Abstract
Liquefied dimethyl ether (DME) was employed as an antisolvent to crystallize glycine from its aqueous solution. The proposed method can be performed at 20-25 °C and has the potential to reduce the energy consumption of drying or crystallizing using ethanol. α-Glycine crystals were successfully obtained from glycine aqueous solutions by mixing in liquefied DME, which was easily removed from the crystals by decompression. Contact with a liquefied DME/water mixture and small γ-glycine crystals resulted in the α-glycine converting to γ-glycine. This was only observed for saturated glycine solutions. We speculated that this conversion occurs via a solution-mediated transition. Pure liquefied DME is not capable of promoting solvent-mediated transitions, so saturated glycine solutions treated with the pure antisolvent can give α-glycine as the sole product.