Quantum mechanical and molecular mechanical studies of the hydrolysis of methyl nitrate and the solvent effect

The alkaline hydrolysis reaction of methyl nitrate was simulated by quantum mechanical and molecular mechanical methods. The gas-phase reaction was calculated to proceed with no barrier when ab initio calculations at the STO-3G level were utilized, and with a very small barrier (5.70 kJ mol−1) when the MINDO/3 method was applied. In solution, the solvation energy was estimated to be 70.33 kJ mol−1 by molecular mechanical calculations. Thus the activation energy (76.03 kJ mol−1) of alkaline hydrolysis of methyl nitrate was found to be in good agreement with the available experimental value (82.42 kJ mol−1). The results indicated that the substantial activation barrier in alkaline hydrolysis was essentially solvent-induced.