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

Abstract

Desired goals of crystal synthesis include high crystal quality (e.g., pure solid forms and uniform size distribution) and high process efficiency and reproducibility. A simple reactor/crystallizer has been designed based on slug flow, for continuous generation of high-quality L-glutamic acid crystals (model compound), from solution reaction of monosodium glutamate and sulfuric acid. Multiple average crystal sizes can be consistently achieved (e.g., from 19 μm to 37 μm), while maintaining the uniformity in both α-crystalline form and the crystal size distribution, by adjusting the supersaturation (stoichiometric reactant concentrations) with proper residence time. The whole reaction/crystallization process takes less than 15 minutes at room temperature, without requiring external seeding nor mechanical stirring blades.