Confirmation of the Molecular Structure of Tetramethylene Diperoxide Dicarbamide (TMDD) and Its Sensitiveness Properties

Abstract

Conjecture existed as to the molecular structure of the crystalline organic peroxide reaction product derived from the acidified aqueous mixture of urea, formaldehyde, and hydrogen peroxide. This study used X-ray crystal structure determination to unequivocally define the reaction product as the 14-membered ring structure tetramethylene diperoxide dicarbamide (TMDD). Crystals of TMDD belong to the monoclinic space group Pc, a = 4.587(4), b = 16.080(2), c = 6.690(5) Å, β = 107.44(5)°. The crystal contains one crystallographically independent molecule with approximate Cs symmetry. Intramolecular π-stacking of the carbonyl groups is a feature, while intermolecular H-bonding between the N-H and C═O functionalities affords linear polymeric strands that is associated with the extremely fine needle crystal morphology that necessitated synchrotron radiation for the structure determination. Sensitiveness testing examining susceptibility to initiate due to heat, impact, friction, and electrostatic stimuli was conducted to gauge the hazards associated with the material. It was revealed to be a primary explosive, particularly susceptible to impact initiation.

Crystal Structure, Sensitiveness and Theoretical Explosive Performance of Xylitol Pentanitrate (XPN)

“…This is significantly more sensitive than PETN (40) and similarly impact sensitive compared to lead azide (30), indicative of a primary explosive [31,32]. Intuitively, the volume of gas evolved from an energetic event may be diagnostic of the performance of an explosive [32]. An average gas evolution of 6 mL for XPN is consistent with a moder-ate-to high-performance explosive and is similar to that observed for PETN.…”

“…The explosive did not initiate when subjected to 16 N of frictional force. This is more sensitive than PETN (42 N) and ETN (40 N), but not as sensitive as lead azide (5 N), which is highly susceptible to ignition by frictional stimuli [31,32]. As with Rotter Impact analysis, BAM friction results depict XPN as a primary explosive.…”

“…Rotter Impact analysis of XPN produced an F of I of 25 (standardized to RDX, F of I = 80, Table 3) from 50 repetitions of the experiment with an average gas evolution of 6 mL. This is significantly more sensitive than PETN (40) and similarly impact sensitive compared to lead azide (30), indicative of a primary explosive [31,32]. Intuitively, the volume of gas evolved from an energetic event may be diagnostic of the performance of an explosive [32].…”

“…Sensitiveness testing data for XPN are included in Table 3, along with previously reported results for PETN, RDX and lead azide [18,31,32]. For comparison, Table 3 also includes sensitiveness data for ETN, measured at the Defence Science and Technology Group explosive testing facility [33].…”

“…Comparison of the T of I points of XPN, ETN, PETN and lead azide show XPN to be significantly more sensitive to elevated temperatures compared to lead azide, and similarly sensitive compared to ETN and PETN [18,19,31,32]. It should be noted, however, that the T of I and DSC experi-…”