molecule and permit the nucleophilic attack of water oxygen on the positively charged nitrogen atom.…”

“…To scan the reaction paths, several scenarios were considered. For the reaction of ANs with a single water molecule, water was treated mainly as a nucleophilic agent , that might cleave into OH and H upon reaction. Also, the inhibitory/catalytic role of water in auto-cleavage/intramolecular rearrangement of ANs was studied as a possible alternative.…”

Thermodynamics of basic ionization of some aminoethers in water

“…This positive shift in AC,* was attributed to a temperature dependent solvation effect, a rationalization supported by reference to corresponding effects found for ACPao for the aqueous ionization of anisic acid (3,4). Further support for this view is apparent in the hydrolysis of 3-methoxybenzyl nitrate (5).…”