Aqueous‐phase ketonization of acetic acid over Zr/Mn mixed oxides

Aqueous‐phase ketonization possesses significant advantages over gas‐ or organic‐phase ketonization for improved conversion efficiency of aqueous fraction accompanied by algal bio‐oil production. In this study, synthetized ZrO 2 and Zr/Mn oxides are used for aqueous‐phase ketonization of acetic acid. ZrMn 0.5 O x shows the highest ketonization activity at 340°C for 12 h, achieving maximum acetone yield of 88.27%; and all catalysts exhibited selectivity higher than 96.75%. Apparent activation energy and acid reaction order are 161.2 kJ mol −1 and 0.70, respectively. Results suggest high ketonization activity of poorly crystallized tetragonal ZrO 2 . Addition of Mn results in ZrO 2 /MnO x solid solution and improves active sites. Acid property and Mn 4+ content are important factors, and oxygen vacancy demonstrates relationship with ketonization activity for ZrO 2 . Examination of recovered catalysts indicates that ZrMn y O x exhibits improved stability, and Mn leaching and crystal phase transformation are main causes of deactivation in aqueous‐phase ketonization. © 2017 American Institute of Chemical Engineers AIChE J , 63: 2958–2967, 2017