Kinetics and Mechanism for the Basic Hydrolysis of BIS (2,2-Dinitropropyl) Acetal (BDNPA) and BIS (2,2-Dinitropropyl) Formal (BDNPF)

摘要

The kinetics for the alkaline homogeneous hydrolysis of bis (2,2-dinitropropyl) acetal (BDNPA) and bis (2,2-dinitropropyl) formal (BDNPF) in water and 53% dioxane-water with sodium hydroxide concentrations between 0.14 and 1.9 molar and temperatures between 40 and 70 C have been investigated. Both BDNPA and BDNPF were found to react with slightly more than four moles of base to yield nitrite, 1,1-dinitroethane, acetate and formate anions. Good second order rate constants were obtained for both BDNPA and BDNPF for the expression -d(BDNPA/dt = k sub 1 (BDNPA) = k sub 2(B(-)) (BDNPA), were k sub 1 is the first order rate constant with excess base, B(-). BDNPA and BDNPF were found to react faster in dioxane-water than in water. The rates of disappearance of both BDNPA and BDNPF were very nearly equal to one half the combined rates for the formation of nitrite and 1,1-dinitroethane anions, and suggest concurrent competing E-2 elimination (78 + for - 5%) and Sn-2 nucleophilic displacement (20 + or - 3%) reactions with base. On the basis of relative K sub 2 values, BDNPA and BDNPF were found to react forty times faster with aqueous base than triethyleneglycol dinitrate (TEGDN), but one thousand times slower than 1,3,5-triaza-1-3,5-trinitrocyclohexane (RDX). The kinetics of the alkaline hydrolysis of BDNPA and BDNPF are discussed in terms of the products formed, and mechanisms are suggested for the formation of these products.