Reduction of detonating liquid nitromethane’s chemical reaction-zone length by chemical sensitization

Abstract

We examine the effect of the addition of small amounts of the organic base diethylenetriamine [NH2(CH2CH2)NH(CH2CH2)NH2] on the chemical reaction-zone length (CRZ) of detonating liquid nitromethane (CH3NO2). This is done by making accurate measurements of the detonating materials’ diameter-effect curves (i.e., detonation speed versus lateral charge size) as a function of the amount of chemical sensitizer added. Detonation speed experiments were performed with additions of the organic base in amounts between 0.00 and 0.25wt%. Reductions in the CRZ of as much as 25% were produced by base addition. Most of the reduction in length is produced by very small amounts of base addition—i.e., ca. 0.05wt% of base or less (i.e., 1 molecule of the base per 3300 nitromethane molecules or less). Measured detonation speeds are given for five compositions of nitromethane and base as a function of charge internal diameter. Absolute CRZs are estimated using a value of liquid nitromethane’s CRZ obtained by other means. Earlier work has determined a relationship between the failure diameter of sensitized nitromethane compositions and the amount of base addition. Here we have found a relationship between relative CRZ and the amount of base addition. By eliminating the base parameterization, we give a phenomenological relationship between the failure diameter of such materials and their steady one-dimensional CRZs.