The present study reports aqueous-phase ketonization of acetic acid over different ZrO2/C catalysts and promotion of carbon in ketonization activity. Highly carbonized ZrO2 catalysts are synthesized via a sol–gel and Zr-based metal–organic framework carbonization method, which possess high acetone production of 62.09 and 34.13 mmol/gZrO2, respectively. ZrO2 catalysts with little carbon are synthesized via hydrothermal precipitation and a hydrolysis method, which possess acetone production of 13.54 and 15.51 mmol/gZrO2, respectively. ZrO2 supported on carbon nanotubes (CNTs) exhibits increased acetone production with high CNT content but lower activity than carbonized ZrO2. Carbon release, accompanied by crystal phase transformation, leads to activity loss. Carbon species in carbonized catalysts significantly reduce crystallite size of t-ZrO2 and enhance surface properties, resulting in high activity. Small particle size also benefits aqueous-phase ketonization. Larger nanoparticles of supported ZrO2cover on CNT supports, and carbon and ZrO2 show much weaker interaction, resulting in lower activity than carbonized catalysts. For carbonized catalysts, acetic acid is enriched on the catalyst surface and water adsorption is weakened, enhancing ketonization reaction over active ZrO2 species.

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 ZrO2 and Zr/Mn oxides are used for aqueous‐phase ketonization of acetic acid. ZrMn0.5Ox 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 ZrO2. Addition of Mn results in ZrO2/MnOx solid solution and improves active sites. Acid property and Mn4+ content are important factors, and oxygen vacancy demonstrates relationship with ketonization activity for ZrO2. Examination of recovered catalysts indicates that ZrMnyOx 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

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The co-liquefaction process of D. tertiolecta and PP was investigated and the addition of PP mainly impacts the composition of the bio-oil.

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