Polymorphism, morphologies and bulk densities of DL-methionine agglomerate crystals

摘要

To explain the experimentally determined operation conditons to produce DL-methionine (DL-Met) crystalline particles haivng hgih bulk density from reaction crysalliation, the morphoogies of DL-Met agglomerated crystals in additon to the crysallogrpahic structres were investigated. The existence fo the third polymoprhy, the γ-form was confirmed. Both the observed and predicted morphologies for he elementary particles were plate-like and were strongly affected by the crystal structures. The effect of polymorphism and morphology of resulting particles from reaction crystallization on the bulk density of the product agglomerates was discussed. The bulk density was strongly affected by the agglomerationand the morphology of the constituent elementary crystals. The morphology change with pH of the solution was also experimentally found. Local pH druing the reaction crystallization is concluded essential to determine the morphoogy of the elementary particle, and hence the bulk denstiy of the aggomeraes.