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

Crystal growth rates and secondary nucleation threshold for γ-dl-methionine in aqueous solution

“…The morphology of g-DL-met is thin rod-like, prism-like, or plate-like having a hexagonal cross section [6,13]. For this study the shape of the seed crystals (g-DL-met crystals) obtained from an aqueous solution is plate-like having a hexagonal cross section, but the shape is not perfect.…”

“…It is also used in active pharmaceutical ingredients, and as a precursor to other amino acids. DL-met has previously been shown to exhibit polymorphism and exists in the solid phase as a-DL-met, b-DL-met, and g-DL-met [5,6]. a-DL-met and b-DL-met forms are almost equally stable [5], and the crystal structures of each polymorph are known [7].…”

“…b-DL-met was discovered accidentally while attempting to grow a-DL-met crystals of greater plate thickness. Moreover, a-DL-met crystals can be obtained by the reaction crystallization of aqueous solutions of sodium methioninate (Na-met) using liquid acids such as hydrochloric, acetic, nitric, sulfuric, or formic acids [6]. Matsuoka et al [6] reported the third polymorph, g-DL-met, as well as its preparation method and crystal structure.…”

“…Moreover, a-DL-met crystals can be obtained by the reaction crystallization of aqueous solutions of sodium methioninate (Na-met) using liquid acids such as hydrochloric, acetic, nitric, sulfuric, or formic acids [6]. Matsuoka et al [6] reported the third polymorph, g-DL-met, as well as its preparation method and crystal structure. g-DL-met crystals were obtained by reaction crystallization of aqueous solutions of Na-Met with a solid benzoic acid, or by cooling crystallization of aqueous solutions of DL-met.…”

Study of spontaneous cleavage and change in surface structure of dl-methionine crystals

“…Relationship between the spontaneous cleavage and solid-state transformation from g-to a-form Table 1 [5]. As is seen in Fig.…”