Extraction and purification of paeonol from Moutan Cortex by a combined method of steam distillation and antisolvent recrystallization to reduce energy consumption and carbon dioxide emissions

This study aimed to obtain paeonol with high purity by using the combination of steam distillation and antisolvent recrystallization (ASR) and to reduce the energy consumption and CO₂ emission in the preparation process. First, different experimental parameters were optimized by response surface methodology (RSM). Under the optimal conditions, the purity and yield of the as-obtained paeonol were about 98% and 56.97%, respectively. The physicochemical properties of purified paeonol were tested, showing consistency with those of standard paeonol. The energy consumption and CO₂ emission of the preparation process of ASR and single-solvent recrystallization were also investigated. Results showed that the energy consumption and CO₂ emission of ASR were about 4.41 J/mg and 0.006 kg/mg, respectively, which were 6.89 J/mg and 0.0095 kg/mg lower than those of ethanol recrystallization, respectively, and 50.22 J/mg and 0.0144 kg/mg lower than methanol those of recrystallization, respectively. The above results showed that ASR could obtain paeonol with high purity in a high-efficiency, low-energy, and environmentally protective manner.