Insight into the Undesired Racemization of l-Glufosinate during Heating in the Aqueous Phase

l-glufosinate has garnered increasing attention as an ideal herbicide for weed control in agriculture. However, the underlying racemization process of l-glufosinate in the aqueous phase remains unclear. In this work, we elucidated the racemization mechanisms through heating reactions and theoretical calculations. Results showed that temperature has a significant impact on the racemization of l-glufosinate. The higher the temperature, the faster racemization occurs, which follows first-order kinetics. Moreover, it is evident that water plays an important role in the racemization process of l-glufosinate, as demonstrated by the heating of crystals and deuterium experiments. Additional computational results suggested a dual-step transformation, with a decrease in the energy barrier of about 29.25 kcal/mol for racemization attributed to the participation of water molecules, thereby promoting the racemization process. This work offers valuable insights into the important mechanistic and kinetic features of these reactions through the combination of experiments and theoretical calculations, guiding the chiral control of l-glufosinate in industrial production.