Melt crystallization of 2,4-dinitrochlorobenzene: Purification and process parameters evaluation

This work evaluated the pot and 2,6-DNCB mixture was measured and modeled to reveal the relationship between temperature and composition. Next, according to the phase diagram, an operation trajectory was optimized to balance the purity and yield to meet the industrial application requirement. The results indicated the purity and yield of 2,4-DNCB could reach 99.48% and 66.6%, respectively. During the trajectory optimization, process parameters including the separation performance Kc and crystal packing structure parameters τaveandΦ were used to describe the separation process. At last, boundary limitation (BL) and sweating intensity (SI) models were proposed to describe the pores in crystal packing structure and explain the sweating behavior, respectively. The results revealed the features of pores connection degree in high porosity system and sweating intensity impacts on the product yield and purity, which were both highly consistent with the experimental results. Overall, melt crystallization is an effective technique for 2,4-DNCB purification, and the proposed evaluation parameters can describe the experimental results precisely.