Growth behavior of β form DL-methionine crystal in the presence of inorganic acids and bases additives: A combination of experiments and molecular dynamics simulation study

Abstract

Crystal habit plays an important role in processing efficiency and product quality of DL-methionine (DL-met). In this paper, β form DL-met crystals with small aspect ratio are acquired by adding inorganic acids or bases during cooling or evaporation crystallization. Crystal growth experiments were performed to study the effect of additives on β form DL-met growth behavior. It is observed that increasing inorganic acid leads to a decrease while increasing inorganic base leads to a decrease first and then an increase in the growth rate of face (111), increasing inorganic acid leads to an increase then a decrease while increasing inorganic base leads to an increase in the growth rate of face (20–2). Molecular dynamics (MD) simulation is also carried out to predict the crystal habit and further study the mechanism, namely specific adsorption and solvation disruption, of additives on crystal growth. The influence of additives on crystal growth depends on the chemical nature of both crystal faces and additives and the concentration of additives.