Theoretical insight into the temperature-dependent acetonitrile (ACN) solvent effect on the diacetone diperoxide (DADP)/1,3,5-tribromo-2,4,6-trinitrobenzene (TBTNB) cocrystallization

Abstract

A temperature-dependent diacetone diperoxide (DADP)/1,3,5-tribromo-2,4,6-trinitrobenzene (TBTNB)-acetonitrile (ACN) interfacial model was constructed to study the solvent effect on cocrystal formation. The DADP/TBTNB cocrystal morphology was predicted by Growth Morphology Model. The interfacial models were built and simulated by molecular dynamics (MD) method at temperatures ranging from 298 to 358K with 10K intervals. The surface electrostatic potentials of DADP/TBTNB cocrystal framework and ACN molecule were calculated at B3LYP/6-311++G (d, p) level of density functional theory. Properties of the interfacial model (i.e. surface areas and polarities) have been recognized to be significant factors that influence the preparation of the cocrystal. The results of the properties and energy analyses indicate that ACN molecules adsorbed on (11−1) cocrystal surface are stronger than those on (200), (110), and (020) surfaces; DADP molecules are more inclined to interact with TBTNB in (200) and (110) interfacial models. Combining with the similar solubility parameter values of DADP and TBTNB in ACN solvent, the solvent effects on the DADP/TBTNB cocrystallization could not only inhibit growth of the cocrystal in a special face but promote the interaction strength between coformers. The influence becomes more significant as the increasing of properties (such as S, polarities). In addition, the theoretical study shows that the best condition of forming DADP/TBTNB cocrystal in ACN solvent is near 338K.