Crystallization of l-glutamic acid under microfluidic conditions and levitation

Influence of Taylor Vortex Flow on the Crystallization ofl-Glutamic Acid as an Organic Model Compound

“…The result showed the presence of nanoscale particles with a diameter of 10–20 nm (see red arrow in Figure a); SAED revealed that these are in an amorphous state (see the inset picture in Figure a). Based on earlier contributions, it is reasonable to assume that these amorphous intermediates form from prenucleation clusters that already existed in the precritical stage. , Based on TEM analysis, it was reported that these prenucleation clusters contain about 25–68 molecules and feature sizes of 5.0–7.0 nm. , In the course of the formation process, these particles were found to grow larger (to 100–120 nm, see Figure b), probably due to the aggregation/coalescence processes (see yellow arrow in Figure a). In contrast to the expected spherical morphology of these precursors (see Figure b), also amorphous intermediates with distinct shapes were found, ranging from oval, and ellipsoid, to irregular shapes (see Figure c–f).…”

“…37,45 Based on TEM analysis, it was reported that these prenucleation clusters contain about 25−68 molecules and feature sizes of 5.0−7.0 nm. 37,45 In the course of the formation process, these particles were found to grow larger (to 100−120 nm, see Figure 6b), probably due to the aggregation/ coalescence processes (see yellow arrow in Figure 6a). In contrast to the expected spherical morphology of these precursors (see Figure 6b), also amorphous intermediates with distinct shapes were found, ranging from oval, and ellipsoid, to irregular shapes (see Figure 6c−f).…”

“…Based on earlier contributions, it is reasonable to assume that these amorphous intermediates form from prenucleation clusters that already existed in the precritical stage. 37,45 Based on TEM analysis, it was reported that these prenucleation clusters contain about 25−68 molecules and feature sizes of 5.0−7.0 nm. 37,45 In the course of the formation process, these particles were found to grow larger (to 100−120 nm, see Figure 6b), probably due to the aggregation/ coalescence processes (see yellow arrow in Figure 6a).…”

Shaping particle size distribution of a metastable polymorph in additive-assisted reactive crystallization by the Taguchi method

“…Although the solubility of L-GLU in water or water/organic solvent mixtures has been determined, [66][67][68] it is much less common to prepare L-GLU polymorphs by antisolvent crystallization in the literature. 45,69 As ethanol was used as an antisolvent, the mass fraction of α-GLU increased with the increasing ratio of antisolvent-to-solvent. 45 For the same case, pure α-GLU crystals were obtained under commonly stirred conditions, whereas a mixture of αand β-GLU crystals was formed in a microfluidic device.…”

l-Glutamic acid crystals of pure α form and uniform size distribution from continuous non-seeded reaction crystallization in slug flow

“…S1 †), the metastable α-form of prismatic shapes, 14 and the stable β-form of needle or flower shapes. 15 α-Form crystals are preferred in LGA manufacturing, as their prismatic shape is easier for post-synthesis separation, powder tapping, with less water retention and gelatinization. 16,17 Much progress has been made towards manufacturing pure α-form LGA crystals (Table 1), [18][19][20][21][22][23][24][25][26] almost all based on gradual addition of the acid reactant (sulfuric or hydrochloric acid) to the other reactant (monosodium glutamate, MSG), in tank/flask reactors under vigorous stirring.…”