Rearrangement of Α-Terpineol by Using PTA/TiO2 Catalyst Synthesized by Ultrasonic-Assisted Impregnation Method

1,8-cineole was synthesized via alpha-terpineol rearrangement over SiO2- and TiO2-supported phosphotungstic acid (PTA) catalysts prepared by ultrasonic impregnation. The structures of the catalysts were analyze using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy. The effects of reaction conditions on alpha-terpineol conversation and 1,8-cineole selectivity were investigated and the optimal reaction conditions are PTA loading of 20 wt%, mass fraction of 0.02, reaction temperature of 50 degrees C, and reaction time of 6 h. Under these conditions, the alpha-terpineol conversion and 1,8-cineole selectivity over PTA/TiO2 were 98.96% and 48.77%, respectively, which were better than that over PTA/SiO2. (C) 2022 Elsevier Ltd. All rights reserved.