Hydrodynamics and kinetics in semi-batch stirred tank precipitation of l -glutamic acid based on pH shift with mineral acids

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

“…25 As the two reactants mix and react, LGA is generated in solution, then gets supersaturated. The supersaturation value ( S ) in Table 2 is calculated 21 as the ratio between the maximal possible solution concentration of LGA throughout the whole process and the α-form LGA solubility (9.225 g LGA per kg water at the experiment temperature 20 °C, Fig. S1a†).…”

“…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. It is not clear whether these tanks are the only feasible reactor/crystallizer configuration, and whether the semi-batch mode (e.g., reactant addition to a stirred-tank reactor over extended time) 27 is the only feasible operation mode.…”

“…It is not clear whether these tanks are the only feasible reactor/crystallizer configuration, and whether the semi-batch mode (e.g., reactant addition to a stirred-tank reactor over extended time) 27 is the only feasible operation mode. In addition, the size distribution of product LGA crystals are typically wide, even with advanced strategies, such as tuning the acid addition rate, 18,19,21,22 agitation intensity, 19,22,25 and supersaturations, 20,[22][23][24] and applying additives 19 or ultrasonication. 24 Similarly, wide size distributions of product crystals from stirred tank crystallizers have been demonstrated with other molecules and/or other types of crystallizations.…”

“…Much progress has been made towards manufacturing pure α-form LGA crystals (Table 1), 18–26 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. It is not clear whether these tanks are the only feasible reactor/crystallizer configuration, and whether the semi-batch mode ( e.g.…”

A Novel Shadowgraphic Inline Measurement Technique for Image-Based Crystal Size Distribution Analysis

“…Other variants are image-giving inline probes, which have been developed and established in the last twenty years [12,[41][42][43][44][45]. These common incident-light probes are inserted into the reactor, acquiring the information at the point of interest.…”