Synthesis of 2-Ethyl-3-oxazolidineethanol from Propanal and Diethanolamine: Kinetic and Process Optimization Study

Abstract

2-Ethyl-3-oxazolidineethanol (OE) is an important pharmaceutical intermediate for the treatment of dental plaque. A systematic investigation of the one-pot synthesis of OE from propanal (PA) and diethanolamine (DEA) was conducted herein. The process was carried out under mild reaction conditions without any addition of catalyst, and the product was characterized by Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (NMR), and electrospray ionization-tandem mass spectrometry (ESI-MS/MS). Additionally, the effects of the PA/DEA ratio, methanol/DEA ratio, reaction time, and temperature on the reaction results were explored. Based on the single-factor experiments, response surface methodology (RSM) was used to optimize the reaction conditions and it achieved a high OE yield of 98.48%, which is close to the prediction value of 98.38%. Furthermore, the reaction kinetics were calculated utilizing the second-order kinetic model, and activation energies of the forward and reverse reactions were 31.35 and 41.85 kJ·mol–1, respectively. Under the optimization reaction conditions, OE was efficiently synthesized, indicating a significant potential for industrial applications.