Controlling the Crystal Morphology and Polymorphism of 2,4-Dinitroanisole

Abstract

Nitroaromatic 2,4-dinitroanisole (DNAN) was used as a model compound for the study of surface-poisoning effects in crystallization. In addition to the expected solvent effect, it was found that the concentration of solutions and presence of additives control the formation of polymorphs and forms. In some cases, aromatic and/or nitro-containing additives interact with DNAN, probably competing with intrinsic intermolecular interactions that allow the formation and growth of DNAN crystals. It was also found that singlecrystal-to-single-crystal phase transitions take place between two β forms and from the β form to the α form. This β-to-α transformation is most probably possible because of a similarity between the two crystal structures. Hence, the barrier for this transformation is rather low. Nevertheless, the formation of α-DNAN in the typically β morphology introduces strain in the crystals, causing defects. It was also found that the orientations of the molecules against the unit cell faces for the two α forms (blocks and needles) are markedly different.

Rapid and High‐Yielding Formation of CL‐20/DNDAP Cocrystals via Self‐Assembly in Slightly Soluble‐Medium with Improved Sensitivity and Thermal Stability

“…For explosives, the crystal morphology, size, and arrangement state play a great impaction for many military applications. Usually, explosive crystal with spherical shape, narrow size distribution, and good dispersion performance presents high charge density, low mechanical sensitivity, good flowability and mechanical properties for both the powder and its compositions . The use of molecular additives is an effective approach to gain control over crystal morphology .…”

High-pressure structural studies and pressure-induced sensitisation of 3,4,5-trinitro-1H-pyrazole

“…For example, five polymorphs of RDX (1,3,5trinitrohexahydro-1,3,5-triazine) have been identified, including three high-pressure forms. [3][4][5][6][7][8] Three polymorphs of DNAN (2,4-dinitroanisole) 9 and five solid forms of HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) have been identified. 10 In another study, the crystal structure of a high-pressure phase of CL-20…”

Tuning the Solution-Mediated Concomitant Phase Transformation Outcome of the Piroxicam Monohydrate by Two Hydroxyl-Containing Additives: Hydroxypropyl Cellulose and H2O

“…Polymorphism and solvate-polymorphism are common phenomena in the manufacture of pharmaceuticals. , The crystals of pharmaceuticals may form different morphologies and polymorphs under different conditions such as the degree of supersaturation, temperature, and pressure and so on. − Sometimes, two or more polymorphs would crystallize under essentially the same conditions simultaneously, which is called concomitant crystallization. − This will affect quality and even safety of a drug product. So, the crystallization of a pharmaceutical is a requisite step for the pharmaceutical industry, and it is essential for the pharmaceutical industry to control the morphology and obtain the pure polymorph. − …”